Neutrino experiment repeat at Cern finds same result

The team which found that neutrinos may travel faster than light has carried out an improved version of their experiment – and confirmed the result.

Neutrinos travel through 700km of rock before reaching Gran Sasso’s underground laboratories

If confirmed by other experiments, the find could undermine one of the basic principles of modern physics.

Critics of the first report in September had said that the long bunches of neutrinos (tiny particles) used could introduce an error into the test.

The new work used much shorter bunches.

It has been posted to the Arxiv repository and submitted to the Journal of High Energy Physics, but has not yet been reviewed by the scientific community.

The experiments have been carried out by the Opera collaboration – short for Oscillation Project with Emulsion (T)racking Apparatus.

It hinges on sending bunches of neutrinos created at the Cern facility (actually produced as decays within a long bunch of protons produced at Cern) through 730km (454 miles) of rock to a giant detector at the INFN-Gran Sasso laboratory in Italy.

The initial series of experiments, comprising 15,000 separate measurements spread out over three years, found that the neutrinos arrived 60 billionths of a second faster than light would have, travelling unimpeded over the same distance.

The idea that nothing can exceed the speed of light in a vacuum forms a cornerstone in physics – first laid out by James Clerk Maxwell and later incorporated into Albert Einstein’s theory of special relativity.

Timing is everything

Initial analysis of the work by the wider scientific community argued that the relatively long-lasting bunches of neutrinos could introduce a significant error into the measurement.

Those bunches lasted 10 millionths of a second – 160 times longer than the discrepancy the team initially reported in the neutrinos’ travel time.

To address that, scientists at Cern adjusted the way in which the proton beams were produced, resulting in bunches just three billionths of a second long.

When the Opera team ran the improved experiment 20 times, they found almost exactly the same result.

“This is reinforcing the previous finding and ruling out some possible systematic errors which could have in principle been affecting it,” said Antonio Ereditato of the Opera collaboration.

“We didn’t think they were, and now we have the proof,” he told BBC News. “This is reassuring that it’s not the end of the story.”

The first announcement of evidently faster-than-light neutrinos caused a stir worldwide; the Opera collaboration is very aware of its implications if eventually proved correct.

The error in the length of the bunches, however, is just the largest among several potential sources of uncertainty in the measurement, which must all now be addressed in turn; these mostly centre on the precise departure and arrival times of the bunches.

“So far no arguments have been put forward that rule out our effect,” Dr Ereditato said.

“This additional test we made is confirming our original finding, but still we have to be very prudent, still we have to look forward to independent confirmation. But this is a positive result.”

That confirmation may be much longer in coming, as only a few facilities worldwide have the detectors needed to catch the notoriously flighty neutrinos – which interact with matter so rarely as to have earned the nickname “ghost particles”.

Next year, teams working on two other experiments at Gran Sasso experiments – Borexino and Icarus – will begin independent cross-checks of Opera’s results.

The US Minos experiment and Japan’s T2K experiment will also test the observations. It is likely to be several months before they report back.

__________

Full article and photo: http://www.bbc.co.uk/news/science-environment-15791236

Dutch Scientists Drive Single-Molecule Car

Scientists in the Netherlands have introduced a molecule-sized car. Legroom might be an issue.

Its wheels are comprised of a few atoms each; its motor, a mere jolt of electricity. Scientists in the Netherlands have introduced the world’s smallest car — and it’s only a single molecule long.

It’s certainly no Porsche, but scientists at the University of Groningen in the Netherlands are still excited about their latest achievement: creating a “car” that’s only a billionth of a meter long.

The nanometer-sized vehicle, introduced in the British journal Nature on Wednesday, is comprised of a miniscule frame with four rotary units, each no wider than a few atoms. In fact, the whole construction is 60,000 times thinner than a human hair, according to the AFP news agency.

The research team was able to propel the nanocar six billionths of a meter by firing electrons at it with a tunnelling electron microscope. The “electronic and vibrational excitation” of the jolts changes the way the atoms of the “wheels” interact with those on a copper surface, the reports says, propelling the car forward in a single direction. The only problem, it would seem, is getting all the wheels to turn in the same direction every time.

A Small Future

It might be tough to imagine the use of such a diminutive roadster. But nanotechnology is widely considered one of the most exciting fields of the 21st century, and the researchers view their design as “a starting point for the exploration of more sophisticated molecular mechanical systems with directionally controlled motion.”

Utilizing materials at an atomic or molecular level — “nano” comes from the Greek word for “dwarf” — finds applications in everything from medicine and engineering to consumer products, such as sunscreen, ketchups and even powdered sugar.

__________

Full article and photo: http://www.spiegel.de/international/zeitgeist/0,1518,796970,00.html

Going round in circles

Cosmology

In contradiction to most cosmologists’ opinions, two scientists have found evidence that the universe may have existed for ever

WHAT happened before the beginning of time is—by definition, it might be thought—metaphysics. At least one physicist, though, thinks there is nothing meta about the question at all. Roger Penrose, of Oxford University, believes that the Big Bang in which the visible universe began was not actually the beginning of everything. It was merely the latest example of a series of such bangs that renew reality when it is getting tired out. More importantly, he thinks that the pre-Big Bang past has left an imprint on the present that can be detected and analysed, and that he and a colleague in Armenia have found it.

The imprint in question is in the cosmic microwave background (CMB). This is a bath of radiation that fills the whole universe. It was frozen in its present form some 300,000 years after the Big Bang, and thus carries information about what the early universe was like. The CMB is almost, but not quite, uniform, and the known irregularities in it are thought to mark the seeds from which galaxies—and therefore stars and planets—grew.

Dr Penrose, though, predicts another form of irregularity—great circles in the sky where the microwave background is slightly more uniform than it should be. These, if they exist, would be fossil traces of black holes from the pre-Big Bang version of reality. And in a paper just published in arXiv.org, an online database, he claims they do indeed exist.

Once upon a time

The Penrose version of cosmology stands in sharp distinction to received wisdom. This is that the universe popped out of nowhere about 13.7 billion years ago in a quantum fluctuation similar to the sort that constantly create short-lived virtual particles in so-called empty space. Before this particular fluctuation could disappear again, though, it underwent a process called inflation that both stabilised it and made it 1078 times bigger than it had previously been in a period of 10-32 seconds. Since then, it has expanded at a more sedate rate and will continue to do so—literally for ever.

Dr Penrose, however, sees inflation as a kludge. The main reason it was dreamed up (by Alan Guth, a cosmologist at the Massachusetts Institute of Technology) was to explain the extraordinary uniformity of the universe. A period of rapid inflation right at the beginning would impose such uniformity by stretching any initial irregularities so thin that they would become invisible.

As kludges go, inflation has been successful. Those of its predictions that have been tested have all been found true. But that does not mean it is right. Dr Penrose’s explanation of the uniformity is that, rather than having been created at the beginning of the universe, it is left over from the tail end of reality’s previous incarnation.

Dr Penrose’s version of events is that the universe did not come into existence at the Big Bang but instead passes through a continuous cycle of aeons. Each aeon starts off with the universe being of zero size and high uniformity. At first the universe becomes less uniform as it evolves and objects form within it. Once enough time has passed, however, all of the matter around will end up being sucked into black holes. As Stephen Hawking has demonstrated, black holes eventually evaporate in a burst of radiation. That process increases uniformity, eventually to the level the universe began with.

Thus far, Dr Penrose’s version of cosmology more or less matches the standard version. At this point, though, he introduces quite a large kludge of his own. This is the idea that when the universe becomes very old and rarefied, the particles within it lose their mass.

That thought is not entirely bonkers. The consensus among physicists is that particles began massless and got their mass subsequently from something known as the Higgs field—the search for which was one reason for building the Large Hadron Collider, a huge and powerful particle accelerator located near Geneva. Mass, then, is not thought an invariable property of matter. So Dr Penrose found himself speculating one day about how a universe in which all particles had lost their mass through some as-yet-undefined process might look. One peculiarity of massless particles is that they have to travel at the speed of light. That (as Einstein showed) means that from the particle’s point of view time stands still and space contracts to nothingness. If all particles in the universe were massless, then, the universe would look to them to be infinitely small. And an infinitely small universe is one that would undergo a Big Bang.

Uncommon sense

It is well known that fundamental physics is full of ideas that defy what humans are pleased to call common sense. Even by those standards, however, Dr Penrose’s ideas are regarded as a little eccentric by his fellow cosmologists. But they do have one virtue that gives them scientific credibility: they make a prediction. Collisions between black holes produce spherical ripples in the fabric of spacetime, in the form of gravitational waves. In the Penrose model of reality these ripples are not abolished by a new Big Bang. Images of black-hole collisions that happened before the new Bang may thus imprint themselves as concentric circular marks in the emerging cosmic microwave background.

The actual search for such cosmic circles has been carried out by Vahe Gurzadyan of the Yerevan Physics Institute in Armenia. Dr Gurzadyan analysed seven years’ worth of data from WMAP, an American satellite whose sole purpose is to measure the CMB, and also looked at data from another CMB observatory, the BOOMERanG balloon experiment in Antarctica. His verdict, arrived at after he scoured over 10,000 points on the microwave maps, is that Dr Penrose’s concentric circles are real. He says he has found a dozen sets of them—one of which is illustrated. (The visible rings in the picture have been drawn on subsequently to show where computer analysis has found circle-defining uniformity.)

This is, of course, but a single result—and supporters of inflation do not propose to give up without a fight. Amir Hajian, a physicist at Princeton, for example, says he is concerned about distortions in the WMAP data caused by the satellite spending more time mapping some parts of the sky than others. Then there is the little matter of how the masslessness comes about.

Dr Guth, meanwhile, claims that a handful of papers are published every year pointing to inconsistencies between the microwave background data and inflation, and that none has withstood the test of time. Moreover, even if the circles do hold up, they may have a cause different from the one proposed by Dr Penrose. Nevertheless, when a strange theory makes a strange prediction and that prediction proves correct, it behoves science to investigate carefully. For if what Dr Penrose and Dr Gurzadyan think they have found is true, then much of what people thought they knew about the universe is false.

___________

Full article and photo: http://www.economist.com/node/17626874

Stone Power

Q. I’ve heard that if a penny is dropped from the Empire State Building it could kill someone. But what about hail? It’s often much larger and falls from much higher, so why do I never hear about any deaths caused by it?

A. Hail can cause human fatalities, but does not usually do so, according to the National Severe Storms Laboratory of the National Oceanic and Atmospheric Administration.

While one hail event in India in 1988 caused 246 deaths, this was truly exceptional. In the United States, most years see no deaths at all, though one or two are very rarely reported. It has been suggested that one reason for this is that Americans spend less time out in the open than people who live in regions like northern India where hail is a greater risk to human life.

Another important factor is that hail does not fall uninterrupted from the high reaches of the atmosphere, but is tossed up and down by the winds of a thunderstorm, bumping into raindrops and other hailstones, a process that slows the fall. The winds also frequently make the hailstones fall at an angle.

The friction with other precipitation deforms a hailstone from a perfect sphere, making its velocity hard to calculate when it does become heavy enough to fall to earth. One estimate is that a half-inch stone falls about 30 feet a second, while a three-inch stone falls nearly 160 feet a second.

C. Clairbone Ray, New York Times

__________

Full article and photo: http://www.nytimes.com/2010/10/19/science/19qna.html

Dr Hawking’s bright idea

Mimicking black holes

A long-predicted phenomenon has turned up in an unexpected place

IN 1974 Stephen Hawking, pictured right, had a startling theoretical insight about black holes—those voracious eaters of matter and energy from whose gravitational clutches not even light can escape. He predicted that black holes should not actually be black. Instead, because of the quirks of quantum mechanics, they should glow ever so faintly, like smouldering embers in a dying fire. The implications were huge. By emitting this so-called Hawking radiation, a black hole would gradually lose energy and mass. If it failed to replenish itself it would eventually evaporate completely, like a puddle of water on a hot summer’s day.

Unfortunately for physicists, Dr Hawking also predicted that the typical temperature at which a black hole radiates should be about a billionth of that of the background radiation left over from the Big Bang itself. Proving his theory by observing actual Hawking radiation from a black hole in outer space has therefore remained a practical impossibility.

In a paper just accepted by Physical Review Letters, however, a team of researchers led by Daniele Faccio from the University of Insubria, in Italy, report that they have observed Hawking radiation in the laboratory. They managed this trick not by creating an Earth-gobbling black hole on a benchtop but by firing pulses of laser light into a block of glass. This created a region from which light could not escape (analogous to a black hole) and also its polar opposite, a region which light could not enter. When the team focused a sensitive camera on to the block, they saw the faint glow of Hawking radiation.

Black and light

If a dying star is massive enough, it can collapse to form a region of infinite density, called a singularity. The gravity of such an object is so strong that nothing, not even light itself, can break free if it strays too close. Once something has passed through the so-called event horizon that surrounds this region, it is doomed to a one-way trip.

Dr Hawking’s insight came from considering what happens in the empty space just outside the event horizon. According to quantum mechanics, empty space is anything but empty. Rather, it is a roiling, seething cauldron of evanescent particles. For brief periods of time, these particles pop into existence from pure nothingness, leaving behind holes in the nothingness—or antiparticles, as physicists label them. A short time later, particle and hole recombine, and the nothingness resumes.

If, however, the pair appears on the edge of an event horizon, either particle or hole may wander across the horizon, never to return. Deprived of its partner, the particle (or the hole) has no “choice” but to become real. These particles, the bulk of which are photons (the particles of light), make up Hawking radiation—and because photons and antiphotons are identical, the holes contribute equally. The energy that goes into these now-real photons has to come from somewhere; that somewhere is the black hole itself, which thus gradually shrinks. By linking the disparate fields of gravitational science, quantum mechanics and thermodynamics, Hawking radiation has become a crucial concept in theoretical physics over the past quarter of a century.

In 1981, that concept was extended. William Unruh of the University of British Columbia pointed out that black holes are actually extreme examples of a broader class of physical systems that can form event horizons. Consider a river approaching a waterfall. As the water nears the edge, the current moves faster and faster. In theory, it can move so fast that ripples on the surface are no longer able to escape back upstream. In effect, an event horizon has formed in the river, preventing waves from making their way out. Since then, other researchers have come up with other quotidian examples of event horizons.

Dr Faccio and his team were able to create their version because, as the laser pulse moves through the glass block, it changes the glass’s refractive index (the speed at which light travels through a material). Light in the vicinity of the pulse is slowed more and more when the refractive index changes as the pulse passes by.

To see how the pulse can act like a black hole, imagine that it is sent chasing after a slower, weaker pulse. It will gradually catch up with this slow pulse, reducing the speed of light in the slow pulse’s vicinity. That will slow the slow pulse down still more until eventually it is slowed so much that it is stuck. Essentially, the leading edge of the chasing pulse sucks it in, acting like the event horizon of a black hole.

Now imagine that the chasing pulse is itself being chased, but again by a much weaker pulse. As this third pulse approaches the tail of the second one it will also slow down (because the speed of light in the glass it is passing through has been reduced by the second pulse’s passage). The closer it gets, the slower it travels, and it can never quite catch up. The trailing edge of the second pulse, therefore, also acts as an event horizon. This time, though, it stops things getting in rather than stopping them getting out. It resembles the opposite of a black hole—a white hole, if you like.

In the actual experiment, there were no leading and trailing pulses. Instead, their role was played by evanescent photons continually popping into existence around the strong pulse. As the pulse passed through the glass, its event horizons should have swept some of these photons up, producing Hawking radiation from the partners they left behind.

Sure enough, when Dr Faccio and his team focused a suitable camera on the block and fired 3,600 pulses from their laser, they recorded a faint glow at precisely the range of frequencies which the theory of Hawking radiation predicts. After carefully considering and rejecting other possible sources for this light, they conclude that they have indeed observed Hawking radiation for the first time.

Because of its tabletop nature, other groups will certainly attempt to replicate and extend Dr Faccio’s experiment. Although such studies cannot prove that real black holes radiate and evaporate, they lend strong support to the ideas that went into Dr Hawking’s line of reasoning. Unless a tiny black hole turns up in the collisions of a powerful particle accelerator, that may be the best physicists can hope for. It may even be enough to convince Sweden’s Royal Academy of Science to give Dr Hawking the Nobel prize that many think he deserves, but which a lack of experimental evidence has hitherto caused it to withhold.

__________

Full article and photo: http://www.economist.com/node/17145159

Ye cannae change the laws of physics

Or can you?

RICHARD FEYNMAN, Nobel laureate and physicist extraordinaire, called it a “magic number” and its value “one of the greatest damn mysteries of physics”. The number he was referring to, which goes by the symbol alpha and the rather more long-winded name of the fine-structure constant, is magic indeed. If it were a mere 4% bigger or smaller than it is, stars would not be able to sustain the nuclear reactions that synthesise carbon and oxygen. One consequence would be that squishy, carbon-based life would not exist.

Why alpha takes on the precise value it has, so delicately fine-tuned for life, is a deep scientific mystery. A new piece of astrophysical research may, however, have uncovered a crucial piece of the puzzle. In a paper just submitted to Physical Review Letters, a team led by John Webb and Julian King from the University of New South Wales in Australia present evidence that the fine-structure constant may not actually be constant after all. Rather, it seems to vary from place to place within the universe. If their results hold up to the scrutiny, and can be replicated, they will have profound implications—for they suggest that the universe stretches far beyond what telescopes can observe, and that the laws of physics vary within it. Instead of the whole universe being fine-tuned for life, then, humanity finds itself in a corner of space where, Goldilocks-like, the values of the fundamental constants happen to be just right for it.

Slightly belying its name, the fine-structure constant is actually a compound of several other physical constants, whose values can be found in any physics textbook. You start with the square of an electron’s charge, divide it by the speed of light and Planck’s constant, then multiply the whole lot by two pi. The point of this convoluted procedure is that this combination of multiplication and division produces a pure, dimensionless number. The units in which the original measurements were made cancel each other out and the result is 1/137.036, regardless of the measuring system you used in the first place.

Despite its convoluted origin, though, alpha has a real meaning. It characterises the strength of the force between electrically charged particles. As such, it governs—among other things—the energy levels of an atom formed from negatively charged electrons and a positive nucleus. When electrons jump between these energy levels, they absorb and emit light of particular frequencies. These frequencies show up as lines (dark for absorption; bright for emission) in a spectrum. When many different energy levels are involved, as they are in the spectrum of a chemically mixed star, the result is a fine, comb-like structure—hence the constant’s name. If it were to take on a different value, the wavelengths of these lines would change. And that is what Dr Webb and Mr King think they have found.

The light in question comes not from individual stars but from quasars. These are extremely luminous (and distant) galaxies whose energy output is powered by massive black holes at their centres. As light from a quasar travels through space, it passes through clouds of gas that imprint absorption lines onto its spectrum. By measuring the wavelengths of a large collection of these absorption lines and subtracting the effects of the expansion of the universe, the team led by Dr Webb and Mr King was able to measure the value of alpha in places billions of light-years away.

Dr Webb first conducted such a study almost a decade ago, using 76 quasars observed with the Keck telescope in Hawaii. He found that, the farther out he looked, the smaller alpha seemed to be. In astronomy, of course, looking farther away means looking further back in time. The data therefore indicated that alpha was around 0.0006% smaller 9 billion years ago than it is now. That may sound trivial. But any detectable deviation from zero would mean that the laws of physics were different there (and then) from those that pertain in the neighbourhood of the Earth.

Such an important result needed independent verification using a different telescope, so in 2004 another group of researchers looked from the European Southern Observatory’s Very Large Telescope (VLT) in Chile. They found no evidence for any variation of alpha. Since then, though, flaws have been discovered in that second analysis, so Dr Webb and his team set out to do their own crosscheck with a sample of 60 quasars observed by the VLT.

What they found shocked them. The further back they looked with the VLT, the larger alpha seemed to be—in seeming contradiction to the result they had obtained with the Keck. They realised, however, that there was a crucial difference between the two telescopes: because they are in different hemispheres, they are pointing in opposite directions. Alpha, therefore, is not changing with time; it is varying through space. When they analysed the data from both telescopes in this way, they found a great arc across the sky. Along this arc, the value of alpha changes smoothly, being smaller in one direction and larger in the other. The researchers calculate that there is less than a 1% chance such an effect could arise at random. Furthermore, six of the quasars were observed with both telescopes, allowing them to get an additional handle on their errors.

If the fine-structure constant really does vary through space, it may provide a way of studying the elusive “higher dimensions” that many theories of reality predict, but which are beyond the reach of particle accelerators on Earth. In these theories, the constants observed in the three-dimensional world are reflections of what happens in higher dimensions. It is natural in these theories for such constants to change their values as the universe expands and evolves.

Unfortunately, their method does not allow the team to tell which of the constants that goes into alpha might be changing. But it suggests that at least one of them is. On the other hand, the small value of the change over a distance of 18 billion light-years suggests the whole universe is vastly bigger than had previously been suspected. A diameter of 18 billion light-years (9 billion in each direction) is a considerable percentage of observable reality. The universe being 13.7 billion years old, 13.7 billion light-years—duly stretched to allow for the expansion of the universe—is the maximum distance it is possible to see in any direction. If the variation Dr Webb and Mr King have found is real, and as gradual as their data suggest, you would have to go a very long way indeed to come to a bit of space where the fine-structure constant was more than 4% different from its value on Earth.

If. Other teams of astronomers are already on the case, and Victor Flambaum, one of Dr Webb’s colleagues at the University of New South Wales, points out in a companion paper that laboratory tests involving atomic clocks only slightly better than those that exist already could provide an independent check. These would vary as the solar system moves through the universe. But if and when such confirmation comes, it will break one of physics’s greatest taboos, the assumption that physical laws are the same everywhere and everywhen. And the fine-structure constant will have shown itself to be more mysterious than even Feynman conceived.
__________

Full article and photo: http://www.economist.com/node/16930866

Sun storm

Meet the northern lights

THIS PAST week, residents of several US states had a rare opportunity to see the northern lights bathe the sky in their eerie glow of pale green and red. The lights are normally only visible in far northern latitudes, but a surge of activity from the sun pushed them far enough south that there was even a chance we’d get a glimpse in Massachusetts. And fortunately for sky watchers, this may only be the beginning: Scientists say the sun is being roused into a period of high activity, which may bring more displays over the next few years.

The northern lights are a rare visible manifestation of space weather, the currents of matter and energy that roil above the earth’s lower atmosphere. The lights are caused by solar wind — protons and electrons streaming outwards from the sun — which can gust at speeds up to thousands of kilometers per second. When these winds push against the earth’s magnetic field, the result is a geomagnetic storm that appears to us as an aurora — arcs, sheets, or rippled filaments of light. In northern latitudes, this phenomenon is called the aurora borealis, after the Roman goddess of dawn and the Greek word for north wind. The aurora borealis only reaches the Boston area every few years; our last glimpse was in 2005.

The recent storm was created by an enormous blast from the sun called a coronal mass ejection. Although it made for some beautiful displays, it’s by no means the most impressive we’ve seen. In the summer of 1859, a huge solar flare lit up skies across Europe, the United States, and even Japan. A New York Times article from Sept. 2 that year said the northern lights in Boston were “so brilliant that at about one o’clock ordinary print could be read by the light.” That night, two operators of the telegraph line between Boston and Portland conversed for two hours powered solely by current induced by the aurora.

The sun’s cycles of activity last about 11 years on average, and after two quiet years — a longer rest than usual — the sun is stirring back into action. This means more opportunities for watching the dramatic storms it causes. In the meantime, you can see spectacular views of the sun’s activity at NASA’s Solar Dynamics Observatory website. A gallery of images of the recent aurora taken from around the world is on display at spaceweather.com, and devoted sky watchers can also sign up there for “aurora alerts” on their cellphones. Anyone who wants to track space weather conditions, including opportunities to view aurorae, can follow the National Weather Service’s Space Weather Prediction Center (swpc.noaa.gov). Should another chance come, the best way to see the northern lights is to escape city light pollution, ideally by finding a remote spot in the country with unobstructed views of the northern sky.

Courtney Humphries, author of ”Superdove: How the Pigeon Took Manhattan…And the World,” is a regular contributor to Ideas.

__________

Full article and photo: http://www.boston.com/bostonglobe/ideas/articles/2010/08/08/sun_storm/

Five Best Books on Inventions

Eureka! William Rosen hails these books about inventions

1. Longitude

By Dava Sobel
Walker, 1995

The story of the first marine chronometer, invented by the self-taught British clockmaker John Harrison, had a remarkable number of dramatic elements. Thanks to the Longitude Act of 1714, the protagonist’s goal—a £20,000 prize for a method of determining longitude to within 30 nautical miles—could not have been clearer. Even more theatrically, Harrison was a legitimate “lone genius,” who spent 19 solitary years on a single version of a clock accurate enough to compare local noon at sea with noon back home. And, in the devious Nevil Maskelyne, astronomer royal and champion of a competing method of calculating longitude, the story had a perfect villain. To this raw material Dava Sobel added a sculptor’s sense for the physicality of things—for the self-lubricating gears that Harrison carved from close-grained wood—and enough poetic imagination to describe H-1, Harrison’s first chronometer, as “a model ship, escaped from its bottle, afloat on the sea of time.”

2. The Making of the Atomic Bomb

By Richard Rhodes
Simon & Schuster, 1986

Richard Rhodes’s story of the birth of the nuclear age is an epic that, in terms of scientific discovery, unfolds in the blink of an eye—Hiroshima, after all, was destroyed just 34 years after the discovery of the atomic nucleus. His cast of characters is a virtual Who’s Who of 20th-century physics, from Albert Einstein to J. Robert Oppenheimer, but one that also gives star turns to brilliant and dogged engineers like Vannevar Bush and Gen. Leslie Groves. Rhodes pays his readers the compliment of assuming that they are familiar enough with the story to foresee critical moments. We know, for instance, before Glenn Seaborg himself, that Seaborg will name element 94 (“this speck of matter God had not welcomed at the Creation,” Rhodes writes) for the Roman god of the dead: plutonium.

3. To Conquer the Air

By James Tobin
Free Press, 2003

The story of the onetime bicycle-shop owners from Dayton, Ohio (in 1900, America’s per capita patent leader), is simultaneously a brilliant panorama of early 20th-century America and an unforgettable portrait of Wilbur Wright. Both Wilbur and his brother Orville were exemplars of grace under pressure, showing high intelligence, modesty and determination without foolhardiness—all the while competing against everyone from Alexander Graham Bell to the motorcycle-racing champion Glenn Curtiss to be the first aloft. But Wilbur is clearly the star. His decision to master airborne stability and balance before power—to create the optimal wing and let the engine take care of itself—gives James Tobin’s tale an enormously satisfying structure, as well as an entirely apt metaphor for Wilbur Wright’s life.

4. The Deltoid Pumpkin Seed

By John McPhee
Farrar, Straus & Giroux, 1973

In the late 1960s, an unlikely team of ex-Navy airship specialists, model builders, aeronautics professors and the pastor of the Fourth Presbyterian Church in Trenton, N.J., who instigated it all, set out to build a new airborne means of transporting heavy freight. What they envisioned was a helium-filled hybrid of an airplane and a rigid airship. What they created was the Aereon 26, the triangular oblate “pumpkin seed” of the title of John McPhee’s book, which succeeds as a narrative despite the ultimate failure of the craft’s design. McPhee’s genius is for understanding the eccentricity of human motivation as he depicts, with an unerring eye for the telling detail, characters toiling to revive the world of lighter-than-air flight.

5. The Soul of a New Machine

By Tracy Kidder
Little, Brown, 1981

The holy grail for Tom West and his team of computer engineers was a machine that was smaller and nimbler than a mainframe but still able to process 32 bits of information: a superminicomputer. Tracy Kidder chronicled their painstaking quest in one of the more improbable best sellers ever. (A book about writing software code?) But even now “The Soul of a New Machine” is capable of inducing in readers the same sleepless nights that the project demanded of the twentysomething geeks who designed and built the machine they dubbed the Eagle. “The real game is pinball,” West tells them. “You win one game, you get to play another; you build this machine, you get to build another.”

Mr. Rosen is the author of “The Most Powerful Idea in the World: A Story of Steam, Industry, and Invention.”

__________

Full article: http://online.wsj.com/article/SB10001424052748704324304575307131646830558.html

A New Clue to Explain Existence

Physicists at the Fermi National Accelerator Laboratory are reporting that they have discovered a new clue that could help unravel one of the biggest mysteries of cosmology: why the universe is composed of matter and not its evil-twin opposite, antimatter. If confirmed, the finding portends fundamental discoveries at the new Large Hadron Collider outside Geneva, as well as a possible explanation for our own existence.

In a mathematically perfect universe, we would be less than dead; we would never have existed. According to the basic precepts of Einsteinian relativity and quantum mechanics, equal amounts of matter and antimatter should have been created in the Big Bang and then immediately annihilated each other in a blaze of lethal energy, leaving a big fat goose egg with which to make stars, galaxies and us. And yet we exist, and physicists (among others) would dearly like to know why.

Sifting data from collisions of protons and antiprotons at Fermilab’s Tevatron, which until last winter was the most powerful particle accelerator in the world, the team, known as the DZero collaboration, found that the fireballs produced pairs of the particles known as muons, which are sort of fat electrons, slightly more often than they produced pairs of anti-muons. So the miniature universe inside the accelerator went from being neutral to being about 1 percent more matter than antimatter.

“This result may provide an important input for explaining the matter dominance in our universe,” Guennadi Borissov, a co-leader of the study from Lancaster University, in England, said in a talk Friday at Fermilab, in Batavia, Ill. Over the weekend, word spread quickly among physicists. Maria Spiropulu of CERN and the California Institute of Technology called the results “very impressive and inexplicable.”

The results have now been posted on the Internet and submitted to the Physical Review.

It was Andrei Sakharov, the Russian dissident and physicist, who first provided a recipe for how matter could prevail over antimatter in the early universe. Among his conditions was that there be a slight difference in the properties of particles and antiparticles known technically as CP violation. In effect, when the charges and spins of particles are reversed, they should behave slightly differently. Over the years, physicists have discovered a few examples of CP violation in rare reactions between subatomic particles that tilt slightly in favor of matter over antimatter, but “not enough to explain our existence,” in the words of Gustaaf Brooijmans of Columbia, who is a member of the DZero team.

The new effect hinges on the behavior of particularly strange particles called neutral B-mesons, which are famous for not being able to make up their minds. They oscillate back and forth trillions of times a second between their regular state and their antimatter state. As it happens, the mesons, created in the proton-antiproton collisions, seem to go from their antimatter state to their matter state more rapidly than they go the other way around, leading to an eventual preponderance of matter over antimatter of about 1 percent, when they decay to muons.

Whether this is enough to explain our existence is a question that cannot be answered until the cause of the still-mysterious behavior of the B-mesons is directly observed, said Dr. Brooijmans, who called the situation “fairly encouraging.”

The observed preponderance is about 50 times what is predicted by the Standard Model, the suite of theories that has ruled particle physics for a generation, meaning that whatever is causing the B-meson to act this way is “new physics” that physicists have been yearning for almost as long.

Dr. Brooijmans said that the most likely explanations were some new particle not predicted by the Standard Model or some new kind of interaction between particles. Luckily, he said, “this is something we should be able to poke at with the Large Hadron Collider.”

Neal Weiner of New York University said, “If this holds up, the L.H.C. is going to be producing some fantastic results.”

Nevertheless, physicists will be holding their breath until the results are confirmed by other experiments.

Joe Lykken, a theorist at Fermilab, said, “So I would not say that this announcement is the equivalent of seeing the face of God, but it might turn out to be the toe of God.”

Dennis Overebye, New York Times

__________

Full article: http://www.nytimes.com/2010/05/18/science/space/18cosmos.html

Is Anybody Out There?

After 50 years, astronomers haven’t found any signs of intelligent life beyond Earth. They could be looking in the wrong places

Fifty years ago this week, on April 8, 1960, a little-known astronomer named Frank Drake sat at the controls of an 85-foot radio telescope at an observatory in Green Bank, W.Va., and began to sweep the skies, looking for a signal from an alien civilization. It was the start of the most ambitious scientific experiment in history.

Barely an hour had passed when the equipment suddenly went wild. A loudspeaker hooked up to the giant antenna began booming and the pen recorder gyrated manically. The radio telescope was pointed at a nearby star called Epsilon Eridani. Mr. Drake was nonplussed. Surely his quest couldn’t be that easy? He was right. The commotion turned out to be a signal from a secret military radar.

The astronomer’s solitary vigil lasted for a few weeks; he ran out of telescope time with little to report. Nevertheless, his pioneering effort sparked the genesis of a 50-year project known as the Search for Extraterrestrial Intelligence, now an international research program with a multimillion-dollar budget. It has included renting time on some of the biggest radio telescopes in the world—such as the 1,000-foot dish at Arecibo in Puerto Rico, featured in the James Bond movie “GoldenEye.”

After five decades of patient listening, however, all the astronomers have to show for it is an eerie silence. Does that mean we are alone in the universe after all? Or might we be looking for the wrong thing in the wrong place at the wrong time?

The search for extraterrestrial intelligence, once considered a quixotic enterprise at best, has now become part of mainstream science. In the past decade or so, over 400 planets have been found orbiting nearby stars, and astronomers estimate there could be billions of Earth-like planets in the Milky Way alone. Biologists have discovered microbes living in extreme environments on Earth not unlike conditions on Mars, and have detected the molecular building blocks of life in deep space as well as in meteorites. Many scientists now maintain that the universe is teeming with life, and that some planets could harbor intelligent organisms.

Speculation about other worlds populated by sentient beings stretches back into pre-history. For millennia, the subject remained squarely in the provinces of religion and philosophy, but by the 19th century, science had become involved. Astronomical observations hinted that Mars could be a congenial abode for life, and in the 1870s the Italian astronomer Giovanni Schiaparelli fancied he could see lines on the surface of the red planet. A wealthy American writer, Percival Lowell, became fixated with the idea that Martians had built a network of canals to irrigate their parched planet, a conjecture fueled by the publication of H.G. Wells’s novel “The War of the Worlds.” Mr. Lowell built an observatory in Flagstaff, Ariz., specifically to map the canals and to look for other signs of Martian engineering.

Sadly for Mr. Lowell, there were no canals. Space probes sent to Mars in the 1960s found no sign of Martian engineering projects, and no sign of life either, just a freeze-dried desert bathed in deadly ultraviolet radiation.

In the next few decades, the search for radio messages from the stars was taken seriously enough to attract government funding. From 1970 to 1993, NASA spent about $78 million on projects that sought to refine Mr. Drake’s trail-blazing observations, starting with a feasibility study for the construction of an array of 1,000 dishes sensitive enough to pick up routine television and radio transmissions from nearby stars. In 1992, NASA officially launched a program called the High Resolution Microwave Survey—but Congress killed it the following year, ending NASA’s involvement.

Most of the funding today comes from private donations through the SETI Institute, a private nonprofit founded in 1984 in Mountain View, Calif. The jewel in its crown is the Allen Telescope Array, a $35 million dedicated network of 42 small dishes in northern California, with about $30 million of the funding contributed by Microsoft co-founder Paul Allen. The goal is to ultimately increase the network to 350 dishes. Donors on other projects have included David Packard and Bill Hewlett (co-founders of Hewlett-Packard) and Gordon Moore (co-founder of Intel).

__________

Starry-Eyed Believers

Views of intelligent alien life through history.

Titus Lucretius Carus

The ancient Roman poet Titus Lucretius Carus covered atoms, humans and the cosmos in his epic poem “De rerum natura” (“The nature of things”). Because space is infinite and the same physical laws occur throughout the universe, he wrote, there must be intelligent beings in other worlds.

Nicholas of Cusa

In the 15th century, the German cardinal Nicholas of Cusa held advanced scientific views for his time, including that the Earth was not the center of the universe. He also speculated that life existed on other planets, writing: “It may be conjectured that in the area of the sun there exist solar beings, bright and enlightened intellectual denizens, and by nature more spiritual than such as may inhabit the moon—who are possibly lunatics.”

Johannes Kepler

The invention of the telescope led scientists to ponder alien civilization. In the early 1600s, astronomer Johannes Kepler believed that because the moon’s craters were perfectly round, they must have been made by intelligent creatures.

Rev. Thomas Dick

The Scottish Rev. Thomas Dick wrote several successful books on religion and astronomy. In his 1838 book “Celestial Scenery,” he calculated the populations of planets and other bodies in Earth’s solar system, based on the number of people per square mile in England at the time. His estimates included 4.2 billion inhabitants on the moon and 8.1 trillion on Saturn’s rings.

Guglielmo Marconi

In 1919, radio pioneer Guglielmo Marconi reported picking up strange radio signals, saying they might come from beyond Earth. Some guessed that the signals originated from Mars or Venus. Others tackled the issue of how to respond: Elmer Sperry of the Sperry Gyroscope Company proposed sending a beacon to Mars using 150 to 200 of his company’s searchlights.

__________

Our own radio stations broadcast continuous narrow-band signals, that is, radio waves tuned to a sharply-defined frequency. Searches have mostly focused on something similar coming from space. The late Carl Sagan, a charismatic champion of searching for extraterrestrial signals in the 1980s, envisaged an advanced alien civilization deliberately beaming narrow-band radio messages at Earth to attract our attention. That scenario now seems very unlikely. Even optimists like Mr. Drake, still an active researcher, suppose that the nearest alien civilization would be hundreds of light years away. Because nothing travels faster than light, these hypothetical aliens would have no idea that a radio-savvy society exists on Earth yet.

A more likely sign could be a beacon, a radio source that goes bleep on a regular basis for anyone who might be listening, sweeping the plane of the Milky Way galaxy like the beam from a lighthouse. It would show up in a radio telescope as a brief pulse that repeats periodically—perhaps every few months or years.

Astronomers do occasionally detect brief radio bursts coming from space. A famous example was the so-called “Wow!” signal, recorded on Aug. 15, 1977, by Jerry Ehman using Ohio State University’s Big Ear radio telescope. Mr. Ehman discovered it while perusing the antenna’s computer printout, and was so excited he wrote “Wow!” in the margin. Radio pulses can arise from a variety of astronomical phenomena, ranging from spinning neutron stars to black hole explosions, but the characteristics of the Wow signal don’t fit any known natural event. Nor did the pulse match a man-made disturbance. Nothing has been detected again from that part of the sky when astronomers have looked.

The logistics of building beacons have been analyzed by the astrophysicist Gregory Benford of the University of California at Irvine and his brother James Benford, an expert on high-powered beamed microwaves. The main unknown is how often a beacon would repeat, so the Benfords are urging for a systematic search to be made. It would need a dedicated set of radio telescopes, oriented to stare for years on end at a fixed patch of the sky—preferably towards the center of the galaxy, where the oldest stars are found and the most advanced and best-resourced civilizations are likely to be located.

By focusing on radio signals, however, the search for intelligent life has been extremely limited. As in forensic science, the clues left by alien activity might be very subtle and require sophisticated scientific techniques. An advanced civilization might engage in large-scale astro-engineering, reconfiguring its planetary system or even modifying its host star, effects that could be observed from Earth or near space. The physicist Freeman Dyson once suggested that an energy-hungry alien community might create a shell of material around a star to trap most of its heat and light to run its industry—a solar energy program with a vengeance. Dyson spheres would betray their existence by radiating strongly in the infrared region of the spectrum. A few searches have been made using satellite data, but without success.

[CovJump1]

If a civilization endures for long enough, it might seek to migrate beyond its planetary system and colonize, or at least explore, the galaxy. The Milky Way is huge—about 100,000 light years across—and contains 400 billion stars, but given enough time, a determined civilization could spread far and wide. Our solar system is about 4.5 billion years old, but the galaxy is much older; there were stars and planets around long before Earth even existed. There has been plenty of time for at least one of those expansionary civilizations to reach our galactic neighborhood—a prospect that once led the physicist Enrico Fermi to famously utter “Where is everybody?”

How do we know they haven’t been here already?

It would be an incredible coincidence if Earth had been visited by aliens during the brief span of human history. On purely statistical grounds any visitation is likely to have been a very long time ago. To pluck a figure out of midair, imagine that an alien expedition passed our way 100 million years ago. Would any traces remain?

Not many. However, some remnants might still persist. Buried nuclear waste could be detectable even after billions of years. Large-scale mineral exploitation such as quarrying leaves distinctive scars that, in the case of Earth, would eventually become obscured by overlying strata but would still show up in geological surveys. Space probes parked in orbit round the sun might lie dormant yet intact for an immense period of time. Scientists could look for such hallmarks of alien technology on Earth and the moon, in near space, on Mars and among the asteroids.

Another physical object with enormous longevity is DNA. Our bodies contain some genes that have remained little changed in 100 million years. An alien expedition to Earth might have used biotechnology to assist with mineral processing, agriculture or environmental projects. If they modified the genomes of some terrestrial organisms for this purpose, or created their own micro-organisms from scratch, the legacy of this tampering might endure to this day, hidden in the biological record.

Which leads to an even more radical proposal. Life on Earth stores genetic information in DNA. A lot of DNA seems to be junk, however. If aliens, or their robotic surrogates, long ago wanted to leave us a message, they need not have used radio waves. They could have uploaded the data into the junk DNA of terrestrial organisms. It would be the modern equivalent of a message in a bottle, with the message being encoded digitally in nucleic acid and the bottle being a living, replicating cell. (It is possible—scientists today have successfully implanted messages of as many as 100 words into the genome of bacteria.) A systematic search for gerrymandered genomes would be relatively cheap and simple. Incredibly, a handful of (unsuccessful) computer searches have already been made for the tell-tale signs of an alien greeting.

One of the hazards of searching for alien life is an inbuilt anthropocentric bias. There is a natural temptation to fall back on what we would do when trying to guess the motives and activities of aliens. But this is almost certainly misleading. Unless alien communities inevitably destroy themselves, they could last for tens of millions of years or more. It is impossible for us to guess what such immensely long-lived civilizations would be like or how they would affect their environment.

One thing seems clear, though. Biological intelligence is likely to be merely a brief phase in the evolution of intelligence in the universe. Even in our own young species, computers now outperform people in arithmetic and chess, and Google is smarter than any human being on the planet. Soon, most of the mental heavy lifting will be done by designed and distributed systems, and over time those systems will themselves design better systems. Given a very long period of development, information and knowledge processing, networks could merge and in principle expand to cover the entire surface of a moon or planet. If we ever do make contact with E.T., it is unlikely to be a flesh-and-blood being with a big head, but a gigantic throbbing artificial brain. Whether such an entity, inhabiting the highest reaches of the intellectual universe, would have the slightest interest in us is moot.

We have no evidence whatsoever for any life beyond Earth, let alone intelligent life. It could be that life’s origin was a stupendous fluke, and that we are alone after all. But the consequences of discovering that other intelligences exist, or have existed, are so momentous it seems worth taking a penetrating look at how we could uncover evidence for it. While astronomers painstakingly monitor the hiss and crackle of the natural universe for any hint of a signal, scientists of all disciplines should reflect on how alien technology might reveal its existence in other ways, both across the vastness of space, and in our own astronomical backyard.

For many nonscientists, the fascination with the search for extraterrestrial intelligence is its tantalizing promise of wisdom in the sky. Frank Drake has said that the search for alien intelligence is really a search for ourselves, and how we fit into the great cosmic scheme. To know that we are not the only sentient beings in a mysterious and sometimes frightening universe—that an alien community had endured for eons, overcoming multiple problems—would represent a powerful symbol of hope for mankind.

Paul Davies is author of “The Eerie Silence.” He is director of the Beyond Center for Fundamental Concepts in Science at Arizona State University.

__________

Full article and photo: http://online.wsj.com/article/SB10001424052702304198004575172041886354262.html

For Nuclear Reactors, Metals That Heal Themselves

A nuclear reactor is a tough place for metals. All those neutrons bouncing around wreak havoc with the crystalline structure of steel, tungsten and other metals used in fuel rods and other parts. Over time, the metals can swell and become brittle. (They become radioactive, too, but that’s another story.)

Now researchers at Los Alamos National Laboratory in New Mexico have shown that by altering the microstructure of metals, metallurgists may be able to make reactor parts that are self healing.

Blas P. Uberuaga, Xian-Ming Bai and colleagues conducted computer simulations of the long-term impact of neutron emissions on copper — not because much copper is used in nuclear plants, but because it is a relatively well-modeled metal. Their findings are published in Science.

When a neutron hits metal, it displaces atoms within the crystal lattice. In a metal with a largely uniform structure, these atoms move to the surface, eventually causing the metal to swell, and the vacancies they leave behind can lead to voids that further weaken the material.

But it is possible to fabricate metals that have a nonuniform structure, with very small crystal grains, or regions of different phase or orientation. When atoms are displaced in this nanocrystalline material, rather than traveling to the surface they migrate to the boundaries between the grains. In their simulations, the researchers found that these atoms can then travel back away from the boundary and, if they find a vacancy, fill it, in effect healing the defect.

Dr. Uberuaga said that the basic principle should apply to other metals and complex alloys, and that if self-healing metals were used in the cladding around nuclear fuel, the fuel might be able to be “burned” at higher rates, with less damage to the metal. But there are many technological hurdles to overcome. “It’s not going to change how we design reactors tomorrow,” he said.

Henry Fountain, New York Times

__________

Full article: http://www.nytimes.com/2010/04/06/science/06obnuke.html

Scientists Discover Heavy New Element

A team of Russian and American scientists has discovered a new element that has long stood as a missing link among the heaviest bits of atomic matter ever produced. The element, still nameless, appears to point the way toward a brew of still more massive elements with chemical properties no one can predict.

The team produced six atoms of the element by smashing together isotopes of calcium and a radioactive element called berkelium in a particle accelerator about 75 miles north of Moscow on the Volga River, according to a paper that has been accepted for publication at the journal Physical Review Letters.

Data collected by the team seem to support what theorists have long suspected: that as newly created elements become heavier and heavier they will eventually become much more stable and longer-lived than the fleeting bits of artificially produced matter seen so far.

If the trend continues toward a theorized “island of stability” at higher masses, said Dawn A. Shaughnessy, a chemist at Lawrence Livermore National Laboratory in California who is on the team, the work could generate an array of strange new materials with as yet unimagined scientific and practical uses.

By scientific custom, if the latest discovery is confirmed elsewhere, the element will receive an official name and take its place in the periodic table of the elements, the checkerboard that begins with hydrogen, helium and lithium and hangs on the walls of science classrooms and research labs the world over.

“For a chemist, it’s so fundamentally cool” to fill a square in that table, said Dr. Shaughnessy, who was much less forthcoming about what the element might eventually be called. A name based on a laboratory or someone involved in the find is considered one of the highest honors in science. Berkelium, for example, was first synthesized at the University of California, Berkeley.

“We’ve never discussed names because it’s sort of like bad karma,” she said. “It’s like talking about a no-hitter during the no-hitter. We’ve never spoken of it aloud.”

Other researchers were equally circumspect, even when invited to suggest a whimsical temporary moniker for the element. “Naming elements is a serious question, in fact,” said Yuri Oganessian, a nuclear physicist at the Joint Institute for Nuclear Research in Dubna, Russia, and the lead author on the paper. “This takes years.”

Various aspects of the work were done at the particle accelerator in Dubna; the Livermore lab; Oak Ridge National Laboratory and Vanderbilt University in Tennessee; the University of Nevada, Las Vegas; and the Research Institute of Atomic Reactors in Dimitrovgrad, Russia.

For the moment, the discovery will be known as ununseptium, a very unwhimsical Latinate placeholder that refers to the element’s atomic number, 117.

“I think they have an excellent convincing case for the first observation of element 117; most everything has fallen into line very well,” said Walter D. Loveland, a professor of chemistry at Oregon State University who was not involved in the work.

Elements are assigned an atomic number according to the number of protons — comparatively heavy particles with a positive electric charge — in their nuclei. Hydrogen has one proton, helium has two, and uranium has 92, the most in any atom known to occur naturally. Various numbers of charge-free neutrons add to the nuclear mass of atoms but do not affect the atomic number.

As researchers have artificially created heavier and heavier elements, those elements have had briefer and briefer lifetimes — the time it takes for unstable elements to decay by processes like spontaneous fission of the nucleus. Then, as the elements got still heavier, the lifetimes started climbing again, said Joseph Hamilton, a physicist at Vanderbilt who is on the team.

The reason may be that the elements are approaching a theorized “island of stability” at still higher masses, where the lifetimes could go from fractions of a second to days or even years, Dr. Hamilton said.

In recent years, scientists have created several new elements at the Dubna accelerator, called a cyclotron, by smacking calcium into targets containing heavier radioactive elements that are rich in neutrons — a technique developed by Dr. Oganessian.

Because calcium contains 20 protons, simple math indicates scientists would have to fire the calcium at something with 97 protons — berkelium — to produce ununseptium, element 117.

Berkelium is mighty hard to come by, but a research nuclear reactor at Oak Ridge produced about 20 milligrams of highly purified berkelium and sent it to Russia, where the substance was bombarded for five months late last year and early this year.

An analysis of decay products from the accelerator indicated that the team had produced a scant six atoms of ununseptium. But that was enough to title the paper, “Synthesis of a new element with atomic number Z=117.”

That is about the closest thing to “Eureka!” that the dry conventions of scientific publication will allow. The new atoms and their decay products displayed the trend toward longer lifetimes seen in past discoveries of such heavy elements. The largest atomic number so far created is 118, also at the Dubna accelerator.

Five of the six new atoms contained 176 neutrons to go with their 117 protons, while one atom contained 177 neutrons, said Jim Roberto, a physicist at Oak Ridge on the project.

Atomic nuclei can be thought of as concentric shells of protons and neutrons. The most stable nuclei occur when the outermost shells are filled. Some theories predict this will happen with 184 neutrons and either 120 or 126 protons: the presumed center of the island of stability.

What happens beyond that point is anyone’s guess, said Kenton Moody, a radiochemist on the team at Livermore. “The question we’re trying to answer is, ‘Does the periodic table come to an end, and if so, where does it end?’ ” Dr. Moody said.

James Glanz, New York Times

__________

Full article and photo: http://www.nytimes.com/2010/04/07/science/07element.html

A Second Big Bang In Geneva?

The Large Hadron Collider could unlock the secrets of genesis.

Champagne bottles were popped Tuesday in Geneva where the largest science machine ever built finally began to smash subatomic particles together. After 16 years—and an accident that crippled the machine a year and a half ago—the Large Hadron Collider successfully smashed two beams of protons at the astounding energy of 3.5 trillion electron volts apiece. This act produced temperatures not seen since the Big Bang occurred 13.7 billions years ago.

The LHC is colossal. It is a gigantic doughnut, 17 miles in circumference, in which two beams of protons will eventually create energies of 14 trillion electron volts. Yet by nature’s standards the LHC is a pea shooter. For billions of years the earth has been bathed in cosmic rays much more powerful than those created by the LHC.

Despite this great achievement, European taxpayers are asking if this 10 billion euro machine is a waste of money, particularly given the current financial crisis. These skeptics would do well to remember that the LHC could help us understand not only the instant of genesis, but will help unify the four fundamental forces that rule the universe. Each time one of these forces was deciphered it changed the course of human history.

When Sir Isaac Newton worked out the theory of the first force—gravity—in the 17th century, he created the mechanics that laid the groundwork for steam engines and the Industrial Revolution. The Machine Age unleashed humanity from the bondage of subsistence farming, lifting untold numbers from grinding poverty.

When Thomas Edison, James C. Maxwell and Michael Faraday helped to decipher and harness the second force—electromagnetism—it eventually gave us TV, radio, radar, computers and the Internet.

When Albert Einstein wrote down E=mc2, it helped to unlock the secret of the two nuclear forces (weak and strong), which unraveled the secret of the stars and unleashed nuclear power.

Today the LHC may have the potential to explain the origin of all four fundamental forces—gravity, electromagnetism, and the strong and weak nuclear forces. Physicists believe that at the beginning of time there was a single superforce which unified these fundamental forces. Finding it could be the crowning achievement in the history of science, ending 2,000 years of speculation since the Greeks first wondered what the world is made of. It could answer some of the deepest questions facing us, such as: What happened before the Big Bang? Are there parallel universes? Is time travel possible? And are there other dimensions?

In addition to helping us unlock the mysteries of the universe, the LHC may also create a new scientific elite. These scientists will likely spearhead new industries, creating jobs and perhaps significant wealth in Europe.

It’s sobering to remember that this could have happened in the U.S. Back in the 1980s, President Ronald Reagan pushed to create a Superconducting Supercollider just outside Dallas, Texas. This machine would have been three times larger than the LHC and would have maintained U.S. leadership in advanced science for at least a generation. Congress allotted $1 billion to dig the hole for the Supercollider. Then it got cold feet and cancelled the plans in 1993, spending another $1 billion to fill up the hole. U.S. high-energy physics was set back an entire generation and has never recovered. So today the Europeans can brag about being the world’s leader in advanced physics.

Remember that because of World War II, the cream of European science, perhaps no more than a few hundred people, fled Europe for America. They unleashed the greatest explosion in science the world has ever seen. These Europeans trained new generations of American scientists, people that went on to create radar, microwaves, nuclear power, computers, the Internet, the laser and the space program. They created a scientific establishment that is the envy of the world, a source of profound wealth, and a magnet for young scientists world-wide. U.S. technological superiority and all the high-tech wonders of today can, in some sense, be traced back to this exodus. But such leadership is not a given.

I extend my congratulations to the Europeans; the LHC is their well-earned prize. I only hope that U.S. policy makers are paying close attention to Geneva.

Mr. Kaku, a professor of theoretical physics at City College of New York, is the author of “Physics of the Impossible” (Doubleday, 2008) and host of “Sci Fi Science: Physics of the Impossible,” on the Science Channel.

__________

Full article: http://online.wsj.com/article/SB10001424052702304252704575155710695957900.html

Ninth Rock From the Sun

It’s time for a new and improved definition of ‘planet’—one that restores Pluto to its former glory.

I’m not a Republican and I’m not a Democrat . . . for years I’ve been a Plutocrat.

—Clyde Tombaugh, discoverer of Pluto

The 2006 vote by a few hundred astronomers to strip Pluto of its planetary status was supposed to end a longstanding dispute. Instead, hundreds of other astronomers signed a petition saying they didn’t recognize the vote and would continue regarding Pluto as a planet in our solar system. Nonastronomers started peppering me with questions like, “Why did you guys do something so stupid?” An entire blog (laurele.livejournal.com) arose to restore Pluto’s planethood. And a 2009 CNN.com poll found an overwhelming majority of Americans favoring the pro-Pluto side.

The passion for Pluto is understandable. Discovered 80 years ago today by a young astronomer from Kansas named Clyde Tombaugh, Pluto is so distant that sunlight, which takes just eight minutes to reach Earth, requires several hours to strike Pluto. This incredibly distant world—Pluto’s average distance from the Sun is 3.67 billion miles—orbits the Sun only once every 248 years.

It’s little wonder then that Pluto has long inspired explorers. Whereas spacecraft have flown past every planet from Mercury to Neptune, no probe has ventured to Pluto. Thus, no one knows exactly what it looks like. All we know is that Pluto is a frigid world of rock and ice, accompanied by three moons and enveloped in an atmosphere of nitrogen, the same gas that makes up most of our air.

How did astronomers get into a pickle over Pluto? For many years they thought it was larger than it actually is. A 1950 observation put Pluto halfway in size between Mercury and Mars. Thus, Pluto’s diameter seemed to plant it firmly in the planetary firmament. But observations in the 1970s and ’80s revealed that Pluto is smaller. In fact, Pluto is only half the diameter of Mercury. But that’s more than twice the diameter of Ceres, the largest asteroid. So what is Pluto? Planet? Or asteroid?

Then, in 1992, astronomers started to find other objects revolving around the Sun beyond Neptune’s orbit. Most of these objects are much smaller than Pluto. But the discoveries mean Pluto belongs to a belt resembling one that Irish astronomer Kenneth Edgeworth postulated in 1943 and American astronomer Gerard Kuiper in 1951. The Edgeworth-Kuiper belt harbors more than a thousand known objects. All but one are smaller than Pluto.

The controversial 2006 vote demoted Pluto by demanding a proper planet satisfy a newfangled criterion: It must clear its orbital zone around the Sun, which means nothing substantial should cross its path. This criterion Pluto spectacularly fails. For one thing, Pluto belongs to the Edgeworth-Kuiper belt, with its myriad objects. For another, the distant world crosses Neptune’s orbit. From 1979 to 1999, Pluto was the eighth planet from the Sun, not the ninth.

But this definition of a planet runs into major problems. Even if the Earth, whose diameter is more than five times Pluto’s, belonged to the Edgeworth-Kuiper belt, it would not be considered a planet, for it would not have cleared out its orbital zone. Furthermore, astronomers have discovered planets beyond our solar system that—wait for it—cross each other’s orbits, just as Neptune and Pluto do.

Fortunately, a better definition exists: A planet of our solar system is an object that orbits the Sun and has a diameter that equals or exceeds Pluto’s. This definition is clear and simple. It preserves the planethood Pluto has enjoyed since its discovery. And because Pluto is rather large, this definition won’t confer planethood on every last iceball beyond Neptune. So the word planet will continue to connote an important object orbiting the Sun.

Yes, you read that right. Pluto is rather large. It’s the 10th largest object that goes around the Sun. Pluto looks dim primarily because of its great distance. Thus, the sunlight striking it is weak, and this light gets further attenuated during the long trek back to Earth. But put Pluto in place of Mars and, when closest to Earth, Pluto would outshine every star at night.

This definition means the Sun has 10 known planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto and Eris. Discovered in 2005, Eris is the farthest object ever seen in our solar system. It’s currently nine billion miles from the Sun, three times farther than Pluto. And it’s slightly bigger than Pluto. Like Earth, Eris even has a moon.

In 2015, a spacecraft will fly past Pluto and resolve many of the puzzles surrounding a world that has been mysterious since its discovery. But Eris ensures that the mysteries of another distant planet will beckon, inspiring future generations just as Pluto has inspired ours.

Mr. Croswell, an astronomer, is the author of “Ten Worlds” (Boyds Mills Press, 2007) and “The Lives of Stars” (Boyds Mills Press, 2009).

__________

Full article: http://online.wsj.com/article/SB10001424052748703525704575061663532338380.html

Feynman and the Futurists

On Dec. 29, 1959, Richard P. Feynman gave an after-dinner talk at an annual American Physical Society meeting in Pasadena, Calif. Feynman was not the public figure he would later become—he had not yet received a Nobel Prize, unraveled the cause of the Challenger accident, written witty books of popular science, or been the subject of biographies, documentaries and even a play starring Alan Alda. But the 41-year-old was already respected by fellow physicists for his originality, his crackling intellect, and his roguish charm.

Physicist and writer Richard Feynman in 1959.

The announced title of Feynman’s lecture, “There’s Plenty of Room at the Bottom,” mystified the attendees. One later told science writer Ed Regis that the puzzled physicists in the room feared Feynman meant that “there are plenty of lousy jobs in physics.”

Feynman said that he really wanted to discuss “the problem of manipulating and controlling things on a small scale.” By this he meant not mere miniaturization but something much more extreme. “As far as I can see,” Feynman said, the principles of physics “do not speak against the possibility of maneuvering things atom by atom.” In fact, he argued, it is “a development which I think cannot be avoided.” The physicist spoke of storing all the information in all the world’s books on “the barest piece of dust that can be made out by the human eye.” He imagined shrinking computers and medical devices, and developing new techniques of manufacturing and mass production. In short, a half-century ago he anticipated what we now call nanotechnology—the manipulation of matter at the level of billionths of a meter.

Some historians depict the speech as the start of this now-burgeoning field of research. Yet Feynman didn’t use the word “nanotechnology” himself, and his lecture went for years almost entirely unmentioned in the scientific literature. Not until the 1980s did nanotechnology researchers begin regularly citing Feynman’s lecture. So why, then, does one encyclopedia call it “the impetus for nanotechnology”? Why would one of Feynman’s biographers claim that nanotechnology researchers think of Feynman “as their spiritual father”?

The story of how his talk was forgotten and then, decades later, inserted into the history of nanotechnology is worth understanding less because of what it tells us about the past than because of what it hints about the future, a future in which billions of dollars in research and development funds are at stake.

Much of the work that now goes under the rubric of nanotechnology is essentially a specialized form of materials science. In the years ahead, it is expected to result in new medical treatments and diagnostic tools, ultraefficient water-filtration systems, strong and lightweight materials for military armor, and breakthroughs in energy, computing and medicine. Meanwhile, hundreds of consumer products using (or at least claiming to use) nanomaterials or nanoparticles went on the market in the past decade, including paints and cosmetics, stain-resistant garments, and bacteria-battling washing machines and food containers.

The most prominent scientists involved in this mainstream version of nanotechnology have admitted that Feynman’s “Plenty of Room” talk had no influence on their work. Christopher Toumey, a University of South Carolina cultural anthropologist, interviewed several of nanotech’s biggest names, including Nobel laureates; they uniformly told him that Feynman’s lecture had no bearing on their research, and several said they had never even read it.

But there is another kind of nanotechnology, one associated with much more hype. First described in the 1980s by K. Eric Drexler, this vision involves building things “from the bottom up” through molecular manufacturing. It was Mr. Drexler who first brought the term “nanotechnology” to a wide audience, most prominently with his 1986 book “Engines of Creation.” And it is Mr. Drexler’s interpretation that has captured the public imagination, as witness the novels, movies and video games that name-drop nanotechnology with the same casual hopefulness that the comic books of the 1960s mentioned the mysteries of radiation.

Using the theoretical techniques Mr. Drexler outlined, personal desktop nanofactories the size of a microwave oven could one day be programmed to convert raw materials into gleamingly perfect complex objects such as laptop computers. More radically, nanoscale machines might replace or repair damaged cells in your body, staving off aging—or they could be employed in terrible new weapons. In short, if mainstream nanotechnology promises to make our lives easier, Mr. Drexler’s version aims to remake the world.

These two understandings of nanotechnology are regularly conflated in the press—a fact that vexes mainstream researchers, in part because Mr. Drexler’s more ambitious take on nanotech is cherished by several colorful futurist movements (transhumanism, cryonics, and so forth). Worse, for all the fantastical speculation that Drexlerian nanotechnology invites, it has also driven critics, like the late novelist Michael Crichton and the software entrepreneur Bill Joy, to warn of nanotech nightmares.

Hoping to dissociate their nanotechnology work from dystopian scenarios and fringe futurists, some prominent mainstream researchers have taken to belittling Mr. Drexler and his theories. And that is where Feynman re-enters the story: Mr. Drexler regularly invokes the 1959 lecture, which broadly corresponds with his own thinking. As he told Mr. Regis, the science writer: “It’s kind of useful to have a Richard Feynman to point to as someone who stated some of the core conclusions. You can say to skeptics, ‘Hey, argue with him!'” It is thanks to Mr. Drexler that we remember Feynman’s lecture as crucial to nanotechnology, since Mr. Drexler has long used Feynman’s reputation as a shield for his own.

If this dispute over nano-nomenclature only involved some sniping scientists and a few historians watching over a tiny corner of Feynman’s legacy, it would be of little consequence. But hundreds of companies and universities are teeming with nanotech researchers, and the U.S. government has been pouring billions of dollars into its multiagency National Nanotechnology Initiative.

So far, none of that federal R&D funding has gone toward the kind of nanotechnology that Drexler proposed, not even toward the basic exploratory experiments that the National Research Council called for in 2006. If Drexler’s revolutionary vision of nanotechnology is feasible, we should pursue it for its potential for good, while mindful of the dangers it may pose to human nature and society. And if Drexler’s ideas are fundamentally flawed, we should find out—and establish just how much room there is at the bottom after all.

Mr. Keiper is the editor of The New Atlantis and a fellow at the Ethics and Public Policy Center.

___________

Full article and photo: http://online.wsj.com/article/SB10001424052748703580904574638160601840456.html

A Dark Matter Breakthrough?

New evidence of the invisible matter that could make up 90% of the universe.

In early December, the Cold Dark Matter Search (CDMS) experiment located in the deep Soudan Mine in northern Minnesota leaked a tantalizing hint that they may have discovered something remarkable. The experiment is designed to directly detect new elementary particles that might make up the dark matter known to dominate our own Milky Way galaxy, all galaxies, and indeed all mass in the universe—so news of a possible breakthrough was thrilling.

The actual result? Two pulses were detected over the course of almost a year that might have been due to dark matter, CDMS announced on Dec. 17. However, there is a 25% chance that the pulses were actually caused by background radioactivity in and around the detector.

Physicists remain fascinated by the possibility that the events at CDMS, reported on the back pages of the world’s newspapers, might nevertheless be real. If they are, they will represent the culmination of one of the most incredible detective stories in the history of science.

Beginning in the 1970s, evidence began to accumulate that there was much more mass out there than meets the eye. Scientists, mostly by observing the speed of rotation of our galaxy, estimated that there was perhaps 10 times as much dark matter as visible material.

At around the same time, independent computer calculations following the possible gravitational formation of galaxies supported this idea. The calculations suggested that only some new type of material that didn’t interact as normal matter does could account for the structures we see.

Meanwhile, in the completely separate field of elementary particle physics, my colleagues and I had concluded that in order to understand what we see, it is quite likely that a host of new elementary particles may exist at a scale beyond what accelerators at the time could detect. This is one of the reasons there is such excitement about the new Large Hadron Collider in Geneva, Switzerland. Last month, it finally began to produce collisions, and it might eventually directly produce these new particles.

Theorists who had proposed the existence of such particles realized that they could have been produced during the earliest moments of the fiery Big Bang in numbers that could account for the inferred abundance of dark matter today. Moreover, these new particles would have exactly the properties needed for such material. They would interact so weakly with normal matter that they could go through the Earth without a single interaction.

Emboldened by all of these arguments, a brave set of experimentalists began to devise techniques by which they might observe such particles. This required building detectors deep underground, far from the reach of most cosmic rays that would overwhelm any sensitive detector, and in clean rooms with no radioactivity that could produce a false signal.

So when the physics community heard rumors that one of these experiments had detected something, we all waited with eager anticipation. A convincing observation would vindicate almost half a century of carefully developed, if fragile, arguments suggesting a whole new invisible world waiting to be discovered.

For the theorist working at his desk alone at night, it seems almost unfathomable that nature might actually obey the delicate theories you develop on pieces of paper. This is especially true when the theories involve ideas from so many different areas of science and require leaps of imagination.

Alas, to celebrate would be premature: The reported results are intriguing, but less than convincing. Yet if the two pulses observed last week in Minnesota are followed by more signals as bigger detectors turn on in the coming year or two, it will provide serious vindication of the power of human imagination. Combined with rigorous logical inference and technological wizardry—all the things that make science worth celebrating—scientists’ creativity will have uncovered hidden worlds that a century ago could not have been conceived.

If, on the other hand, the events turn out to have been mere background radioactivity, physicists will not give up. It will only force us to be more clever and more energetic as we try to unravel nature’s mysteries.

Mr. Krauss is director of the Origins Institute at Arizona State University, and a theoretical physicist who has been involved in the search for dark matter for 30 years. His newest book, “Quantum Man,” will appear in 2010.

__________

Full article: http://online.wsj.com/article/SB10001424052748704304504574610113807816216.html

Solving a Tonal Mystery in Orbit Around Saturn

The Cassini spacecraft took this photo of Saturn’s moon Iapetus in September 2007.

Researchers have solved what may be the oldest mystery in planetary science: the two-tone surface of Saturn’s moon Iapetus.

The odd feature — the moon’s trailing side is about 10 times brighter than its leading side — has been a mystery since it was first observed by Giovanni Cassini in 1671. In two papers published online by Science, researchers have unraveled the mystery, using images and data from instruments aboard the spacecraft named for Cassini.

The studies confirm an earlier idea that dust, most likely from another of Saturn’s moons, falls on the leading side of Iapetus as it orbits the planet.

“It’s just like a motorcyclist, who only gets the flies on the leading side of the helmet rather than the trailing side,” said Tillmann Denk of the Free University of Berlin, an author with John R. Spencer of the Southwest Research Institute of one of the papers and lead author of the other.

But the pattern of the surface features — the dark area extends to the trailing side at the equator, for example — is not fully explained by the deposition dust. Rather, the researchers say, the reason has a lot to do with the moon’s rotation on its axis, which takes 80 earth days.

Such a slow rotation (“midday” lasts for a couple of weeks) allows the distant Sun to warm the dark dust-covered areas enough that water ice becomes vapor.

The vapor migrates elsewhere, freezing to ice again when it reaches colder areas. The areas where the ice was lost become darker, and those that gained ice become brighter.

Henry Fountain, New York Times

__________

Full article and photo: http://www.nytimes.com/2009/12/15/science/15obmoon.html

Quantum Leap

This biography is a gift. It is both wonderfully written (certainly not a given in the category Accessible Biographies of Mathematical Physicists) and a thought-provoking meditation on human achievement, limitations and the relations between the two. Here we find a man with an almost miraculous apprehension of the structure of the physical world, coupled with gentle incomprehension of that less logical, messier world, the world of other people.

At Cambridge University in 1930, Subrahmanyan Chandrasekhar took a class in quantum mechanics from the 28-year-old Paul Dirac. Three years later, Dirac would become the youngest theoretician to receive the Nobel Prize in Physics up to that time (50 years after that, Chandrasekhar would become one of the older ones). Chandrasekhar described Dirac as a “lean, meek, shy young ‘Fellow’ ” (i.e., of the Royal Society) “who goes slyly along the streets. He walks quite close to the walls (like a thief!), and is not at all healthy.” Dirac’s class — which Chandrasekhar took in its entirety four times, even though Dirac taught it by repeating material from his recently published textbook word for word — was “just like a piece of music you want to hear over and over again.”

Dirac is the main character of a thousand humorous tales told among physicists for his monosyllabic approach to conversation and his innocent, relentless application of logic to everything. Listening to a Dirac story is like slipping into an alternate universe: Dirac reads “Crime and Punishment” and reports it “nice” but notes that in one place the sun rises two times in a day; Dirac eats his dinner in silence until his companion asks, “Have you been to the theater or cinema this week?” and Dirac replies, “Why do you wish to know?”

His work was as sui generis as his social skills. “The great papers of the other quantum pioneers were more ragged, less perfectly formed than Dirac’s,” explained Freeman Dyson, who took Dirac’s course as a precocious 19-year-old. Dirac’s discoveries “were like exquisitely carved marble statues falling out of the sky, one after another. He seemed to be able to conjure laws of nature from pure thought.” (Most notably, Dirac predicted the existence of antimatter in 1928 because his just discovered relativistic electron equation required it.) “It was this purity that made him unique.”

In 1990, Helge Kragh wrote “Dirac: A Scientific Biography,” a useful resource comprising physics, a little history and a dessert of Dirac stories in a chapter entitled “The Purest Soul.” And indeed, what else besides quantum mechanics and amusing anecdotes did this great and single-minded physicist’s life hold?

“The purest soul” is a quotation about Dirac from Niels Bohr, as is Graham Farmelo’s title. (“Dirac is the strangest man,” Bohr said, “who ever visited my institute.”) But purity and strangeness were not the whole story. Kragh’s book offers a collage of a brilliant and peculiar man seen from the outside; Farmelo’s is a tapestry, and he provides glimpses of the inside.

A senior research fellow at the Science Museum in London, Farmelo gives us the texture of Dirac’s life, much of it spent outdoors — from long Sunday walks as a young man, looking like “the bridegroom in an Italian wedding photograph,” “dressed in the suit he wore all week, his hands joined behind his back, both feet pointing outwards as he made his way around the countryside in his metronomic stride”; to late-life canoeing trips with Leopold Halpern, a physicist even stranger than he, “through forests of sassafras and American beech trees, draped with Spanish moss. The alligators made scarcely a sound: the silence was broken only by the rhythmic sloshing of the paddles, the cry of a circling osprey, the occasional shuffling of wind passing through shoreline gaps in the forest.” (After lunch, they swam and paddled back, “scarcely exchanging a word.”)

We follow Dirac from his pinched and chilly childhood in Bristol (a few blocks away from the two-years-younger Archie Leach, a k a Cary Grant); through his discovery, visiting the Bohrs in Copenhagen, of what a happy family was like; his fiercely loyal friendship with Werner Heisenberg; his joyful beach honeymoon, still in a three-piece suit; his careful fatherhood (constructing for his daughters’ cat a door wider than its whiskers); to his death in Florida — “a place where recreational walkers are regarded as perverse” — in 1984.

The science writing in “The Strangest Man” isn’t glib, but neither does it require problem-solving on the part of the reader. In most cases, Farmelo presents the technical matter clearly and efficiently, and in all cases — one of the great joys of the book — Dirac’s scientific insights are placed within the circumstances in which they were born: e.g., the “sweltering July” of 1926 when Dirac, sitting at his college desk, produced his paper on what became Fermi-Dirac statistics.

In a prologue, Farmelo describes a visit to the elderly Dirac paid by his biologist colleague Kurt Hofer. Through the eyes of Hofer, we see Dirac suddenly break out of monosyllables to talk for two hours with increasing vehemence about his monstrous father. This represents the author’s careful decision to keep the tale Dirac told about his childhood separate from — even as it overshadows — the rest of the book, and it ends with Hofer’s thoughts, not Dirac’s: “ ‘I simply could not conceive of any childhood as dreadful as Dirac’s.’ . . . Could it be that Dirac — usually as literal-minded as a computer — was exaggerating? Hofer could not help asking himself, over and again: ‘Why was Paul so bitter, so obsessed with his father?’ ”

The conflict between this prologue (which gives ample reason for Dirac to be bitter about his father) and the seemingly warm family life that emerges in the first chapter casts a tension over the rest of the book very similar to that felt when reading a mystery. And as in a mystery, the penultimate chapter sheds new light. There Farmelo delves into a sensitive exploration of the possibility that Dirac was autistic, and of the ways in which his lack of facility in reading the emotions of others affected their perceptions of him and his perceptions of them. The emphasis on Dirac’s childhood as a story — one Farmelo (along with me) believes to be true — usefully reinforces the importance of point of view.

In a memorable episode, Dirac and his wife visit their closest friends, Peter and Anna Kapitza, in Russia. In 1934, the long arm of the Soviet state had wrenched Kapitza, despite his devoted long-distance fellow-traveling, away from his lab at Cambridge under Ernest Rutherford and back into the Soviet Union. In 1937 the friends reunited at the Kapitzas’ summer house in the piney woods of Bolshevo, “with wild strawberries ripe for gathering and a fast-flowing river close by.” They arrived only “days before Stalin authorized the torture of suspected enemies of the people,” Farmelo writes. “On the roads around Bolshevo, some of the trucks marked ‘Meat’ and ‘Vegetables’ hid prisoners on their way to be shot and buried in the forests to the north of the city which Dirac admired through his binoculars.”

Farmelo handles such scenes with a refreshing, cleareyed understanding of how complicated the world actually is. Dirac did not — probably could not — know what the Soviet Union really was; he also could not know who his father really was, and his father could not really know him. These complexities and unresolvably cubist perspectives make, paradoxically, for the most satisfying and memorable biography I have read in years.

Louisa Gilder is the author of “The Age of Entanglement: When Quantum Physics Was Reborn,” which will be published in paperback in November.

__________

Full article and photo: http://www.nytimes.com/2009/09/13/books/review/Gilder-t.html

Science and the Sublime

In this big two-hearted river of a book, the twin energies of scientific curiosity and poetic invention pulsate on every page. Richard Holmes, the pre-eminent biographer of the Romantic generation and the author of intensely intimate lives of Shelley and Coleridge, now turns his attention to what Coleridge called the “second scientific revolution,” when British scientists circa 1800 made electrifying discoveries to rival those of Newton and Galileo. In Holmes’s view, “wonder”-driven figures like the astronomer William Herschel, the chemist Humphry Davy and the explorer Joseph Banks brought “a new imaginative intensity and excitement to scientific work” and “produced a new vision which has rightly been called Romantic science.”

A major theme of Holmes’s intricately plotted “relay race of scientific stories” is the double-edged promise of science, the sublime “beauty and terror” of his subtitle. Both played a role in the great balloon craze that swept across Europe after 1783, when the Montgolfier brothers sent a sheep, a duck and a rooster over the rooftops of Versailles, held aloft by nothing more substantial than “a cloud in a paper bag.” “What’s the use of a balloon?” someone asked Benjamin Franklin, who witnessed the launching from the window of his carriage. “What’s the use of a newborn baby?” he replied. The Gothic novelist Horace Walpole was less enthusiastic, fearing that balloons would be “converted into new engines of destruction to the human race — as is so often the case of refinements or discoveries in Science.”

The British, more advanced in astronomy, could afford to scoff at lowly French ballooning. William Herschel, a self-taught German immigrant with “the courage, the wonder and the imagination of a refugee,” supported himself and his hard-working assistant, his sister Caroline, by teaching music in Bath. The two spent endless hours at the enormous telescopes that Herschel constructed, rubbing raw onions to warm their hands and scanning the night sky for unfamiliar stars as musicians might “sight-read” a score. The reward for such perseverance was spectacular: Herschel discovered the first new planet to be identified in more than a thousand years.

Holmes describes how the myth of this “Eureka moment,” so central to the Romantic notion of scientific discovery, doesn’t quite match the prolonged discussion concerning the precise nature of the tail-less “comet” that Herschel had discerned. It was Keats, in a famous sonnet, who compared the sudden sense of expanded horizons he felt in reading Chapman’s Elizabethan translation of Homer to Herschel’s presumed elation at the sight of Uranus: “Then felt I like some watcher of the skies / When a new planet swims into his ken.” Holmes notes the “brilliantly evocative” choice of the verb “swims,” as though the planet is “some unknown, luminous creature being born out of a mysterious ocean of stars.” As a medical student conversant with scientific discourse, Keats may also have known that telescopes can give the impression of objects viewed “through a rippling water surface.”

Though Romanticism, as Holmes says, is often presumed to be “hostile to science,” the Romantic poets seem to have been positively giddy — sometimes literally so — with scientific enthusiasm. Coleridge claimed he wasn’t much affected by Herschel’s discoveries, since as a child he had been “habituated to the Vast” by fairy tales. It was the second great Romantic field of science that lighted a fire in Coleridge’s mind. “I shall attack Chemistry, like a Shark,” Coleridge announced, and invited the celebrated scientist Humphry Davy, who also wrote poetry, to set up a laboratory in the Lake District.

Coleridge wrote that he attended Davy’s famous lectures on the mysteries of electricity and other chemical processes “to enlarge my stock of metaphors.” But he was also, predictably, drawn to Davy’s notorious experiments with nitrous oxide, or laughing gas. “The objects around me,” Davy reported after inhaling deeply, “became dazzling, and my hearing more acute.” Coleridge, an opium addict who coined the word “psycho­somatic,” compared the pleasurable effects of inhalation to the sensation of “returning from a walk in the snow into a warm room.” Davy passed out frequently while under the influence, but strangely, as Holmes notes, failed to pursue possible applications in anesthesia.

In assessing the quality of mind that poets and scientists of the Romantic generation had in common, Holmes stresses moral hope for human betterment. Coleridge was convinced that science was imbued with “the passion of Hope,” and was thus “poetical.” Holmes finds in Davy’s rapid and systematic invention of a safety lamp for English miners, one that would not ignite methane, a perfect example of such Romantic hope enacted. Byron celebrated “Davy’s lantern, by which coals / Are safely mined for,” but his Venetian mistress wondered whether Davy, who was visiting, might “give me something to dye my eyebrows black.”

Yet it is in his vivid and visceral accounts of the Romantic explorers Joseph Banks and Mungo Park, whose voyages were both exterior and interior, that Holmes is best able to unite scientific and poetic “wonder.” Wordsworth had imagined Newton “voyaging through strange seas of Thought, alone.” When Banks accompanied Captain Cook to Tahiti and witnessed exotic practices like surfing and tattooing and various erotic rites, he returned to England a changed man; as president of the Royal Society, he steadily encouraged others, like Park, to venture into the unknown.

“His heart,” Holmes writes of Park, “was a terra incognita quite as mysterious as the interior of Africa.” At one low point in his African travels in search of Timbuktu, alone and naked and 500 miles from the nearest European settlement, Park noticed a piece of moss “not larger than the top of one of my fingers” pushing up through the hard dirt. “At this moment, painful as my reflections were, the extraordinary beauty of a small moss in fructification irresistibly caught my eye,” he wrote, sounding a great deal like the Ancient Mariner. “I could not contemplate the delicate conformation of its roots, leaves and capsula, without admiration.”

For Holmes, the “age of wonder” draws to a close with Darwin’s voyage aboard the Beagle in 1831, partly inspired by those earlier Romantic voyages. “With any luck,” Holmes writes wistfully, “we have not yet quite outgrown it.” Still, it’s hard to read his luminous and horizon-expanding “Age of Wonder” without feeling some sense of diminution in our own imaginatively circumscribed times. “To us, their less tried successors, they appear magnified,” as Joseph Conrad, one of Park’s admirers, wrote in “Lord Jim,” “pushing out into the unknown in obedience to an inward voice, to an impulse beating in the blood, to a dream of the future. They were wonderful; and it must be owned they were ready for the wonderful.”

Christopher Benfey is the Mellon professor of English at Mount Holyoke College. His books include “A Summer of Hummingbirds” and an edition of Lafcadio Hearn’s “American Writings” for the Library of America.

__________

Full article and photo: http://www.nytimes.com/2009/07/19/books/review/Benfey-t.html

__________

See also:

‘The Age of Wonder’

INTRODUCTION:

The Age of Wonder is a relay-race of scientific stories, and they link together to explore a larger historical narrative. This is my account of the second scientific revolution, which swept through Britain at the end of the 18th century, and produced a new vision which has rightly been called Romantic science. [See Sources for the recent work of Golinski; Cunningham and Jardine; Fulford, Kitson, and Lee; Ruston et al. since 1990, who all use the term “Romantic Science” ]

Romanticism as a cultural force is generally regarded as intensely hostile to science, its ideal of subjectivity eternally opposed to that of scientific objectivity. But I do not believe this was always the case, or that the terms are so mutually exclusive. The notion of wonder seems to be something that once united them, and can still do so. In effect there is Romantic science in the same sense there is Romantic poetry, and often for the same enduring reasons.

The first scientific revolution of the 17th century is familiarly associated with the names of Newton, Hooke, Locke and Descartes, and the almost simultaneous foundations of the Royal Society in London, and the Acadèmie des Sciences in Paris. It existence has long been accepted, and the biographies of its leading figures are well known.

But this second revolution was something different. The first person who referred to a “second scientific revolution” was probably the poet Coleridge in his Philosophical Lectures of 1819 [See also The Friend, 1819; RH Coleridge DR p482; pp490-2] It was inspired primarily by a sudden series of break-throughs in the fields of astronomy and chemistry. It was a movement that grew out of 18th century Enlightenment rationalism, but largely transformed it, by bringing a new imaginative intensity and excitement to scientific work . It was driven by a common ideal of intense, even reckless, personal commitment to discovery.

It was also a movement of transition. It flourished for a relative brief time, perhaps two generations, but produced long-lasting consequences – raising hopes and questions – that are still with us today. Romantic Science can be dated roughly, and certainly symbolically, between two celebrated voyages of exploration. These were Captain Cook’s first round the world expedition aboard the Endeavour, begun in 1768; and Charles Darwin’s voyage to the Galapagos islands aboard the Beagle begun in 1831. This was the time I have called the Age of Wonder, and with any luck we have not yet quite outgrown it.

The idea of the exploratory voyage, often lonely and perilous, is in one form or another a central and defining metaphor of Romantic science. That is how William Wordsworth brilliantly transformed the great Enlightenment image of Sir Isaac Newton into a Romantic one. As a university student in the 1780’s Wordsworth had often contemplated the full-size marble statue of Newton, with his severely close-cropped hair, that still dominates the stone-flagged entrance hall to the chapel of Trinity College, Cambridge. As Wordsworth originally put it, he could see a few yards off from his bedroom window, over the brick wall of St John’s College

“The Antechapel, where the Statue stood
Of Newton, with his Prism and silent Face.”

Sometime after 1805, Wordsworth animated this static figure, so monumentally fixed in his assured religious setting. Newton became a haunted and restless Romantic traveller amidst the stars:

“And from my pillow, looking forth by light
Of moon or favouring stars, I could behold
The Antechapel where the Statue stood
Of Newton, with his prism and his silent face,
The marble index of a Mind for ever
Voyaging through strange seas of Thought, alone.”
[The Prelude, 1850, Book 3, lines 58-64]

Around such a vision Romantic science created, or crystallised, several other crucial conceptions – or misconceptions – which are still with us. First, the dazzling idea of the solitary scientific “genius”, thirsting and reckless for knowledge, for its own sake and perhaps at any cost. This neo-Faustian idea, celebrated by many of the imaginative writers of the period including Goethe and Mary Shelley, is certainly one of the great, ambiguous creations of Romantic science which we have all inherited.

Closely connected with this is the idea of the Eureka moment, the intuitive inspired instant of invention or discovery, for which no amount of preparation or preliminary analysis can really prepare. Originally the cry of the Greek philosopher Archimedes, this became the “fire from heaven” of Romanticism, the other true mark of scientific genius, which also allied it very closely to poetic inspiration and creativity. Romantic science would seek to identify such moments of singular, almost mystical vision in its own history. One of its first and most influential examples, was to become the story of the solitary brooding Newton in his orchard, seeing an apple fall and “suddenly” having his vision of universal gravity. This story was never told by Newton at the time, but only began to emerge in the mid 18th century, in a series of memoirs and reminiscences.

The notion of an infinite, mysterious Nature, waiting to be discovered or seduced into revealing all her secrets was widely held. Scientific instruments played an increasingly important role in this process of revelation, allowing man not merely to extend his senses passively – using the telescope, the microscope, the barometer – but to intervene actively, using the voltaic battery, the electrical generator, the scalpel or the air pump. Even the Montfgolfier balloon could be seen as an instrument of discovery, or indeed of seduction.

There was, too, a subtle the reaction against the idea of a purely mechanistic universe, the mathematical world of Newtonian physics, the hard material world of objects and impacts. These doubts, expressed especially in Germany, favoured a softer “dynamic” science of invisible powers and mysterious energies, of fluidity and transformations, of growth and organic change. This is one of the reasons that the study of electricity (and chemistry in general) became the signature science of the period; though astronomy itself, once the exemplary science of the Enlightenment, would also be changed by Romantic cosmology. [Eg Coleridge again, see RH DR p548-9]

The ideal of a pure, “disinterested” science, independent of political ideology and even religious doctrine, also began slowly to emerge. The emphasis of on secular, humanist (even atheist) body of knowledge, dedicated to the “benefit of all mankind” was particularly strong in revolutionary France. This would soon involve Romantic science in new kinds of controversy: for instance, whether it could be an instrument of the state, in the case of inventing weapons of war? Or a handmaiden of the Church, supporting the widely held view of “Natural theology”, in which science reveals evidence of a divine Creation or intelligent design?

With these went the new notion of a popular science, a people’s science. The scientific revolution of the late 17th century had promulgated an essentially private, elitist, specialist form of knowledge. Its lingua franca was Latin, and its common currency mathematics. Its audience were a small (if international) circle of scholars and savants. Romantic science, on the other hand, had a new commitment to explain, to educate, to communicate to a general public.

This became the first great age of the public scientific lecture, the laboratory demonstration, and the introductory textbook, often written by women. It was the age when science began to be taught to children, and the “experimental method” became the basis of a new, secular philosophy of life, in which the infinite wonders of creation (whether divine or not) were increasingly valued for their own sake. It was a science that, for the first time, generated sustained public debates, such as the great Regency controversy over “Vitalism”: whether there was such a thing as a life force or principle, or whether men and women (or animals) had souls.

Finally, it was the age which broke the elite monopoly of the Royal Society, and saw the foundation of scores of new scientific institutions, mechanics institutes and “philosophical” societies, most notably the Royal Institution in Albemarle Street in 1799, the Geological Society in 1807, the Astronomical Society in 1820, and the British Association for the Advancement of Science in 1831.

Much of this transition from Enlightenment to Romantic science is expressed in the iconic paintings of Joseph Wright of Derby. Closely attached to the Lunar Society, and the friend of Erasmus Darwin and Joseph Priestley, Wright became a dramatic painter of experimental and laboratory scenes, which reinterpreted late 18th century Enlightenment science as a series of mysterious, romantic moments of revelation and vision. The calm glowing light of reason is surrounded by the intense, psychological chiaroscuro associated with George de la Tour. This is most evident in his famous series of scientific demonstration scenes, painted at the hight of his career: “The Orrery” (1766, Derby City Museum and book cover), “The Air Pump” (1767, National Gallery, London), and “The Alchemist” (1768, Derby City Museum).

2

Was all this such a good thing? There is a counter view that sees Romantic science as a disastrous betrayal of the benign Enlightenment view of Nature, modest, respectful and pious. It replaced it with a fatal commitment to a blind, positivist view of human progress driven by personal ambition, technology and material greed. We have certainly inherited this dillema in the Western world. Romantic science was originally the product of a revolutionary age. The wave of political optimism that carried first the American Declaration of Independence, and then the French Revolution, also inspired Romantic science with a progressive secular idealism, carrying strong radical and republican overtones. But under the patriotic demands and pressures of the Napoleonic Wars its free spirit was curbed, tamed and professionalized. An open, radical science became institutionalized, conservative and doctrinaire.

In the process the international scientific co-operation of 18th century Europe was changed into intense national rivalries. This was especially so between public “men of science” in Britain and France. Co-operative science became competitive. The secular ideals of Enlightenment science, with its notions of disinterestedness and universal human benevolence, became corrupted by Imperial ambitions. Considerations of commercial, religious missionary and national interest fatally compromised pure science. Exploration became colonization.

Worse still, the open imaginative spirit of the Enlightenment, celebrated by poets and writers, was increasingly displaced by an inhuman science, analytical, industrial, invasive, which damaged and exploited both Nature and the human soul. It could not be trusted because, in John Keats’s words, it would “unweave the rainbow”. It drove a profound split between the artistic and scientific response to the world.

Finally, the figure of the inspired, unworldly scientific genius shut away in his lonely laboratory or observatory, following his dreams like Isaac Newton, was changed into a more ambiguous symbol. He was now seen as someone intoxicated by worldly power, or driven by mad ambition, like Dr Victor Frankenstein. The Romantic scientist was a danger to society, not a benefactor.

3

The Age of Wonder asks which version of Romantic science in Britain is really true; or more true. Yet in the end it remains a narrative, a piece of biographical story telling. It aims to capture the inner life of science, its impact on the heart as well as on the mind. In the broadest sense it aims to present scientific passion, so much of which is summed up in that childlike, but infinitely complex word, wonder. Plato had argued that the notion of “wonder” was central to all philosophical thought: “In Wonder all Philosophy began: in Wonder it ends….But the first Wonder is the Offspring of Ignorance; the last is the Parent of Adoration.”

Wonder, in other words, goes through various stages, evolving both with age and with knowledge, but retaining an irreducible fire and spontaneity. This seems to be the implication of Wordsworth famous lyric of 1802, which was inspired not by Newton’s prism, but by Nature’s:

“My heart leaps up when I behold
A rainbow in the sky;
So was it when my life began;
So is it now I am a man;
So be it when I shall grow old,
Or let me die!….”

[Plato’s wonder as interpreted by Coleridge in Aids to Reflection, 1825 “Spiritual Aphorism 9″p236 see RH DR p540]

This book is centered on two scientific lives, those of the astronomer William Herschel and the chemist Humphry Davy. Their discoveries dominate the period, yet they offer two almost diametrically opposed versions of the Romantic “scientist”, a term not coined until 1833, after they were both dead. It also gives an account of their assistants and protégées, who eventually became much more than that, and handed on the flame into the very different world of professional Victorian science. But it draws in many others lives (see Appendix “Cast List”), and it is interrupted by different moments of scientific endeavour and high adventure so characteristic of the Romantic spirit: ballooning, exploring, soul-hunting. These were all part of the great journey.

It is also held together by as a kind of chorus figure, a scientific Virgil, to whom (it must be admitted) I have become greatly attached. It is no coincidence that he began his career a young and naïve scientific traveller and secret journal-keeper. However he ended it as the longest-serving, most experienced and most domineering President of the Royal Society : the botanist, diplomat and eminence grise Sir Joseph Banks. As a young man Banks sailed with Captain Cook round the world, setting out in 1768 on that perilous three-year voyage into the unknown. This voyage may count as one of the earliest distinctive exploits of Romantic science, not least because it involved a long stay in a beautiful but ambiguous version of Paradise – Otaheite, or the South Pacific island of Tahiti.

Excerpted by arrangement with Random House from “The Age of Wonder” by Richard Holmes.

__________

Full article: http://www.nytimes.com/2009/07/09/books/excerpt-age-of-wonder.html

Sons of Atom

The first quarter of the 20th century produced two theories, relativity and quantum mechanics, that are still changing our universe.

With special relativity, Albert Einstein upended the long-understood meaning of time, space and simultaneity. With general relativity, he swapped Newton’s law of gravity based on force for curved space­time, and cosmology became a science. Just after World War I, relativity made front-page news when astronomers saw the Sun bend starlight. Overnight, Einstein became famous as no physical scientist before or since, his theory the subject of poetry, painting and architecture.

Then, with the development of quantum mechanics in the 1920s, physics got ­really interesting. Quantum physics was a theory so powerful — and so powerfully weird — that nearly a century later, we’re still arguing about how to reconcile it with Einsteinian relativity and debating what it tells us about causality, locality and realism.

Relativity leads to a world far from every­day intuition. But relativity was still classical physics: classical in the sense that it was as causal, maybe even more so, as the physics of Newton. The relativist could defend the view that we could refine our local specification of the state of things now — that we could spell out what every last particle was up to — and then predict the future, as accurately as wanted. Back in the Enlightenment, Pierre-Simon de Laplace imagined a machine that could calculate the future. He didn’t know relativity, of course, but you could imagine a Laplace 2.0 (with relativity) that kept his predictive dream alive.

Quantum mechanics shattered that Laplacian vision. From 1925 to 1927, Niels Bohr, Werner Heisenberg, Erwin Schrödinger, Max Born and many others made the theory into a toolkit that could be used to calculate how copper conducted electricity, how nuclei fissioned, how transistors worked. Quantum mechanics was easy to use, but hard to understand. For example, two particles that interacted might subsequently fly to opposite sides of the solar system, and still act as if they were dependent. Measuring one near Pluto affected measurements as the other zipped by Mercury. Einstein viewed this inseparability, now known as “entanglement,” as the fatal mark of the incompleteness of quantum mechanics: he sought a successor theory that would be local, realist and therefore complete.

Looking back on the early 20th century, Bohr wistfully reflected that Einstein had done so much of relativity theory by himself, while quantum mechanics took a whole generation of physicists 30 years. Telling the quantum story up to 1927 has been an industry for the past 80 years. In the first half of her new book, “The Age of Entanglement,” Louisa Gilder does her level best to cope with this plethora of sources, characters and topics, with mixed results. She writes engagingly, using dialogue reconstructed from letters, papers and memoirs to capture the spirit of confrontation among the players. That’s good. But she seems ill at ease with the German sources and so is reliant on the secondary literature — some of which is well done, some not. That’s not so good.

But on Page 181, the clouds part and Gilder reveals a sparkling, original book. Leaving Copenhagen, Berlin and Göt­tingen behind, she recounts a history of the quantum physics that did not end in 1927. With a smaller, more contemporary cast of characters from Berkeley, Innsbruck, Harvard and CERN, the big accelerator outside Geneva, Gilder brings the reader into a mix of ideas and personalities handled with a verve reminiscent of Jeremy Bernstein’s scientific portraits in The New Yorker.

This second-half book begins with the story of David Bohm, a student of J. Robert Oppenheimer who dissented from political orthodoxy and paid for it with his career. Hauled before the House Un-American Activities Committee in 1949, he refused their bullying questions, lost his job, and fled to Brazil and then to Israel. Often ill, the isolated Bohm railed against the orthodox interpretation of quantum physics as well, and agitated for a theory he hoped would replace it. He had the sympathy of Einstein and Richard Feynman but somehow always orbited outside the action — his work, Wolfgang Pauli once said, like an uncashed check. Gilder movingly portrays Bohm’s lonely trajectory. Even Einstein turned away from Bohm in 1952, calling his approach “too cheap,” while Max Born later wrote back that Pauli had come up with a new idea that “slays Bohm not only philosophically but physically.”

Next comes the real center of her story, John Bell, a remarkable Irish theorist at CERN. Like Bohm, Bell resisted the too easy slide into orthodoxy that had made one interpretation of quantum physics into a canon law from which even questioning was greeted suspiciously. For several years, Bell worked through Bohm’s studies, isolating what was so troubling about quanta. Better yet, he derived predictions.

Bell’s theorem, stated in a 1964 paper: You cannot have a theory consistent with his experimental predictions of quantum mechanics and have that theory describe the world in a completely local way. To put it differently, we may be troubled by various aspects of quantum physics and hope it can be replaced by some other theory that will capture its predictions but go deeper, giving a local, un-entangled account. But Bell showed that if a certain measurable inequality was confirmed experimentally, it would follow that any successor theory to quantum physics you tried to write would itself exhibit one of the strangest features of quantum theory: it will still be non-local.

Bell’s prediction bore on correlations in properties between particles that had once been entangled — even if the particles flew far apart. Suddenly interpretations of quantum mechanics opened into something else: a laboratory test to demonstrate that local hidden variable theories could not exist. Experimentalists, not theorists, now had the floor, and Gilder beautifully evokes their world: equipment catalogs instead of books; piles of dry ice; messy clockwork; boiling metal. Gilder captures the vaulting ambition of this recent generation in joining engineering with the foundations of quantum theory — no easy task. Alongside the successes, she shows the frustration of contradictory results, the worries about whether these results reflected reality — or were just a stupid machine bug.

Some experimentalists wanted quantum mechanics to succeed. Others hoped it would crash and burn. These experiments seemed all at once to be playing for the highest stakes possible and yet might just confirm again what almost every physicist already accepted. Would the experiments kill the greatest theory, or wreck careers not yet begun?

Quantum physics survived Bell’s test. But in all the testing in those years since the mid-1960s, the nature — the weirdness — of quantum mechanics gained a clarity and force it had never had, even in the hands of Einstein and Bohr. Entanglement was here to stay: Bell’s inequality, powered by experiment, said so. What’s more, the oddness of entanglement makes a new kind of computing imaginable. Odd as it might seem, these foundational ideas of quantum mechanics have led governments, industries and militaries to explore how the entangled state of separated particles might accelerate computing to a staggering degree: instead of taking, say, a million steps to crack a secret password, the still-nascent quantum computer promises a solution in the square-root number of steps — in this case, a mere thousand steps.

What had been for generations a story of theoretical malcontents now intrigues spooks and start-ups. All this radiates from Louisa Gilder’s story. Quantum physics lives.

Peter Galison is a professor of the history of science at Harvard and the author of “Einstein’s Clocks, Poincaré’s Maps.” His film “Secrecy,” made with Robb Moss, had its premiere at the 2009 Sundance Film Festival.

__________

Full article and photo: http://www.nytimes.com/2009/03/29/books/review/Galison-t.html

__________

See also:

‘The Age of Entanglement’

The Socks
1978 and 1981

In 1978, when John Bell first met Reinhold Bertlmann, at the weekly tea party at the Organisation Européenne pour la Recherche Nucléaire, near Geneva, he could not know that the thin young Austrian, smiling at him through a short black beard, was wearing mismatched socks. And Bertlmann did not notice the characteristically logical extension of Bell’s vegetarianism — plastic shoes.

Deep under the ground beneath these two pairs of maverick feet, ever-increasing magnetic fields were accelerating protons (pieces of the tiny center of the atom) around and around a doughnut-shaped track a quarter of a kilometer in diameter. Studying these particles was part of the daily work of CERN, as the organization was called (a tangled history left the acronym no longer correlated with the name). In the early 1950s, at the age of twenty-five, Bell had acted as consultant to the team that designed this subterranean accelerator, christened in scientific pseudo-Greek “the Proton Synchrotron.” In 1960, the Irish physicist returned to Switzerland to live, with his Scottish wife, Mary, also a physicist and a designer of accelorators. CERN’s charmless, colorless campus of box-shaped buildings with protons flying through their foundations became Bell’s intellectual home for the rest of his life, in the green pastureland between Geneva and the mountains. At such a huge and impersonal place, Bell believed, newcomers should be welcomed. He had never seen Bertlmann before, and so he walked up to him and said, his brogue still clear despite almost two decades in Geneva: “I’m John Bell.”

This was a familiar name to Bertlmann — familiar, in fact, to almost anyone who studied the high-speed crashes and collisions taking place under Bell’s and Bertlmann’s feet (in other words, the disciplines known as particle physics and quantum field theory). Bell had spent the last quarter of a century conducting piercing investigations into these flying, decaying, and shattering particles. Like Sherlock Holmes, he focused on details others ignored and was wont to make startlingly clear and unexpected assessments. “He did not like to take commonly held views for granted but tended to ask, ‘How do you know?,'” said his professor, Sir Rudolf Peierls, a great physicist of the previous generation. “John always stood out through his ability to penetrate to the bottom of any argument,” an early co-worker remembered, “and to find the flaws in it by very simple reasoning.” His papers — numbering over one hundred by 1978 — were an inventory of such questions answered, and flaws or treasures discovered as a result.

Bertlmann already knew this, and that Bell was a theorist with an almost quaint sense of responsibility who shied away from grand speculations and rooted himself in what was directly related to experiments at CERN. Yet it was this same responsibility that would not let him ignore what he called a “rottenness” or a “dirtiness” in the foundations of quantum mechanics, the theory with which they all worked. Probing the weak points of these foundations — the places in the plumbing where the theory was, as he put it, “unprofessional” — occupied Bell’s free time. Had those in the lab known of this hobby, almost none of them would have approved. But on a sabbatical in California in 1964, six thousand miles from his responsibilities at CERN, Bell had made a fascinating discovery down there in the plumbing of the theory.

Revealed in that extraordinary paper of 1964, Bell’s theorem showed that the world of quantum mechanics — the base upon which the world we see is built — is composed of entities which are either, in the jargon of physics, not locally causal, not fully separable, or even not real unless observed.

If the entities of the quantum world are not locally causal, then an action like measuring a particle can have instantaneous “spooky” effects across the universe. As for separability: “Without such an assumption of the mutually independent existence (the ‘being-thus’) of spatially distant things …,” Einstein insisted, “physical thought in the sense familiar to us would not be possible. Nor does one see how physical laws could be formulated and tested without such a clean separation.” The most extreme version of nonseparability is the idea that the quantum entities are not independently real: that atoms do not become solid until they are observed, like the proverbial tree that makes no sound when it falls unless a listener is around. Einstein found the implications ludicrous: “Do you really believe the moon is not there if nobody looks?”

Up to that point, the idea of science rested on separability, as Einstein had said. It could be summarized as humankind’s long intellectual journey away from magic (not locally causal) and from anthropocentricism (not independently real). Perversely, and to the consternation of Bell himself, his theorem brought physics to the point where it seemingly had to choose between these absurdities.

Whatever the ramifications, it would become obvious by the beginning of this century that Bell’s paper had caused a sea change in physics. But in 1978 the paper, published fourteen years before in an obscure journal, was still mostly unknown.

Bertlmann looked with interest at his new acquaintance, who was smiling affably with eyes almost shut behind big metal-rimmed glasses. Bell had red hair that came down over his ears — not flaming red, but what was known in his native country as “ginger” — and a short beard. His shirt was brighter than his hair, and he wore no tie.

In his painstaking Viennese-inflected English, Bertlmann introduced himself: “I’m Reinhold Bertlmann, a new fellow from Austria.”

Bell’s smile broadened. “Oh? And what are you working on?”

It turned out that they were both engaged with the same calculations dealing with quarks, the tiniest bits of matter. They found they had come up with the same results, Bell by one method on his desktop calculator, Bertlmann by the computer program he had written.

So began a happy and fruitful collaboration. And one day, Bell happened to notice Bertlmann’s socks.

Three years later, in an austere room high up in one of the majestic stone buildings of the University of Vienna, Bertlmann was curled over the screen of one of the physics department’s computers, deep in the world of quarks, thinking not in words but in equations. His computer — at fifteen feet by six feet by six feet one of the department’s smaller ones — almost filled the room. Despite the early spring chill, the air-conditioning ran, fighting the heat produced by the sweatings and whirrings of the behemoth. Occasionally Bertlmann fed it a new punch card perforated with a line of code. He had been at his work for hours as the sunlight moved silently around the room.

He didn’t look up at the sound of someone’s practiced fingers poking the buttons that unlocked the door, nor when it swung open. Gerhard Ecker, from across the hall, was coming straight at him, a sheaf of papers in hand. He was the university’s man in charge of receiving preprints — papers that have yet to be published, which authors send to scientists whose work is related to their own.

Ecker was laughing. “Bertlmann!” he shouted, even though he was not four feet away.

Bertlmann looked up, bemused, as Ecker thrust a preprint into his hands: “You’re famous now!”

The title, as Bertlmann surveyed it, read:

Bertlmann’s Socks and the Nature of Reality
J. S. Bell
CERN, Geneve, Suisse

The article was slated for publication in a French physics periodical, Journal de Physique, later in 1981. Its title was almost as incomprehensible to Bertlmann as it would be for a casual reader.

“But what’s this about? What possibly—”

Ecker said, “Read it, read it.”

He read.

The philosopher in the street, who has not suffered a course in quantum mechanics, is quite unimpressed by Einstein-Podolsky-Rosen correlations. He can point to many examples of similar correlations in everyday life. The case of Bertlmann’s socks is often cited.

My socks? What is he talking about? And EPR correlations? It’s a big joke, John Bell is playing a big published joke on me.

“EPR” — short for the paper’s authors, Albert Einstein, Boris Podolsky, and Nathan Rosen — was, like Bell’s 1964 theorem, which it inspired thirty years later, something of an embarrassment for physics. To the question posed by their title, “Can Quantum-Mechanical Description of Physical Reality Be Considered Complete?,” Einstein and his lesser-known cohorts answered no. They brought to the attention of physicists the existence of a mystery in the quantum theory. Two particles that had once interacted could, no matter how far apart, remain “entangled” — the word Schrödinger coined in that same year — 1935 — to describe this mystery. A rigorous application of the laws of quantum mechanics seemed to force the conclusion that measuring one particle affected the state of the second one: acting on it at a great distance by those “spooky” means. Einstein, Podolsky, and Rosen therefore felt that quantum mechanics would be superseded by some future theory that would make sense of the case of the correlated particles.

Physicists around the world had barely looked up from their calculations. Years went by, and it became more and more obvious that despite some odd details, ignored like the eccentricities of a general who is winning a war, quantum mechanics was the most accurate theory in the history of science. But John Bell was a man who noticed details, and he noticed that the EPR paper had not been satisfactorily dealt with.

Bertlmann felt like laughing in confusion. He looked at Ecker, who was grinning: “Read on, read on.”

Dr. Bertlmann likes to wear two socks of different colors. Which color he will have on a given foot on a given day is quite unpredictable. But when you see (Fig. 1) that the first sock is pink…

What is Fig. 1? My socks? Bertlmann ruffled through the pages and found, appended at the end, a little line sketch of the kind John Bell was fond of doing. He read on:

But when you see that the first sock is pink you can be already sure that the second sock will not be pink. Observation of the first, and experience of Bertlmann, give immediate information about the second. There is no accounting for tastes, but apart from that there is no mystery here. And is not the EPR business just the same?

Bertlmann imagined John’s voice saying this, conjured up his amused face. For three years we worked together every day and he never said a thing.

Ecker was laughing. “What do you think?”

Bertlmann had already dashed past him, out the door, down the hall to the phone, and with trembling fingers was calling CERN.

Bell was in his office when the phone rang, and Bertlmann came on the line, completely incoherent. “What have you done? What have you done?”

Bell’s clear laugh alone, so familiar and matter-of-fact, was enough to bring the world into focus again. Then Bell said, enjoying the whole thing: “Now you are famous, Reinhold.”

“But what is this paper about? Is this a big joke?”

“Read the paper, Reinhold, and tell me what you think.”

A tigress paces before a mirror. Her image, down to the last stripe, mimics her every motion, every sliding muscle, the smallest twitch of her tail. How are she and her reflection correlated? The light shining down on her narrow slinky shoulders bounces off them in all directions. Some of this light ends up in the eye of the beholder: either straight from her fur, or by a longer route, from tiger to mirror to eye. The beholder sees two tigers moving in perfectly opposite synchrony.

Look closer. Look past the smoothness of that coat to see its hairs; past its hairs to see the elaborate architectural arrangements of molecules that compose them, and then the atoms of which the molecules are made. Roughly a billionth of a meter wide, each atom is (to speak very loosely) its own solar system, with a dense center circled by distant electrons. At these levels — molecular, atomic, electronic — we are in the native land of quantum mechanics.

The tigress, though large and vividly colored, must be near the mirror for a watcher to see two correlated cats. If she is in the jungle, a few yards’ separation would leave the mirror showing only undergrowth and swinging vines. Even out in the open, though, at a certain distance the curvature of the earth would rise up to obscure mirror from tigress and decouple their synchrony. But the entangled particles Bell was talking about in his paper can act in unison with the whole universe in between.

Quantum entanglement, as Bell would go on to explain in his paper, is not really like Bertlmann’s socks. No one puzzles over how he always manages to pick different-colored socks, or how he pulls the socks onto his feet. But in quantum mechanics there is no idiosyncratic brain “choosing” to coordinate distant particles, and it is hard not to compare how they do it to magic.

In the “real world,” correlations are the result of local influences, unbroken chains of contact. One sheep butts another — there’s a local influence. A lamb comes running to his mother’s bleat after waves of air molecules hit each other in an entirely local domino effect, starting from her vocal cords and ending when they beat the tiny drum in the baby’s ear in a pattern his brain recognizes as Mom. Sheep scatter at the arrival of a coyote: the moving air has carried bits of coyote musk and dandruff into their nostrils, or the electromagnetic waves of light from the moon have bounced off the coyote’s pelt and into the retinas of their eyes. Either way, it’s all local, including the nerves firing in each sheep’s brain to say danger, and carrying the message to her muscles.

Grown up, sold, and separated on different farms, twin lambs both still chew their cud after eating, and produce lambs that look eerily similar. These correlations are still local. No matter how far the lambs ultimately separate, their genetic material was laid down when they were a single egg inside their mother’s womb.

Bell liked to talk about twins. He would show a photograph of the pair of Ohio identical twins (both named “Jim”) separated at birth and then reunited at age forty, just as Bell was writing “Bertlmann’s Socks.” Their similarities were so striking that an institute for the study of twins was founded, appropriately enough at the University of Minnesota in the Twin Cities. Both Jims were nail-biters who smoked the same brand of cigarettes and drove the same model and color of car. Their dogs were named “Toy,” their ex-wives “Linda,” and current wives “Betty.” They were married on the same day. One Jim named his son James Alan, his twin named his son James Allen. They both liked carpentry — one made miniature picnic tables and the other miniature rocking chairs.

(Continues…)

Excerpted from The Age of Entanglement by Louisa Gilder

__________

Full article: http://www.nytimes.com/2009/03/29/books/chapters/chapter-age-of-entanglement.html

The Circular Logic of the Universe

Vasily Kandinsky, “Several Circles,” 1926.

CIRCLING my way not long ago through the Vasily Kandinsky show now on display in the suitably spiral setting of the Guggenheim Museum, I came to one of the Russian master’s most illustrious, if misleadingly named, paintings: “Several Circles.”

Those “several” circles, I saw, were more like three dozen, and every one of them seemed to be rising from the canvas, buoyed by the shrewdly exuberant juxtapositioning of their different colors, sizes and apparent translucencies. I learned that, at around the time Kandinsky painted the work, in 1926, he had begun collecting scientific encyclopedias and journals; and as I stared at the canvas, a big, stupid smile plastered on my face, I thought of yeast cells budding, or a haloed blue sun and its candied satellite crew, or life itself escaping the careless primordial stew.

I also learned of Kandinsky’s growing love affair with the circle. The circle, he wrote, is “the most modest form, but asserts itself unconditionally.” It is “simultaneously stable and unstable,” “loud and soft,” “a single tension that carries countless tensions within it.” Kandinsky loved the circle so much that it finally supplanted in his visual imagination the primacy long claimed by an emblem of his Russian boyhood, the horse.

PAINTING IN THE ROUND “Circular Forms,” oil on canvas by Robert Delaunay. Another artist, the Russian master Vasily Kandinsky, loved the circle, which he described as “a single tension that carries countless tensions within it.”

Quirkily enough, the artist’s life followed a circular form: He was born in December 1866, and he died the same month in 1944. This being December, I’d like to honor Kandinsky through his favorite geometry, by celebrating the circle and giving a cheer for the sphere. Life as we know it must be lived in the round, and the natural world abounds in circular objects at every scale we can scan. Let a heavenly body get big enough for gravity to weigh in, and you will have yourself a ball. Stars are giant, usually symmetrical balls of radiant gas, while the definition of both a planet like Jupiter and a plutoid like Pluto is a celestial object orbiting a star that is itself massive enough to be largely round.

On a more down-to-earth level, eyeballs live up to their name by being as round as marbles, and, like Jonathan Swift’s ditty about fleas upon fleas, those soulful orbs are inscribed with circular irises that in turn are pierced by circular pupils. Or think of the curved human breast and its bull’s-eye areola and nipple.

Our eggs and those of many other species are not egg-shaped at all but spherical, and when you see human eggs under a microscope they look like tranquil suns with Kandinsky coronas behind them. Raindrops start life in the clouds not with the pear-shaped contours of a cartoon teardrop, but as liquid globes, aggregates of water molecules that have condensed around specks of dust or salt and then mutually clung themselves into the rounded path of least resistance. Only as the raindrops fall do they lose their symmetry, their bottoms often flattening out while their tops stay rounded, a shape some have likened to a hamburger bun.

Sometimes roundness is purely a matter of physics. “The shape of any object represents the balance of two opposing forces,” explained Larry S. Liebovitch of the Center for Complex Systems and Brain Sciences at Florida Atlantic University. “You get things that are round when those forces are isotropic, that is, felt equally in all directions.”

In a star, gravity is pulling the mass of gas inward toward a central point, while pressure is pushing the gas outward, and the two competing forces reach a dynamic détente — “simultaneously stable and unstable,” you might say — in the form of a sphere. For a planet like Earth, gravity tugs the mostly molten rock in toward the core, but the rocks and their hostile electrons push back with equal vehemence. Plutoids are also sufficiently massive for gravity to overcome the stubbornness of rock and smooth out their personal lumps, although they may not be the gravitationally dominant bodies in their neighborhood

In precipitating clouds, water droplets are exceptionally sticky, as the lightly positive end of one water molecule seeks the lightly negative end of another. But, again, mutually hostile electrons put a limit on molecular intimacy, and the compromise conformation is shaped like a ball. “A sphere is the most compact way for an object to form itself,” said Denis Dutton, an evolutionary theorist at the University of Canterbury in New Zealand.

A sphere is also tough. For a given surface area, it’s stronger than virtually any other shape. If you want to make a secure container using the least amount of material, Dr. Liebovitch said, make that container round. “That’s why, when you cook a frankfurter, it always splits in the long direction,” he said, rather than along its circumference. The curved part has the tensile strength of a sphere, the long axis that of a rectangle: no contest.

The reliability of bubble wrap may help explain some of the round objects found among the living, where the shapes of body parts are assumed to have some relation to their purpose. Eggs are a valuable commodity in nature, and if a round package is the safest option, by all means, make them caviar round. Among many birds, of course, eggs are oval rather than round, a trait that biologists attribute to both the arduous passage the egg makes through the avian oviduct, and the fact that oval eggs roll in a circle rather than a straight line and thus are less likely to fall out of a nest.

Yet scientists admit that they don’t always understand the evolutionary pressures that sculpture a given carbon-based shape.

While studying the cornea at Columbia University College of Physicians and Surgeons, Dr. Liebovitch became curious about why eyeballs are round. “It seemed like their most salient feature,” he said. He explored the options. To aid in focusing? But only a small region of the retina is involved in focusing, he said, and the whole spherical casing seems superfluous to the optical needs of that foveal patch. To enable the eye to roll easily in the socket and dart this way and that? But birds and other animals with fixed eyes still have bulging round eyeballs. “It’s not really clear what the reason is,” he said.

And for speculative verve, nothing beats the assortment of hypotheses that have been put forth to explain the roundness of the human female breast. It’s a buttock mimic. It’s a convenient place to store fat for hard times. It’s a fertility signal, a youth signal, a health signal, a wealth symbol. Large breasts emphasize the woman’s comparatively small waist, which is really what men are interested in. As for me, I’m waiting for somebody to explain why a man’s well-developed bicep looks like a wandering breast.

Whatever the prompt, our round eyes are drawn to round things. Jeremy M. Wolfe of Harvard Medical School and his colleagues found that curvature was a basic feature we used while making a visual search. Maybe we are looking for faces, a new chance to schmooze.

Studying rhesus monkeys, Doris Tsao of the California Institute of Technology and her colleagues identified a set of brain cells that responded strongly to images of faces, monkey and otherwise. The only other sort of visual stimulus that aroused those face tracing neurons, Dr. Tsao said, were round objects — clocks, apples and the like. She suspects the results would be similar for humans. We make a fetish of faces. “If you have a round object with two spots in the middle,” she said, “that instantly attracts your attention.”

Or maybe the circle beckons not for its resemblance to human face but as a mark of human art. Dr. Dutton, author of “The Art Instinct,” pointed out that perfect shapes were exceedingly rare in nature. “Take a look at a billiard ball,” he said. “It’s impossible to imagine that nature threw that one up.” We are predisposed to recognize “human artifacture,” he said, and roundness can be a mark of our handiwork. When nature does play the meticulous Michelangelo, we are astonished.

“People come to see the Moeraki boulders of New Zealand,” he said, “and ooh and aah because they’re so amazingly spherical.”

Artists in turn have used the circle as shorthand for the divine: in mandalas, rose windows, the lotus pad of the Buddha, the halos of Christian saints. For Kandinsky, said Tracey Bashkoff, who curated the Guggenheim exhibition, the circle was part of a “cosmic language” and a link to a grander, more spiritual plane. A round of applause! We’ve looped back to Kandinsky again.

Natalie Angier, New York Times

__________

Full article and photos: http://www.nytimes.com/2009/12/08/science/08angier.html

The Man Behind The God Particle

Meet Peter Higgs

The Large Hadron Collider accelerator in Geneva was constructed to search for the Higgs boson, among other things.

Physicist Peter Higgs is now world famous because of the subatomic particle bearing his name. But his ideas were initially snubbed by the academic world, with his landmark publication predicting the existence of the Higgs boson being rejected at first. The editor apparently didn’t understand a word of it.

Inside the walls of NIKHEF, the Dutch institute for nuclear research in Amsterdam, a group of renowned Dutch physicists have joined Peter Higgs in the cafeteria. Higgs is in town for the premiere of the Dutch documentary “Higgs, Into the Heart of the Imagination.”

Higgs, who is 80, has become world famous because of the subatomic particle bearing his name, the so-called Higgs boson. Thousands of physicists are now chasing after the elusive particle at CERN, the European Organization for Nuclear Research in Geneva. The quest prompted the construction of the Large Hadron Collider, the most powerful particle accelerator on the planet, which cost more than €6 billion to build.

Did the idea that would lead to the discovery of the Higgs boson just pop into his head in 1964? “No,” Higgs says, munching on a cheese sandwich and sipping orange juice. “That is not how it went.”

His ideas formed more gradually, he says. “By the summer of 1964 I knew I was on to something. That was perhaps the reason — because my head was full of thoughts — that I forgot the instructions for putting up the tent when we went for a camping trip in the Scottish mountains.”

A Fruitful End to a Dreary Holiday

Typically for Scotland, it was raining cats and dogs. The couple holed up in a bed and breakfast, and returned home earlier than intended. “I was pleased to get back,” Higgs recalls. Back at the University of Edinburgh, he wrote the article that would make him world famous. “But I wasn’t walking around shouting ‘eureka,'” Higgs says, taking another bite out of his sandwich.

Physicists often refer to the Higgs particle, which is nicknamed the “God particle,” as the pinnacle of the so-called Standard Model. That model describes the smallest particles of which all discernable matter in the universe is composed: stars, planets, people and atoms.

The Higgs particle might explain why so many of those particles have mass, causing them to move slowly and stick together, unlike the wispy photons that shoot through space at the speed of light.

Because Higg’s theory is so complicated, metaphors have been invented to describe it. “Spontaneous broken symmetry,” for instance, has been compared with the asymmetries caused by fibres and veins running through wood. Particles travelling along the lines of the veins experience little or no resistance, while those travelling at a perpendicular angle are slowed down, becoming heavy, like the matter of which stars and people are constructed.

Another metaphor is that of the US president making his entry at a party. When Barack Obama — representing, in this analogy, a very heavy particle — enters the room, the commotion caused by his arrival — the Higgs boson — spreads quickly and draws everybody in his direction. Because of all the people now flocking around him — the Higgs field — Obama is no longer able to move through the room quickly. He is far slower than the relatively unknown Dutch Prime Minister Jan Peter Balkenende, a much lighter particle in this metaphor.

Genius Unrecognised

The question the scientists at CERN are hoping to answer is whether or not the Higgs particle is really at work in the physical world. In other words, if it actually exists or not.

It is “somewhat ironic,” says Higgs, that his article was first rejected by Physics Letters, a journal published at the same CERN, in 1964. “It was only much later that my roommate at university in Edinburgh told me the editor had not understood it at all,” he recalls. The editor replied that he “did not see the relevance of the work for physics” and wrote a polite letter suggesting he send his article to another magazine, like Nuovo Cimento.

“It was only later that I discovered that that suggestion was not so polite after all,” Higgs recalls, “since Nuovo Cimento publishes all articles without peer review” — in other words, regardless of their quality.

Higgs had gone another route by then. He had added a paragraph to the article demonstrating his “new” mechanism would be able to produce particles with proper mass. “But I was thinking in the wrong direction,” Higgs adds. “I thought of hadrons.” Hadrons, which are subject to the strong force, one of the four elementary forces in nature, were a hot topic among scientists at the time.

Still, it was that extra paragraph, Higgs suspects, that led to his article being accepted by the American scientific journal Physical Review Letters, and, more importantly, that drew attention to it.

The Shoulders of Giants

At a speech given to colleagues last Friday at NIKHEF, Higgs credited the scientists who paved the way for him and who dotted the i’s and crossed the t’s of his work. He thanked countless people, including a number of Nobel Prize winners. Among the latter were people like Yoichiro Nambu, who got the idea for spontaneous broken symmetry from superconductor research into particle physics. Or Phil Anderson, who came close, but never drew the same final conclusions that Higgs did. Or Sheldon Glashow, Abdus Salam and Steven Weinberg, who unified the electromagnetic and weak nuclear forces under the Standard Model. And the Dutch scientists Gerard ‘t Hooft and Martin Veltman, who gave this electroweak force a sturdy theoretical foundation.

It was with the electroweak force that the Higgs mechanism proved particularly useful. This theory covers the interaction between weightless particles (the photons of the electroweak force) and massive particles (like the W- and Z-particles of the weak nuclear force). Only Higgs’ mechanism could explain the asymmetrical masses, through the existence of a particle which came to be known as the Higgs particle, or Higgs boson, since a well-attended congress in 1972.

Over the years, physicists became convinced the Higgs particle might actually be detectable. Indirectly, through precise measurements of the electroweak force at CERN and Fermilab in the United States, they established how. “And that is when my life as a boson really started,” Higgs says.

It could have been different. When Higgs’ manuscript arrived at Physical Review Letters on Aug. 31, 1964, the magazine had just published an article by the Belgian physicists Francois Englert and Robert Brout. They had come to the same conclusion through different means. “Because their method was quite complicated they were somewhat uncertain of their results. Perhaps that is why they did not tout the applications it might have in particle physics,” Higgs says carefully.

This may be true, but the “Englert field” never gained popular recognition, and neither did the Brout boson. And this is despite the fact that his name only has five letters, as Brout is said to have remarked somewhat wryly. And even Higgs’ painstaking efforts to pay tribute to his fellow researchers can do little to change the fact that it is his name that is now forever associated with the elusive boson.

What If It Doesn’t Exist?

But what if the Higgs particle isn’t found? “Then I no longer understand a whole area of physics which puzzled me as an undergraduate,” Higgs answers, sounding determined. “And I thought the one thing we understand rather well now is the electromagnetic interaction and how it relates to electroweak theory.”

Isn’t it strange to see billions being invested in pursuit of a particle bearing his own name? “If physicists were looking for a different particle they would have constructed an accelerator just as strong and experiments just as complex,” Higgs says with a shrug.

__________

Full article and photo: http://www.spiegel.de/international/europe/0,1518,665144,00.html

Physicists Move One Step Closer to Quantum Computing

Physicists at UC Santa Barbara have made an important advance in electrically controlling quantum states of electrons, a step that could help in the development of quantum computing. The work is published online November 20 on the Science Express Web site.

The researchers have demonstrated the ability to electrically manipulate, at gigahertz rates, the quantum states of electrons trapped on individual defects in diamond crystals. This could aid in the development of quantum computers that could use electron spins to perform computations at unprecedented speed.

Using electromagnetic waveguides on diamond-based chips, the researchers were able to generate magnetic fields large enough to change the quantum state of an atomic-scale defect in less than one billionth of a second. The microwave techniques used in the experiment are analogous to those that underlie magnetic resonance imaging (MRI) technology.

The key achievement in the current work is that it gives a new perspective on how such resonant manipulation can be performed. “We set out to see if there is a practical limit to how fast we can manipulate these quantum states in diamond,” said lead author Greg Fuchs, a postdoctoral researcher at UCSB. “Eventually, we reached the point where the standard assumptions of magnetic resonance no longer hold, but to our surprise we found that we actually gained an increase in operation speed by breaking the conventional assumptions.”

While these results are unlikely to change MRI technology, they do offer hope for the nascent field of quantum computing. In this field, individual quantum states take on the role that transistors perform in classical computing.

“From an information technology standpoint, there is still a lot to learn about controlling quantum systems,” said David Awschalom, principal investigator and professor of physics, electrical and computer engineering at UCSB. “Still, it’s exciting to stand back and realize that we can already electrically control the quantum state of just a few atoms at gigahertz rates — speeds comparable to what you might find in your computer at home.”

The work was performed at UCSB’s Center for Spintronics and Quantum Computation, directed by Awschalom. Co-authors on the paper include David. M. Toyli and F. Joseph Heremans, both of UCSB. Slava V. Dobrovitski of Ames Laboratory and Iowa State University contributed to the paper.

__________

Full article: http://www.sciencedaily.com/releases/2009/11/091120095005.htm

By Happy Accident, Chemists Produce a New Blue

Variations of a blue pigment were developed at Oregon State University.

Blue is sometimes not an easy color to make.

Blue pigments of the past have often been expensive (ultramarine blue was made from the gemstone lapis lazuli, ground up), poisonous (cobalt blue is a possible carcinogen and Prussian blue, another well-known pigment, can leach cyanide) or apt to fade (many of the organic ones fall apart when exposed to acid or heat).

So it was a pleasant surprise to chemists at Oregon State University when they created a new, durable and brilliantly blue pigment by accident.

The researchers were trying to make compounds with novel electronic properties, mixing manganese oxide, which is black, with other chemicals and heating them to high temperatures.

Then Mas Subramanian, a professor of material sciences, noticed that one of the samples that a graduate student had just taken out of the furnace was blue.

“I was shocked, actually,” Dr. Subramanian said.

In the intense heat, almost 2,000 degrees Fahrenheit, the ingredients formed a crystal structure in which the manganese ions absorbed red and green wavelengths of light and reflected only blue.

When cooled, the manganese-containing oxide remained in this alternate structure. The other ingredients — white yttrium oxide and pale yellow indium oxide — are also required to stabilize the blue crystal. When one was left out, no blue color appeared.

The pigments have proven safe and durable, Dr. Subramanian said, although not cheap because of the cost of the indium. The researchers are trying to replace the indium oxide with cheaper oxides like aluminum oxide, which possesses similar properties.

The findings appear in the Journal of the American Chemical Society.

 

Kenneth Chang, New York Times

___________

Full article and photo: http://www.nytimes.com/2009/11/24/science/24obpigment.html

Water Found on Moon, Scientists Say

Moon water

This artist’s rendering released by NASA shows the Lunar Crater Observation and Sensing Satellite as it crashed into the moon to test for the presence of water last month.

There is water on the Moon, scientists stated unequivocally on Friday.

“Indeed yes, we found water,” Anthony Colaprete, the principal investigator for NASA’s Lunar Crater Observation and Sensing Satellite, said in a news conference. “And we didn’t find just a little bit. We found a significant amount.”

The confirmation of scientists’ suspicions is welcome news to explorers who might set up home on the lunar surface and to scientists who hope that the water, in the form of ice accumulated over billions of years, holds a record of the solar system’s history.

The satellite, known as Lcross (pronounced L-cross), crashed into a crater near the Moon’s south pole a month ago. The 5,600-miles-per-hour impact carved out a hole 60 to 100 feet wide and kicked up at least 26 gallons of water.

“We got more than just a whiff,” Peter H. Schultz, a professor of geological sciences at Brown University and a co-investigator of the mission, said in a telephone interview. “We practically tasted it with the impact.”

For more than a decade, planetary scientists have seen tantalizing hints of water ice at the bottom of these cold craters where the sun never shines. The Lcross mission, intended to look for water, was made up of two pieces of an empty rocket stage to slam into the floor of Cabeus, a crater 60 miles wide and 2 miles deep, and a small spacecraft to measure what was kicked up.

For space enthusiasts who stayed up, or woke up early, to watch the impact on Oct. 9, the event was anticlimactic, even disappointing, as they failed to see the anticipated debris plume. Even some high-powered telescopes on Earth like the Palomar Observatory in California did not see anything.

The National Aeronautics and Space Administration later said that Lcross did indeed photograph a plume but that the live video stream was not properly attuned to pick out the details.

The water findings came through an analysis of the slight shifts in color after the impact, showing telltale signs of water molecules that had absorbed specific wavelengths of light. “We got good fits,” Dr. Colaprete said. “It was a unique fit.”

The scientists also saw colors of ultraviolet light associated with molecules of hydroxyl, consisting of one hydrogen and one oxygen, presumably water molecules that had been broken apart by the impact and then glowed like neon signs.

In addition, there were squiggles in the data that indicated other molecules, possibly carbon dioxide, sulfur dioxide, methane or more complex carbon-based molecules. “All of those are possibilities,” Dr. Colaprete said, “but we really need to do the work to see which ones work best.”

Remaining in perpetual darkness like other craters near the lunar poles, the bottom of Cabeus is a frigid minus 365 degrees Fahrenheit, cold enough that anything at the bottom of such craters never leaves. These craters are “really like the dusty attic of the solar system,” said Michael Wargo, the chief lunar scientist at NASA headquarters.

The Moon was once thought to be dry. Then came hints of ice in the polar craters. In September, scientists reported an unexpected finding that most of the surface, not just the polar regions, might be covered with a thin veneer of water.

The deposits in the lunar craters may be as informative about the Moon as ice cores from Earth’s polar regions are about the planet’s past climates. Scientists want to know the source and history of whatever water they find. It could have come from the impacts of comets, for instance, or from within the Moon.

“Now that we know that water is there, thanks to Lcross, we can begin in earnest to go to this next set of questions,” said Gregory T. Delory of the University of California, Berkeley.

Dr. Delory said the findings of Lcross and other spacecraft were “painting a really surprising new picture of the Moon; rather than a dead and unchanging world, it could be in fact a very dynamic and interesting one.”

Lunar ice, if bountiful, not only give future settlers something to drink, but could also be broken apart into oxygen and hydrogen. Both are valuable as rocket fuel, and the oxygen would also give astronauts air to breathe.

NASA’s current exploration plans call for a return of astronauts to the Moon by 2020, for the first visit since 1972. But a panel appointed in May recently concluded that trimmings of the agency’s budget made that goal impossible. One option presented to the Obama administration was to bypass Moon landings for now and focus on long-duration missions in deep space.

Even though the signs of water were clear and definitive, the Moon is far from wet. The Cabeus soil could still turn out to be drier than that in deserts on Earth. But Dr. Colaprete also said that he expected that the 26 gallons were a lower limit and that it was too early to estimate the concentration of water in the soil.

The scientists also do not know whether the information from Cabeus is representative of the state of other lunar craters.

Kenneth Chang, New York Times

__________

Full article and photo: http://www.nytimes.com/2009/11/14/science/14moon.html

Sniff test to preserve old books

Old books (ACS)

The test could help to preserve treasured books and documents

The key to preserving the old, degrading paper of treasured, ageing books is contained in the smell of their pages, say scientists.

Researchers report in the journal Analytical Chemistry that a new “sniff test” can measure degradation of old books and historical documents.

The test picks up and identifies the chemicals that the pages release as they degrade.

This could help libraries and museums preserve a range of precious books.

The test is based on detecting the levels of volatile organic compounds.

These are released by paper as it ages and produce the familiar “old book smell”.

The international research team, led by Matija Strlic from University College London’s Centre for Sustainable Heritage, describes that smell as “a combination of grassy notes with a tang of acids and a hint of vanilla over an underlying mustiness”.

“This unmistakable smell is as much part of the book as its contents,” they wrote in the journal article.

Dr Strlic told BBC News that the idea for new test came from observing museum conservators as they worked.

“I often noticed that conservators smelled paper during their assessment,” he recalled.

“I thought, if there was a way we could smell paper and tell how degraded it is from the compounds it emits, that would be great.”

The test does just that. It pinpoints ingredients contained within the blend of volatile compounds emanating from the paper.

That mixture, the researchers say, “is dependent on the original composition of the… paper substrate, applied media, and binding”.

Their new method is called “material degradomics”. The scientists are able to use it to find what chemicals books release, without damaging the paper.

It involves an analytical technique called gas chromatography-mass spectrometry. This simply “sniffs” the paper and separates out the different compounds.

Chemical fingerprint

The team tested 72 historical papers from the 19th and 20th centuries – some of which they bought on eBay – and identified 15 compounds that were “reliable markers” of degradation.

“The aroma is made up of hundreds of compounds, but these 15 contain most of the information that we need,” said Dr Strlic.

Measuring the levels of these individual compounds made it possible to produce a “fingerprint” of each document’s condition.

Such a thorough chemical understanding of the state of a book will help museums and libraries to identify the books and documents most in need of protection from further degradation.

The information could also be used to fine-tune preservation techniques.

The method, the researchers say, is not exclusively applicable to books, and could be used on other historical artefacts.

__________

Full article and photo: http://news.bbc.co.uk/2/hi/science/nature/8355888.stm

CERN Collider Adds New Punchlines to Growing Collection

Particle Physics Slapstick

100908BEX401

The Large Hadron Collider has so far produced a number of odd news stories, but little else.

The list of problems encountered by the Large Hadron Collider, a super-sized particle accelerator in Switzerland, is long and becoming longer. It ranges from French bread to French terrorists, and from black holes to time travel, and makes for increasingly entertaining reading.

One can almost hear the tone of surprise in Monday’s press release from the enormous particle accelerator at the European Organization for Nuclear Research, known as CERN for short. “Particles Have Gone Half Way Round the LHC,” reads the headline, referring to the Large Hadron Collider.

At first glance, it seems odd that the people at the LHC would find such a partial particle peregrination worthy of triumphalism, no matter how tepid. But given that the launch of the ambitious experiments slated for the multi-billion euro science kit is now over a year behind schedule, the LHC has been starved of anything positive to say at all.

Indeed, the periodic hiccups on the way to functionality have become something of a running joke in the media coverage of CERN. This week has seen two new punchlines added to the list. On Monday, CERN announced that a bird carrying a hunk of French bread accidentally dropped its snack on an external power generator last week, creating a short-circuit that briefly shut down the accelerator’s all-important cooling system.

Ties to al-Qaida

And in Bern, the Swiss Federal Prosecutor’s Office confirmed on Monday that it has opened an investigation into a French CERN physicist suspected of having ties to al-Qaida. The Swiss case comes in addition to preliminary charges already filed in France against the 32-year-old Frenchman of Algerian origin, whose identity has not been revealed.

French officials have said that the suspect has admitted to having communicated with al-Qaida regarding potential terror attacks.

But if he were planning an attack on the particle accelerator, he perhaps need not have bothered. Scientists hope that the Large Hadron Collider will provide insights into the behavior of quantum particles, many times smaller than the protons, neutrons and electrons which physicists once thought were the tiniest components of all matter. Some hope to find the as-yet theoretical particle known as Higgs boson — also referred to as the “God particle” because it is presumed to have been present at the Big Bang. Others are looking for verification as to the veracity of string theory, which posits the existence of additional dimensions beyond the four currently known.

Hopes were high for the LHC, the most powerful particle accelerator ever built. Fully 27 kilometers (17 miles) in circumference, the ultra-complex machine is designed to speed up sub-atomic particles to 99.9999991 percent of the speed of light. But problems started almost immediately after it was fired up in September 2008, when an electrical failure resulted in damage that has taken a year to fix.

Sci-Fi Time Travel

Indeed, progress has been so slow that some mathematicians have even posited that the future is sabotaging the present in order to prevent the creation of the God particle. Theoretical physicists think the Higgs boson is responsible for turning energy into mass, thus making the particle responsible for creating all the mass in the universe.

“It must be our prediction that all Higgs producing machines shall have bad luck,” Danish physicist Dr. Holger Bech Nielsen — who, together with his Japanese colleague Dr. Masao Ninomiya, created the bizarre, sci-fi time-travel theory — told the New York Times last month.

CERN scientists insist that the machine is only experiencing “teething problems” and that, after this week’s bird incident, ongoing repairs to the accelerator were delayed by only a few hours. Proton collisions are now set to begin prior to Christmas.

In contrast to last year, however, few now fear that the LHC might cause a black hole to open up and swallow the world, as some had theorized in 2008. After all, the energy achieved by speedy protons will be much lower than originally intended. Rather than the 7 trillion electron volts initially hoped for, the collisions this year will be at a measly 1.1 trillion electron volts, barely higher than at CERN’s rival accelerator, the Tevatron outside Chicago.

__________

Full article and photo: http://www.spiegel.de/international/world/0,1518,660500,00.html

Setting Sail Into Space, Propelled by Sunshine

sunlight 1

DEEP-SPACE TRAVEL If the launching of LightSail-1 goes off according to plan next year, humans may soon be solar-sailing, as shown in this illustration.

Peter Pan would be so happy.

About a year from now, if all goes well, a box about the size of a loaf of bread will pop out of a rocket some 500 miles above the Earth. There in the vacuum it will unfurl four triangular sails as shiny as moonlight and only barely more substantial. Then it will slowly rise on a sunbeam and move across the stars.

LightSail-1, as it is dubbed, will not make it to Neverland. At best the device will sail a few hours and gain a few miles in altitude. But those hours will mark a milestone for a dream that is almost as old as the rocket age itself, and as romantic: to navigate the cosmos on winds of starlight the way sailors for thousands of years have navigated the ocean on the winds of the Earth.

“Sailing on light is the only technology that can someday take us to the stars,” said Louis Friedman, director of the Planetary Society, the worldwide organization of space enthusiasts.

Even as the National Aeronautics and Space Administration continues to flounder in a search for its future, Dr. Friedman announced Monday that the Planetary Society, with help from an anonymous donor, would be taking baby steps toward a future worthy of science fiction. Over the next three years, the society will build and fly a series of solar-sail spacecraft dubbed LightSails, first in orbit around the Earth and eventually into deeper space.

The voyages are an outgrowth of a long collaboration between the society and Cosmos Studios of Ithaca, N.Y., headed by Ann Druyan, a film producer and widow of the late astronomer and author Carl Sagan.

Sagan was a founder of the Planetary Society, in 1980, with Dr. Friedman and Bruce Murray, then director of the Jet Propulsion Laboratory. The announcement was made at the Hart Senate Office Building in Washington at a celebration of what would have been Sagan’s 75th birthday. He died in 1996.

sunlight 2

Ms. Druyan, who has been chief fund-raiser for the society’s sailing projects, called the space sail “a Taj Mahal” for Sagan, who loved the notion and had embraced it as a symbol for the wise use of technology.

There is a long line of visionaries, stretching back to the Russian rocket pioneers Konstantin Tsiolkovsky and Fridrich Tsander and the author Arthur C. Clarke, who have supported this idea. “Sails are just a marvelous way of getting around the universe,” said Freeman Dyson, of the Institute for Advanced Study in Princeton, N.J., and a longtime student of the future, “but it takes a long time to imagine them becoming practical.”

The solar sail receives its driving force from the simple fact that light carries not just energy but also momentum — a story told by every comet tail, which consists of dust blown by sunlight from a comet’s core. The force on a solar sail is gentle, if not feeble, but unlike a rocket, which fires for a few minutes at most, it is constant. Over days and years a big enough sail, say a mile on a side, could reach speeds of hundreds of thousands of miles an hour, fast enough to traverse the solar system in 5 years. Riding the beam from a powerful laser, a sail could even make the journey to another star system in 100 years, that is to say, a human lifespan.

Whether humans could ever take these trips depends on just how starry-eyed one’s view of the future is.

Dr. Friedman said it would take too long and involve too much exposure to radiation to sail humans to a place like Mars. He said the only passengers on an interstellar voyage — even after 200 years of additional technological development — were likely to be robots or perhaps our genomes encoded on a chip, a consequence of the need to keep the craft light, like a giant cosmic kite.

In principle, a solar sail can do anything a regular sail can do, like tacking. Unlike other spacecraft, it can act as an antigravity machine, using solar pressure to balance the Sun’s gravity and thus hover anyplace in space.

And, of course, it does not have to carry tons of rocket fuel. As the writer and folk singer Jonathan Eberhart wrote in his song “A Solar Privateer”:

No cold LOX tanks or reactor banks, just Mylar by the mile.

No stormy blast to rattle the mast, a sober wind and true.

Just haul and tack and ball the jack like the waterlubbers do.

Those are visions for the long haul. “Think centuries or millennia, not decades,” said Dr. Dyson, who also said he approved of the Planetary Society project.

“We ought to be doing things that are romantic,” he said, adding that nobody knew yet how to build sails big and thin enough for serious travel. “You have to get equipment for unrolling them and stretching them — a big piece of engineering that’s not been done. But the joy of technology is that it’s unpredictable.”

At one time or another, many of NASA’s laboratories have studied solar sails. Scientists at the Jet Propulsion Laboratory even once investigated sending a solar sail to rendezvous and ride along with Halley’s Comet during its pass in 1986.

But efforts by the agency have dried up as it searches for dollars to keep the human spaceflight program going, said Donna Shirley, a retired J.P.L. engineer and former chairwoman of the NASA Institute for Advanced Concepts. Dr. Shirley said that the solar sail was feasible and that the only question was, “Do you want to spend some money?” Until the technology had been demonstrated, she said, no one would use it.

Japan continues to have a program, and test solar sails have been deployed from satellites or rockets, but no one has ever gotten as far as trying to sail them anywhere.

Dr. Friedman, who cut his teeth on the Halley’s Comet proposal, has long sought to weigh anchor in space. An effort by the Planetary Society and the Russian Academy of Sciences to launch a sail about 100 feet on a side, known as Cosmos-1, from a Russian missile submarine in June 2005 ended with what Ms. Druyan called “our beautiful spacecraft” at the bottom of the Barents Sea.

Ms. Druyan and Dr. Friedman were beating the bushes for money for a Cosmos-2, when NASA asked if the society wanted to take over a smaller project known as the Nanosail. These are only 18 feet on a side and designed to increase atmospheric drag and thus help satellites out of orbit.

And so LightSail was born. Its sail, adapted from the Nanosail project, is made of aluminized Mylar about one-quarter the thickness of a trash bag. The body of the spacecraft will consist of three miniature satellites known as CubeSats, four inches on a side, which were first developed by students at Stanford and now can be bought on the Web, among other places. One of the cubes will hold electronics and the other two will carry folded-up sails, Dr. Friedman said.

Assembled like blocks, the whole thing weighs less than five kilograms, or about 11 pounds. “The hardware is the smallest part,” Dr. Friedman said. “You can’t spend a lot on a five-kilogram system.”

The next break came when Dr. Friedman was talking about the LightSail to a group of potential donors. A man — “a very modest dear person,” in Ms. Druyan’s words — asked about the cost of the missions and then committed to paying for two of them, and perhaps a third, if all went well.

After the talk, the man, who does not wish his identity to be known, according to the society, came up and asked for the society’s bank routing number. Within days the money was in its bank account. The LightSail missions will be spread about a year apart, starting around the end of 2010, with the exact timing depending on what rockets are available. The idea, Dr. Friedman said, is to piggyback on the launching of a regular satellite. Various American and Russian rockets are all possibilities for a ride, he said.

Dr. Friedman said the first flight, LightSail-1, would be a success if the sail could be controlled for even a small part of an orbit and it showed any sign of being accelerated by sunlight. “For the first flight, anything measurable is great,” he said. In addition there will be an outrigger camera to capture what Ms. Druyan called “the Kitty Hawk moment.”

The next flight will feature a larger sail and will last several days, building up enough velocity to raise its orbit by tens or hundreds of miles, Dr. Friedman said.

For the third flight, Dr. Friedman and his colleagues intend to set sail out of Earth orbit with a package of scientific instruments to monitor the output of the Sun and provide early warning of magnetic storms that can disrupt power grids and even damage spacecraft. The plan is to set up camp at a point where the gravity of the Earth and Sun balance each other — called L1, about 900,000 miles from the Earth — a popular place for conventional scientific satellites. That, he acknowledges, will require a small rocket, like the attitude control jets on the shuttle, to move out of Earth orbit, perhaps frustrating to a purist.

But then again, most sailboats do have a motor for tooling around in the harbor, which is how Dr. Friedman describes being in Earth orbit. Because the direction of the Sun keeps changing, he said, you keep “tacking around in the harbor when what you want to do is get out on the ocean.”

The ocean, he said, awaits.

Dennis Overbye, New York Times

__________

Full article and photos: http://www.nytimes.com/2009/11/10/science/space/10solar.html?ref=science

Tweak Gravity: What If There Is No Dark Matter?

Modifications to the theory of gravity could account for observational discrepancies, but not without introducing other complications.

Theorists and observational astronomers are hot on the trail of dark matter, the invisible material thought to account for puzzling mass disparities in large-scale astronomical structures. For instance, galaxies and galactic clusters behave as if they were far more massive than would be expected if they comprised only atoms and molecules, spinning faster than their observable mass would explain. What is more, the very presence of assemblages such as our Milky Way Galaxy speaks to the influence of more mass than we can see. If the mass of the universe were confined to atoms, the clumping of matter that allowed galaxies to take shape would never have transpired.

Dark matter was theorized into existence to account for the missing mass. The prevailing view holds that dark matter contributes five times as much to the mass of the universe as ordinary matter does.

But some researchers have taken to approaching the problem from the other direction: What if the discrepancy arises from a flaw in our theory of gravity rather than from some provider of mass that we cannot see? In the 1980s physicist Mordehai Milgrom of the Weizmann Institute of Science in Rehovot, Israel, proposed a modification to Newtonian dynamics that would explain many of the observational discrepancies without requiring significant mass to be hidden away in dark matter. But it fell short of describing all celestial objects, and to incorporate the full span of gravitational interactions, a modification to Albert Einstein’s theory of general relativity is needed.

A review article in the November 6 Science checks in on the status of these modified-gravity theories, including a proposal put forth by physicist Jacob Bekenstein of The Hebrew University of Jerusalem in 2004. Pedro Ferreira, a University of Oxford cosmologist and one of the review paper’s co-authors, says that there is good news and bad news for proponents of such models.

The bad news is that in order for modified versions of general relativity to work, some sort of unseen—or “dark”—presence must be in play, which in some cases can look a lot like dark matter. “If you try and build a consistent, relativistic theory that gives you modified Newtonian dynamics, you have no choice but to introduce extra stuff,” Ferreira says. “I don’t think it will be described by particles, in the way that dark matter is described—it may be described in a more wavelike form or a more fieldlike form.”

In other words, a theory of gravity can do away with dark matter but cannot describe the universe simply as the product of a tweaked Einsteinian gravity acting on the mass we can see. “The old paradigm where all you were doing was modifying gravity simply doesn’t hold,” Ferreira says. “You modify gravity, but through the backdoor you introduce extra fields, which means that the distinction between dark matter and modified gravity isn’t as clear as people thought before.”

The good news? According to Ferreira, “all is not lost.” Observational campaigns now in the works, such as the Joint Dark Energy Mission planned by NASA and the U.S. Department of Energy as well as an international radio telescope project known as Square Kilometer Array, should allow astronomers and cosmologists to test competing worldviews in the next decade or so.

By cross-correlating large-scale surveys of galaxies and observations of how galaxies distort background light in a relativistic process known as weak lensing, Ferreira says, the true nature of mass and the forces acting on it can be tested. “Whether gravity is modified or not will greatly affect the result,” he predicts.

Although Ferreira works on theories of modified gravity, he is careful to note that the new paper does not advocate for those theories’ correctness over the prevailing model. In his personal view, Ferreira says, “by far the simplest proposal is normal gravity plus dark matter.”

John Matson, Scientific American

__________

Full article: http://www.scientificamerican.com/article.cfm?id=dark-matter-modified-gravity&sc=physics_20091106

African Desert Rift Confirmed As New Ocean In The Making

newocean

New research confirms that the volcanic processes at work beneath the Ethiopian rift are nearly identical to those at the bottom of the world’s oceans, and the rift is indeed likely the beginning of a new sea.

In 2005, a gigantic, 35-mile-long rift broke open the desert ground in Ethiopia. At the time, some geologists believed the rift was the beginning of a new ocean as two parts of the African continent pulled apart, but the claim was controversial.

Now, scientists from several countries have confirmed that the volcanic processes at work beneath the Ethiopian rift are nearly identical to those at the bottom of the world’s oceans, and the rift is indeed likely the beginning of a new sea.

The new study, published in the latest issue of Geophysical Research Letters, suggests that the highly active volcanic boundaries along the edges of tectonic ocean plates may suddenly break apart in large sections, instead of little by little as has been predominantly believed. In addition, such sudden large-scale events on land pose a much more serious hazard to populations living near the rift than would several smaller events, says Cindy Ebinger, professor of earth and environmental sciences at the University of Rochester and co-author of the study.

“This work is a breakthrough in our understanding of continental rifting leading to the creation of new ocean basins,” says Ken Macdonald, professor emeritus in the Department of Earth Science at the University of California, Santa Barbara, and who is not affiliated with the research. “For the first time they demonstrate that activity on one rift segment can trigger a major episode of magma injection and associated deformation on a neighboring segment. Careful study of the 2005 mega-dike intrusion and its aftermath will continue to provide extraordinary opportunities for learning about continental rifts and mid-ocean ridges.”

“The whole point of this study is to learn whether what is happening in Ethiopia is like what is happening at the bottom of the ocean where it’s almost impossible for us to go,” says Ebinger. “We knew that if we could establish that, then Ethiopia would essentially be a unique and superb ocean-ridge laboratory for us. Because of the unprecedented cross-border collaboration behind this research, we now know that the answer is yes, it is analogous.”

Atalay Ayele, professor at the Addis Ababa University in Ethiopia, led the investigation, painstakingly gathering seismic data surrounding the 2005 event that led to the giant rift opening more than 20 feet in width in just days. Along with the seismic information from Ethiopia, Ayele combined data from neighboring Eritrea with the help of Ghebrebrhan Ogubazghi, professor at the Eritrea Institute of Technology, and from Yemen with the help of Jamal Sholan of the National Yemen Seismological Observatory Center. The map he drew of when and where earthquakes happened in the region fit tremendously well with the more detailed analyses Ebinger has conducted in more recent years.

Ayele’s reconstruction of events showed that the rift did not open in a series of small earthquakes over an extended period of time, but tore open along its entire 35-mile length in just days. A volcano called Dabbahu at the northern end of the rift erupted first, then magma pushed up through the middle of the rift area and began “unzipping” the rift in both directions, says Ebinger.

Since the 2005 event, Ebinger and her colleagues have installed seismometers and measured 12 similar — though dramatically less intense — events.

“We know that seafloor ridges are created by a similar intrusion of magma into a rift, but we never knew that a huge length of the ridge could break open at once like this,” says Ebinger. She explains that since the areas where the seafloor is spreading are almost always situated under miles of ocean, it’s nearly impossible to monitor more than a small section of the ridge at once so there’s no way for geologists to know how much of the ridge may break open and spread at any one time. “Seafloor ridges are made up of sections, each of which can be hundreds of miles long. Because of this study, we now know that each one of those segments can tear open in a just a few days.”

Ebinger and her colleagues are continuing to monitor the area in Ethiopia to learn more about how the magma system beneath the rift evolves as the rift continues to grow.

Additional authors of the study include Derek Keir, Tim Wright, and Graham Stuart, professors of earth and environment at the University of Leeds, U.K.; Roger Buck, professor at the Earth Institute at Columbia University, N.Y.; and Eric Jacques, professor at the Institute de Physique du Globe de Paris, France.

__________

Full article and photo: http://www.sciencedaily.com/releases/2009/11/091102172037.htm