Cold, Dead Stars Could Help Limit Dark Matter

Hunting for cold stellar corpses near the center of the galaxy or in star clusters could put new limits on the properties of dark matter.

“You can exclude a big class of theories that the experiments cannot exclude just by observing the temperature of a neutron star,” said physicist Chris Kouvaris of the University of Southern Denmark, lead author of a paper in the Sept. 28 Physical Review D. “Maybe by observations, which come cheaper than expensive experiments, we might get some clues about dark matter.”

Dark matter is the irritatingly invisible stuff that makes up some 23 percent of the universe, but makes itself known only through its gravitational tug on ordinary matter.

There are several competing theories about what dark matter actually is, but one of the most widely pursued is a hypothetical weakly interacting massive particle (WIMP). Physicists in search of WIMPs have placed experimental detectors deep underground in mines and mountains, and are waiting for a dark matter particle to hit them.

Others have proposed looking for the buildup of dark matter in stars like the sun or white dwarfs. But both subterranean and stellar-detection strategies will light up only for WIMPs larger than a certain size. That size is miniscule — about a trillionth of a quadrillionth of a square centimeter — but dark matter particles could be smaller still.

One way to rule out such diminutive particles is to look to neutron stars, suggest Kouvaris and co-author Peter Tinyakov of the Université Libre de Bruxelles in Belgium.

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Inside the Soviets’ Secret Failed Moon Program

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Lunar Craft antenna dish.

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By Matt Hardigree, Jalopnik

The Soviet lunar program was covered up, forgotten after failing to put a man on the moon. These rare photos from a lab inside the Moscow Aviation Institute show a junkyard of rarely-seen spacecraft, including a never-to-be-used Soviet lunar lander.

Soviet scientists were well ahead of their American counterparts in moon exploration before President John F. Kennedy pronounced the U.S. would put a man there first. The Soviets had already landed the probe Luna 2 on the surface of the moon in 1959 and had an orbiting satellite in 1966.

The Soviets developed a similar multi-step approach to NASA, involving a module used to orbit the moon and one for landing. Their version was decidedly less complex and lighter to account for inferior rockets. These photos show the LK “Lunar Craft” lander, which has a similar pod-over-landing gear structure but numerous key differences.

All the activities done by two astronauts is done by one. To make the craft lighter, the LK only fits the one cosmonaut, who was supposed to peer through a tiny window on the side of the craft to land it. After landing the vehicle the pod separates from the landing gear, as with the Apollo Lunar Module, but uses the same engine for landing as it does for take off as another weight savings. Continue Reading “Inside the Soviets’ Secret Failed Moon Program” »

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Antarctic Ice Sheet Preserves Invisible Mountain Range

Buried deep beneath East Antarctica’s ice sheet, the Gamburtsev Mountains are the world’s most invisible range. New research suggests that overlying ice like that hiding them from view today could have preserved their rugged topography for the past 300 million years.

sciencenewsThe work bolsters the counterintuitive notion that glaciers, rather than just carving down young peaks into eroded hills like a buzzsaw, could sometimes protect high jagged terrain.

“It’s feasible for topography to be preserved,” says Stephen Cox, a graduate student at Caltech and coauthor of a paper scheduled to appear in Geophysical Research Letters. A supercold cap of ice could have allowed the ancient Gamburtsevs to look like the Alps instead of the highly eroded Appalachians.

Russian scientists first identified the Gamburtsevs in 1958 as part of a survey during the International Geophysical Year, and geologists have been puzzled ever since about how the range came to be. The mountains are in a stable part of the continent that hasn’t seen much tectonic activity — usually the way mountains are born — in more than 500 million years. “The Gamburtsevs are either really old, or some big part of the tectonic puzzle is missing,” says Cox.

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Large Hadron Collider Starts Edging Out Rivals

The Large Hadron Collider has made its first steps beyond the standard model of particle physics. With just four months of data gathered, the monster collider has already edged past the Tevatron, its particle-smashing rival.

“The surprising thing for me is how quickly the experiments started to top the Tevatron data,” commented theoretical particle physicist Ulrich Baur of the State University of New York at Buffalo, who is not on the LHC team but whose theoretical predictions laid the groundwork for new research done there. “You really see the power of the Large Hadron Collider coming in here.”

The contest concerns an exotic hypothetical particle called an excited quark. In the standard model — the theoretical picture of what physicists think matter is made of — atomic nuclei are broken down into protons and neutrons, which are broken down further into fundamental particles called quarks and gluons. Electrons, which orbit atomic nuclei and give atoms their distinctive characters, are also considered fundamental particles.

Under the standard model, that’s as far as it goes. You can’t break a quark or an electron into anything smaller.

“But it turns out the model, we know it’s not the complete picture,” said particle physicist Andreas Warburton of McGill University in Montreal. Particle physicists turn to enormous colliders to refine the model and search for particles that break it.

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Love Makes You Increasingly Ignorant of Your Partner

BASEL, Switzerland — Long-lasting marriages may thrive on love, compromise and increasing ignorance about one another. Couples married for an average of 40 years know less about one another’s food, movie and kitchen-design preferences than do partners who have been married or in committed relationships for a year or two, a new study finds.

sciencenewsTwo University of Basel psychologists, Benjamin Scheibehenne and Jutta Mata, working with psychologist Peter Todd of Indiana University in Bloomington, observed this counterintuitive pattern in 38 young couples aged 19 to 32, and 20 older couples aged 62 to 78. The greatest gap in partner knowledge was in predicting food preferences, an area with particular relevance to daily life, the scientists report in a paper scheduled to appear in the Journal of Consumer Psychology.

“That wasn’t what we expected to find, but this evidence lends support to a hypothesis that accuracy in predicting each other’s preferences decreases over the course of a relationship despite greater time and opportunity to learn about each other’s likes and dislikes,” Todd said October 13 during a visit to the University of Basel.

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How to Make a White Hole in Your Kitchen Sink

That ring of water in your kitchen sink is actually a model white hole. For the first time, scientists have shown experimentally that liquid flowing from a tap embodies the same physics as the time-reversed equivalent of black holes.

When a stream of tap water hits the flat surface of the sink, it spreads out into a thin disc bounded by a raised lip, called the hydraulic jump. Physicists’ puzzlement with this jump dates back to Lord Rayleigh in 1914. More recently, physicists have suggested that, if the water waves inside the disc move faster than the waves outside, the jump could serve as an analogue event horizon. Water can approach the ring from outside, but it can’t get in.

“The jump would therefore constitute a one-directional membrane or white hole,” wrote physicist Gil Jannes and Germain Rousseaux of the University of Nice Sophia Antipolis in France and colleagues in a study on ArXiv Oct. 8. “Surface waves outside the jump cannot penetrate in the inner region; they are trapped outside in precisely the same sense as light is trapped inside a black hole.”

The analogy is not just surface-deep. The math describing both situations is exactly equivalent. But so far, no one had been able to prove experimentally that what’s going on in the kitchen sink really represents a white hole.

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Human Genome Still Chock-Full of Mysteries

BOSTON — No one really knows all the genetic parts needed to make a human being.

Exactly how many genes make up the human genome remains a mystery, even though scientists announced the completion of the Human Genome Project a decade ago. The project to decipher the genetic blueprint of humans was supposed to reveal all of the protein-producing genes needed to build a human body.

sciencenews“Not only do we not know what all the genes are, we don’t even know how many there are,” Steven Salzberg of the University of Maryland in College Park said October 11 during a keynote address at the Beyond the Genome conference, held in Boston. Most estimates place the human gene count in the neighborhood of 22,000 genes, which falls between the number of genes in a chicken and the number in a grape.

Grape plants have 30,434 genes, by the latest count. Chickens have 16,736 genes, a number Salzberg said will likely grow as scientists put the finishing touches on the chicken genome. As in humans, the gene totals for each species are not as precise as they seem and are subject to revision.

The most accurate estimate of the human gene count is the RefSeq database maintained by the U.S. National Institutes of Health, Salzberg said. He laid out arguments for favoring this estimate, such as its inclusion of all confirmed genes to date, in a paper published in May in Genome Biology. By the RefSeq count, humans have 22,333 genes. But another government database lists 38,621 human genes. And a different project called Gencode currently recognizes 21,671.

Such disparate numbers stem from the fact that genes comprise only about 1 percent of the 3 billion As, Ts, Gs and Cs that make up the human genetic instruction book. And the genes aren’t conveniently laid out as single, continuous stretches of genetic code. Instead, human genes are found in protein-encoding pieces called exons, interspersed with stretches of DNA that don’t make protein. These spacers are called introns.

To make matters worse, each exon in a gene codes for only a portion of a protein. Cells can mix and match different combinations of exons to make various proteins.

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Implants May Help Heroin Addiction

People addicted to heroin or prescription opiates might have a hands-free device for getting through the rigors of drug withdrawal. The medication buprenorphine implanted under the skin and released over 24 weeks can ease drug cravings and helps some patients stay clean, researchers report in the Oct. 13 Journal of the American Medical Association.

sciencenewsBuprenorphine is a semisynthetic opioid compound prescribed for pain relief and for addiction withdrawal. Buprenorphine works something like methadone, a synthetic opioid developed in the 1930s. Both drugs are prescribed for withdrawal from addiction to heroin or prescription pain relievers such oxycodone, Dilaudid, codeine and Vicodin.

But buprenorphine in tablet form can be misused by patients who crush the pills, liquefy them and inject them for a stronger effect.

To get around such abuse and to ensure that a person is getting a standardized dose of the drug, researchers devised the implants — polymer compounds composed of ethylene vinyl acetate and buprenorphine — that slowly release the drug into the body over 24 weeks. They recruited 163 adults diagnosed with opioid dependence and randomly assigned 108 to get the implants and 55 to receive placebo implants. The study’s subjects included users of heroin or prescription opioids. All participants received drug counseling during the trial and submitted regular urine samples.

People in either group could request additional doses of buprenorphine as under-the-tongue tablets if they felt their treatment was insufficient to control cravings. Nearly 60 percent of those assigned to buprenorphine requested the extra tablets during the first 16 weeks, as did more than 90 percent of those who had placebo implants. Even so, 37 percent of urine samples from people with buprenorphine implants tested clean for illicit opioids during the trial, compared with only 22 percent of those with placebo implants.

About two-thirds of people with a buprenorphine implant completed the study, compared with less than one-third of those who had a placebo implant.

“In the addiction field, there’s a pretty close relationship between sticking around in treatment — what we call retention — and how well you are doing,” says study coauthor Walter Ling, a psychiatrist at the UCLA School of Medicine.

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The Year’s Best Fossil Finds

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Fossils provide unparalleled peeks into Earth’s living history in the form of mineralized bones and shells, body imprints and even piles of poop. There always seems to be another twist and turn in evolution’s creations awaiting trowel-wielding scientists.

From dinosaur-eating snakes to shark-bitten piles of crocodile dung (seriously), dig up some of this year’s best finds with us in celebration of National Fossil Day.

Squashed Jurassic Spider

This almost perfectly preserved spider fossil from China (one of two) dates back 165 million years ago, to the middle Jurassic era.

Known as Eoplectreurys gertschi, the spiders are older than the only two other specimens known by around 120 million years and rival their detail, paleontologists said in February.

Spider fossils are tough to find because their soft bodies don’t preserve well. Thanks to fine volcanic ash, however, this spider was squashed without breaking up its delicate exoskeleton.

Image: Paul Selden

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Will there be a cheap solar cell that can compete with grid electricity?

Thoughts on a Smarter Planet is a special blogger series in partnership with leading IBM experts. Join the conversation as these experts discuss the innovations in science, business and systems like transportation that are helping build a Smarter Planet. About this program.


thoughtssmarterplanet_ibm_bugModern solar cells are based on a design and prototype that was reported by Bell Labs scientists in 1954. It made the front page of The New York Times, which predicted solar cells would eventually lead “to the realization of one of mankind’s most cherished dreams—the harnessing of the almost limitless energy of the sun for the uses of civilization.” How are we doing on that dream? Compared to the past, solar panel prices have plunged, but they contribute to less than 0.1% of the world’s electricity production because solar electricity still isn’t cheap enough to compete with grid electricity. There is certainly plenty of sunlight available to bring us close to this utopia. But are there any solar cell technologies that can meet this promise?

Let’s look at some numbers. The total power produced from solar panels installed worldwide is approximately about 30 Gigawatts. If we wanted 5% of the world’s electricity production to come from solar panels, installed capacities would need to increase more than 50 fold to about 2000 Gigawatts. In order to get there in say, 25 years, we need about 75-80 Gigawatts of capacity installed every year, on average. So not only do these new solar cells have to be cheap, the materials used need to be available in vast quantities.

More than 80% of solar cells today are made of silicon. There is certainly more than enough silicon available: it is the second most common element in the earth’s crust. Can silicon fulfill this need? Opinions are split. Since silicon does not absorb visible light too well, one needs thick, high quality layers that can be expensive. Based upon this, one group argues that the prospects for really cheap silicon solar cells are dim. Then there is the “don’t bet against silicon” school, who put their money on this old warhorse with the view that economies of scale, and the constant innovation that has always accompanied silicon technology, will eventually drive prices down.

The remaining 20% of the solar cells are built using thin-film technologies, based on materials that are deposited in the form of micron-thick films on glass substrates. The most popular of these right now is a technology based upon a two-element compound called CdTe (cadmium telluride). But cadmium is toxic (countries like Japan will not allow solar cells with Cd), and tellurium is one of the rarest elements in the world. Therefore it appears unlikely that CdTe can fuel the kind of growth desired for the future of solar.

The second thin-film technology gaining steam, with a handful of manufacturers already selling products, is CIGS, a 3- (or 4-) element compound called copper indium gallium selenide (the gallium is optional). It is more likely to hit higher efficiencies than CdTe, but the technology is not as far along the maturity curve as CdTe is. The concern with CIGS centers around the availability of the element indium. This is an element that is also sought after by the flat screen business and it is questionable whether there is enough indium available to sustain growth rates of more than 10-20 Gigawatts/year.

Which brings us to the question: is there a thin film solar material that we anticipate will be really cheap? That could be slapped onto cheap substrates in massive volumes, the way we make things like roofing and sheet metal? Right now the answer is no, though the desire for something like this has driven much research.

One promising thin-film material is a compound called CZTS (copper zinc tin sulfide). In terms of maturity it is far behind CIGS and CdTe: nobody manufactures a CZTS solar cell yet. But all of the elements in CZTS are plentiful and cheaply available, and efficiencies are rising. Researchers (primarily in Japan and Europe) worked on CZTS through the 1990s, and till last year the best power conversion efficiencies in this material stood at 6.8% (by comparison the best silicon solar cells, CIGS, and CdTe solar cells have efficiencies of about 25%, 20%, and 16%, respectively). Then in 2009, IBM researchers were able to increase the efficiency to around 9.7% by adding a bit of selenium and changing the deposition process. There is now worldwide research interest in this material.

What do the costs of solar panels need to be? Today an installed solar panel system costs anywhere from between $3/Watt to around $6/Watt (approximately) around the world. The US Department of Energy has an ambitious cost target of less than $1/Watt, which means that the panels themselves should be around $0.50/Watt. If we come within striking distance of these numbers, and these solar panels were available in plenty, the energy production landscape of the world would change.

Supratik Guha is the director of the Physical Sciences Department at IBM Research, where he’s responsible for IBM’s worldwide research strategy in the physical sciences.

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