time travel

The brightest stellar explosion ever recorded may be a long-sought new type of supernova, according to observations by NASA’s Chandra X-ray Observatory and ground-based optical telescopes. This discovery indicates that violent explosions of extremely massive stars were relatively common in the early universe, and that a similar explosion may be ready to go off in our own galaxy.
“This was a truly monstrous explosion, a hundred times more energetic than a typical supernova,” said Nathan Smith of the University of California at Berkeley, who led a team of astronomers from California and the University of Texas in Austin. “That means the star that exploded might have been as massive as a star can get, about 150 times that of our sun. We’ve never seen that before.”

Astronomers think many of the first generation of stars were this massive, and this new supernova may thus provide a rare glimpse of how the first stars died. It is unprecedented, however, to find such a massive star and witness its death. The discovery of the supernova, known as SN 2006gy, provides evidence that the death of such massive stars is fundamentally different from theoretical predictions.

“Of all exploding stars ever observed, this was the king,” said Alex Filippenko, leader of the ground-based observations at the Lick Observatory at Mt. Hamilton, Calif., and the Keck Observatory in Mauna Kea, Hawaii. “We were astonished to see how bright it got, and how long it lasted.”

The Chandra observation allowed the team to rule out the most likely alternative explanation for the supernova: that a white dwarf star with a mass only slightly higher than the sun exploded into a dense, hydrogen-rich environment. In that event, SN 2006gy should have been 1,000 times brighter in X-rays than what Chandra detected.

“This provides strong evidence that SN 2006gy was, in fact, the death of an extremely massive star,” said Dave Pooley of the University of California at Berkeley, who led the Chandra observations.

The star that produced SN 2006gy apparently expelled a large amount of mass prior to exploding. This large mass loss is similar to that seen from Eta Carinae, a massive star in our galaxy, raising suspicion that Eta Carinae may be poised to explode as a supernova. Although SN 2006gy is intrinsically the brightest supernova ever, it is in the galaxy NGC 1260, some 240 million light years away. However, Eta Carinae is only about 7,500 light years away in our own Milky Way galaxy.

“We don’t know for sure if Eta Carinae will explode soon, but we had better keep a close eye on it just in case,” said Mario Livio of the Space Telescope Science Institute in Baltimore, who was not involved in the research. “Eta Carinae’s explosion could be the best star-show in the history of modern civilization.”

Supernovas usually occur when massive stars exhaust their fuel and collapse under their own gravity. In the case of SN 2006gy, astronomers think that a very different effect may have triggered the explosion. Under some conditions, the core of a massive star produces so much gamma ray radiation that some of the energy from the radiation converts into particle and anti-particle pairs. The resulting drop in energy causes the star to collapse under its own huge gravity.

After this violent collapse, runaway thermonuclear reactions ensue and the star explodes, spewing the remains into space. The SN 2006gy data suggest that spectacular supernovas from the first stars - rather than completely collapsing to a black hole as theorized - may be more common than previously believed.

“In terms of the effect on the early universe, there’s a huge difference between these two possibilities,” said Smith. “One pollutes the galaxy with large quantities of newly made elements and the other locks them up forever in a black hole.”

The results from Smith and his colleagues will appear in The Astrophysical Journal. NASA’s Marshall Space Flight Center, Huntsville, Ala., manages the Chandra program for the agency’s Science Mission Directorate. The Smithsonian Astrophysical Observatory controls science and flight operations from the Chandra X-ray Center in Cambridge, Mass. Additional information and images are available at:

France became the first country to open its files on UFOs Thursday when the national space agency unveiled a website documenting more than 1,600 sightings spanning five decades.

The online archives, which will be updated as new cases are reported, catalogues in minute detail cases ranging from the easily dismissed to a handful that continue to perplex even hard-nosed scientists.

“It is a world first,” said Jacques Patenet, the aeronautical engineer who heads the office for the study of “non-identified aerospatial phenomena.”

Known as OVNIs in French, UFOs have always generated intense interest along with countless conspiracy theories about secretive government cover-ups of findings deemed too sensitive or alarming for public consumption.

“Cases such as the lady who reported seeing an object that looked like a flying roll of toilet paper” are clearly not worth investigating, said Patenet.

But many others involving multiple sightings — in at least one case involving thousands of people across France — and evidence such as burn marks and radar trackings showing flight patterns or accelerations that defy the laws of physics are taken very seriously.

A phalanx of beefy security guards formed a barrier in front of the space agency (CNES) headquarters where the announcement was made, “to screen out uninvited UFOlogists,” an official explained.

Of the 1,600 cases registered since 1954, nearly 25 percent are classified as “type D”, meaning that “despite good or very good data and credible witnesses, we are confronted with something we can’t explain,” Patenet said.

On January 8, 1981 outside the town of Trans-en-Provence in southern France, for example, a man working in a field reported hearing a strange whistling sound and seeing a saucer-like object about 2.5 meters (eight feet) in diameter land in his field about 50 meters (yards) away.

A dull-zinc grey, the saucer took off, he told police, almost immediately, leaving burn marks. Investigators took photos, and then collected and analyzed samples, and to this day no satisfactory explanation has been made.

The nearly 1,000 witness who said they saw flashing lights in the sky on November 5, 1990, by contrast, had simply seen a rocket fragment falling back into earth’s atmosphere.

Patenet’s answer to questions about evidence of life beyond Earth was sure to inflame the suspicions of those convinced the government is holding back: “We do not have the least proof that extra-terrestrials are behind the unexplained phenomena.”

But then he added: “Nor do we have the least proof that they aren’t.”

The CNES fields between 50 and 100 UFO reports ever year, usually written up by police. Of these, 10 percent are the object of on-site investigations, Patenet said.

Other countries collect data more or less systematically about unidentified flying objects, notably in Britain and in the United States, where information can be requested on a case-by-case basis under the Freedom of Information Act.

“But we decided to do it the other way around and made everything available to the public,” Patenet said.

The aim was to make it easier for scientists and other UFO buffs to access the data for research.

The website itself — which crashed host servers hours after it was unveiled due to heavy traffic — is extremely well organized and complete, even including scanned copies of police reports.

To visit the website: www.cnes-geipan.fr.

Tiny tremors and temblors recently discovered in fault zones from California to Japan are generated by slow-moving earthquakes that may foreshadow catastrophic seismic events, according to scientists at Stanford University and the University of Tokyo.

In a study published in the March 15 issue of the journal Nature, the research team focused on weak seismic signals known as “non-volcanic tremor” and “low-frequency earthquakes,” which seismologists say may be useful in forecasting the likelihood of potentially destructive mega-quakes of magnitude 8 or higher.

“Non-volcanic tremor is a weak shaking of the Earth that was discovered about five years ago in Japan,” said Gregory C. Beroza, professor of geophysics at Stanford and co-author of the Nature study. “It’s often accompanied by low-frequency earthquakes [LFEs]—small temblors of magnitude 1 or 2. Some people believe that LFEs and tremor are separate phenomena, but what we’ve shown in this paper is that they are actually the same thing. Tremor is simply a swarm of low-frequency earthquakes, but rather than happening quickly and impulsively like ordinary earthquakes, tremor shakes the Earth for hours, days or even weeks at a time.”
Destructive zones

To date, non-volcanic tremor and LFEs have been found primarily in subduction zones—seismically active faults where two tectonic plates meet and one plate constantly dives beneath the other. The most destructive earthquakes ever recorded have occurred in subduction zones, in places such as Chile, Japan, Alaska, Washington state and British Columbia. A recent example was the devastating 2004 earthquake near Sumatra, where a magnitude 9.2 temblor triggered powerful tsunamis that killed more than 200,000 people.

These violent mega-thrusts occur every 100 to 600 years, depending on the location. Recent studies suggest that giant quakes, which form at relatively shallow depths, are preceded by a series of much deeper events called slow (or silent) earthquakes, which displace the ground without shaking it. A slow earthquake can last days, months or years without being felt at the surface.

“In Japan, the deep section of the fault where slow earthquakes form is particularly significant, because it lies next to the shallower locked portion of the fault, where big quakes periodically strike,” Beroza said. “So each time a slow earthquake happens, it adds stress to the locked section and increases the likelihood of a magnitude 8 mega-thrust. Therefore, knowing when a slow earthquake has occurred could be useful in seismic hazard forecasting.”
Tremor trauma

But detecting slow quakes is a difficult task, he added. That’s one reason why seismologists were particularly excited by the recent discovery of non-volcanic tremor and LFEs in the subduction zone near Shikoku, Japan.

“Shikoku experiences a big earthquake every 100 years or so,” said Stanford graduate student David R. Shelly, lead author of the Nature study. “The last one happened in 1946, a magnitude 8.1 event that killed 1,330 people, and the next big one could strike in less than 40 years.”

Seismologists believe that since the violent 1946 fault rupture, Shikoku has experienced a series of slow earthquakes every six months or so. These events, which can last a few days or up to two weeks, cause an imperceptible shift in the Earth’s crust equivalent to the ground displacement produced by an ordinary earthquake of magnitude 6. Although harmless on the surface, these slow-slip events may be causing stress to accumulate in the adjacent locked section of the fault, scientists say.

Concerned about the hazards posed by earthquakes, the Japanese government installed a network of highly sensitive seismic instruments 10 years ago throughout the region. This advanced technology soon led to the discovery of slow earthquakes accompanied by LFEs and non-volcanic tremor in the Shikoku fault zone. Since then, some seismologists have proposed using LFEs and tremor to monitor slow earthquakes and assess seismic hazard. Others maintain that these weak signals are of little use in earthquake forecasting.

“Some people draw an analogy between non-volcanic and volcanic tremor,” Beroza said. “In volcanoes, fluids moving through shallow conduits cause the Earth to vibrate. But in earthquakes, waves are generated by slip on a fault. That’s the fundamental earthquake mechanism.”
Fluids vs. slip

Is non-volcanic tremor a vibration caused by fluids moving deep in the subduction zone, or is it a seismic signal produced when the fault slips during a silent earthquake? To find out, Shelly pored over hundreds of seismograms recorded in the Shikoku region between 2002 and 2005. His analysis revealed an almost perfect correlation between tremor events and low-frequency earthquakes.

“David found that the wiggles that tremor makes on seismographs matches the wiggles of the low-frequency earthquakes,” Beroza explained. “This demonstrates that tremor is actually a swarm of hundreds of thousands of LFEs, each of which is caused by slip on the deep part of the fault—the same mechanism by which regular earthquakes are generated but with a twist. The slip in deep tremor happens more slowly than in ordinary earthquakes.”

This insight may open new avenues of research for predicting earthquake hazards, Shelly said. “We now understand that tremor is generated directly by slip on the deep extension of the fault,” he said. “Combining this understanding with our new ability to locate tremor precisely in time and space, we can now track the details of how slip evolves during a weeklong slow-slip event. This could also improve our ability to predict the effects on the shallower, earthquake-generating portion of the subduction fault and potentially lead to an improved ability to forecast a major earthquake there.”

Besides Japan, non-volcanic tremor also has been detected under California’s San Andreas Fault and in the Cascadia subduction zone, which stretches from northern California to British Columbia. Cascadia includes four heavily populated urban areas—Portland, Seattle, Vancouver and Victoria, B.C. In 2003, Canadian scientists discovered that slow quakes and tremors in Cascadia occur like clockwork every 13 to 15 months. Scientists worry that these predictable slow events are loading stress on the locked portion of the fault, where a devastating magnitude 9 earthquake is expected to strike sometime in the next 300 years.

“In early February, Cascadia experienced one of those slow events, and the Canadian Geological Survey issued a public warning based on increased tremor activity,” Shelly noted. “The survey announced that there was a greater likelihood of a major earthquake in the next two or three weeks based on the activity of the tremor. Fortunately, the earthquake didn’t happen, but the real utility of the warning was to get people thinking about earthquake hazard in that region. It shows that tremor is starting to be used for earthquake forecasting.”

Seismologist Satoshi Ide of the University of Tokyo is the third co-author on the Nature study, which was supported by the National Science Foundation.

From Stanford University

After four years of intensive collaboration, 18 top mathematicians and computer scientists from the United States and Europe have successfully mapped E8, one of the largest and most complicated structures in mathematics, scientists said late Sunday.

Jeffrey Adams, project leader and mathematics professor at the University of Maryland said E8 was discovered over a century ago, in 1887, and until now, no one thought the structure could ever be understood.

“This groundbreaking achievement is significant both as an advance in basic knowledge, as well as a major advance in the use of large scale computing to solve complicated mathematical problems,” Adams said.

He added that the mapping of E8 may well have unforeseen implications in mathematics and physics which won’t be evident for years to come.

E8 belongs to so-called Lie groups that were invented by a 19th century Norwegian mathematician, Sophus Lie, to study symmetry.

The theory holds that underlying any symmetrical object, such as a sphere, is a Lie group.

Balls, cylinders or cones are familiar examples of symmetric three-dimensional objects.

However, mathematicians study symmetries in higher dimensions. In fact, E8 itself is 248-dimensional.

Today string theorists search for a theory of the universe by looking at E8 X E8.

While the human genome, which contains all the genetic information of a cell, is less than a gigabyte in size, the result of the E8 calculation, which contains all the information about E8, is 60 gigabytes in size, they said.

This is enough to store 45 days of continuous music in MP3-format. If written out on paper, the answer would cover an area the size of Manhattan.

From Forward Unlimited

By casting a wide net, astronomers have captured an image of more than a thousand supermassive black holes. These results give astronomers a snapshot of a crucial period when these monster black holes are growing, and provide insight into the environments in which they occur.

The new black hole panorama was made with data from NASA’s Chandra X-ray Observatory, the Spitzer Space Telescope and ground-based optical telescopes. The black holes in the image are hundreds of millions to several billion times more massive than the sun and lie in the centers of galaxies.

Material falling into these black holes at high rates generates huge amounts of light that can be detected in different wavelengths. These systems are known as active galactic nuclei, or AGN.

“We’re trying to get a complete census across the universe of black holes and their habits,” said Ryan Hickox of the Harvard-Smithsonian Center for Astrophysics (CfA) in Cambridge, Mass. “We used special tactics to hunt down the very biggest black holes.”

Instead of staring at one relatively small part of the sky for a long time, as with the Chandra Deep Fields — two of the longest exposures obtained with the observatory — and other concentrated surveys, this team scanned a much bigger portion with shorter exposures. Since the biggest black holes power the brightest AGN, they can be spotted at vast distances, even with short exposures.

“With this approach, we found well over a thousand of these monsters, and have started using them to test our understanding of these powerful objects,” said co-investigator Christine Jones, also of the CfA.

The new survey raises doubts about a popular current model in which a supermassive black hole is surrounded by a doughnut-shaped region, or torus, of gas. An observer from Earth would have their view blocked by this torus by different amounts, depending on the orientation of the torus.

According to this model, astronomers would expect a large sample of black holes to show a range of absorption of the radiation from the nuclei. This absorption should range from completely exposed to completely obscured, with most in-between. Nuclei that are completely obscured are not detectable, but heavily obscured ones are.

“Instead of finding a whole range, we found nearly all of the black holes are either naked or covered by a dense veil of gas,” said Hickox. “Very few are in between, which makes us question how well we know the environment around these black holes.”

This study found more than 600 obscured and 700 unobscured AGN, located between about six and 11 billion light years from Earth. They were found using an early application of a new search method. By looking at the infrared colors of objects with Spitzer, AGN can be separated from stars and galaxies. The Chandra and optical observations then verify these objects are AGN. This multi-wavelength method is especially efficient at finding obscured AGN.

“These results are very exciting, using two NASA Great Observatories to find and understand the largest sample of supermassive black holes ever found in the distant universe”, said co-investigator Daniel Stern, of NASA’s Jet Propulsion Laboratory in Pasadena, Calif.

The Chandra image is the largest contiguous field ever obtained by the observatory. At 9.3 square degrees, it is over 40 times larger than the full moon seen on the night sky and over 80 times larger than either of the Chandra Deep Fields. This survey, taken in a region of the constellation Bootes, involved 126 separate pointings of 5,000-second Chandra exposures each. The researchers combined this with infrared data obtained from Spitzer, and optical data from Kitt Peak’s 4-meter Mayall Telescope and the MMT 6.5-meter optical telescopes, both located outside Tuscon, Ariz., for the same patch of sky.

NASA’s Marshall Space Flight Center, Huntsville, Ala., manages the Chandra program for the agency’s Science Mission Directorate. The Smithsonian Astrophysical Observatory controls science and flight operations from the Chandra X-ray Center, Cambridge, Mass.

From NASA

A new wind turbine blade design that researchers at Sandia National Laboratories developed in partnership with Knight & Carver (K&C) of San Diego promises to be more efficient than current designs. It should significantly reduce the cost-of-energy (COE) of wind turbines at low-wind-speed sites.Named “STAR” for Sweep Twist Adaptive Rotor, the blade is the first of its kind produced at a utility-grade size. Its most distinctive characteristic is a gently curved tip, termed “sweep,” which unlike the vast majority of blades in current use, is specially designed for low-wind-speed regions like the Midwest. The sites targeted by this effort have annual average wind speeds of 5.8 meters per second, measured at 10-meter height. Such sites are abundant in the U.S. and would increase by 20-fold the available land area that can be economically developed for wind energy.

Sized at 27.1 meters — almost three meters longer than the baseline it will replace — the blade improves energy capture at lower wind speeds. Instead of the traditional linear shape, the blade features a curvature toward the trailing edge, which allows the blade to respond to turbulent gusts in a manner that lowers fatigue loads on the blade. It is made of fiberglass and epoxy resin.

“This design allows the blade to twist more than traditional designs, thus relieving some of the effects of gusty turbulent wind on blade life,” says Tom Ashwill, who leads Sandia’s blade research efforts. “This then allows us to grow the blade length for the same rotor, providing for increased energy capture of 5-10 percent and yet retaining the same expected fatigue life.”

Sandia is a National Nuclear Security Administration (NNSA) laboratory.

The K&C contract is part of the Low Wind Speed Technology (LWST) project that targets wind sites that are not the strongest but plentiful. In late 2005 the Department of Energy (DOE) and Sandia awarded Knight & Carver the $2 million contract that includes $800,000 in K&C cost share. Because of budget reallocations, this project was the only one of several LWST projects to receive 2007 funding.

Sandia’s role in the project has been in directing design and test planning. The K&C team provided the detailed design and blade fabrication.

The first STAR blade was tested in January at Knight & Carver’s fabrication facility in San Diego to determine its bending and twist behavior due to static loads. Natural frequencies were also measured. This data will be compared to design simulations to determine how well the design concept performs. Four additional blades will be fabricated in the first quarter of 2007 — three of which will be flight-tested on a turbine in Iowa.

Other members of the design team are Dynamic Design of Davis, Calif.; MDZ Consulting of Clear Lake Shores, Texas; University of California, Davis; and NSE Composites of Seattle, Wash.

“The DOE interest and funding are a big step for us,” Ashwill says. “We’ve been pushing for the incorporation of innovative concepts into utility-scale blades for some time now as a way of reaching program goals of lowered cost of energy.”

He adds that the continued increase in the average size of utility-grade wind turbines may come to an end before all efficiencies are wrung out unless blade weight growth (which is nonlinear) can be reined in. The challenge is to develop new concepts that reduce the rate of weight growth, such as the swept STAR blade.

Other weight-reducing concepts such as carbon spar caps, off-axis carbon fibers that facilitate bend-twist coupling, and new “structural” airfoils have been incorporated at a smaller scale in 9-meter-long prototype blade being flight-tested at Sandia’s test site in Bushland, Texas, at the U.S. Department of Agriculture ARS (Agriculture Research Station) facility.

From SANDIA

Sandia’s huge Z machine, which generates termperatures hottter than the sun, has turned water to ice in nanoseconds. However, don’t expect anything commercial just yet: the ice is hotter than the boiling point of water. “The three phases of water as we know them — cold ice, room temperature liquid, and hot vapor — are actually only a small part of water’s repertory of states,” says Sandia researcher Daniel Dolan. “Compressing water customarily heats it. But under extreme compression, it is easier for dense water to enter its solid phase [ice] than maintain the more energetic liquid phase [water].”

Sandia is a National Nuclear Security Administration (NNSA) laboratory.

In the Z experiment, the volume of water shrank abruptly and discontinuously, consistent with the formation of almost every known form of ice except the ordinary kind, which expands. (One might wonder why this ice shrank instead of expanding, given the common experience of frozen water expanding to wreck garden hoses left out over winter. The answer is that only “ordinary” ice expands when water freezes. There are at least 11 other known forms of ice occurring at a variety of temperatures and pressures.)

“This work,” says Dolan, “is a basic science study that helps us understand materials at extreme conditions.”

But it has potential practical value. The work, which appears online March 11 in Nature Physics, was undertaken partly because phase diagrams that predict water’s state at different temperatures and pressures are not always correct — a fact worrisome to experimentalists working at extreme conditions, as well as those having to work at distances where direct measurement is impractical. For example, work reported some months ago at Z demonstrated that astronomers’ ideas about the state of water on the planet Neptune were probably incorrect.

Closer at hand, water in a glass could be cooled below freezing and remain water, in what is called a supercooled state.

Accurate knowledge of water’s behavior is potentially important for Z because the 20-million-ampere electrical pulses the accelerator sends through water compress that liquid. Ordinarily, the water acts as an insulator and as a switch. But because the machine is being refurbished with more modern and thus more powerful equipment, questions about water’s behavior at extreme conditions are of increasing interest to help avoid equipment failure for the machine or its more powerful successors, should those be built.

One unforeseen result of Dolan’s test was that the water froze so rapidly. The freezing process as it is customarily observed requires many seconds at the very least.

The answer, says Dolan, seems to be that very fast compression causes very fast freezing. At Z and also at Sandia’s nearby STAR (Shock Thermodynamic Applied Research) gas gun facility, thin water samples were compressed to pressures of 50,000-120,000 atmospheres in less than 100 nanoseconds. Under such pressures, water appears to transform to ice VII, a phase of water first discovered by Nobel laureate Percy Bridgman in the 1930s. The compressed water appeared to solidify into ice within a few nanoseconds.

Ice VII has nothing to do with ice-nine, an entirely fictional creation of author Kurt Vonnegut in his 1963 novel Cat’s Cradle. There, a few molecules of the invented substance acts as a precipitating seed to cause an extended chemical reaction that freezes almost all of Earth’s water. Ice VII, on the other hand, only stays frozen as long as it is under enormous pressure. The pressure relenting, the ice changes back to ordinary water.

Nucleating agents, of course, are often used to hasten sluggish chemical processes, such as when clouds are “seeded” with silver iodide to induce rain. Dolan already had demonstrated, as a graduate physics student at Washington State University, that water can freeze on nanosecond time scales in the presence of a nucleating agent.

However, the behavior of pure water under high pressure remained a mystery.

Sandia instruments observed the unnucleated water becoming rapidly opaque — a sign of ice formation in which water and ice coexist — as pressure increased. At the 70,000 atmosphere mark and thereafter, the water became clear, a sign that the container now held entirely ice.

“Apparently it’s virtually impossible to keep water from freezing at pressures beyond 70,000 atmospheres,” Dolan says.

For these tests, Z created the proper conditions by magnetic compression. Twenty million amperes of electricity passed through a small aluminum chamber, creating a magnetic field that isentropically compressed aluminum plates roughly 5.5 by 2 inches in cross section. This created a shockless but rapidly increasing compression across a 25-micron-deep packet of water.

The multipurpose Z machine, whose main use is to produce data to improve the safety and reliability of the US nuclear deterrent, has compressed spherical capsules of hydrogen isotopes to release neutrons — the prerequisite for controlled nuclear fusion and essentially unlimited energy for humanity.

From SANDIA

New measurements of Mars’ south polar region indicate extensive frozen water. The polar region contains enough frozen water to cover the whole planet in a liquid layer approximately 11 meters (36 feet) deep. A joint NASA-Italian Space Agency instrument on the European Space Agency’s Mars Express spacecraft provided these data.

This new estimate comes from mapping the thickness of the ice. The Mars Express orbiter’s radar instrument has made more than 300 virtual slices through layered deposits covering the pole to map the ice. The radar sees through icy layers to the lower boundary, which is as deep as 3.7 kilometers (2.3 miles) below the surface.

“The south polar layered deposits of Mars cover an area bigger than Texas. The amount of water they contain has been estimated before, but never with the level of confidence this radar makes possible,” said Jeffrey Plaut of NASA’s Jet Propulsion Laboratory, Pasadena Calif. Plaut is co-principal investigator for the radar and lead author of a new report on these findings published in the March 15 online edition of the journal Science.

The instrument, named the Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS), also is mapping the thickness of similar layered deposits at the north pole of Mars.

“Our radar is doing its job extremely well,” said Giovanni Picardi, a professor at the University of Rome “La Sapienza,” and principal investigator for the instrument.

“MARSIS is showing itself to be a very powerful tool to probe underneath the Martian surface, and it’s showing how our team’s goals, such as probing the polar layered deposits, are being successfully achieved,” Picardi said. “Not only is MARSIS providing us with the first-ever views of Mars subsurface at those depths, but the details we are seeing are truly amazing. We expect even greater results when we have concluded an ongoing, sophisticated fine-tuning of our data processing methods. These should enable us to understand even better the surface and subsurface composition.”

Polar layered deposits hold most of the known water on modern Mars, though other areas of the planet appear to have been very wet at times in the past. Understanding the history and fate of water on Mars is a key to studying whether Mars has ever supported life, since all known life depends on liquid water.

The polar layered deposits extend beyond and beneath a polar cap of bright-white frozen carbon dioxide and water at Mars’ south pole. Dust darkens many of the layers. However, the strength of the echo that the radar receives from the rocky surface underneath the layered deposits suggests the composition of the layered deposits is at least 90 percent frozen water. One area with an especially bright reflection from the base of the deposits puzzles researchers. It resembles what a thin layer of liquid water might look like to the radar instrument, but the conditions are so cold that the presence of melted water is deemed highly unlikely.

Detecting the shape of the ground surface beneath the ice deposits provides information about even deeper structures of Mars. “We didn’t really know where the bottom of the deposit was,” Plaut said. “Now we can see that the crust has not been depressed by the weight of the ice as it would be on the Earth. The crust and upper mantle of Mars are stiffer than the Earth’s, probably because the interior of Mars is so much colder.”

The MARSIS instrument on the European Space Agency’s Mars Express orbiter was developed jointly by the Italian Space Agency and NASA, under the scientific supervision of the University of Rome “La Sapienza,” in partnership with JPL and the University of Iowa, Iowa City. JPL manages NASA’s roles in Mars Express for the NASA Science Mission Directorate, Washington.

From NASA

NASA-funded researchers are refining a tool that could not only check for the faintest traces of life’s molecular building blocks on Mars, but could also determine whether they have been produced by anything alive.The instrument, called Urey: Mars Organic and Oxidant Detector, has already shown its capabilities in one of the most barren climes on Earth, the Atacama Desert in Chile. The European Space Agency has chosen this tool from the United States as part of the science payload for the ExoMars rover planned for launch in 2013. Last month, NASA selected Urey for an instrument-development investment of $750,000.

The European Space Agency plans for the ExoMars rover to grind samples of Martian soil to fine powder and deliver them to a suite of analytical instruments, including Urey, that will search for signs of life. Each sample will be a spoonful of material dug from underground by a robotic drill.

“Urey will be able to detect key molecules associated with life at a sensitivity roughly a million times greater than previous instrumentation,” said Dr. Jeffrey Bada of Scripps Institution of Oceanography at the University of California, San Diego. Bada is the principal investigator for an international team of scientists and engineers working on various components of the device.

To aid in interpreting that information, part of the tool would assess how rapidly the environmental conditions on Mars erase those molecular clues.

Dr. Pascale Ehrenfreund of the University of Leiden in the Netherlands, said, “The main objective of ExoMars is to search for life. Urey will be a key instrument for that because it is the one with the highest sensitivity for organic chemicals.” Ehrenfreund, one of two deputy principal investigators for Urey, coordinates efforts of team members from five other European countries.

Urey can detect several types of organic molecules, such as amino acids, at concentrations as low as a few parts per trillion.

All life on Earth assembles chains of amino acids to make proteins. However, amino acids can be made either by a living organism or by non-biological means. This means it is possible that Mars has amino acids and other chemical precursors of life but has never had life. To distinguish between that situation and evidence for past or present life on Mars, the Urey instrument team will make use of the knowledge that most types of amino acids can exist in two different forms. One form is referred to as “left-handed” and the other as “right-handed.” Just as the right hand on a human mirrors the left, these two forms of an amino acid mirror each other.

Amino acids from a non-biological source come in a roughly 50-50 mix of right-handed and left-handed forms. Life on Earth, from the simplest microbes to the largest plants and animals, makes and uses only left-handed amino acids, with rare exceptions. Comparable uniformity — either all left or all right — is expected in any extraterrestrial life using building blocks that have mirror-image versions because a mixture would complicate biochemistry.

“The Urey instrument will be able to distinguish between left-handed amino acids and right-handed ones,” said Allen Farrington, Urey project manager at NASA’s Jet Propulsion Laboratory, which will build the instrument to be sent to Mars.

If Urey were to find an even mix of the mirror-image molecules on Mars, that would suggest life as we know it never began there. All-left or all-right would be strong evidence that life now exists on Mars, with all-right dramatically implying an origin separate from Earth life. Something between 50-50 and uniformity could result if Martian life once existed, because amino acids created biologically gradually change toward an even mixture in the absence of life.

The 1976 NASA Viking mission discovered that strongly oxidizing conditions at the Martian surface complicate experiments to search for life. The Urey instrument has a component, called the Mars oxidant instrument, for examining those conditions.

The oxidant instrument has microsensors coated with various chemical films. “By measuring the reaction of the sensor films with chemicals present in the Martian soil and atmosphere, we can establish if organisms could survive and if evidence of past life would be preserved,” said Dr. Richard Quinn, a co-investigator on Urey from the SETI Institute, Mountain View, Calif., who also works at NASA Ames Research Center, Moffett Field, Calif.

“In order to improve our chances of finding chemical evidence of life on Mars, and designing human habitats and other equipment that will function well on Mars’ surface, we need to improve our understanding of oxidants in the planet’s surface environment,” said Dr. Aaron Zent, a Urey co-investigator at NASA Ames.

A Urey component called the sub-critical water extractor handles the task of getting any organic compounds out of each powdered sample the ExoMars rover delivers to the instrument. “It’s like an espresso maker,” explained JPL’s Dr. Frank Grunthaner, a deputy principal investigator for Urey. “We bring the water with us. It is added to the sample, and different types of organic compounds dissolve into the liquid as the temperature increases. We keep it under pressure the whole time.”

The dissolved compounds are highly concentrated by stripping away water in a tiny oven.

Then a detector checks for fluorescent glowing, which would indicate the presence of amino acids, some components of DNA and RNA, or other organic compounds that bind to a fluorescing chemical added by the instrument.

A Urey component called the micro-capillary electrophoresis unit has the critical job of separating different types of organic compounds from one another for identification, including separation of mirror-image amino acids from each other. “We have essentially put a laboratory onto a single wafer,” said Dr. Richard Mathies of the University of California, Berkeley, a Urey co-investigator. The device for sending to Mars will be a small version incorporating this detection technology, which is already in use for biomedical procedures such as law-enforcement DNA tests and checking for hazardous microbes.

Switzerland will provide electronics design and packaging expertise for Urey. Micro-Cameras and Space Exploration S.A., Neuchatel, will collaborate with JPL and the European Space Agency to accomplish this significant contribution to the heart of the instrument. Dr. Jean-Luc Josset, Urey co-investigator at the University of Neuchatel will coordinate this effort and help provide detector selection and support. JPL is a division of the California Institute of Technology in Pasadena.

From NASA

The sun is a cosmic spinmeister.

Using the highly sensitive radar telescope at the Cornell University-managed Arecibo Observatory in Puerto Rico and Goldstone antenna in California, Cornell astronomers have confirmed a theory that sunlight and the asteroid’s shape determine how an asteroid’s rotation evolves. Their research is reported today in Science Express, the online edition of the journal Science.

The Yarkovsky-O’Keefe-Radzievskii-Paddack Effect, named after a nineteenth century Russian civil engineer Ivan Yarkovsky, a late American planetary scientist John A. O’Keefe, a late Russian astronomer V.V. Radzievskii and NASA aerospace engineer Stephen J. Paddack, affectionately known as YORP, says that solar radiation will increase or decrease the rate of an asteroid’s spin. This effect could help explain the formation of binary asteroids: The created centrifugal forces are so strong, that rubble-pile asteroids could break and form into two parts.

“For this particular asteroid, we confirmed that the expected strength of the YORP effect roughly matched the observed effect,” says Jean-Luc Margot, Cornell assistant professor of astronomy.

Margot and Patrick A. Taylor, Cornell doctoral student in astronomy, are the lead authors of the research, “Spin Rate of Asteroid (54509) 2000 PH5 Increasing due to the YORP Effect.” A companion paper, “Direct Detection of the Asteroidal YORP Effect,” with research led by Stephen C. Lowry from Queen’s University Belfast, United Kingdom, will be published concurrently in Science Express.

The astronomers examined asteroid 2000 PH5, which was discovered by MIT’s Lincoln Laboratory’s near-Earth asteroid search program (LINEAR) in August 2000.

The Arecibo Observatory takes high-resolution radar images, enabling the astronomers to construct digital shape models. With these models, the astronomers compared the predicted effect of YORP with the change in spin rate observed by Lowry’s team. The theoretical calculations and the observed change in the spin rate agreed with each other, resulting in the first direct detection of YORP. And Arecibo’s radar produces a more-detailed shape than data from an optical telescope, says Taylor.

From Cornell University