Humanoid Robot Plays Soccer

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Mars In 40 Days

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WhiteKnightTwo at AirVenture 2009

WhiteKnightTwo at AirVenture 2009.

Will Computers Replace Lawyers?

Source and Credit:  ICT Results

European researchers have created a legal analysis query engine that combines artificial intelligence, game theory and semantics to offer advice, conflict prevention and dispute settlement for European law, and it even supports policy.

European law is complex, many layered and expanding. There are thousands of regulations, so many that compliance is difficult, time-consuming and expensive.

While harmonization is underway, the process itself demands that individuals, companies and law firms often have to relearn the system.

Meanwhile, areas like intellectual property rights (IPR) and digital rights regulation that seek to combat piracy are becoming evermore complex to understand and apply consistently across Europe.

Thankfully, help is at hand. The ALIS project has developed a computerised platform that uses artificial intelligence (AI), game theory and semantic technologies to ‘understand’ and track the regulations in a large, and expanding area of expertise – in this case IPR.

ALIS sought to develop a working system in IPR to tackle the fundamental technological challenges before expanding it to more areas later on.

The system is much more than a simple database of relevant legal regulations. It uses insights from game theory to help contentious parties come to an amicable agreement, either through conflict prevention or dispute resolution, and it can assist lawmaking too.

Game theory looks at how strategic interactions between rational people lead to outcomes reflecting real player preferences. In the Ultimatum game, for example, two players decide how a sum is to be divided. The proposer suggests what the split should be, the responder either can accept or reject this offer. But if the responder rejects the split, both players get nothing.

Researchers have found that often proposers offer 50:50, even though the responder might accept less. They also found that responders always reject splits where they get less than 20 percent. In economics, this would be considered irrational, because the responder loses too, but this illustrates that fairness is a very important element in strategic interactions.

These types of interactions can be rendered mathematically thanks to game theory, and the concept is so powerful that it has migrated from applied mathematics to social sciences like economics, political science, international relations and philosophy, as well as hard sciences like biology, engineering and computer science.

Game theory can be used to develop algorithms that find equilibria in games, markets, computational auctions, peer-to-peer systems, security and information markets. And, now with ALIS, it is available for legal systems too. This concept of equilibria supports conflict prevention, dispute resolution and offers decision support for lawmaking.

A key factor in the system is its test for regulatory compliance. This is very powerful. It can help citizens, companies and lawyers quickly scan the relevant legal corpus to discover if they are compliant. It is a key factor for the other roles in the ALIS system as well.

For conflict prevention, dispute resolution and lawmaking, the ALIS first establishes if the parties, or the proposed legislation, are compliant with current law. Once compliance is established, the system can present a series of options based on an analysis of the potential conflict or dispute, or it can provide information to further assist lawmakers to formulate policy.

Similarly, the tool aims to rapidly speed up the work done by lawyers, helping to resolve relatively straightforward cases faster, so they can concentrate on more complex problems.

Here, semantic technologies play a key role by establishing a machine-readable annotation of copyright law for several European countries. 

The ALIS project’s exploitation and dissemination activities are noteworthy. Mailings, brochures, as well as many presentations and meetings have taken place between potential customers and beneficiaries of the ALIS system.

There are two primary customers or users; software providers who could benefit from the methods, logic and innovative information processing techniques developed within ALIS; and legal service providers, lawyers, solicitors and others who can use the system to keep them up to date with a rapidly evolving legal framework and speed up query handling for clients.

In all, ALIS has created a platform that should help ensure legal compliance by citizens, companies and lawyers. And it will help improve the efficiency of justice, by contributing to conflict prevention and dispute resolution, keeping cases out of overworked courts.

But ALIS’ true genius is that it creates a powerful technological platform to access legal knowledge, a platform that will become stronger over time.

Robotic Collaboration

More here from New Scientist.

Yes, Virginia, E.T. Does Exist . . .

. . . at least according to Newsweek magazine.

Ad Astra Per Aspera

A rough road leads to the stars.

A confluence of recent events has prompted me to consider the broader symbolism of human space flight: the 40^th anniversary of the Apollo moon landing, the passing of broadcasting icon Walter Cronkite, the recent record-setting STS-127 mission of the Shuttle Endeavour to the International Space Station (13 humans in space at once!) -- and my own recent visit to Kennedy Space Center.

Why do we invest the enormous sums of energy, money, and the tragic loss of human life in this endeavour? For me, the symbolism of human space flight is best summed up as individual sacrifice in pursuit of a greater good, specifically two deeply human impulses: to discover, and to survive.

Many months ago my wife Anastasia and I scheduled a 2-day visit to Kennedy Space Center on July 10 and 11. At the time we had hoped we might be lucky enough to catch the initial test launch of the Ares 1-X; that flight was ultimately delayed until later this year. However, in the meantime, STS-127 was delayed because of mechanical problems from a planned June launch until a launch window that began on the second day of our planned tour, July 11. In the end, that launch day was scrubbed due to concerns over possible lightning damage from a storm that blew in while we toured the space center, and we missed the launch that ultimately occurred on July 15.

However, the day before the planned launch, we took the Cape Canaveral Then & Now tour, which I cannot recommend more highly. This tour actually takes you off the Kennedy Space Center and onto the original home of America’s manned space program, the neighboring Cape Canaveral Air Force station. In particular, we visited several sites that brought home to me the human element of our space program.

The first site we visited on the tour was the launch pad and block house for the first two American manned space launches in 1961, Alan Shepard’s Freedom 7 and Gus Grissom’s Liberty Bell 7 missions. The block house in particular has been preserved much as it appeared during those historic launches. (Separate from the tour, at the Kennedy Space Center’s visitor complex you can view a recreation, using the original equipment, of the Mercury flight control center – talk about history! I felt like I was on the movie set of The Right Stuff.) On the outside of the block house, pictured below, is a photo of Alan Shepard’s face on the day of his historic flight on May 5, 1961. In his eyes are reflected what must have been a curious mixture of courage, anticipation and even fear ahead of his fearless act.

The most moving part of the tour, however, is a visit to the ruins of Cape Canaveral’s Launch Complex 34, which was used for numerous Saturn 1 and Saturn 1B launches from 1961 to 1968. It was from this complex that the first manned Apollo flight, the 11-day Earth-orbital Apollo 7 mission, which launched on October 11, 1968.

Launch Complex 34’s lasting emotional impact, however, stems from an earlier Apollo mission, the tragic launch pad fire of Apollo 1 that claimed the lives of astronauts Gus Grissom, Ed White and Roger Chaffee on January 27, 1967. Rising from the Cape like a modern Stonehenge, the remains of LC 34 retain a haunting, lonely quality that drives home horror and sadness of that day. Stenciled on one of the nearby concrete pillars is a sign that reads only “Abandon in place.” Three inscribed granite benches memorialize the lost astronauts, as do two plaques, one inscribed with Latin: Ad Astra Per Aspera (A Rough Road Leads to the Stars.)

Ad astra per aspera. The plaque memorizes three astronauts “who made the ultimate sacrifice so others could reach for the stars.” Over at the Kennedy Space Center’s Visitor Complex, the Space Mirror Memorial is dedicated to the memories of these three Apollo 1 heroes as well as to 21 other American men and women who have died while pursuing their duties in the American space program, including the crews of the Challenger and Columbia disasters. Eight cosmonauts have died in the former Soviet and now Russian space program, including the first human to fly in space, Yuri Gagarin, who died in a 1968 crash of a training flight.

Shortly before the Apollo 1 fire, Grissom said: "If we die, we want people to accept it. We are in a risky business . . . conquest of Space is worth the risk of life."

A rough road leads to the stars.

What is the meaning for you of the sacrifices made by these men and women, these brave pioneers?

Could Betelgeuse Fry Earth?

Source and Credit: Astrobiology Magazine

When stars go pop, a murderous torrent of energy is released. Life on Earth may have been partly extinguished by just such a violent outburst, but there's little hard evidence yet to justify such a claim. A new study plans to fill in the forensic details.

"We are trying to get a better estimate of how dangerous a particular event will be," says Brian Thomas of Washburn University in Topeka, Kansas.

Thomas and his colleagues will be studying the wide-range of astrophysical phenomena that could fling high energy radiation across interstellar space to Earth's doorstep [as occured in a colossal blast detected in 2004]. The team also will radiate different types of phytoplankton to understand how life would be affected by a stellar blast, since life around the globe is highly dependent on these microscopic plants.

The danger from stellar explosions has been considered before, but this will be the first comprehensive study. "We are building on previous work by broadening it to a wide range of astrophysical events and by making the biological modeling more precise," Thomas says. The project is part of NASA's Exobiology and Evolutionary Biology Program.

The usual suspects

Stars are generally too far away to be a concern for life on our planet. But certain stellar eruptions have the potential to reach across tens or even thousands of light-years.

The most familiar of these is a supernova, which is the curtain call of a massive star with eight or more times the mass of our sun. When the nuclear fuel runs out for such a behemoth, the collapsing core generates an explosion that outshines an entire galaxy-worth of stars while it lasts.

A couple supernovae go off in our galaxy every century. But for one of these to haveserious consequences for Earth, we would need to be roughly within a 10 light-year radius of the blast.

Certain star explosions, called hypernovae, have much greater reach. Ten times more powerful than typical supernovae, hypernovae are the source for long-duration gamma ray bursts (GRBs), which are high-energy beams emitted along the dying star's axis. A GRB could travel 6,500 light-years and still inflict terrific damage on Earth, Thomas says.

The number of GRBs is much less than the number of supernovae, but the exact rate in our galaxy is still a matter of debate. A few years ago, a group of astronomers calculated that the likelihood of a GRB going off near us was very low, due to the fact that GRBs tend to arise in young galaxies with less heavy elements than the Milky Way.

But Thomas says that subsequent analyses have called this calculation into question, partly because our galaxy has merged in the past with smaller, younger galaxies that could have brought GRB-ticking-time-bombs in with them. "Our likelihood for hosting a GRB could vary with time," Thomas says.

He speculates that on average a GRB lights up our galaxy about once every 10 million years.

Other possible culprits

Long-duration GRBs and supernovae may be the best-understood, but they are not the only super-stellar calamities.

Short-duration GRBs do not arise from massive star deaths, but instead are believed to mainly be the merger of two neutron stars. Although less energy is released than in a long-duration GRB, the fraction of high-energy gamma rays is higher. Moreover, short-duration GRBs are more likely to occur in mature galaxies like ours, where neutron stars are more common.

Soft gamma-ray repeaters also originate from neutron stars – supposedly when the super-dense surface cracks. If one of these happened 10 light-years away, the effects could be dramatic. Indeed, on Dec. 27, 2004, the radiation from a soft gamma-ray repeater disrupted radio wave transmissions on Earth. Nothing was damaged, but the source object was an amazing 50,000 light-years away.

Thomas and his colleagues will be pulling together recent data from the Swift satellite and the Fermi Gamma-Ray Space Telescope to better estimate the rates and radiation output of soft gamma-ray repeaters, GRBs and supernovae.

Although there's no evidence that one of these went off recently in our neighborhood, it's important to note that our sun migrates around the galaxy and therefore could have brushed next to a star having a high-energy fit.

Worldwide ozone hole

The other half of the study will look at the possible biological aftermath of an astrophysical firework going off nearby.

Gamma rays and X-rays cannot penetrate very far into the Earth's atmosphere, but they still can have a long-lasting impact. The high-energy radiation breaks apart nitrogen and oxygen molecules in the Earth's stratosphere, allowing them to reform as nitric oxide (NO). This molecule destroys ozone in the same way that chlorofluorocarbons (CFCs) do.

"The effect is like the current ozone hole, but spread over the globe," Thomas says.

Ozone protects life on Earth from the sun's ultraviolet rays. By shattering this atmospheric shield, an astrophysical blast could lead to higher rates of DNA and protein damage in organisms from greater sunlight exposure.

Thomas' group has previously determined that a relatively close GRB could destroy 75 percent of the ozone in certain regions, with a globally averaged depletion of around 35 to 40 percent. In contrast, the ozone hole that currently hovers over Antarctica is at most 60 percent depleted but only accounts for a globally-averaged depletion of 3 to 5 percent.

Thomas says that the ozone destruction would begin as soon as the radiation hits, and would continue for several years. It may take more than a decade for the Earth's ozone shield to return to full strength.

Fried plankton

The loss of ozone would have serious effects on life across the planet. One of the most susceptible organisms would be phytoplankton. These single-celled organisms live at the top of the water column, where UV light is able to reach. They also reproduce quickly, so DNA damage would accumulate over several generations.

If phytoplankton began dying off, the effects would ripple throughout the ocean, since these photosynthetic microbes are the base of the marine food chain. They also produce at least half of the world's oxygen.

The team has selected a couple representative species of phytoplankton to irradiate at different levels, and see how their productivity levels change. The results of the study should give astrobiologists a better sense of how likely it is that our planet or another planet in our galaxy was zapped by a stellar eruption.

Possible signs of such astrophysical foul play are seen in the Ordovician extinction, which occurred 450 million years ago and resulted in the loss of 60 percent of marine invertebrates. The fossil record shows that organisms near the top of the water column and at mid-latitudes were hardest hit, as one would expect from a sudden loss of ozone.

Ancient Martian Lake

Image Credit: G. Di Achille, University of Colorado

Source and Credit: University of Colorado at Boulder

A University of Colorado at Boulder research team has discovered the first definitive evidence of shorelines on Mars, an indication of a deep, ancient lake there and a finding with implications for the discovery of past life on the Red Planet.

Estimated to be more than 3 billion years old, the lake appears to have covered as much as 80 square miles and was up to 1,500 feet deep -- roughly the equivalent of Lake Champlain bordering the United States and Canada, said CU-Boulder Research Associate Gaetano Di Achille, who led the study. The shoreline evidence, found along a broad delta, included a series of alternating ridges and troughs thought to be surviving remnants of beach deposits.

"This is the first unambiguous evidence of shorelines on the surface of Mars," said Di Achille. "The identification of the shorelines and accompanying geological evidence allows us to calculate the size and volume of the lake, which appears to have formed about 3.4 billion years ago."

A paper on the subject by Di Achille, CU-Boulder Assistant Professor Brian Hynek and CU-Boulder Research Associate Mindi Searls, all of the Laboratory for Atmospheric and Space Physics, is in press in Geophysical Research Letters, a publication of the American Geophysical Union.

Images used for the study were taken by a high-powered camera known as the High Resolution Imaging Science Experiment, or HiRISE. Riding on NASA's Mars Reconnaissance Orbiter, HiRISE can resolve features on the surface down to one meter in size from its orbit 200 miles above Mars.

An analysis of the HiRISE images indicate that water carved a 30-mile-long canyon that opened up into a valley, depositing sediment that formed a large delta. This delta and others surrounding the basin imply the existence of a large, long-lived lake, said Hynek, also an assistant professor in CU-Boulder's geological sciences department. The lake bed is located within a much larger valley known as the Shalbatana Vallis.

"Finding shorelines is a Holy Grail of sorts to us," said Hynek.

In addition, the evidence shows the lake existed during a time when Mars is generally believed to have been cold and dry, which is at odds with current theories proposed by many planetary scientists, he said. "Not only does this research prove there was a long-lived lake system on Mars, but we can see that the lake formed after the warm, wet period is thought to have dissipated."

Planetary scientists think the oldest surfaces on Mars formed during the wet and warm Noachan epoch from about 4.1 billion to 3.7 billion years ago that featured a bombardment of large meteors and extensive flooding. The newly discovered lake is believed to have formed during the Hesperian epoch and postdates the end of the warm and wet period on Mars by 300 million years, according to the study.

The deltas adjacent to the lake are of high interest to planetary scientists because deltas on Earth rapidly bury organic carbon and other biomarkers of life, according to Hynek. Most astrobiologists believe any present indications of life on Mars will be discovered in the form of subterranean microorganisms.

But in the past, lakes on Mars would have provided cozy surface habitats rich in nutrients for such microbes, Hynek said.

The retreat of the lake apparently was rapid enough to prevent the formation of additional, lower shorelines, said Di Achille. The lake probably either evaporated or froze over with the ice slowly turning to water vapor and disappearing during a period of abrupt climate change, according to the study.

Di Achille said the newly discovered pristine lake bed and delta deposits would be a prime target for a future landing mission to Mars in search of evidence of past life.

"On Earth, deltas and lakes are excellent collectors and preservers of signs of past life," said Di Achille. "If life ever arose on Mars, deltas may be the key to unlocking Mars' biological past."

Seeing Water On Exoplanets

Earth as seen from Deep Impact spacecraft (NASA). Yes, that's the Moon also.

Source and Credit: University of Washington

Since the early 1990s astronomers have discovered more than 300 planets orbiting stars other than our sun, nearly all of them gas giants like Jupiter. Powerful space telescopes, such as the one that is central to NASA's recently launched Kepler Mission, will make it easier to spot much smaller rocky extrasolar planets, or exoplanets, more similar to Earth.

But seen from dozens of light years away, an Earth-like exoplanet will appear in telescopes as little more than a "pale blue dot," the term coined by the late astronomer Carl Sagan to describe how Earth appeared in a 1990 photograph taken by the Voyager spacecraft from near the edge of the solar system.

Using instruments aboard the Deep Impact spacecraft, a team of astronomers and astrobiologists has devised a technique to tell whether such a planet harbors liquid water, which in turn could tell whether it might be able to support life.

"Liquid water on the surface of a planet is the gold standard that people are looking for," said Nicolas Cowan, a University of Washington doctoral student in astronomy and lead author of a paper explaining the new technique that has been accepted for publication in Astrophysical Journal.

As part of NASA's Extrasolar Planet Observation and Characterization mission, the scientists obtained two separate 24-hour observations of light intensity from Earth in seven bands of visible light, from shorter wavelengths near ultraviolet to longer wavelengths near infrared. Earth appears gray at most wavelengths because of cloud cover, but it appears blue at short wavelengths because of the same atmospheric phenomenon that makes the sky look blue to people on the surface.

The researchers studied small deviations from the average color caused by surface features like clouds and oceans rotating in and out of view. They found two dominant colors, one reflective at long, or red, wavelengths and the other at short, or blue, wavelengths. They interpreted the red as land masses and the blue as oceans.

The analysis was undertaken "as if we were aliens looking at Earth with the tools we might have in 10 years" and did not already know Earth's composition, Cowan said. "You sum up the brightness into a single pixel in the telescope's camera, so it truly is a pale blue dot."

Since Earth's colors changed throughout the 24-hour-long observations, the scientists made maps of the planet in the dominant red and blue colors and then compared their interpretations with the actual location of the planet's continents and oceans.

"You could tell that there were liquid oceans on the planet," Cowan said. "The idea is that to have liquid water the planet would have to be in its system's habitable zone, but being in the habitable zone doesn't guarantee having liquid water."

The observations on March 18 and June 4, 2008 were made when the spacecraft was between 17 million and 33 million miles from Earth, and while it was directly above the equator. Observations from above a polar region likely would show up as white, Cowan said.

It will be some years before the launch of space telescopes capable of making similar observations for Earth-sized exoplanets, but devising this technique now could guide the construction of those instruments, he said. And while those planets will be much farther away, the technique still will be applicable.

"You will still have all the spectral information, and more importantly to us you'll still have the information so that you can see how the brightness of that speck is changing over time, Cowan said."

Co-authors are Eric Agol, Victoria Meadows and Tyler Robinson of the UW, Timothy Livengood and Drake Deming of the NASA Goddard Space Flight Center, Carey Lisse of Johns Hopkins University, Michael A'Hearn and Dennis Wellnitz of the University of Maryland, Sara Seager of the Massachusetts Institute of Technology and David Charbonneau of the Harvard-Smithsonian Center for Astrophysics. The work was funded by the Natural Sciences and Engineering Research Council of Canada, the National Science Foundation and the NASA Discovery Program.

Cowan notes that some non-habitable planets, such as Neptune, also can appear to be blue, but the color is constant and, in the case of Neptune, likely caused by methane in the atmosphere.

"It looks blue from every angle, the same blue all the way around. If you had an ocean planet it might look like that, but you can do other tests to determine that," he said. "For Earth, the blue varies from one place to another, which indicates that it's not something in the atmosphere."

Habitable Zones Smaller Than Thought?

Image Credit: ESO

Source and Credit: University of Washington

A number of planets have been discovered orbiting red dwarf stars, which make up about three-quarters of the stars close to our solar system. Potentially habitable planets must orbit close to those stars -- perhaps one-fiftieth the distance of Earth to the sun -- since those stars are smaller and generate less heat than our sun.

But new calculations indicate that, with planets so close, tidal forces exerted on planets by the parent star's gravity could limit what is regarded as a star's habitable zone and change the criteria for planets where life could potentially take root.

Scientists believe liquid water is essential for life. But a planet also must have plate tectonics to pull excess carbon from its atmosphere and confine it in rocks to prevent runaway greenhouse warming. Tectonics, or the movement of the plates that make up a planet's surface, typically is driven by radioactive decay in the planet's core, but a star's gravity can cause tides in the planet, which creates more energy to drive plate tectonics.

"If you have plate tectonics, then you can have long-term climate stability, which we think is a prerequisite for life," said Rory Barnes, a University of Washington postdoctoral researcher in astronomy.

However, tectonic forces cannot be so severe that geologic events quickly repave a planet's surface and destroy life that might have gotten a foothold, he said. The planet must be at a distance where tugging from the star's gravitational field generates tectonics without setting off extreme volcanic activity that resurfaces the planet in too short a time for life to prosper.

Barnes is lead author of a paper to be published by The Astrophysical Journal Letters that uses new calculations from computer modeling to define a "tidal habitable zone." Co-authors are Brian Jackson and Richard Greenberg from the University of Arizonaand Sean Raymond from the University of Colorado. The research was funded by NASA.

"Overall, the effect of this work is to reduce the number of habitable environments in the universe, or at least what we have thought of as habitable environments," Barnes said. "The best places to look for habitability are where this new definition and the old definition overlap."

The new calculations have implications for planets previously considered too small for habitability. An example is Mars, which used to experience tectonics but that activity ceased as heat from the planet's decaying inner core dissipated.

But as planets get closer to their suns, the gravitational pull gets stronger, tidal forces increase and more energy is released. If Mars were to move closer to the sun, the sun's tidal tugs could possibly restart the tectonics, releasing gases from the core to provide more atmosphere. If Mars harbors liquid water, at that point it could be habitable for life as we know it.

Various moons of Jupiter have long been considered as potentially harboring life. But one of them, Io, has so much volcanic activity, the result of tidal forces from Jupiter, that it is not regarded as a good candidate. Tectonic activity remakes Io's surface in less than 1 million years.

"If that were to happen on Earth, it would be hard to imagine how life would develop," Barnes said.

A potential Earth-like planet, but eight times more massive, called Gliese 581d was discovered in 2007 about 20 light years away in the constellation Libra. At first it was thought the planet was too far from its sun, Gliese 581, to have liquid water, but recent observations have determined the orbit is within the habitable zone for liquid water. However, the planet is outside the habitable zone for its sun's tidal forces, which the authors believe drastically limits the possibility of life.

"Our model predicts that tides may contribute only one-quarter of the heating required to make the planet habitable, so a lot of heat from decay of radioactive isotopes may be required to make up the difference," Jackson said.

Barnes added, "The bottom line is that tidal forcing is an important factor that we are going to have to consider when looking for habitable planets."

Planetary Disaster In Offing?

From the Bad Astronomical News of the Week department:

More here from New Scientist.

Is This What An Alien Looks Like?

Source and Credit: Society for General Microbiology

A novel bacterium that has been trapped more than three kilometres under glacial ice in Greenland for over 120 000 years, may hold clues as to what life forms might exist on other planets.

Dr Jennifer Loveland-Curtze and a team of scientists from Pennsylvania State University report finding the novel microbe, which they have called Herminiimonas glaciei, in the current issue of the International Journal of Systematic and Evolutionary Microbiology. The team showed great patience in coaxing the dormant microbe back to life; first incubating their samples at 2˚C for seven months and then at 5˚C for a further four and a half months, after which colonies of very small purple-brown bacteria were seen.

H. glaciei is small even by bacterial standards – it is 10 to 50 times smaller than E. coli. Its small size probably helped it to survive in the liquid veins among ice crystals and the thin liquid film on their surfaces. Small cell size is considered to be advantageous for more efficient nutrient uptake, protection against predators and occupation of micro-niches and it has been shown that ultramicrobacteria are dominant in many soil and marine environments.

Most life on our planet has always consisted of microorganisms, so it is reasonable to consider that this might be true on other planets as well. Studying microorganisms living under extreme conditions on Earth may provide insight into what sorts of life forms could survive elsewhere in the solar system.

"These extremely cold environments are the best analogues of possible extraterrestrial habitats", said Dr Loveland-Curtze, "The exceptionally low temperatures can preserve cells and nucleic acids for even millions of years. H. glaciei is one of just a handful of officially described ultra-small species and the only one so far from the Greenland ice sheet; studying these bacteria can provide insights into how cells can survive and even grow under extremely harsh conditions, such as temperatures down to -56˚C, little oxygen, low nutrients, high pressure and limited space."

"H. glaciei isn't a pathogen and is not harmful to humans", Dr Loveland-Curtze added, "but it can pass through a 0.2 micron filter, which is the filter pore size commonly used in sterilization of fluids in laboratories and hospitals. If there are other ultra-small bacteria that are pathogens, then they could be present in solutions presumed to be sterile. In a clear solution very tiny cells might grow but not create the density sufficient to make the solution cloudy".

Robots That Read Human Intent

Source and Credit: ICT Results

European researchers in robotics, psychology and cognitive sciences have developed a robot that can predict the intentions of its human partner. This ability to anticipate (or question) actions could make human-robot interactions more natural.

The walking, talking, thinking robots of science fiction are far removed from the automated machines of today. Even today's most intelligent robots are little more than slaves – programmed to do our bidding.

Many research groups are trying to build robots that could be less like workers and more like companions. But to play this role, they must be able to interact with people in natural ways, and play a pro-active part in joint tasks and decision-making. We need robots that can ask questions, discuss and explore possibilities, assess their companion's ideas and anticipate what their partners might do next.

The EU-funded JAST project brings a multidisciplinary team together to do just this. The project explores ways by which a robot can anticipate/predict the actions and intentions of a human partner as they work collaboratively on a task.

Who knows best?

You cannot make human-robot interaction more natural unless you understand what 'natural' actually means. But few studies have investigated the cognitive mechanisms that are the basis of joint activity (i.e. where two people are working together to achieve a common goal).

A major element of the JAST project, therefore, was to conduct studies of human-human collaboration. These experiments and observations could feed into the development of more natural robotic behaviour.

The researchers participating in JAST are at the forefront of their discipline and have made some significant discoveries about the cognitive processes involved in joint action and decision-making. Most importantly, they scrutinised the ways in which observation plays an important part in joint activity.

Scientists have already shown that a set of 'mirror neurons' are activated when people observe an activity. These neurons resonate as if they were mimicking the activity; the brain learns about an activity by effectively copying what is going on. In the JAST project, a similar resonance was discovered during joint tasks: people observe their partners and the brain copies their action to try and make sense of it.

In other words, the brain processes the observed actions (and errors, it turns out) as if it is doing them itself. The brain mirrors what the other person is doing either for motor-simulation purposes or to select the most adequate complementary action.

Resonant robotics

The JAST robotics partners have built a system that incorporates this capacity for observation and mirroring (resonance).

“In our experiments the robot is not observing to learn a task,” explains Wolfram Erlhagen from the University of Minho and one of the project consortium's research partners. “The JAST robots already know the task, but they observe behaviour, map it against the task, and quickly learn to anticipate [partner actions] or spot errors when the partner does not follow the correct or expected procedure.”

The robot was tested in a variety of settings. In one scenario, the robot was the 'teacher' – guiding and collaborating with human partners to build a complicated model toy. In another test, the robot and the human were on equal terms. “Our tests were to see whether the human and robot could coordinate their work,” Erlhagen continues. “Would the robot know what to do next without being told?”

By observing how its human partner grasped a tool or model part, for example, the robot was able to predict how its partner intended to use it. Clues like these helped the robot to anticipate what its partner might need next. “Anticipation permits fluid interaction,” says Erlhagen. “The robot does not have to see the outcome of the action before it is able to select the next item.”

The robots were also programmed to deal with suspected errors and seek clarification when their partners’ intentions were ambiguous. For example, if one piece could be used to build three different structures, the robot had to ask which object its partner had in mind.

From JAST to Jeeves

But how is the JAST system different to other experimental robots?

“Our robot has a neural architecture that mimics the resonance processing that our human studies showed take place during joint actions,” says Erlhagen. “The link between the human psychology, experimentation and the robotics is very close. Joint action has not been addressed by other robotics projects, which may have developed ways to predict motor movements, but not decisions or intentions. JAST deals with prediction at a much hig

Before robots like this one can be let loose around humans, however, they will have to learn some manners. Humans know how to behave according to the context they are in. This is subtle and would be difficult for a robot to understand.

Nevertheless, by refining this ability to anticipate, it should be possible to produce robots that are proactive in what they do.

Not waiting to be asked, perhaps one day a robot may use the JAST approach to take initiative and ask: “Would you care for a cup of tea?”

Search For E.T. Just Got Easier

Image Credit: Gabriel Perez Diaz, SMM, Instituto de Astrofisica de Canarias (IAC)

Source and Credit: Science & Technology Facilities Council

Astronomers using the Science and Technology Facilities Council’s (STFC) William Herschel Telescope (WHT) on La Palma have confirmed an effective way to search the atmospheres of planets for signs of life, vastly improving our chances of finding alien life outside our solar system.

The team from the Instituto de Astrofisica de Canarias (IAC) used the WHT and the Nordic Optical Telescope (NOT) to take the first transmission spectrum of the Earth - information about the chemical composition of the Earth’s atmosphere from sunlight that has passed through it. The research is published today (11th June) in Nature.

When a planet passes in front of its parent star, part of the starlight passes through the planet’s atmosphere and contains information about the constituents of the atmosphere, providing vital information about the planet itself. This is called a transmission spectrum and even though astronomers can’t use exactly the same method to look at the Earth’s atmosphere, they were able to gain a spectrum of our planet by observing light reflected from the Moon towards the Earth during a lunar eclipse. This is the first time the transmission spectrum of the Earth has been measured.

The spectrum not only contained signs of life but these signs were unmistakably strong. It also contained unexpected molecular bands and the signature of the earth ionosphere.

Enric Palle, lead author of the paper, from the Instituto de Astrofisica de Canarias, said, “Now we know what the transmission spectrum of a inhabited planet looks like, we have a much better idea of how to find and recognize Earth like planets outside our solar system where life may be thriving. The information in this spectrum shows us that this is a very effective way to gather information about the biological processes that may be taking place on a planet.”

Pilar Montañes-Rodriguez, from the Instituto de Astrofisica de Canarias, added, “Many discoveries of Earth-size planets are expected in the next decades and some will orbit in the habitable zone of their parent stars. Obtaining their atmospheric properties will be highly challenging; the greatest reward will happen when one of those planets shows a spectrum like that of our Earth.”

The past two decades have witnessed the discovery of hundreds of exoplanets (planets beyond our solar system). Ambitious missions, ground and space based, are already being planned for the next decades, and the discovery of Earth-like planets is only a matter of time. Once these planets are found, techniques like transmission spectra will be invaluable to their further exploration.

Professor Keith Mason, Chief Executive of the Science and Technology Facilities Council (STFC), said, “This new transmission spectrum is good news for future upcoming ground and space based missions dedicated to the search for life in the universe. The UK is committed to cutting edge science and UK owned facilities like the WHT are helping to make many groundbreaking discoveries and expand our knowledge of the Universe. Not only do these results improve our knowledge of our own planet but we now have an effective way to search for life on the increasing number of exoplanets being found by astronomers.”

Earth's Billion-Year Reprieve

Source and Credit: Caltech

Roughly a billion years from now, the ever-increasing radiation from the sun will have heated Earth into inhabitability; the carbon dioxide in the atmosphere that serves as food for plant life will disappear, pulled out by the weathering of rocks; the oceans will evaporate; and all living things will disappear.

Or maybe not quite so soon, say researchers from the California Institute of Technology (Caltech), who have come up with a mechanism that doubles the future lifespan of the biosphere—while also increasing the chance that advanced life will be found elsewhere in the universe.

Earth maintains its surface temperatures through the greenhouse effect. Although the planet's greenhouse gases—chiefly water vapor, carbon dioxide, and methane-have become the villain in global warming scenarios, they're crucial for a habitable world, because they act as an insulating blanket in the atmosphere that absorbs and radiates thermal radiation, keeping the surface comfortably warm.

As the sun has matured over the past 4.5 billion years, it has become both brighter and hotter, increasing the amount of solar radiation received by Earth, along with surface temperatures. Earth has coped by reducing the amount of carbon dioxide in the atmosphere, thus reducing the warming effect. (Despite current concerns about rising carbon dioxide levels triggering detrimental climate change, the pressure of carbon dioxide in the atmosphere has dropped some 2,000-fold over the past 3.5 billion years; modern, man-made increases in atmospheric carbon dioxide offset a fraction of this overall decrease.)

The problem, says Joseph L. Kirschvink, the Nico and Marilyn Van Wingen Professor of Geobiology at Caltech and a coauthor of the PNAS paper, is that "we're nearing the point where there's not enough carbon dioxide left to regulate temperatures following the same procedures."

Kirschvink and his collaborators Yuk L. Yung, a Caltech professor of planetary science, and graduate students King-Fai Li and Kaveh Pahlevan, say that the solution is to reduce substantially the total pressure of the atmosphere itself, by removing massive amounts of molecular nitrogen, the largely nonreactive gas that makes up about 78 percent of the atmosphere. This would regulate the surface temperatures and allow carbon dioxide to remain in the atmosphere, to support life, and could tack an additional 1.3 billion years onto Earth's expected lifespan.

In the "blanket" analogy for greenhouse gases, carbon dioxide would be represented by the cotton fibers making up the blanket. "The cotton weave may have holes, which allow heat to leak out," explains Li, the lead author of the paper.

"The size of the holes is controlled by pressure," Yung says. "Squeeze the blanket," by increasing the atmospheric pressure, "and the holes become smaller, so less heat can escape. With less pressure, the holes become larger, and more heat can escape," he says, helping the planet to shed the extra heat generated by a more luminous sun.

Strikingly, no external influence would be necessary to take nitrogen out of the air, the scientists say. Instead, the biosphere itself would accomplish this, because nitrogen is incorporated into the cells of organisms as they grow, and is buried with them when they die.

In fact, "this reduction of nitrogen is something that may already be happening," says Pahlevan, and that has occurred over the course of Earth's history. This suggests that Earth's atmospheric pressure may be lower now than it was earlier in the planet's history.

Proof of this hypothesis may come from other research groups that are examining the gas bubbles formed in ancient lavas to determine past atmospheric pressure: the maximum size of a forming bubble is constrained by the amount of atmospheric pressure, with higher pressures producing smaller bubbles, and vice versa.

If true, the mechanism also would potentially occur on any extrasolar planet with an atmosphere and a biosphere.

"Hopefully, in the future we will not only detect earth-like planets around other stars but learn something about their atmospheres and the ambient pressures," Pahlevan says. "And if it turns out that older planets tend to have thinner atmospheres, it would be an indication that this process has some universality.

Adds Yung: "We can't wait for the experiment to occur on Earth. It would take too long. But if we study exoplanets, maybe we will see it. Maybe the experiment has already been done."

Increasing the lifespan of our biosphere—from roughly 1 billion to 2.3 billion years—has intriguing implications for the search for life elsewhere in the universe. The length of the existence of advanced life is a variable in the Drake equation, astronomer Frank Drake's famous formula for estimating the number of intelligent extraterrestrial civilizations in the galaxy. Doubling the duration of Earth's biosphere effectively doubles the odds that intelligent life will be found elsewhere in the galaxy.

"It didn't take very long to produce life on the planet, but it takes a very long time to develop advanced life," says Yung. On Earth, this process took four billion years. "Adding an additional billion years gives us more time to develop, and more time to encounter advanced civilizations, whose own existence might be prolonged by this mechanism. It gives us a chance to meet."

The work described in the paper, "Atmospheric Pressure as a Natural Regulator of the Climate of a Terrestrial Planet with Biosphere," was funded by NASA and the Virtual Planetary Laboratory at Caltech.

Planets Common Around Binary Stars?

Image Credit: David A. Aguilar (CfA)

Source and Credit: Astrobiology Magazine (NASA/JPL)

Astronomers have announced that a sequence of images collected with the Smithsonian’sSubmillimeter Array (SMA) radio telescope system clearly reveals the presence of a rotating, molecular disk orbiting the young binary star system V4046 Sagittarii.

The SMA images of V4046 Sagittarii, which were presented by UCLA graduate student David Rodriguez in a press conference at the American Astronomical Society meeting in Pasadena, Calif., provide an unusually vivid snapshot of the process offormation of giant planets, comets, and Pluto-like bodies. The results also confirm that such objects may just as easily form around double stars as around single stars like our sun.

“It’s a case of seeing is believing,” says Joel Kastner of Rochester (NY) Institute of Technology, the lead scientist on the study. “We had the first evidence for this rotating disk in radio telescope observations of V4046 Sagittarii that we made last summer. But at that point, all we had were molecular spectra, and there are different ways to interpret the spectra. Once we saw the image data from the SMA, there was no doubt that we have a rotating disk here.”

According to Rodriguez, the images clearly demonstrate that the molecular disk orbiting the V4046 Sagittarii binary system extends from within the approximate radius of Neptune’s orbit out to about 10 times that orbit. This region corresponds to the zone where the solar system’s giant planets, as well as its Pluto-like Kuiper Belt objects, may have formed.

We believe that V4046 Sagittarii provides one of the clearest examples yet discovered of a Keplerian, planet-forming disk orbiting a young star system,” Wilner says. “This particular system is made that much more remarkable by the fact that it consists of a pair of roughly solar-mass stars that are approximately 12 million years old and are separated by a mere 5 solar diameters.”

“This could be the oldest known orbiting protoplanetary molecular disk and it shows that, at least for some stars, formation of Jovian-mass planets may continue well after the few million years, which astronomers have deduced is characteristic of the formation time for most such planets,” Zuckerman says.

Findings of the SMA imaging study build on previous work published in the December 2008 issue of Astronomy and Astrophysics in which Kastner and his team first suggested that the case of V4046 Sagittarii well illustrates how planets may easily form around certain types of binary stars.

“We thought the molecular gas around these two stars almost literally represented ‘smoking gun’ evidence of recent or possibly ongoing ‘giant,’ Jupiter-like planet formation around the binary star system, Kastner says. “The SMA images showing an orbiting disk certainly support that idea.”

The evidence for a molecular disk orbiting these twin young suns in the constellation Sagittarius suggested to the scientists that many such binary systems should also host as-yet undetected planets.

“The most successful technique used so far for discovery of extrasolar planets -- that of measurement of precision radial velocities – is exceedingly difficult for close binary stars such as V4046 Sagittarii. So these radio observations are probing a new region of discovery space for extrasolar planets,” says Rodriguez.

“At a distance of only 240 light-years from the solar system, the V4046 Sagittarii binary is at least two times closer to Earth than almost all known planet-forming star systems, which gives us a good shot at imaging any planets that have already formed and are now orbiting the stars,” he continued.

Kastner and collaborators had previously used the 30-meter radio telescope operated by the Institut de Radio Astronomie Millimetrique (IRAM) to study radio molecular spectra emitted from the vicinity of the twin stars. The scientists used these data to identify the raw materials for planet formation around V4046 Sagittarii -- circumstellar carbon monoxide and hydrogen cyanide -- in the noxious circumstellar molecular gas cloud.

“In this case the stars are so close together, and the profile of the gas -- in terms of the types ofmolecules that are there -- is so much like the types of gaseous disks that we see around single stars, that we now have a direct link between planets forming around single stars and planets forming around double stars,” Kastner says.

Domestic Robots

More here from New Scientist.

Did Meteors Make Life Possible?

Image Credit: NASA/JPL

Source and Credit: Imperial College of London

Large bombardments of meteorites approximately four billion years ago could have helped to make the early Earth and Mars more habitable for life by modifying their atmospheres, suggests the results of a paper published today in the journal Geochimica et Cosmochima Acta.

When a meteorite enters a planet’s atmosphere, extreme heat causes some of the minerals and organic matter on its outer crust to be released as water and carbon dioxide before it breaks up and hits the ground.

Researchers suggest the delivery of this water could have made Earth’s and Mars’ atmospheres wetter. The release of the greenhouse gas carbon dioxide could have trapped more energy from sunlight to make Earth and Mars warm enough to sustain liquid oceans.

In the new study, researchers from Imperial College London analysed the remaining mineral and organic content of fifteen fragments of ancient meteorites that had crashed around the world to see how much water vapour and carbon dioxide they would release when subjected to very high temperatures like those that they would experience upon entering the Earth’s atmosphere.

The researchers used a new technique called pyrolysis-FTIR, which uses electricity to rapidly heat the fragments at a rate of 20,000 degrees Celsius per second, and they then measured the gases released.

They found that on average, each meteorite was capable of releasing up to 12 percent of its mass as water vapour and 6 percent of its mass as carbon dioxide when entering an atmosphere. They concluded that contributions from individual meteorites were small and were unlikely to have a significant impact on the atmospheres of planets on their own.

The researchers then analysed data from an ancient meteorite shower called the Late Heavy Bombardment (LHB), which occurred 4 billion years ago, where millions of rocks crashed to Earth and Mars over a period of 20 million years.

Using published models of meteoritic impact rates during the LHB, the researchers calculated that 10 billion tonnes of carbon dioxide and 10 billion tonnes of water vapour could have been delivered to the atmospheres of Earth and Mars each year.

This suggests that the LHB could have delivered enough carbon dioxide and water vapour to turn the atmospheres of the two planets into warmer and wetter environments that were more habitable for life, say the researchers.

Professor Mark Sephton, from Imperial’s Department of Earth Science and Engineering believes the study provides important clues about Earth’s ancient past:

“For a long time, scientists have been trying to understand why Earth is so water rich compared to other planets in our solar system. The LHB may provide a clue. This may have been a pivotal moment in our early history where Earth’s gaseous envelope finally had enough of the right ingredients to nurture life on our planet.”

Lead- author of the study, Dr Richard Court from Imperial’s Department of Earth Science and Engineering, adds:

“Because of their chemistry, ancient meteorites have been suggested as a way of furnishing the early Earth with its liquid water. Now we have data that reveals just how much water and carbon dioxide was directly injected into the atmosphere by meteorites. These gases could have got to work immediately, boosting the water cycle and warming the planet.”

However, researchers say Mars’ good fortune did not last. Unlike Earth, Mars doesn’t have a magnetic field to act as a protective shield from the Sun’s solar wind. As a consequence, Mars was stripped of most of its atmosphere. A reduction in volcanic activity also cooled the planet. This caused its liquid oceans to retreat to the poles where they became ice.

Climate Change: We're So Screwed

From the Bad News of the Week Department (via an MIT press release):

Climate change odds much worse than thought

New analysis shows warming could be double previous estimates

The most comprehensive modeling yet carried out on the likelihood of how much hotter the Earth's climate will get in this century shows that without rapid and massive action, the problem will be about twice as severe as previously estimated six years ago - and could be even worse than that.

The study uses the MIT Integrated Global Systems Model, a detailed computer simulation of global economic activity and climate processes that has been developed and refined by the Joint Program on the Science and Policy of Global Change since the early 1990s. The new research involved 400 runs of the model with each run using slight variations in input parameters, selected so that each run has about an equal probability of being correct based on present observations and knowledge. Other research groups have estimated the probabilities of various outcomes, based on variations in the physical response of the climate system itself. But the MIT model is the only one that interactively includes detailed treatment of possible changes in human activities as well - such as the degree of economic growth, with its associated energy use, in different countries.

Study co-author Ronald Prinn, the co-director of the Joint Program and director of MIT's Center for Global Change Science, says that, regarding global warming, it is important "to base our opinions and policies on the peer-reviewed science," he says. And in the peer-reviewed literature, the MIT model, unlike any other, looks in great detail at the effects of economic activity coupled with the effects of atmospheric, oceanic and biological systems. "In that sense, our work is unique," he says.

The new projections, published this month in the American Meteorological Society's Journal of Climate, indicate a median probability of surface warming of 5.2 degrees Celsius by 2100, with a 90% probability range of 3.5 to 7.4 degrees. This can be compared to a median projected increase in the 2003 study of just 2.4 degrees. The difference is caused by several factors rather than any single big change. Among these are improved economic modeling and newer economic data showing less chance of low emissions than had been projected in the earlier scenarios. Other changes include accounting for the past masking of underlying warming by the cooling induced by 20th century volcanoes, and for emissions of soot, which can add to the warming effect. In addition, measurements of deep ocean temperature rises, which enable estimates of how fast heat and carbon dioxide are removed from the atmosphere and transferred to the ocean depths, imply lower transfer rates than previously estimated.

Prinn says these and a variety of other changes based on new measurements and new analyses changed the odds on what could be expected in this century in the "no policy" scenarios - that is, where there are no policies in place that specifically induce reductions in greenhouse gas emissions. Overall, the changes "unfortunately largely summed up all in the same direction," he says. "Overall, they stacked up so they caused more projected global warming."

While the outcomes in the "no policy" projections now look much worse than before, there is less change from previous work in the projected outcomes if strong policies are put in place now to drastically curb greenhouse gas emissions. Without action, "there is significantly more risk than we previously estimated," Prinn says. "This increases the urgency for significant policy action."

Get the rest of the Bad News here.

Super-Bolide!

From SpaceWeather.com:

On May 31st, evening sky watchers in northern Poland were temporarily blinded by a sudden flash of light brighter than the full Moon. An automated camera in the town of Gniewowo captured this snapshot of the "un-night" sky:

What happened? A meteoroid of unknown origin hit Earth's atmosphere and exploded. "It was a huge fireball, probably brighter than magnitude -13," reports Gniewowo resident Przemyslaw Zoladek. "The explosion occured at 20:48 UT and was observed by many casual witnesses and at least two Polish Fireball Network video stations." No one knows if fragments of the object reached the ground. Click here for updates.

Those Damn Romulans . . .

and their infernal cloaking devices.

From a Purdue University press release:

Researchers have created a new type of invisibility cloak that is simpler than previous designs and works for all colors of the visible spectrum, making it possible to cloak larger objects than before and possibly leading to practical applications in "transformation optics."

Whereas previous cloaking designs have used exotic "metamaterials," which require complex nanofabrication, the new design is a far simpler device based on a "tapered optical waveguide," said Vladimir Shalaev, Purdue University's Robert and Anne Burnett Professor of Electrical and Computer Engineering.

Waveguides represent established technology - including fiber optics - used in communications and other commercial applications.

The research team used their specially tapered waveguide to cloak an area 100 times larger than the wavelengths of light shined by a laser into the device, an unprecedented achievement. Previous experiments with metamaterials have been limited to cloaking regions only a few times larger than the wavelengths of visible light.

Because the new method enabled the researchers to dramatically increase the cloaked area, the technology offers hope of cloaking larger objects, Shalaev said.

Findings are detailed in a research paper appearing May 29 in the journal Physical Review Letters. The paper was written by Igor I. Smolyaninov, a principal electronic engineer at BAE Systems in Washington, D.C.; Vera N. Smolyaninova, an assistant professor of physics at Towson University in Maryland; Alexander Kildishev, a principal research scientist at Purdue's Birck Nanotechnology Center; and Shalaev.

"All previous attempts at optical cloaking have involved very complicated nanofabrication of metamaterials containing many elements, which makes it very difficult to cloak large objects," Shalaev said. "Here, we showed that if a waveguide is tapered properly it acts like a sophisticated nanostructured material."

The waveguide is inherently broadband, meaning it could be used to cloak the full range of the visible light spectrum. Unlike metamaterials, which contain many light-absorbing metal components, only a small portion of the new design contains metal.

Theoretical work for the design was led by Purdue, with BAE Systems leading work to fabricate the device, which is formed by two gold-coated surfaces, one a curved lens and the other a flat sheet. The researchers cloaked an object about 50 microns in diameter, or roughly the width of a human hair, in the center of the waveguide.

"Instead of being reflected as normally would happen, the light flows around the object and shows up on the other side, like water flowing around a stone," Shalaev said.

The research falls within a new field called transformation optics, which may usher in a host of radical advances, including cloaking; powerful "hyperlenses" resulting in microscopes 10 times more powerful than today's and able to see objects as small as DNA; computers and consumer electronics that use light instead of electronic signals to process information; advanced sensors; and more efficient solar collectors.

Unlike natural materials, metamaterials are able to reduce the "index of refraction" to less than one or less than zero. Refraction occurs as electromagnetic waves, including light, bend when passing from one material into another. It causes the bent-stick-in-water effect, which occurs when a stick placed in a glass of water appears bent when viewed from the outside. Each material has its own refraction index, which describes how much light will bend in that particular material and defines how much the speed of light slows down while passing through a material.

Natural materials typically have refractive indices greater than one. Metamaterials, however, can be designed to make the index of refraction vary from zero to one, which is needed for cloaking.

The precisely tapered shape of the new waveguide alters the refractive index in the same way as metamaterials, gradually increasing the index from zero to 1 along the curved surface of the lens, Shalaev said.

Previous cloaking devices have been able to cloak only a single frequency of light, meaning many nested devices would be needed to render an object invisible.

Kildishev reasoned that the same nesting effect might be mimicked with the waveguide design. Subsequent experiments and theoretical modeling proved the concept correct.

Researchers do not know of any fundamental limit to the size of objects that could be cloaked, but additional work will be needed to further develop the technique.

Recent cloaking findings reported by researchers at other institutions have concentrated on a technique that camouflages features against a background. This work, which uses metamaterials, is akin to rendering bumps on a carpet invisible by allowing them to blend in with the carpet, whereas the Purdue-based work concentrates on enabling light to flow around an object.

Finding Water On Other Earths

Source and Credit: University of Washington

Since the early 1990s astronomers have discovered more than 300 planets orbiting stars other than our sun, nearly all of them gas giants like Jupiter. Powerful space telescopes, such as the one that is central to NASA's recently launched Kepler Mission, will make it easier to spot much smaller rocky extrasolar planets, or exoplanets, more similar to Earth.

But seen from dozens of light years away, an Earth-like exoplanet will appear in telescopes as little more than a "pale blue dot," the term coined by the late astronomer Carl Sagan to describe how Earth appeared in a 1990 photograph taken by the Voyager spacecraft from near the edge of the solar system.

Using instruments aboard the Deep Impact spacecraft, a team of astronomers and astrobiologists has devised a technique to tell whether such a planet harbors liquid water, which in turn could tell whether it might be able to support life.

"Liquid water on the surface of a planet is the gold standard that people are looking for," said Nicolas Cowan, a University of Washington doctoral student in astronomy and lead author of a paper explaining the new technique that has been accepted for publication in Astrophysical Journal.

As part of NASA's Extrasolar Planet Observation and Characterization mission, the scientists obtained two separate 24-hour observations of light intensity from Earth in seven bands of visible light, from shorter wavelengths near ultraviolet to longer wavelengths near infrared. Earth appears gray at most wavelengths because of cloud cover, but it appears blue at short wavelengths because of the same atmospheric phenomenon that makes the sky look blue to people on the surface.

The researchers studied small deviations from the average color caused by surface features like clouds and oceans rotating in and out of view. They found two dominant colors, one reflective at long, or red, wavelengths and the other at short, or blue, wavelengths. They interpreted the red as land masses and the blue as oceans.

The analysis was undertaken "as if we were aliens looking at Earth with the tools we might have in 10 years" and did not already know Earth's composition, Cowan said. "You sum up the brightness into a single pixel in the telescope's camera, so it truly is a pale blue dot."

Since Earth's colors changed throughout the 24-hour-long observations, the scientists made maps of the planet in the dominant red and blue colors and then compared their interpretations with the actual location of the planet's continents and oceans.

"You could tell that there were liquid oceans on the planet," Cowan said. "The idea is that to have liquid water the planet would have to be in its system's habitable zone, but being in the habitable zone doesn't guarantee having liquid water."

The observations on March 18 and June 4, 2008 were made when the spacecraft was between 17 million and 33 million miles from Earth, and while it was directly above the equator. Observations from above a polar region likely would show up as white, Cowan said.

It will be some years before the launch of space telescopes capable of making similar observations for Earth-sized exoplanets, but devising this technique now could guide the construction of those instruments, he said. And while those planets will be much farther away, the technique still will be applicable.

"You will still have all the spectral information, and more importantly to us you'll still have the information so that you can see how the brightness of that speck is changing over time, Cowan said."

Co-authors are Eric Agol, Victoria Meadows and Tyler Robinson of the UW, Timothy Livengood and Drake Deming of the NASA Goddard Space Flight Center, Carey Lisse of Johns Hopkins University, Michael A'Hearn and Dennis Wellnitz of the University of Maryland, Sara Seager of the Massachusetts Institute of Technology and David Charbonneau of the Harvard-Smithsonian Center for Astrophysics. The work was funded by the Natural Sciences and Engineering Research Council of Canada, the National Science Foundation and the NASA Discovery Program.

Cowan notes that some non-habitable planets, such as Neptune, also can appear to be blue, but the color is constant and, in the case of Neptune, likely caused by methane in the atmosphere.

"It looks blue from every angle, the same blue all the way around. If you had an ocean planet it might look like that, but you can do other tests to determine that," he said. "For Earth, the blue varies from one place to another, which indicates that it's not something in the atmosphere."

A Planet As Big As Its Star

Image Credit: NASA/JPL

Source and Credit: PlanetQuest (NASA/JPL)

A long-proposed tool for hunting planets has netted its first catch -- a Jupiter-like planet orbiting one of the smallest stars known.

The technique, called astrometry, was first attempted 50 years ago to search for planets outside our solar system, called exoplanets. It involves measuring the precise motions of a star on the sky as an unseen planet tugs the star back and forth. But the method requires very precise measurements over long periods of time, and until now, has failed to turn up any exoplanets.

A team of two astronomers from NASA's Jet Propulsion Laboratory, Pasadena, Calif., has, for the past 12 years, been mounting an astrometry instrument to a telescope at the Palomar Observatory near San Diego. After careful, intermittent observations of 30 stars, the team has identified a new exoplanet around one of them -- the first ever to be discovered around a star using astrometry.

"This method is optimal for finding solar-system configurations like ours that might harbor other Earths," said astronomer Steven Pravdo of JPL, lead author of a study about the results to be published in the Astrophysical Journal. "We found a Jupiter-like planet at around the same relative place as our Jupiter, only around a much smaller star. It's possible this star also has inner rocky planets. And since more than seven out of 10 stars are small like this one, this could mean planets are more common than we thought."

The finding confirms that astrometry could be a powerful planet-hunting technique for both ground- and space-based telescopes. For example, a similar technique would be used by SIM Lite, a NASA concept for a space-based mission that is currently being explored.

The newfound exoplanet, called VB 10b, is about 20 light-years away in the constellation Aquila. It is a gas giant, with a mass six times that of Jupiter's, and an orbit far enough away from its star to be labeled a "cold Jupiter" similar to our own. In reality, the planet's own internal heat would give it an Earth-like temperature.

The planet's star, called VB 10, is tiny. It is what's known as an M-dwarf and is only one-twelfth the mass of our sun, just barely big enough to fuse atoms at its core and shine with starlight. For years, VB 10 was the smallest star known -- now it has a new title: the smallest star known to host a planet. In fact, though the star is more massive than the newfound planet, the two bodies would have a similar girth.

Because the star is so small, its planetary system would be a miniature, scaled-down version of our own. For example, VB 10b, though considered a cold Jupiter, is located about as far from its star as Mercury is from the sun. Any rocky Earth-size planets that might happen to be in the neighborhood would lie even closer in.

"Some other exoplanets around larger M-dwarf stars are also similar to our Jupiter, making the stars fertile ground for future Earth searches," said Stuart Shaklan, Pravdo's co-author and the SIM Lite instrument scientist at JPL. "Astrometry is best suited to find cold Jupiters around all kinds of stars, and thus to find more planetary systems arranged like our home."

Two to six times a year, for the past 12 years, Pravdo and Shaklan have bolted their Stellar Planet Survey instrument onto Palomar's five-meter Hale telescope to search for planets. The instrument, which has a 16-megapixel charge-coupled device, or CCD, can detect very minute changes in the positions of stars. The VB 10b planet, for instance, causes its star to wobble a small fraction of a degree. Detecting this wobble is equivalent to measuring the width of a human hair from about three kilometers away.

Other ground-based planet-hunting techniques in wide use include radial velocity and the transit method. Like astrometry, radial velocity detects the wobble of a star, but it measures Doppler shifts in the star's light caused by motion toward and away from us. The transit method looks for dips in a star's brightness as orbiting planets pass by and block the light. NASA's space-based Kepler mission, which began searching for planets on May 12, will use the transit method to look for Earth-like worlds around stars similar to the sun.

"This is an exciting discovery because it shows that planets can be found around extremely light-weight stars," said Wesley Traub, the chief scientist for NASA's Exoplanet Exploration Program at JPL. "This is a hint that nature likes to form planets, even around stars very different from the sun."

Life 4.4 Billion Years Ago?

Image Credit:  NASA/JPL

Source and Credit:  UC-Boulder

The bombardment of Earth nearly 4 billion years ago by asteroids as large as Kansas would not have had the firepower to extinguish potential early life on the planet and may even have given it a boost, says a new University of Colorado at Boulder study.

Impact evidence from lunar samples, meteorites and the pockmarked surfaces of the inner planets paints a picture of a violent environment in the solar system during the Hadean Eon 4.5 to 3.8 billion years ago, particularly through a cataclysmic event known as the Late Heavy Bombardment about 3.9 million years ago. Although many believe the bombardment would have sterilized Earth, the new study shows it would have melted only a fraction of Earth's crust, and that microbes could well have survived in subsurface habitats, insulated from the destruction.

"These new results push back the possible beginnings of life on Earth to well before the bombardment period 3.9 billion years ago," said CU-Boulder Research Associate Oleg Abramov. "It opens up the possibility that life emerged as far back as 4.4 billion years ago, about the time the first oceans are thought to have formed."

A paper on the subject by Abramov and CU-Boulder geological sciences Professor Stephen Mojzsis appears in the May 21 issue of Nature.

Because physical evidence of Earth's early bombardment has been erased by weathering and plate tectonics over the eons, the researchers used data from Apollo moon rocks, impact records from the moon, Mars and Mercury, and previous theoretical studies to build three-dimensional computer models that replicate the bombardment. Abramov and Mojzsis plugged in asteroid size, frequency and distribution estimates into their simulations to chart the damage to the Earth during the Late Heavy Bombardment, which is thought to have lasted for 20 million to 200 million years.

The 3-D models allowed Abramov and Mojzsis to monitor temperatures beneath individual craters to assess heating and cooling of the crust following large impacts in order to evaluate habitability, said Abramov. The study indicated that less than 25 percent of Earth's crust would have melted during such a bombardment.

The CU-Boulder researchers even cranked up the intensity of the asteroid barrage in their simulations by 10-fold -- an event that could have vaporized Earth's oceans. "Even under the most extreme conditions we imposed, Earth would not have been completely sterilized by the bombardment," said Abramov.

Instead, hydrothermal vents may have provided sanctuaries for extreme, heat-loving microbes known as "hyperthermophilic bacteria" following bombardments, said Mojzsis. Even if life had not emerged by 3.9 billion years ago, such underground havens could still have provided a "crucible" for life's origin on Earth, Mojzsis said.

The researchers concluded subterranean microbes living at temperatures ranging from 175 degrees to 230 degrees Fahrenheit would have flourished during the Late Heavy Bombardment. The models indicate that underground habitats for such microbes increased in volume and duration as a result of the massive impacts. Some extreme microbial species on Earth today -- including so-called "unboilable bugs" discovered in hydrothermal vents in Yellowstone National Park -- thrive at 250 F.

Geologic evidence suggests that life on Earth was present at least 3.83 billion years ago, said Mojzsis. "So it is not unreasonable to suggest there was life on Earth before 3.9 billion years ago. We know from the geochemical record that our planet was eminently habitable by that time, and this new study sews up a major problem in origins of life studies by sweeping away the necessity for multiple origins of life on Earth."

Most planetary scientists believe a rogue planet as large as Mars smacked Earth with a glancing blow 4.5 billion years ago, vaporizing itself and part of Earth. The collision would have created an immense vapor cloud from which moonlets, and later our moon, coalesced, Mojzsis said. "That event, which preceded the Late Heavy Bombardment by at least 500 million years, would have effectively hit Earth's re-set button," he said.

"But our results strongly suggest that no events since the moon formation were capable of destroying Earth's crust and wiping out any biosphere that was present," Mojzsis said. "Instead of chopping down the tree of life, our view is that the bombardment pruned it."

The results also support the potential for microbial life on other planets like Mars and perhaps even rocky, Earth-like planets in other solar systems that may have been resurfaced by impacts, said Abramov.

"Exactly when life originated on Earth is a hotly debated topic," says NASA's Astrobiology Discipline Scientist Michael H. New, manager of the Exobiology and Evolutionary Biology program. "These findings are significant because they indicate life could have begun well before the Late Heavy Bombardment, during the so-called Hadean Eon of Earth's history 3.8 billion to 4.5 billion years ago."

Lost Robot

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Read the full article at New Scientist.

Kepler's Planet Hunt Begins

Image Credit:  NASA/JPL

Source and Credit:  NASA/JPL

NASA's Kepler spacecraft has begun its search for other Earth-like worlds. The mission, which launched from Cape Canaveral, Fla., on March 6, will spend the next three-and-a-half years staring at more than 100,000 stars for telltale signs of planets. Kepler has the unique ability to find planets as small as Earth that orbit sun-like stars at distances where temperatures are right for possible lakes and oceans. 

"Now the fun begins," said William Borucki, Kepler science principal investigator at NASA's Ames Research Center, Moffett Field, Calif. "We are all really excited to start sorting through the data and discovering the planets." 

Scientists and engineers have spent the last two months checking out and calibrating the Kepler spacecraft. Data have been collected to characterize the imaging performance as well as the noise level in the measurement electronics. The scientists have constructed the list of targets for the start of the planet search, and this information has been loaded onto the spacecraft. 

"If Kepler got into a staring contest, it would win," said James Fanson, Kepler project manager at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "The spacecraft is ready to stare intently at the same stars for several years so that it can precisely measure the slightest changes in their brightness caused by planets." Kepler will hunt for planets by looking for periodic dips in the brightness of stars -- events that occur when orbiting planets cross in front of their stars and partially block the light. 

The mission's first finds are expected to be large, gas planets situated close to their stars. Such discoveries could be announced as early as next year. 

Kepler is a NASA Discovery mission. NASA Ames Research Center, Moffett Field, Calif., is the home organization of the science principal investigator, and is responsible for the ground system development, mission operations and science data analysis. JPL manages the Kepler mission development. Ball Aerospace & Technologies Corp. of Boulder, Colo., is responsible for developing the Kepler flight system and supporting mission operations. 

For more information about the Kepler mission, visit: http://www.nasa.gov/kepler and http://www.kepler.nasa.gov .

First Optical SETI Detection?

From a recent article in The Australian:

AFTER you've spent more than 20 years hunting for an alien signal, you think you'd be celebrating if you noticed a mysterious pulse suddenly rising up on your computer readouts. A regular pulse, amid the random clatter of the cosmos, suggests that someone very smart at the other end is sending a message.

But when Ragbir Bhathal, an astrophysicist at the University of Western Sydney, who teaches the only university-based course on SETI (search for extraterrestrial intelligence) in Australia, detected the suspicious signal on a clear night last December, he knew better than to crack open the special bottle of champagne he has tucked away for the history-making occasion.

Instead, he's spent the past few months meticulously investigating whether the unrecognised signature was caused by a glitch in his instrumentation, a rogue astrophysical phenomenon, or some unknown random noise.

Even if he picks up the signal again - he's been scouring the same co-ordinates of the night sky on an almost daily basis since - the scientific rule book dictates he'll need to get it peer-reviewed before he can take his announcement to the world. "And that is a lot of ifs," he concedes.

Has Bhathal made the first detection of an advanced technological civilization from an extrasolar planetary system?  

According to the article, Bhathal's OZ OSETI program is an optical SETI program searching for extraterrestrial laser bursts.  The only optical SETI program in Earth's southern hemisphere, OZ OSETI searches out to 100 light-years -- an area large enough to contain at least 1000 stars and perhaps 20 times as many planets.

Which could mean -- if Bhathal finds that elusive signal again -- our first confirmed galactic neighbor may be closer than many predicted.

Astro-Comb To Hunt Planets

Artist's impression of an exoplanet.  Credit:  ESO

Source and Credit:  Optical Society of America, via EurekAlert!

Thanks to the ability of astronomers to detect the presence of extrasolar planets orbiting distant stars, scientists today are able to examine hundreds of solar systems. Now researchers at the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass. have created an "astro-comb" to help astronomers detect lighter planets, more like Earth, around distant stars.

In most cases, extrasolar planets can't be seen directly—the glare of the nearby star is too great—but their influence can be discerned through spectroscopy, which analyzes the energy spectrum of the light coming from the star. Not only does spectroscopy reveal the identity of the atoms in the star (each element emits light at a certain characteristic frequency), it can also tell researchers how fast the star is moving away or toward Earth, courtesy of the Doppler effect, which occurs whenever a source of waves is itself in motion. By recording the change in the frequency of the waves coming from or bouncing off of an object, scientists can deduce the velocity of the object.

This process is used to judge the speed of automobiles, storm systems, fastballs, and stars. How can it be used to deduce the presence of a planet? Though the planet might weigh millions of times less than the star, the star will be jerked around a tiny amount owing to the gravity interaction between star and planet. This jerking motion causes the star to move toward or away from Earth slightly in a way that depends on the planet's mass and its nearness to the star. The better the spectroscopy used in this whole process, the better will be the identification of the planet in the first place and the better will be the determination of planetary properties.

Right now standard spectroscopy techniques can determine star movements to within a few meters per second (m/sec). In tests, the Harvard researchers are now able to calculate star velocity shifts of less than 1 m/sec, allowing them to more accurately pinpoint the planet's location.

Smithsonian researcher David Phillips says that he and his colleagues expect to reach a velocity resolution of 60 cm/sec, and maybe even 1 cm/sec, which when applied to the activities of large telescopes presently under construction, would open new possibilities in astronomy and astrophysics, including simpler detection of more Earth-like planets.

With this new approach, Harvard astronomers achieve their great improvement using a frequency comb as the basis for the astro-comb. A special laser system is used to emit light not at a single energy but a series of energies (or frequencies), evenly spaced across a wide range of values. A plot of these narrowly-confined energy components would look like the teeth of a comb, hence the name frequency comb. The energy of these comb-like laser pulses is known so well that they can be used to calibrate the energy of light coming in from the distant star. In effect, the frequency comb approach sharpens the spectroscopy process. The resultant astro-comb should enable a further expansion of extrasolar planetary detection.

The astro-comb method has been tried out on a medium-sized telescope in Arizona and will soon be installed on the much larger William Herschel Telescope, which resides on a mountaintop in the Canary Islands.

R U Transhumanist 2?

More here from New Scientist.

Warp Speed Possible

Source and Credit:  Baylor University

Two Baylor University scientists have come up with a new method to cause a spaceship to effectively travel faster than the speed of light, without breaking the laws of physics.

Dr. Gerald Cleaver, associate professor of physics at Baylor, and Richard Obousy, a Baylor graduate student, theorize that by manipulating the extra spatial dimensions of string theory around a spaceship with an extremely large amount of energy, it would create a "bubble" that could cause the ship to travel faster than the speed of light. To create this bubble, the Baylor physicists believe manipulating the 10th spatial dimension would alter the dark energy in three large spatial dimensions: height, width and length. Cleaver said positive dark energy is currently responsible for speeding up the expansion rate of our universe as time moves on, just like it did after the Big Bang, when the universe expanded much faster than the speed of light for a very brief time.

"Think of it like a surfer riding a wave," said Cleaver, who co-authored the paper with Obousy about the new method. "The ship would be pushed by the spatial bubble and the bubble would be traveling faster than the speed of light."

The method is based on the Alcubierre drive, which proposes expanding the fabric of space behind a ship and shrinking space-time in front of the ship. The ship would not actually move, rather the ship would sit in a bubble between the expanding and shrinking space-time dimensions. Since space would move around the ship, the theory does not violate Einstein's Theory of Relativity, which states that it would take an infinite amount of energy to accelerate a massive object to the speed of light.

String theory suggests the universe is made up of multiple dimensions. Height, width and length are three dimensions, and time is the fourth dimension. String theorists use to believe that there were a total of 10 dimensions, with six other dimensions that we can not yet identify because of their incredibly small size. A new theory, called M-theory, takes string theory one step farther and states that the "strings" that all things are made of actually vibrate in an additional spatial dimensional, which is called the 10th dimension. It is by changing the size of this 10th spatial dimension that Baylor researchers believe could alter the strength of the dark energy in such a manner to propel a ship faster than the speed of light.

The Baylor physicists estimate that the amount of energy needed to influence the extra dimension is equivalent to the entire mass of Jupiter being converted into pure energy for a ship measuring roughly 10 meters by 10 meters by 10 meters.

"That is an enormous amount of energy," Cleaver said. "We are still a very long ways off before we could create something to harness that type of energy."

The paper appears in the Journal of the British Interplanetary Society.

The full paper can be viewed here.

 

Dead Suns, Dead Planets

Image Credit: NASA/JPL-Caltech

Source and Credit:  Royal Astronomical Society

Using NASA’s Spitzer Space Telescope, an international team of astronomers have found that at least 1 in 100 white dwarf stars show evidence of orbiting asteroids and rocky planets, suggesting these objects once hosted Solar Systems similar to our own.

White dwarf stars are the compact, hot remnants left behind when stars like our Sun reach the end of their lives. Their atmospheres should consist entirely of hydrogen and helium but are sometimes found to be contaminated with heavier elements like calcium and magnesium. The new observations suggest that these Earth-sized stars are often polluted by a gradual rain of closely orbiting dust that emits infrared radiation picked up by Spitzer.

The data suggest that at least 1% to 3% of white dwarf stars are contaminated in this way and that the dust originates from rocky bodies like asteroids (also known as minor planets). In our Solar System, minor planets are the left over building blocks of the rocky terrestrial planets like the Earth. The Spitzer results imply that asteroids are found in orbit around a large number of white dwarfs, perhaps as many as 5 million in our own Milky Way Galaxy.

The new findings indicate the dust is completely contained within the Roche limit of the star -- close enough that any object larger than a few kilometres would be ripped apart by gravitational tides (the same phenomenon which led to the creation of Saturn's rings).  This backs up the team’s hypothesis that the dust disks around white dwarfs are produced by tidally disrupted minor planets.  In order to pass this close to the white dwarf, an asteroid must be perturbed from its regular orbit further out – and this can occur during a close encounter with as yet unseen planets.

Because white dwarfs descend from main sequence stars like the Sun, the team’s work implies that at least 1% to 3% of main sequence stars have terrestrial planets around them. Dr Farihi comments. “In the quest for Earth-like planets, we have now identified numerous systems which are excellent candidates to harbour them. Where they persist at white dwarfs, any terrestrial planets will likely not be habitable, but may have been sites where life developed during a previous epoch. “

Perhaps the most exciting and important aspect of this research is that the composition of these crushed asteroids can be measured using the heavy elements seen in the white dwarf.

Dr Farihi sees this as a crucial step forward. “With high quality optical and ultraviolet observations (e.g. the Hubble Space Telescope), we should be able to measure up to two dozen different elements in debris-polluted white dwarfs.  We can then address the question, “Are the rocky extrasolar planets we find similar to the terrestrial planets of our Solar System?”

Comets Made Life Possible

Source and Credit:  Tel Aviv University

Comets have always fascinated us. In early cultures, a mysterious appearance of a comet could symbolize a deity's displeasure with humankind or mean a sure failure in battle, at least for one side. Now Tel Aviv University research adds a new twist to that fascination: comets might have provided the elements for the emergence of life on our planet.

While investigating the chemical make-up of comets, Prof. Akiva Bar-Nun of the Department of Geophysics and Planetary Sciences at Tel Aviv University found they were the source of missing ingredients needed for life in Earth's ancient primordial soup. "When comets slammed into the Earth through the atmosphere about four billion years ago, they delivered a payload of organic materials to the young Earth, adding materials that combined with Earth's own large reservoir of organics and led to the emergence of life," says Prof. Bar-Nun.

It was the chemical composition of comets, Prof. Bar-Nun believes, that allowed them to kickstart life. He has published his theory widely in scientific journals, including recently in the journal Icarus.

A Pinch of Argon, A Dash of Xenon

Using a one-of-a-kind machine built at Tel Aviv University, researchers were able to simulate comet ice, and found that comets contain ingredients necessary for providing the basic nutrients of life.

Specifically, Prof. Bar-Nun looked at the noble gases Argon, Krypton and Xenon, because they do not interact with any other elements and are not destroyed by Earth's oxygen. These elements have maintained stable proportions in the Earth's atmosphere throughout the lifetime of the planet, he explains.

"Now if we look at these elements in the atmosphere of the Earth and in meteorites, we see that neither is identical to the ratio in the sun's composition. Moreover, the ratios in the atmosphere are vastly different than the ratios in meteorites which make up the bulk of the Earth. So we need another source of noble gases which, when added to these meteorites or asteroid influx, could change the ratio. And this came from comets.

Solving the Otherworldly Puzzle

Comets are essentially large chunks of ice, whose temperature ranges from -200 to -250 degrees centigrade. Formed in the early days of the solar system far away from the sun, water vapor condensed directly into ice, making little grains. These grains came together to form the comets, which are less than 2/3 of a mile in diameter, explains Prof. Bar-Nun.

During the comets' formation, the porous ice trapped gases and organic chemicals that were present in outer space. "The pattern of trapping of noble gases in the ice gives a certain ratio of Argon to Krypton to Xenon, and this ratio — together with the ratio of gases that come from rocky bodies — gives us the ratio that we observe in the atmosphere of the Earth."

Thus, the arrival on Earth of comets and asteroids led to the necessary ratio of materials for organic life, "which eventually were dissolved in the ocean and started the long process leading to the emergence of life on Earth," says Prof. Bar-Nun.

Asteroid Showers and Thunderstorms

The story started between 4.6 and 3.8 billion years ago, when both the moon and the Earth were bombarded by a flux of asteroids and comets. "On the Earth, most of the craters were obliterated by continental movement and by weathering winds and water erosion. On the moon, they remained as they were," says Prof. Bar-Nun, who adds that no life could thrive during this period of bombardment.

But the Earth recovered, and three to four hundred million years later, fragile forms of life emerged after the comet-delivered elements precipitated into the ocean. "There was another chemical development of these molecules in water, which became more and more complex," says Prof. Bar-Nun, leading to the origin of life on Earth.

Thought-Controlled Robotic Wheelchair

Paralyzed people may soon be able to drive motorized wheelchairs controlled by a combination of mind-reading computers and autonomous software.  

Full story from New Scientist.

Invisibility Cloak Becomes Reality

Source and Credit:  DOE/Lawrence Berkeley National Laboratory

The great science fiction writer Arthur C. Clarke famously noted the similarities between advanced technology and magic. This summer on the big screen, the young wizard Harry Potter will once again don his magic invisibility cloak and disappear. Meanwhile, researchers with Berkeley Lab and the University of California (UC) Berkeley will be studying an invisibility cloak of their own that also hides objects from view.

A team led by Xiang Zhang, a principal investigator with Berkeley Lab’s Materials Sciences Division and director of UC Berkeley’s Nano-scale Science and Engineering Center, has created a “carpet cloak” from nanostructured silicon that conceals the presence of objects placed under it from optical detection. While the carpet itself can still be seen, the bulge of the object underneath it disappears from view. Shining a beam of light on the bulge shows a reflection identical to that of a beam reflected from a flat surface, meaning the object itself has essentially been rendered invisible.

“We have come up with a new solution to the problem of invisibility based on the use of dielectric (nonconducting) materials,” says Zhang. “Our optical cloak not only suggests that true invisibility materials are within reach, it also represents a major step towards transformation optics, opening the door to manipulating light at will for the creation of powerful new microscopes and faster computers.”

Zhang and his team have published a paper on this research in the journal Nature Materials entitled: An Optical Cloak Made of Dielectrics. Co-authoring the paper with Zhang were Jason Valentine, Jensen Li, Thomas Zentgraf and Guy Bartal, all members of Zhang’s research group.

Get the full story here.

History Of The Drake Equation

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More here at MSNBC.com.

Mind-Reading Computers

They're here.  According to this article (and video, above) from New Scientist, this year you will be able to buy for about $300 a headset that enables you to use EEG technology to control computers with thought alone.

Related:  you can now use this same technology to "tweet" on Twitter.

Alien Detection System Proposed

Source and Credit:  National Institute of Standards and Technology

If a scientific team working at the National Institute of Standards and Technology (NIST) is right, we may be able to find extraterrestrial life even before it leaves its home planet—by looking for left- (or right-) handed light.

The technique the team has developed* for detecting life elsewhere in the universe will not spot aliens directly. Rather, it could allow spaceborne instruments to see a telltale sign that life may have influenced a landscape: a preponderance of molecules that have a certain “chirality,” or handedness. A right-handed molecule has the same composition as its left-handed cousin, but their chemical behavior differs. Because many substances critical to life favor a particular handedness, Thom Germer and his colleagues think chirality might reveal life’s presence at great distances, and have built a device to detect it.

“You don’t want to limit yourself to looking for specific materials like oxygen that Earth creatures use, because that makes assumptions about what life is,” says Germer, a physicist at NIST. “But amino acids, sugars, DNA—each of these substances is either right- or left-handed in every living thing.”

Many molecules not associated with life exhibit handedness as well. But when organisms reproduce, their offspring possess chiral molecules that have the same handedness as those in their parents’ bodies. As life spreads, the team theorizes, the landscape will eventually have a large amount of molecules that favor one handedness.

“If the surface had just a collection of random chiral molecules, half would go left, half right,” Germer says. “But life’s self-assembly means they all would go one way. It’s hard to imagine a planet’s surface exhibiting handedness without the presence of self assembly, which is an essential component of life.”

Because chiral molecules reflect light in a way that indicates their handedness, the research team built a device to shine light on plant leaves and bacteria, and then detect the polarized reflections from the organisms’ chlorophyll from a short distance away. The device detected chirality from both sources.

The team intends to improve its detector so it can look at pond surfaces and then landscape-sized regions on Earth. Provided the team continues to get good results, Germer says, they will propose that it be built into a large telescope or mounted on a space probe.

“We need to be sure we get a signal from our own planet before we can look at others,” he says. “But what’s neat about the concept is that it is sensitive to something that comes from the process behind organic self-assembly, but not necessarily life as we know it.”

Funding for this research was provided by the Space Telescope Science Institute and the European Space Agency.

* W.B. Sparks, J. Hough, T.A. Germer, F. Chen, S. DasSarma, P. DasSarma, F.T. Robb, N. Manset, L. Kolokolova, N. Reid, F.D. Macchetto and W. Martin. Detection of circular polarization in light scattered from photosynthetic microbes. Proceedings of the National Academy of Sciences, April 20, 2009.

Earth -Size Planet Soon?

Artist's impression of the five-Earth mass planet, Gliese 581 c, found in the habitable zone around the red dwarf Gliese 581. Credit: European Southern Observatory

Source and Credit: Astrobiology Magazine (NASA)

The discovery of the lightest exoplanet ever found, less than twice the mass of the Earth, has electrified a week-long meeting on astronomy and space science in Europe. The stunning finding was made by a team headed by Michel Mayor of the Geneva Observatory. The icing on the cake is a related discovery that a previously discovered “super-Earth” orbiting the same star appears to reside in the habitable zone.

Mayor made the very first discovery of an exoplanet, a Jupiter-sized world that orbits the star 51 Pegasi, in 1994. Among his many planet discoveries since then at ESO’s La Silla Observatory in Chile, Mayor has made a specialty of observing the star Gliese 581. Located 20.5 light-years away in the constellation Libra (“the Scales”), Gliese 581 is a red dwarf star with only one-third of the mass of our sun.

Two years ago, Mayor discovered a planet the size of Neptune and two super-Earths orbiting this star. The newly discovered planet, named Gliese 581 e, is now the fourth known planet in this solar system and the lightest, weighing in at only 1.94 Earth masses. It flies round the star at dizzying speed, taking just 3.15 days to complete an orbit. “The surprise for me was to discover a planet with by far the lowest mass seen to date,” says Mayor.

This new planet orbits so close to the star that its water would have boiled away long ago. It is therefore not in the habitable zone – the region of a solar system where water can stay liquid on the surface of a rocky planet, and, consequently, where scientists expect life can occur. In our solar system, the habitable zone is roughly between the orbits of Venus and Mars (with Earth sitting not quite in the middle).

In finding the new planet, Mayor has been able to more accurately determine the orbit for the outermost planet, Gliese 581 d. One of the super-Earths in the solar system, this planet is closer to the host star than was thought when it was discovered in 2007. And that provided the second great surprise. “It is the only (Earth-like) exoplanet found inside the habitable water zone of the parent star,” says Mayor.

Gliese 581 d is 7 Earth-masses, and team member Stephane Udry says the planet is probably too massive to be made only of rocky material. “We can speculate that it is an icy planet that has migrated closer to the star,” he says. At the European meeting, Mayor added the latest news indicated, “No icebergs, but there may be an ocean at the surface, meaning this is a new class of ocean planet.”

To detect exoplanets, Mayor’s team studies a star’s radial velocity, in which the tiny tugs exerted by orbiting exoplanets produce a complex wobble in the star. This wobble can be analyzed to learn about properties of the planets in the solar system. The velocity of a star with multiple planets has to be followed for several years to discover the different properties of its orbiting planets, and this requires instrumentation that is extremely stable from year to year -- one of the big challenges in detecting exoplanets through the radial velocity technique.

The team’s observing program began back in 2004 with a sample of 400 sun-like stars. Mayor is now scooping up small exoplanets that have been missed by a rival search technique (called transit photometry) which involves measuring the tiny fall in a star’s magnitude when an exoplanet passes between the star and the Earth. Both techniques, transit photometry and radial velocity, are strongly biased to catch giant planets with the mass of Jupiter or more, as well as smaller planets that orbit very close to their star. But to find small planets orbiting within a star’s habitable zone, Mayor’s approach now seems to have the edge.

The team has found that one-third (30%) of exoplanet systems found to date include small bodies. “We have discovered a new category of small exoplanets,” says Mayor. “Within a couple of years we will drive down our lower limit of detection to the mass of the Earth. The next challenge after that is to detect a twin of the Earth in the habitable zone of a solar-type star.”

The next stage for Mayor’s team is to migrate the detection technology from the current 3.6-meter telescope to ESO’s 8-meter Very Large Telescope in order to improve the precision of observations. After that, Mayor looks forward to using the European Extremely Large Telescope (E-ELT), a 42-meter eye-on-the-sky that is planned to be operating by 2018. Currently in the later stages of design, this facility will be capable of directly imaging larger exoplanets, and possibly will be able to search their atmospheres for biosignatures. E-ELT will answer fundamental questions on the formation and evolution of exoplanets, bringing us one step closer to answering the question: are we alone?

Smallest Exoplanet Yet!

Image Credit:  ESO

The news I hinted at Sunday is now out:  astronomers at the European Southern Observatory have discovered the least massive and probably smallest extrasolar, a comparative waif of a planet in the well-known extrasolar planetary system Gliese 581. Weighing in at only 1.9 times the mass of Earth, it brings us ever closer to the discovery of the first Earth-like terrestrial exoplanet.  Here's a video report from New Scientist:

Source and Credit:  ESO Press Release

Lightest exoplanet yet discovered

Well-known exoplanet researcher Michel Mayor today announced the discovery of the lightest exoplanet found so far. The planet, “e”, in the famous system Gliese 581, is only about twice the mass of our Earth. The team also refined the orbit of the planet Gliese 581 d, first discovered in 2007, placing it well within the habitable zone, where liquid water oceans could exist. These amazing discoveries are the outcome of more than four years of observations using the most successful low-mass-exoplanet hunter in the world, the HARPS spectrograph attached to the 3.6-metre ESO telescope at La Silla, Chile. 

“The holy grail of current exoplanet research is the detection of a rocky, Earth-like planet in the ‘habitable zone’ — a region around the host star with the right conditions for water to be liquid on a planet’s surface”, says Michel Mayor from the Geneva Observatory, who led the European team to this stunning breakthrough.

Planet Gliese 581 e orbits its host star – located only 20.5 light-years away in the constellation Libra (“the Scales”) — in just 3.15 days. “With only 1.9 Earth-masses, it is the least massive exoplanet ever detected and is, very likely, a rocky planet”, says co-author Xavier Bonfils from Grenoble Observatory.

Being so close to its host star, the planet is not in the habitable zone. But another planet in this system appears to be. From previous observations — also obtained with the HARPS spectrograph at ESO’s La Silla Observatory and announced two years ago — this star was known to harbour a system with a Neptune-sized planet (ESO 30/05) and two super-Earths (ESO 22/07). With the discovery of Gliese 581 e, the planetary system now has four known planets, with masses of about 1.9 (planet e), 16 (planet b), 5 (planet c), and 7 Earth-masses (planet d). The planet furthest out, Gliese 581 d, orbits its host star in 66.8 days. “Gliese 581 d is probably too massive to be made only of rocky material, but we can speculate that it is an icy planet that has migrated closer to the star,” says team member Stephane Udry. The new observations have revealed that this planet is in the habitable zone, where liquid water could exist. “‘d’ could even be covered by a large and deep ocean — it is the first serious 'water world' candidate,” continued Udry.

The gentle pull of an exoplanet as it orbits the host star introduces a tiny wobble in the star’s motion — only about 7 km/hour, corresponding to brisk walking speed — that can just be detected on Earth with today’s most sophisticated technology. Low-mass red dwarf stars such as Gliese 581 are potentially fruitful hunting grounds for low-mass exoplanets in the habitable zone. Such cool stars are relatively faint and their habitable zones lie close in, where the gravitational tug of any orbiting planet found there would be stronger, making the telltale wobble more pronounced. Even so, detecting these tiny signals is still a challenge, and the discovery of Gliese 581 e and the refinement of Gliese 581 d’s orbit were only possible due to HARPS’s unique precision and stability.

“It is amazing to see how far we have come since we discovered the first exoplanet around a normal star in 1995 — the one around 51 Pegasi,” says Mayor. “The mass of Gliese 581 e is 80 times less than that of 51 Pegasi b. This is tremendous progress in just 14 years.”

The astronomers are confident that they can still do better.

“With similar observing conditions an Earth-like planet located in the middle of the habitable zone of a red dwarf star could be detectable,” says Bonfils. “The hunt continues.”

 

A SETI Paradigm Shift?

Image Credit:  ESO  (Artist's Impression)

A recent -- and overall sensible -- New York Times editorial by the SETI Institute's Seth Shostak makes me wonder if a long-overdue paradigm shift is finally underway among American SETI scientists.  

For a long time, as I've written about here many times before, American SETI scientists -- with Shostak predominant among them -- have dismissed out of hand the possibility that an advanced extraterrestrial civilization has ever ventured to travel to our solar system.  Unexplained phenomena such as UFO reports cannot be evidence of extraterrestrial visitation, the reasoning goes, because interstellar travel is simply prohibitively expensive regardless of a civilization's age or technological level of development.  Rather than looking for signs of visitation, they insist, we should limit our search for E.T. to looking for radio and perhaps laser transmissions.

In his recent column, Shostak doesn't back off that stance explicitly.  His column discusses what he views as the apparent futility of human interstellar travel, given our current and projected states of knowledge and technological development.  (I'm going to set aside his main thesis, which many have questioned, including myself.)  

What intrigues me is Shostak's suggestion that what may be within our technological grasp are small, smart interstellar probes that remotely explore extrasolar planetary systems and then radio the results back to Earth.  While such missions may require many decades before we get the results from distant probes sent on long journeys light-years from Earth, such probes are conceivable given our current technological development.

What is intriguing about Shostak's suggestion, of course, are its as-yet unstated implications.  

The SETI radio searches are based on the hypothesis that since we -- an intelligent, technological civilization -- use radio to communicate, so would an advanced technological civilization located in an extrasolar planetary system.  We search for extraterrestrial radio and laser signals because we know we, as a technological civilization, are capable of sending them.

On the other hand, if we are capable of sending unmanned probes to other planetary systems light-years from our own and to wait patiently for the results, then perhaps an intelligent species elsewhere has done the same, and the evidence is hiding somewhere in our own solar system, waiting for us to discover it.

Should SETI radio searches be complemented by a systematic search for evidence of extraterrestrial artifacts in our neighborhood?

Of course they should.