Materials Tortured in Space

An ongoing experiment tests the mettle of glass and other materials

By Kaitlin Miller

High-energy radiation and atomic oxygen wreak havoc on satellite parts. To evaluate the durability of materials being developed for future satellites, the U.S. Naval Research Laboratory is running samples through a space-based torture test called MISSE-8. Astronauts bolted a platform full of one-inch samples of mirror coatings, laser-tuning crystals, structural foam and other materials to the outside of the International Space Station, where it will remain for just over two years. The samples, which were sent to the ISS on one of the last space shuttle flights, in May, will return to Earth in July 2013 on the SpaceX Dragon capsule. Scientists from the labs that made each sample will examine them for pitting, cracks and discolouration.

Breath Taking Photos From NASA

NASA's Kepler Confirms Its First Planet in Habitable Zone Outside Our Solar System

This artist's conception illustrates Kepler-22b, a planet known to comfortably circle in the habitable zone of a sun-like star. (Credit: NASA/Ames/JPL-Caltech)                                         Science Daily  — NASA's Kepler mission has confirmed its first planet in the "habitable zone," the region around a star where liquid water could exist on a planet's surface. Kepler also has discovered more than 1,000 new planet candidates, nearly doubling its previously known count. Ten of these candidates are near-Earth-size and orbit in the habitable zone of their host star. Candidates require follow-up observations to verify they are actual planets.

Previous research hinted at the existence of near-Earth-size planets in habitable zones, but clear confirmation proved elusive. Two other small planets orbiting stars smaller and cooler than our sun recently were confirmed on the very edges of the habitable zone, with orbits more closely resembling those of Venus and Mars.The newly confirmed planet, Kepler-22b, is the smallest yet found to orbit in the middle of the habitable zone of a star similar to our sun. The planet is about 2.4 times the radius of Earth. Scientists don't yet know if Kepler-22b has a predominantly rocky, gaseous or liquid composition, but its discovery is a step closer to finding Earth-like planets.

"This is a major milestone on the road to finding Earth's twin," said Douglas Hudgins, Kepler program scientist at NASA Headquarters in Washington. "Kepler's results continue to demonstrate the importance of NASA's science missions, which aim to answer some of the biggest questions about our place in the universe."

Kepler discovers planets and planet candidates by measuring dips in the brightness of more than 150,000 stars to search for planets that cross in front, or "transit," the stars. Kepler requires at least three transits to verify a signal as a planet.

"Fortune smiled upon us with the detection of this planet," said William Borucki, Kepler principal investigator at NASA Ames Research Center at Moffett Field, Calif., who led the team that discovered Kepler-22b. "The first transit was captured just three days after we declared the spacecraft operationally ready. We witnessed the defining third transit over the 2010 holiday season."

The Kepler science team uses ground-based telescopes and NASA's Spitzer Space Telescope to review observations on planet candidates the spacecraft finds. The star field that Kepler observes in the constellations Cygnus and Lyra can only be seen from ground-based observatories in spring through early fall. The data from these other observations help determine which candidates can be validated as planets.

Kepler-22b is located 600 light-years away. While the planet is larger than Earth, its orbit of 290 days around a sun-like star resembles that of our world. The planet's host star belongs to the same class as our sun, called G-type, although it is slightly smaller and cooler.

Of the 54 habitable zone planet candidates reported in February 2011, Kepler-22b is the first to be confirmed. This milestone will be published in The Astrophysical Journal.

The Kepler team is hosting its inaugural science conference at Ames Dec. 5-9, announcing 1,094 new planet candidate discoveries. Since the last catalog was released in February, the number of planet candidates identified by Kepler has increased by 89 percent and now totals 2,326. Of these, 207 are approximately Earth-size, 680 are super Earth-size, 1,181 are Neptune-size, 203 are Jupiter-size and 55 are larger than Jupiter.

The findings, based on observations conducted May 2009 to September 2010, show a dramatic increase in the numbers of smaller-size planet candidates.

Kepler observed many large planets in small orbits early in its mission, which were reflected in the February data release. Having had more time to observe three transits of planets with longer orbital periods, the new data suggest that planets one to four times the size of Earth may be abundant in the galaxy.

The number of Earth-size, and super Earth-size candidates, has increased by more than 200 and 140 percent since February, respectively.

There are 48 planet candidates in their star's habitable zone. While this is a decrease from the 54 reported in February, the Kepler team has applied a stricter definition of what constitutes a habitable zone in the new catalog, to account for the warming effect of atmospheres, which would move the zone away from the star, out to longer orbital periods.

"The tremendous growth in the number of Earth-size candidates tells us that we're honing in on the planets Kepler was designed to detect: those that are not only Earth-size, but also are potentially habitable," said Natalie Batalha, Kepler deputy science team lead at San Jose State University in San Jose, Calif. "The more data we collect, the keener our eye for finding the smallest planets out at longer orbital periods."

NASA's Ames Research Center manages Kepler's ground system development, mission operations and science data analysis. NASA's Jet Propulsion Laboratory in Pasadena, Calif., managed Kepler mission development.

Ball Aerospace and Technologies Corp. in Boulder, Colo., developed the Kepler flight system and supports mission operations with the Laboratory for Atmospheric and Space Physics at the University of Colorado in Boulder.

The Space Telescope Science Institute in Baltimore archives, hosts and distributes the Kepler science data. Kepler is NASA's 10th Discovery Mission and is funded by NASA's Science Mission Directorate at the agency's headquarters.

For more information about the Kepler mission and to view the digital press kit, visit http://www.nasa.gov/kepler 

Astronomers Find Fastest Rotating Star

This view shows part of the stellar nursery called the Tarantula Nebula in the Large Magellanic Cloud, a small neighbour of the Milky Way. At the centre lies the brilliant star VFTS 102 This view includes both visible-light and infrared images from the Wide Field Imager at the MPG/ESO 2.2-metre telescope at La Silla and the 4.1-metre infrared VISTA telescope at Paranal. VFTS 102 is the most rapidly rotating star ever found. (Credit: ESO/M.-R. Cioni/VISTA Magellanic Cloud survey. Acknowledgment: Cambridge Astronomical Survey Unit)                                                                                               Science Daily  — The European Southern Observatory's Very Large Telescope has picked up the fastest rotating star found so far. This massive bright young star lies in our neighbouring galaxy, the Large Magellanic Cloud, about 160,000 light-years from Earth. Astronomers think that it may have had a violent past and has been ejected from a double star system by its exploding companion.

An international team of astronomers has been using ESO's Very Large Telescope at the Paranal Observatory in Chile, to make a survey of the heaviest and brightest stars in the Tarantula Nebula, in the Large Magellanic Cloud. Among the many brilliant stars in this stellar nursery the team has spotted one, called VFTS 102 [1], that is rotating at more than two million kilometres per hour -- more than three hundred times faster than the Sun [2] and very close to the point at which it would be torn apart due to centrifugal forces. VFTS 102 is the fastest rotating star known to date [3].

The astronomers also found that the star, which is around 25 times the mass of the Sun and about one hundred thousand times brighter, was moving through space at a significantly different speed from its neighbours [4].

"The remarkable rotation speed and the unusual motion compared to the surrounding stars led us to wonder if this star had had an unusual early life. We were suspicious." explains Philip Dufton (Queen's University Belfast, Northern Ireland, UK), lead author of the paper presenting the results.

This difference in speed could imply that VFTS 102 is a runaway star -- a star that has been ejected from a double star system after its companion exploded as a supernova. This idea is supported by two further clues: a pulsar and an associated supernova remnant in its vicinity [5].

The team has developed a possible back story for this very unusual star. It could have started life as one component of a binary star system. If the two stars were close, gas from the companion could have streamed over and in the process the star would have spun faster and faster. This would explain one unusual fact -- why it is rotating so fast. After a short lifetime of about ten million years, the massive companion would have exploded as a supernova -- which could explain the characteristic gas cloud known as a supernova remnant found nearby. The explosion would also have led to the ejection of the star and could explain the third anomaly -- the difference between its speed and that of other stars in the region. As it collapsed, the massive companion would have turned into the pulsar that is observed today, and which completes the solution to the puzzle.

Although the astronomers cannot yet be sure that this is exactly what happened, Dufton concludes "This is a compelling story because it explains each of the unusual features that we've seen. This star is certainly showing us unexpected sides of the short, but dramatic lives of the heaviest stars."

Notes:

[1] The name VFTS102 refers to the VLT-FLAMES Tarantula Survey made using the Fibre Large Array Multi Element Spectrograph (FLAMES) on ESO's Very Large Telescope.

[2] An aircraft travelling at this speed would take about one minute to circle Earth at the equator.

[3] Some stars end their lives as compact objects such as pulsars (see note [5]), which may spin much more rapidly than VFTS 102, but they are also very much smaller and denser and do not shine by thermonuclear reactions like normal stars.

[4] VFTS 102 is moving at roughly 228 kilometres per second, which is slower than other similar stars in the region by about 40 kilometres per second.

[5] Pulsars are the result of supernovae. The core of the star collapses to a very small size creating a neutron star which spins very rapidly and emits powerful jets of radiation. These jets create a regular "pulse" as seen from Earth as the star rotates around its axis. The associated supernova remnant is a characteristic cloud of gas blown away by the shock wave resulting from the collapse of the star into a neutron star.

More information

This research was presented in a paper in the Astrophysical Journal Letters, "The VLT-FLAMES Tarantula Survey: The fastest rotating O-type star and shortest period LMC pulsar -- remnants of a supernova disrupted binary?," by Philip L. Dufton et al.

The team is composed of P.L. Dufton (Astrophysics Research Centre, Queen's University Belfast (ARC/QUB), UK), P.R. Dunstall (ARC/QUB, UK), C.J. Evans (UK Astronomy Technology Centre, Royal Observatory Edinburgh (ROE), UK), I. Brott (University of Vienna, Department of Astronomy, Austria), M. Cantiello (Argelander Institut fur Astronomie der Universitat Bonn, Germany, Kavli Institute for Theoretical Physics, University of California, USA), A. de Koter (Astronomical Institute 'Anton Pannekoek', University of Amsterdam, The Netherlands), S.E. de Mink (Space Telescope Science Institute, USA), M. Fraser (ARC/QUB, UK), V. Henault-Brunet (Scottish Universities Physics Alliance (SUPA), Institute for Astronomy, University of Edinburgh, ROE, UK), I.D. Howarth (Department of Physics & Astronomy, University College London, UK), N. Langer (Argelander Institut fur Astronomie der Universitat Bonn, Germany), D.J. Lennon (ESA, Space Telescope Science Institute, USA), N. Markova (Institute of Astronomy with NAO, Bulgaria), H. Sana (Astronomical Institute 'Anton Pannekoek', University of Amsterdam, The Netherlands), W.D. Taylor (SUPA, Institute for Astronomy, University of Edinburgh, ROE, UK).

Strange New 'Species' of Ultra-Red Galaxy Discovered

This artist's conception portrays four extremely red galaxies that lie almost 13 billion light-years from Earth. Discovered using the Spitzer Space Telescope, these galaxies appear to be physically associated and may be interacting. One galaxy shows signs of an active galactic nucleus, shown here as twin jets streaming out from a central black hole. (Credit: David A. Aguilar (CfA))                                                                       Science Daily  — In the distant reaches of the universe, almost 13 billion light-years from Earth, a strange species of galaxy lay hidden. Cloaked in dust and dimmed by the intervening distance, even the Hubble Space Telescope couldn't spy it. It took the revealing power of NASA's Spitzer Space Telescope to uncover not one, but four remarkably red galaxies. And while astronomers can describe the members of this new "species," they can't explain what makes them so ruddy.

"We've had to go to extremes to get the models to match our observations," said Jiasheng Huang of the Harvard-Smithsonian Center for Astrophysics (CfA). Huang is lead author on the paper announcing the find, which was published online by the Astrophysical Journal.

Spitzer succeeded where Hubble failed because Spitzer is sensitive to infrared light -- light so red that it lies beyond the visible part of the spectrum. The newfound galaxies are more than 60 times brighter in the infrared than they are at the reddest colors Hubble can detect.

Galaxies can be very red for several reasons. They might be very dusty. They might contain many old, red stars. Or they might be very distant, in which case the expansion of the universe stretches their light to longer wavelengths and hence redder colors (a process known as redshifting). All three reasons seem to apply to the newfound galaxies.

All four galaxies are grouped near each other and appear to be physically associated, rather than being a chance line-up. Due to their great distance, we see them as they were only a billion years after the Big Bang -- an era when the first galaxies formed.

"Hubble has shown us some of the first protogalaxies that formed, but nothing that looks like this. In a sense, these galaxies might be a 'missing link' in galactic evolution" said co-author Giovanni Fazio of the CfA.

Next, researchers hope to measure an accurate redshift for the galaxies, which will require more powerful instruments like the Large Millimeter Telescope or Atacama Large Millimeter Array. They also plan to search for more examples of this new "species" of extremely red galaxies.

"There's evidence for others in other regions of the sky. We'll analyze more Spitzer and Hubble observations to track them down," said Fazio.

NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the Spitzer mission for NASA's Science Mission Directorate. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology in Pasadena. NASA's Goddard Space Flight Center built Spitzer's Infrared Array Camera, which took the observations. The instrument's principal investigator is Giovanni Fazio of CfA.

NASA's Fermi Finds Youngest Millisecond Pulsar, 100 Pulsars To-Date

This plot shows the positions of nine new pulsars (magenta) discovered by Fermi and of an unusual millisecond pulsar (green) that Fermi data reveal to be the youngest such object known. With this new batch of discoveries, Fermi has detected more than 100 pulsars in gamma rays. (Credit: NASA/DOE/Fermi LAT Collaboration)

Science Daily — An international team of scientists using NASA's Fermi Gamma-ray Space Telescope has discovered a surprisingly powerful millisecond pulsar that challenges existing theories about how these objects form.

At the same time, another team has located nine new gamma-ray pulsars in Fermi data, using improved analytical techniques.

A pulsar is a type of neutron star that emits electromagnetic energy at periodic intervals. A neutron star is the closest thing to a black hole that astronomers can observe directly, crushing half a million times more mass than Earth into a sphere no larger than a city. This matter is so compressed that even a teaspoonful weighs as much as Mount Everest.

"With this new batch of pulsars, Fermi now has detected more than 100, which is an exciting milestone when you consider that, before Fermi's launch in 2008, only seven of them were known to emit gamma rays," said Pablo Saz Parkinson, an astrophysicist at the Santa Cruz Institute for Particle Physics at the University of California Santa Cruz, and a co-author on two papers detailing the findings.

One group of pulsars combines incredible density with extreme rotation. The fastest of these so-called millisecond pulsars whirls at 43,000 revolutions per minute.

Millisecond pulsars are thought to achieve such speeds because they are gravitationally bound in binary systems with normal stars. During part of their stellar lives, gas flows from the normal star to the pulsar. Over time, the impact of this falling gas gradually spins up the pulsar's rotation.

The strong magnetic fields and rapid rotation of pulsars cause them to emit powerful beams of energy, from radio waves to gamma rays. Because the star is transferring rotational energy to the pulsar, the pulsar's spin eventually slows as the star loses matter.

Typically, millisecond pulsars are around a billion years old. However, in the Nov. 3 issue of Science, the Fermi team reveals a bright, energetic millisecond pulsar only 25 million years old.

The object, named PSR J1823−3021A, lies within NGC 6624, a spherical collection of ancient stars called a globular cluster, one of about 160 similar objects that orbit our galaxy. The cluster is about 10 billion years old and lies about 27,000 light-years away toward the constellation Sagittarius.

Fermi's Large Area Telescope (LAT) showed that eleven globular clusters emit gamma rays, the cumulative emission of dozens of millisecond pulsars too faint for even Fermi to detect individually. But that's not the case for NGC 6624.

"It's amazing that all of the gamma rays we see from this cluster are coming from a single object. It must have formed recently based on how rapidly it's emitting energy. It's a bit like finding a screaming baby in a quiet retirement home," said Paulo Freire, the study's lead author, at the Max Planck Institute for Radio Astronomy in Bonn, Germany.

J1823−3021A was previously identified as a pulsar by its radio emission, yet of the nine new pulsars, none are millisecond pulsars, and only one was later found to emit radio waves.

Despite its sensitivity, Fermi's LAT may detect only one gamma ray for every 100,000 rotations of some of these faint pulsars. Yet new analysis techniques applied to the precise position and arrival time of photons collected by the LAT since 2008 were able to identify them.

"We adapted methods originally devised for studying gravitational waves to the problem of finding gamma-ray pulsars, and we were quickly rewarded," said Bruce Allen, director of the Max Planck Institute for Gravitational Physics in Hannover, Germany. Allen co-authored a paper on the discoveries that was published online in The Astrophysical Journal.

Allen also directs the Einstein@Home project, a distributed computing effort that uses downtime on computers of volunteers to process astronomical data. In July, the project extended the search for gamma-ray pulsars to the general public by including Femi LAT data in the work processed by Einstein@Home users.

NASA's Fermi Gamma-ray Space Telescope is an astrophysics and particle physics partnership. It is managed by NASA's Goddard Space Flight Center in Greenbelt, Md. It was developed in collaboration with the U.S. Department of Energy, with important contributions from academic institutions and partners in France, Germany, Italy, Japan, Sweden and the United States.

Aerospace Entrepreneur/Motelier Robert Bigelow Thinks the Chinese Will Take Over the Moon

By Dan Nosowitz

Claiming the Moon We were there first. NASA

Robert Bigelow is not a small name in the space world. His company Bigelow Aerospace is a pioneer of inflatable spacecraft, and the company has made waves with its plans for an inflatable, orbiting space hotel (not coincidentally, Bigelow's fortunes come from his ownership of the Budget Suites motel chain). So when he says something about the future of space travel, we listen. On the other hand, when he says that China is planning to take over the moon circa 2025, we listen, but with skepticism.

At the International Symposium for Personal and Commercial Spaceflight, Bigelow laid out a timeline of a wild-west-style Chinese takeover of the moon, calling China "the new gunslinger in Dodge." Bigelow's timeline notes China's increasing success in space projects, up to and including last month's launch of the Tiangong Space Station module. He further declares that the moon's abundance in helium-3, a possible future fuel, but more importantly that "claiming" the moon would be a major glory moment for China. The timeline suggests that China will complete surveys of the moon, withdraw from the Outer Space Treaty of 1967 and formally claim the moon as part of China. Bigelow even suggested diverting 10 percent of the defense budget--some $60 billion--to preventing this moon theft.

So, we are skeptical. For lots of reasons. First, there's no evidence that China has any designs on such a plan, which of course they couldn't execute anytime soon, because their space technology is years, possibly decades, behind Russia's and the European Space Agency's. (Behind us, too, but we've sort of taken ourselves out of that game.) For another thing, there's no guarantee that the moon's raw materials will actually be of any use for energy here on Earth.MSNBC contacted an expert, Dean Cheng of the "conservative-leaning Heritage Foundation," who said anything "inflammatory" like claiming possession of the moon is "not likely." And Bigelow may be a private space agency pioneer and a damn fine budget hotelier, but the guy does not exactly have a background in international relations.

[MSNBC]

Faster-Than-Light Neutrinos Might Be Explained By GPS Failing to Account For Special Relativity

A possible victory for Einstein

By Rebecca Boyle

GPS Satellite NASA/Wikimedia Commons

So it turns out that Einstein may not have been wrong about the universal speed limit. Not only is special relativity safe, it provides an explanation for those faster-than-light neutrinos. They’re not breaking the light-speed barrier; they just appear to be, thanks to the relativistic motion of the clocks checking their speed.

As we all remember, a few weeks ago some scientists at CERN set the physics world on fire when they shared data showing neutrinos were moving faster than light. Specifically, they were showing up at a distant neutrino detector about 60 nanoseconds faster than the time in which light would make the same trip. But the rules of physics said this could not be. The Oscillation Project with Emulsion-tRacking Apparatus team (which was not looking for this result, by the way) calibrated their clocks, measured their distances and crunched their numbers in search of an explanation.

Flummoxed, they dumped their findings on the larger physics community, which proceeded to eviscerate the experiment. In the three weeks since, almost 100 papers have shown up on the preprint server arXiv trying to make sense of it all. Physicists have blamed everything from poor geodesy to ill-timed clocks, and other particle physics observatories are hard at work trying toreplicate the results.

Now a Dutch physicist says it’s really very simple — the OPERA team overlooked the relativistic motion of their clocks. Technology Review's arXiv blog highlights the paper here.

OPERA was studying neutrino oscillation, in which these ghostly particles switch from one type to another. They were firing off muon neutrinos from a neutrino beam at CERN and sending them to Gran Sasso, Italy, where researchers counted how many of them had become tau neutrinos. Along with careful Earth-measuring, this experiment required super-precise synchronization of clocks at the two locations. The team did this with GPS satellites, which broadcast a time signal as they orbit about 12,500 miles above the Earth. The OPERA team had to calculate how long it takes for one of these time signals to reach the Earth. But they did not account for the clocks’ relativistic motion, according to physicist Ronald van Elburg at the University of Groningen in the Netherlands.

The radio signals travel from the satellites at light speed, which has nothing to do with the satellites’ speed. This is one of the central tenets of special relativity: “Light is always propagated in empty space with a definite velocity c which is independent of the state of motion of the emitting body,” as Einstein put it himself.

But because the satellites are moving, from their point of view, the positions of the neutrinos andthe detector are changing. The neutrinos are moving toward the detector, and the detector appears to be moving toward the neutrino source. So the distance between the origin and destination appears to be shorter than it would if it were being observed on the ground.

“Consequently, in this reference frame the distance traveled by the [particles] is shorter than the distance separating the source and detector,” van Elburg writes. This phenomenon is overlooked because the OPERA team thinks of the clocks as on the ground — which they are, physically — and not in orbit, which is where their synchronizing reference point is located.

Using the altitude, orbital period, inclination to the equator and other metrics, van Elburg calculates the error rate: “The observed time-of-flight should be about 32 ns shorter than the time-of-flight using a baseline bound clock,” he writes. This is done at both clock locations, so double that, and you get an early-arrival time of 64 nanoseconds. That pretty much accounts for the OPERA anomaly.

“This paper shows that Coordinated Universal Time (UTC) happens to be less universal than the name suggests, and that we have to take in to account how our clocks are moving,” van Elburg writes.

Of course, his paper has not yet been published, and is subject to the same scrutiny and peer review as the OPERA folks, so we can’t accept van Elburg’s theory just yet. But it’s certainly a handy explanation. And it’s a lovely piece of irony, too — not only was Einstein’s special theory of relativity right all along, it even provides a reason why.

[via Technology Review]

Kepler Spacecraft Discovers New Multi-Planet Solar System

The top graphic shows the orbits of the three known planets orbiting Kepler-18 as compared to Mercury's orbit around the Sun. The bottom graphic shows the relative sizes of the Kepler-18 and its known planets to the Sun and Earth. (Credit: Tim Jones/McDonald Obs./UT-Austin)

Science Daily  — A team of researchers led by Bill Cochran of The University of Texas at Austin has used NASA's Kepler spacecraft to discover an unusual multiple-planet system containing a super-Earth and two Neptune-sized planets orbiting in resonance with each other.

They are announcing the find in Nantes, France at a joint meeting of the European Planetary Science Conference and the American Astronomical Society's Division of Planetary Science. The research will be published in a special Kepler issue of The Astrophysical Journal Supplement Series in November.

Cochran's team is announcing three planets orbiting Kepler-18, a star similar to the Sun. Kepler 18 is just 10 percent larger than the Sun and contains 97 percent of the Sun's mass. It may host more planets than the three just announced.

The planets are designated b, c, and d. All three planets orbit much closer to Kepler-18 than Mercury does to the Sun. Orbiting closest to Kepler-18 with a 3.5-day period, planet b weighs in at about 6.9 times the mass of Earth, and twice Earth's size. Planet b is considered a "super-Earth." Planet c has a mass of about 17 Earths, is about 5.5 times Earth's size, and orbits Kepler-18 in 7.6 days. Planet d weighs in at 16 Earths, at 7 times Earth's size, and has a 14.9-day orbit. The masses and sizes of c and d qualify them as low-density 2Neptune-class" planets.

Planet c orbits the star twice for every one orbit d makes. But the times that each of these planets transit the face of Kepler-18 "are not staying exactly on that orbital period," Cochran says. "One is slightly early when the other one is slightly late, [then] both are on time at the same time, and then vice-versa."

Scientifically speaking, c and d are orbiting in a 2:1 resonance. "It means they're interacting with each other," Cochran explains. "When they are close to each other ... they exchange energy, pull and tug on each other."

Kepler uses the "transit method" to look for planets. It monitors a star's brightness over time, looking for periodic dips that could indicate a planet passing in front of the star. A large part of the Kepler science team's work is proving that potential planets they find aren't something else that mimics the transit signature (such as a perfectly aligned background star, specifically either an eclipsing binary star or a single star orbited by a giant planet).

That follow-up work to Kepler is done by scores of scientists using ground-based telescopes the world over (including several at The University of Texas at Austin's McDonald Observatory) as well as Spitzer Space Telescope.

Kepler-18's planets c and d did astronomers a favour by proving their planet credentials up front via their orbital resonance; they had to be in the same planetary system as each other for the resonance to occur.

Confirming the planetary bona fides of planet b, the super-Earth, was much more complicated, Cochran says. His team used a technique called "validation," instead of verification. They set out to figure out the probability that it could be something other than a planet.

First, they used the Palomar 5-meter (200-inch) Hale Telescope with adaptive optics to take an extremely high-resolution look at the space around Kepler-18. They wanted to see if anything close to the star could be positively identified as a background object that would cause the transit signal they had attributed to a super-Earth.

"We successively went through every possible type of object that could be there," Cochran says. "There are limits on the sort of objects that can be there at different distances from the star." Astronomers know how many of different types of objects (various kinds of stars, background galaxies, and more) are seen on average in the sky. They didn't find anything in the Palomar image.

"There's a small possibility that [planet b] is due to a background object, but we're very confident that it's probably a planet," Cochran says. His team calculated that the likelihood the object is a planet is 700 times more likely than the likelihood that it's a background object.

The process is called "planet validation," rather than the usual "planet verification." Cochran says it's important to understand the difference -- not just for this system, but for future discoveries from Kepler and other missions.

"We're trying to prepare the astronomical community and the public for the concept of validation," he says. "The goal of Kepler is to find an Earth-sized planet in the habitable zone [where life could arise], with a one-year orbit. Proving that such an object really is a planet is very difficult [with current technology]. When we find what looks to be a habitable Earth, we'll have to use a validation process, rather than a confirmation process. We're going to have to make statistical arguments."

Kepler was selected as the tenth 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. Jet Propulsion Laboratory, Pasadena, Calif., managed the Kepler mission development. Ball Aerospace & Technologies Corp. of Boulder, Colo., developed the Kepler flight system and supports mission operations with the Laboratory for Atmospheric and Space Physics at the University of Colorado, Boulder. The Space Telescope Science Institute in Baltimore archives, hosts, and distributes the Kepler science data. For more information about the Kepler mission, visit: http://www.nasa.gov/kepler.

NASA Awards the Largest Prize in Aviation History to an All-Electric, Super-Efficient Aircraft

By Clay Dillow

Pipistrel's Taurus G4 NASA HQ Photo

NASA has awarded the single largest prize handed down in aviation history to Team Pipistrel-USA.com for designing and demonstrating its Taurus G4 electric aircraft. Per the rules of the NASA- and Google-sponsored CAFE Green Flight Challenge, Pipistrel’s Taurus G4 covered 200 miles in less than 2 hours and did so on the electricity equivalent of less than one gallon of fuel per passenger, scoring $1.35 million for the effort.

But the cash, substantial though it may be, is only part of the story here. The CAFE (that’s Comparative Aircraft Flight Efficiency) Challenge was created to push aircraft engineers toward new, more efficient airplane designs that would perhaps usher in a new era of ultra-efficient flight, based on either electric engines or extremely efficient fuel-burning engines.

So while you can argue the day belongs to Pipistrel--and we certainly don’t mean to diminish that achievement--the CAFE Foundation and NASA are the real winners here. Consider: The challenge asked teams to average 100 miles per hour over two hours, and to do so on the equivalent of one gallon of gas. Not only did Pipistrel manage this, but so did California-based e-Genius with its electric-powered plane (for which it netted a second place prize of $120,000).

The kicker: both teams did so on just a little more than a half-gallon of fuel equivalent. That means both Pipistrel and e-Genius did twice as well as NASA and CAFE asked them to do (and Pipistrel slightly better than e-Genius, hence the distribution of prizes).

That’s pretty amazing, considering that just a few years ago engineers were still trying to figure out how to get an all-electric powered plane into the air for any considerable length of time, much less at sustained triple-digit speeds and while using very little energy.

Our jetliners aren’t going green just yet of course. But the winning teams in the CAFE Green FLight Challenge collectively spent just two years and $4 million on two aircraft that have pushed the electric airplane field forward by a considerable step. Imagine what ten years and some serious investment might do for the electric aircraft space.

More background/details on Team Pipistrel-USA.com’s winning Taurus G4 in the video below.

[NASA]