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Saturn Moon Has Oxygen Atmosphere

An oxygen atmosphere has been found on Saturn's second largest moon, Rhea, astronomers announced Thursday—but don't hold your breath for colonization opportunities. For one thing, the 932-mile-wide (1,500-kilometer-wide), ice-covered moon is more than 932 million miles (1.5 billion kilometers) from Earth. For another, the average surface temperature is -292 degrees Fahrenheit (-180 degrees Celsius). And at less than 62 miles (100 kilometers) thick, the newfound oxygen layer is so thin that, at Earthlike temperatures and pressure, Rhea's entire atmosphere would fit in a single midsize building. Still, the discovery implies that worlds with oxygen-filled air may not be so unusual in the cosmos. At about 327,000 miles (527,000 kilometers) from Saturn, Rhea orbits inside the planet's magnetic field. The Hubble Space Telescope and NASA's Galileo probe found in 1995 that a similar process creates tenuous oxygen atmospheres on Jupiter's ice moons Europa and Ganymede. Related:  space

Dark Jupiter May Haunt Edge of Solar System | Wired Science A century of comet data suggests a dark, Jupiter-sized object is lurking at the solar system’s outer edge and hurling chunks of ice and dust toward Earth. “We’ve accumulated 10 years’ more data, double the comets we viewed to test this hypothesis,” said planetary scientist John Matese of the University of Louisiana at Lafayette. “Only now should we be able to falsify or verify that you could have a Jupiter-mass object out there.” In 1999, Matese and colleague Daniel Whitmire suggested the sun has a hidden companion that boots icy bodies from the Oort Cloud, a spherical haze of comets at the solar system’s fringes, into the inner solar system where we can see them. In a new analysis of observations dating back to 1898, Matese and Whitmire confirm their original idea: About 20 percent of the comets visible from Earth were sent by a dark, distant planet. “But we began to ask, what kind of an object could you hope to infer from the present data that we are seeing?” See Also:

Radiation Rings Hint Universe Was Recycled Over and Over | Wired Science Most cosmologists trace the birth of the universe to the Big Bang 13.7 billion years ago. But a new analysis of the relic radiation generated by that explosive event suggests the universe got its start eons earlier and has cycled through myriad episodes of birth and death, with the Big Bang merely the most recent in a series of starting guns. That startling notion, proposed by theoretical physicist Roger Penrose of the University of Oxford in England and Vahe Gurzadyan of the Yerevan Physics Institute and Yerevan State University in Armenia, goes against the standard theory of cosmology known as inflation. The researchers base their findings on circular patterns they discovered in the cosmic microwave background, the ubiquitous microwave glow left over from the Big Bang. The circular features are regions where tiny temperature variations in the otherwise uniform microwave background are smaller than average. See Also:

In Flyby of Saturn's Moon Rhea, Cassini Probe Gets First Whiff of Non-Earthly Oxygen NASA's Cassini spacecraft has taken a breath of oxygen while passing over the icy surface of Saturn's second-largest moon, marking the first time a spacecraft has directly sampled oxygen in the atmosphere of another body. Cruising just 60 miles above Rhea, one of more than 60 moons orbiting Saturn, Cassini found an extremely thin atmosphere of oxygen and carbon dioxide likely sustained by high-energy particles slamming into the moon's frozen surface. Rhea's isn't the only other atmosphere in the universe, but it is so thin that Cassini had to fly through it just to confirm that it was there at all (other atmosphere's have been detected and studied from afar by tools like the Hubble Space Telescope). According to Cassini's onboard science instruments, Rhea's atmosphere contains something like 50 billion oxygen molecules per cubic meter, matched by 20 billion carbon dioxide molecules. [Guardian]

Super-Earth Atmosphere May Be Mostly Water | Wired Science The first direct measurement of a super-Earth exoplanet's atmosphere finds the world is either shrouded in steam or covered in clouds. "This is the first probe of an atmosphere of a super-Earth planet," said exoplanet observer Jacob Bean of the Harvard-Smithsonian Center for Astrophysics, lead author of a paper describing the cloudy world in the Dec. 2 Nature. "It's a real big step in the direction of doing this kind of work for a planet that's potentially habitable." The planet, called GJ 1214b, is the smallest planet yet to have its atmosphere examined -- but it's just the latest in nearly a decade of probing exoplanet atmospheres. When the first exoplanet atmosphere was measured in 2002, many astronomers dismissed it as a one-time success. Astronomers hope eventually to find true twins of Earth: small rocky planets with liquid water and atmospheres that could support life. "Ultimately the goal is to try to look for biosignatures," Bean said. Image: Paul A.

Hidden in Plain Sight: Researchers Find Galaxy-Scale Bubbles Extending from the Milky Way A group of astrophysicists has located two massive bubbles of plasma, each extending tens of thousands of light-years, emitting high-energy radiation above and below the plane of the galaxy. The researchers found the structures in publicly released data from NASA's Fermi Gamma-Ray Space Telescope, which was launched in 2008 to investigate sources of extremely energetic photons—namely, gamma rays, which have higher frequencies than x-rays. From its orbital perch hundreds of kilometers above Earth's surface, Fermi has charted the location of gamma-ray sources with its Large Area Telescope (LAT). "There are many kinds of emission in the Fermi maps—there are things that we're expecting to see, like the dust-correlated emission," Finkbeiner said in an interview during the May meeting of the American Astronomical Society. Finkbeiner compared the shape of the lobes of the so-called Fermi bubbles with teardrops or hot-air balloons.

"Supernova in a Jar" Offers Peek Inside Star Death Called the iodate-arsenous acid (IAA) system, the experiment involved injecting a small shot of acid into glycerol to trigger a self-sustaining reaction. The result was a rising "vortex ring," a structure that superficially resembles a smoke ring or the mushroom cloud from an atomic bomb. According to computer simulations, vortex rings are also created inside Type Ia supernovae, which can occur when stellar corpses, known as white dwarfs , siphon gas from healthy neighboring stars. When a white dwarf reaches a critical mass threshold—the equivalent of the shot of acid in the lab experiment—the star explodes in one of the most energetic events known to occur in the universe. Both supernovae and the IAA system are self-mixing reactions, said study co-author Stephen Morris , a physicist at the University of Toronto in Canada. This is especially important for Type Ia supernovae, because these explosions tend to produce consistently bright remnants. Physical Review E .

First Volcano Sighting on Saturn’s Most Earthlike Moon | Wired Science SAN FRANCISCO — Three icy volcanoes line up on Saturn’s moon Titan, giving some of the best evidence yet that explosive eruptions are possible on worlds beyond Earth. The volcanic peaks and pits lie in a region called Sotra Facula on Titan’s southern hemisphere. The mountains rise more than 3,000 feet into the air, and the deepest hole sinks nearly 5,000 feet below the surrounding plains, geologists announced in a press conference here at the American Geophysical Union meeting Dec. 14. “It’s a combination of features that you really can’t make any way other than volcanism,” said geophysicist Randolph Kirk of the U.S. Titan is the only body in the solar system other than Earth to have lakes, rivers, clouds, and a cycle of evaporation and mist or rainfall connecting them all. The frigid moon is shrouded in a dense, hazy atmosphere of methane and other hydrocarbons. An icy volcano, also known as a cryovolcano, could be the methane pump scientists sought. See Also:

Mars Has Liquid Water Close to Surface, Study Hints Pools of liquid water may even now exist just a few meters below the Martian surface, according to new research. The finding hints that humans may one day be able to tap into Mars's watery bounty. Although the surface of Mars is too frigid for liquid water to be stable, pockets of water underground could be kept warm enough by an insulating blanket of porous sediment, an international team writes in the November issue of the journal Icarus. (Related: "Liquid Water Recently Seen on Mars?") The new theory is based on studies of Mars's biggest outflow channels, which stretch for hundreds of kilometers across the southern circum-Chryse region. The ancient channels were likely carved by gushing torrents of water, each hundreds to thousands of times larger than the Mississippi River. In fact, collapsed terrain on the floors of the outflow channels could be showing where some now empty reservoirs once existed. Thermal modeling then revealed an intriguing possibility, said study leader J.

Odds of Finding Earth-Size Exoplanets Are 1-in-4 | Wired Science Nearly one in four sun-like stars should host an Earth-mass planet, according to a new census. The finding is the first quantitative measurement of the frequency of planets of various masses in the galaxy. “It’s a landmark paper,” said exoplanet expert Josh Winn of MIT, who was not involved in the new study. “There’s been all this talk, that low-mass planets like the Earth are very common. But this is the first time it’s been documented.” The study, published in the Oct. 29 Science, also found plenty of planets in a mass range that astronomers expected to be empty, which may prompt an overhaul of planet-formation models. Using the Keck Observatory in Hawaii, astronomer Andrew Howard of the University of California, Berkeley and colleagues watched 166 sun-like stars for the telltale wobbles induced by a planet’s pull. Unlike previous surveys, Howard and colleagues were just as interested in stars that lack planets as stars that host them. “But what we can do is extrapolate,” Howard said.

Pluto Has Oceans Under Ice? Frigid Pluto, home to some of our solar system's chilliest real estate, may well harbor an ocean beneath its miles-thick ice shell, new research suggests. Despite its extreme cold, the dwarf planet still appears to be warm enough to "easily" have a subsurface ocean, according to a new model of the rate at which radioactive heat might still warm Pluto's core. And that ocean wouldn't be a mere puddle, noted planetary scientist Guillaume Robuchon of the University of California, Santa Cruz. Rather, the ocean could be 60 to 105 miles (100 to 170 kilometers) thick beneath a 120-mile (200-kilometer) layer of ice, Robuchon said at an annual meeting of the American Geophysical Union in San Francisco earlier this week. If so, Pluto would join a list of outer solar system bodies—such as Saturn's moons Titan and Enceladus—believed to possibly hold liquid water, a key ingredient for life as we know it. Liquid-Preserving Heat Under Pluto Ice?

Video: Spaceport America Inaugurated By Virgin Galactic’s VSS Enterprise Among the many things about living in the year 2010 that blow my mind (robot vacuums, smartphones, Google Books), the fact that we are at the beginning of commercial space flight is, incredibly, not constantly on my mind. Yet advances are constantly being made, most visibly by Virgin Galactic, which just this last week inaugurated the commercial facility for vertically- and horizontally-launching aircraft. I mean spacecraft. I’m not sure I’ll ever get used to saying that. Spaceport America, in addition to having a snazzy logo, sports training facilities for Virgin Galactic pilots spacemen, a 10,000ft runway, and will serve as Virgin Galactic’s headquarters for the next two decades. Want to visit? It’s put together by travel blog Gadling, whose crew got to chat up the ever-charming Richard Branson, his eerily similar son (though to be fair, why wouldn’t you want to grow up just like Richard Branson?) You may wish to postpone your visit until then.