Five years ago, the Cassini spacecraft first detected plumes of water ice emanating from Saturn’s moon Enceladus, making the moon one of the best hopes for finding life somewhere else in the solar system. Astronomers have argued over whether or not those jets come from a subsurface ocean of liquid water, but new findings by Cassini provide evidence that water could indeed be sloshing around beneath the frozen surface of this small moon.
During a 2008 pass through the plumes, the spacecraft found negatively charged water molecules. Back home this short-lived type of ion is produced where water is moving, such as in waterfalls or crashing ocean waves [Scientific American]. Researcher Andrew Coates led the study, which is coming out in the journal Icarus.
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If you’ve been expecting to hear from a far-off alien civilization, don’t hold your breath, suggests Frank Drake, the founder of Search for Extraterrestrial Intelligence (SETI)–the odds of ET phoning Earth may be diminishing. And your digital TV might well be to blame.
Speaking at a meeting of the Royal Society in London, Drake said that digital transmissions are effectively “gagging” the planet. In the fast-fading analog age, TV and radio signals transmitted around the world escaped into space. At present, the Earth is surrounded by a 50 light year-wide ‘’shell” of radiation from analogue TV, radio and radar transmissions, he said [The Telegraph]. Those signals reach distant stars, which means that if someone is home at any of those stars, they could heard us.
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NASA’s Mars Reconnaissance Orbiter (MRO) has taken detailed pictures of what scientists are saying is evidence that large lakes of liquid water sat on the planet’s surface relatively recently–which is to say, about 3 billion years ago.
MRO imaged several deep depressions that scientists previously attributed to the sublimation of underground ice 4 billion years ago. However, the new images show that the depressions are connected by long channels, and researchers say these channels could only be formed by running water, and not by ice turning directly into gas. The scientists’ ageing of the region, which on bodies like Mars is done by counting craters, suggests the features formed during the so-called Hesperian Epoch on the Red Planet [BBC News]. Essentially, this means that there was water on Mars a billion years more recently than previously thought. The findings were published in the journal Geology.
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And the exoplanet count marches on. A few days ago astronomers announced they had found a handful of new planets around sun-like stars, some only 29 light years away. Now, in a study published today in Nature, a team led by David Charbonneau unveils a new super-Earth that’s hot, watery, and only 2.68 times the size of our own world.
The planet currently bares the name GJ 1214b, and while Charbonneau says it’s probably not habitable (because of the 400-degree Fahrenheit surface temperature), it’s not too far off the mark. Geoffrey W. Marcy, a planet hunter from the University of California, Berkeley, wrote in an accompanying article in Nature that the new work provided “the most watertight evidence so far for a planet that is something like our own Earth, outside our solar system” [The New York Times].
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As the tally of known planets beyond our solar system continues to grow, so does the number of them that look familiar—planets close to Earth’s size around stars that resemble our sun. Today astronomers announced that they’ve found a new batch of planets that not only fit that description but also reside in our cosmic neighborhood.
Three planets with masses ranging from 5.3 to 24.9 Earth masses were found orbiting the star 61 Virginis, which is 28 light years from Earth in the constellation of Virgo [Herald Sun]. That star can be seen with the naked eye under dark skies, and team member Chris Tinney says the system is strikingly like our own, noting that Neptune is only 17 Earth masses. In addition, NASA’s Spitzer Space Telescope recently found a ring of dust around 61 Virginis that’s about twice the distance from that star as Pluto is from our sun. The region between the newly discovered planets and that disk remains unexplored, the astronomers say, and could be the home of even more planets.
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It’s back. ALH 84001, the meteorite of Martian origin that NASA scientists claimed in 1996 contained evidence of life on Mars, has returned to the scene. This time, the team published a paper in the journal Geochimica et Cosmochimica Acta (the journal of the Geochemical and Meteoritic Society). And the scientists say they’re more confident than ever that the meteorite shows signs of martian life.
The NASA team of David McKay, Everett Gibson and Kathie Thomas-Keprta garnered widespread attention and even an announcement by President Bill Clinton when the 1996 paper came out. The NASA claim focused on nano-sized evidence: magnetite crystals embedded in the meteorite, which arrived here on Earth 13,000 years ago. Because some Earth bacteria secrete magnetite, McKay and his team argued that the mineral in the meteorite could be of biological origin, and the ‘biomorphs” in this image (which is from the new study) could be a fossilized colony of tiny bacteria. But the research was widely panned, and the NASA team making claims for life on Mars subsequently retreated [Discovery News].
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With its thick atmosphere, chemical makeup, and an atmospheric pressure not too far from Earth’s, Titan is one of the most likely candidates for finding life elsewhere in our solar system. But at a temperature close to -300 degrees Fahrenheit, the surface of this Saturnian moon in anything but what we humans would call hospitable. Since this frigid place is far too cold for liquid water, any life there would need an alternative survival method. A new study published in Astrophysical Journal Letters suggests that the simple hydrocarbon acetylene, proposed as a possible energy source for life on Titan, could be much more abundant than scientists previously thought.
Titan has previously been shown to be dotted with lakes of liquid hydrocarbons, primarily methane and ethane. An estimate made in 1989 suggested bodies of liquid hydrocarbons on Titan would contain a few parts in 10,000 of acetylene. But an updated estimate based on data from the Cassini-Huygens mission to Saturn now suggests the lakes contain much more food for any hungry alien life-forms that might be present [New Scientist]. Lead researcher Daniel Cordier says the acetylene abundance could be as high as one part in 100, or 1 percent, of the surface lakes on Titan.
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Had he lived to what would have been his 75th birthday on Monday, Carl Sagan would’ve seen a surprising new collaborator in pondering whether there’s life out there in the cosmos: the Vatican. The Pontifical Academy of Sciences held a conference of scientists and theologians this week that probed the possibility of extraterrestrial life, and the peculiar religious questions that life on other worlds would raise.
Father Jose Funes, director of the Vatican Observatory, became the Catholic Church’s chief evangelist this week spreading the notion that alien life is compatible with Christianity. “This is not in contradiction with our faith, because we cannot establish limits to God’s creative freedom. To say it with St Francis, if we can consider some earthly creatures as ‘brothers’ or ’sisters’, why could we not speak of a ‘brother alien’? He would also belong to the creation” [The Guardian].
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Astronomers have conclusive evidence that a planet spotted in a star system 500 light years away is rocky and solid, just like Earth. Scientists have long figured that if life begins on a planet, it needs a solid surface to rest on, so finding one elsewhere is a big deal. “We basically live on a rock ourselves,” said co-discoverer Artie Hartzes…. “It’s as close to something like the Earth that we’ve found so far. It’s just a little too close to its sun” [AP].
Yes, for while the exoplanet, Corot-7b, is rocky like Earth and is only about five times more massive than our home planet, it’s hardly our twin. Its close proximity to its star means that it completes an orbit (its “year”) in just 20 hours, and the climate extremes are punishing. Temperatures soar above 2,000 degrees on its day side and sink to minus 200 degrees on the night side. It means the surface could be covered with molten lava or boiling oceans and it certainly could not hold any form of life as we know it [Scientific American].
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One of the building blocks of life has been found on a comet hurtling through the solar system, adding evidence to the theory that earthly biology began when comets and meteors bombarded our young planet and seeded it with the precursors of life. The amino acid, glycine, was found in a sample returned by the space probe Stardust that buzzed by the comet Wild 2 in 2004. The probe swept up particles fizzing off the object’s surface as it passed some 240km (149 miles) from the comet’s core, or nucleus. These tiny grains, just a few thousandths or a millimetre in size, were then returned to Earth in 2006 in a sealed capsule [BBC News].
Amino acids are crucial to life because they form the basis of proteins, the molecules that run cells. The acids form when organic, carbon-containing compounds and water are zapped with a source of energy, such as photons – a process that can take place on Earth or in space [New Scientist].
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NASA’s Kepler spacecraft has only been in operation for 10 days, but it’s already spotted a planet, according to a report in Science. That leaves experts optimistic about the craft’s potential to find other Earth-like planets.
Scientists already knew that the planet Kepler found existed. It’s called HAT-P-7b, and it’s a planetary body that’s too heavy and too hot to support life. Still, Kepler gave scientists new details about the planet, including that the planet has a hazy, ozone-like atmosphere. The analysis proves that Kepler’s onboard telescope and light-detecting instruments are at least 100 times more precise than the ground-based detectors that originally found HAT-P-7b [L.A. Times], because Earth-based telescopes must wrestle with distortion from the atmosphere, while Kepler only looks through the clear near-vacuum of space.
Scientists say that Kepler’s capabilities should be sufficient to find Earth-like planets in the “habitable zone” of a star system–that is, the ring where temperatures climb high enough to allow liquid water to exist, but aren’t so scorching as to burn up the surface of the planet.
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A new study of the atmosphere of Mars casts doubt on the enticing possibility that methane plumes emanating from the planet are a signature of microbial life. The researchers found that the variations in methane concentration across Mars could only be explained if the methane produced was quickly broken down by unknown forces, before atmospheric currents could distribute the gas evenly around the planet. But methane is the simplest organic molecule, so if something is destroying it, then other, more complex organic molecules could suffer the same fate [New Scientist].
The mystery began in 2003, when scientists first detected plumes of methane coming from the Martian surface; further observations revealed that the hotspots varied with the Martian seasons. Researchers said the methane could come from volcanic activity, but said it could also, theoretically, be the gaseous excretions of bacteria buried deep underground. To probe the mystery, researchers used a model of the Martian climate that accounted for the chemistry of the atmosphere and its wind patterns, and studied whether the planet’s conditions would allow for the isolated bursts of methane that researchers had previously observed.
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What lies beneath the icy crust of Enceladus? Ever since the NASA space probe Cassini snapped pictures of the Saturnian moon expelling enormous jets of icy vapor from fissures near its south pole in 2005, planetary scientists have debated whether the evidence points to liquid oceans beneath the moon’s surface. Now, a new chemical analysis of the plume bolsters the oceanic theory, thanks to the detection of a mundane chemical: ammonia. Says study coauthor Jonathan Lunine: “This is the first time Cassini has actually been able to ’smell’ ammonia…. And because ammonia is an antifreeze, it probably ensures that there is liquid water in the interior of Enceladus.” And where there’s water, there could be life [Wired.com].
Last month, another team of researchers also argued for the presence of an ocean when they published their discovery of sodium salts in Saturn’s outer-most ring which is thought to originate from Enceladus’ plume material. “The two studies are complimentary and now, for the first time, we are getting an idea of the full picture of what’s happening on Enceladus,” [Chemistry World], says Frank Postberg, lead author of that earlier study. However, Postberg’s study was contested by another paper that found no traces of sodium vapor around Enceladus, leaving the debate unresolved. Sodium is thought to be an indicator of liquid water because it suggests that salt leached from rocks into the water.
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Saturn’s moon Enceladus got humanity’s attention in 2005 when surprised astronomers detected jets of ice and gas spraying out from the moon’s icy surface, and since then researchers have eagerly investigated the possibility that the jets might emanate from liquid oceans beneath the frozen crust. A moon with liquid water would be of great interest, because it would be more likely to host extraterrestrial microbes. Now, two new studies with somewhat contradictory results have deepened the mystery of what lies beneath Enceladus’s shell of ice.
Both groups of researchers were looking for sodium near Enceladus; one found it, the other didn’t. Sodium is interesting because it indicates that deep under the ice, liquid water has been in contact with rocks, which leach salts [ScienceNOW Daily News]. The dissolved sodium, along with water, would be shot into space in the geysers, and some of the sodium would be trapped in ice crystals as they formed. The first research group found sodium traces in Saturn’s E ring, a wide band of ice particles that is believed to be replenished by Enceladus’s jets. “Those salty grains provide our current best smoking (or steaming) gun pointing to present-day liquid water near the surface of Enceladus” [Wired.com], wrote space scientist John Spencer in an essay accompanying the findings.
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After 120,000 years of slumbering in a Greenland glacier beneath almost two miles of ice, an ultra-small bacteria has been resurrected by the patient efforts of scientists. After incubating the bacteria for almost a year in water that was just above freezing temperature, colonies of the tiny purple-brown bacteria began to grow in a petri dish. Researchers say the bacteria’s resilience provides clues to how life can survive in hostile environments like the Arctic–and maybe even other planets.
The Herminiimonas glaciei bug is not the oldest to ever be resurrected, but it’s the first “ultramicrobacteria” to be revived. Ultramicrobacteria, tiny even by bacterial standards, are about 10 to 50 times smaller than the common human intestinal microbe E. coli. Their diminutive size could give the bacteria a survival advantage over other microorganisms. H. glaciei, for example, is thought to have survived in thin capillaries of nutrient-rich water in the Greenland glacier that would have been too tight a fit for larger bacteria [National Geographic News].
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