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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By pretending to observe the sunlight shining through the Earth’s atmosphere from the vantage point of the moon, astronomers have gained a clue that may help them in the search for Earth-like exoplanets that could be harboring life.
The astronomers made their observations on 16 August 2008 during a lunar eclipse — in which the Moon moves into Earth’s shadow. Even when the Moon is totally eclipsed by Earth, it is still bathed in a dim red light — from sunlight that has been bent as it passes through the edge of Earth’s atmosphere. Using Earth-based telescopes, the astronomers detected some of this light after it bounced back from the Moon [Nature News].
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Water is crucial to the only kinds of living things we’ve ever seen, so the presence of the wet stuff on another planet could be a sign of potential life. Unfortunately, scientists have been unsure how to detect water on distant planets. But the Deep Impact spacecraft has recently given researchers a glimpse of what a wet planet looks like from far away by turning its detectors onto the Earth itself.
Essentially, Deep Impact has turned Earth into a case study of a planet replete with water. The spacecraft, which is 30 million miles away, or halfway to Venus from Earth, has shown scientists how overlapping continents and bodies of water alter the way that light of seven different wavelengths reflects off of the planet’s surface. When scientists observed light from Earth twice over a 24-hour period, they found small deviations in colour caused when clouds or oceans rotated into view. The results mean they should now be able to recognise similar features on alien planets using giant telescopes in space [Scientific American].
The researchers were able to identify key features that could help identify a water-laden planet using telescopes, chemical-analyzing spectrographs and other instruments…. As Earth completed a 24-hour rotation, the change in brightness varied by about 30 percent up and down. The shift is caused by the planet’s reflectivity as the sun [alternately] shines on oceans and then continents [Discovery News]. The findings will be published in an upcoming issue of Astrophysical Journal.
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Astronomers still haven’t discovered Earth’s twin orbiting another star out in the cosmos, but they’re beginning to find worlds with a passing resemblance to our own. New studies of the red dwarf star Gliese 581 have revealed a small, rocky exoplanet with only twice the mass of Earth, and have also shed new light on a larger planet orbiting farther out, which researchers now say could have liquid water. Team member Stephane Udry believes that the larger planet could have a “large and deep” ocean. “It is the first serious ‘water-world’ candidate,” Udry said [AP].
Researchers had previously discovered three planets orbiting the star, including the potential water world, Gliese 581 d. Based on earlier observations, researchers thought that the planet took 83 days to orbit its star, which would indicate that the planet was too far from the red dwarf’s weak heat to have liquid water. But more extensive observations have shown that the planet actually has an orbital period of 66 days, putting the planet just inside the star’s “habitable zone.” Lead researcher Michel Mayor says the planet may be warm enough to bear oceans that are thousands of miles deep. “Maybe this is the first of a new class of ocean planets. That is my favourite interpretation,” says Mayor. “Whether there is life or not, I don’t know” [New Scientist]. However, not everyone is convinced that Gliese 581 d is wet and wild. Other experts say it’s more likely to be an ice giant, like Neptune and Uranus.
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Life sure turns up in the darnedest places. The latest discovery comes from Blood Falls, a rusty red discolouration on the face of the Taylor Glacier in Antarctica [that] occasionally gushes forth a transparent, briny, iron-rich liquid that quickly oxidizes and turns red, staining the ice below [Nature News].
The source of that water is an intensely salty lake trapped beneath 1,300 feet of ice, and a new study has now found that microbes have carved out a niche for themselves in that inhospitable environment, living on sulfur and iron compounds. The bacteria colony has been isolated there for about 1.5 million years, researchers say, ever since the glacier rolled over the lake and created a cold, dark, oxygen-poor ecosystem.
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The Mars Phoenix Lander conked out in November, ending the active mission of the robotic scientist, but the results of its five months of research on Martian geology are still coming in. In a late-breaking update, some Phoenix scientists now declare that they spotted several drops of liquid salt water on the lander’s legs; this would be the first time liquid water has been detected and photographed beyond Earth.
The researcher who proposed the hypothesis, Nilton Renno, was careful to say, “This is not a proof.” But he added: “I think the evidence is overwhelming. It’s not circumstantial evidence” [The New York Times]. Liquid water would boost the possibility that microbial life could survive beneath the Martian surface.
Renno bases his claim on images that show several blobs on the lander’s legs that changed between snapshots, seeming to merge and grow in size. The dramatic assertion has divided the Phoenix’s science team, with some researchers arguing that the low-resolution pictures actually show nothing more than clumps of frost. “It’s highly unlikely that [liquid water is] the explanation,” said Michael Hecht of NASA’s Jet Propulsion Laboratory…. “It’s just water vapor moving around. It’s an ordinary, unexciting explanation” [AP].
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On Friday night, a Delta 2 rocket blasted off from the Kennedy Space Center and roared into space carrying a satellite that will search the heavens for Earth-like planets. The craft, Kepler, named after the German astronomer Johannes Kepler, who discovered the planetary laws of motion, is to spend the next three and a half years in an orbit around the Sun, where it will count planets by looking for the tiny blips in starlight caused by planets eclipsing their suns [The New York Times].
The $600 million satellite will stare into a region of the Milky Way that’s thick with stars, in the direction of the constellations Cygnus and Lyra. While Kepler is expected to identify many new planets beyond our solar system, known as exoplanets, the real prize would be to find rocky planets in the “habitable zone” around a star, where conditions might be right for life as we know it. “The habitable zone is where we think water will be,” Bill Borucki, Kepler principal investigator at NASA Ames, says in a video on the space agency’s Kepler site. “If you can find liquid water on the surface we think we may very well find life there. So that zone is not too close to the star, because it’s too hot and water boils, and not too far away where the water is condensed…a planet covered with glaciers. It’s the Goldilocks zone–not too hot, not too cold, just right for life” [CNET].
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NASA has proposed sending both an orbiter and a robotic explorer to Mars in the next decade to follow up on the recent report that Mars “hotspots” emit plumes of methane gas, which could be produced by either geothermal reactions or by deeply buried bacteria that breathe out methane as a waste product. That exciting phenomenon, which is still being debated by Mars experts, was observed by researchers using ground-based telescopes to measure seasonal fluctuations of gases on the planet. Researchers say closer observations would have a much better chance of determining whether the methane does signal the ultimate prize: extraterrestrial life.
NASA officials sketched out their proposal at a meeting of Mars scientists, but stressed that plans could change. The current idea is to launch the Mars Science Orbiter in 2016 followed by a exobiology lander or rover mission launched during a particularly juicy launch window in 2018 (the best since the Spirit and Opportunity rovers)…. The plan would also follow a natural progression: MSO would map the methane; the lander or rover would go after it with a suite of astrobiological instruments [Nature blog].
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