What’s the News: NASA’s considering launching a boat from Earth, hurling it 746 million miles through space, and plopping it onto one of the minus-290 degrees Fahrenheit methane oceans of Titan. This mission to Saturn’s largest moon would the first of its kind to probe an alien ocean and—depending on the weather conditions—could be the first spacecraft to witness extraterrestrial rain. If the proposed mission beats out two other finalists, it could launch within the next five years. “Titan is an endpoint [in] exploring … the limits to life in our solar system,” project leader Ellen Stofan told New Scientist. “We’re going to be looking for patterns in abundances of compounds to look for evidence for more complex or interesting reactions.”
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What’s the News: Astronomers have known for many years that Saturn’s moon Titan sports lakes of liquid methane. And in the past couple years, scientists have suggested that it also has an underground ocean composed of water and ammonia. Now, based on past observations by NASA’s Cassini spacecraft, astronomers are saying that Titan’s rotation indeed points to an underground sea—and where there’s water, there may also be life. “Our analysis strengthens the possibility that Titan has a subsurface ocean, but it does not prove it undoubtedly,” researcher Rose-Marie Baland told Astrobiology Magazine. “So there is still work to do.”
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E. coli
What’s the News: Some bacteria can live in extreme “hypergravity,” found a new study published in the Proceedings of the National Academy of Sciences, surviving and reproducing in forces 400,000 times greater than what’s felt on Earth. These findings fit with the idea that microbes carried on meteorites or other debris—a ride that would have subjected them to hypergravity-strength forces—may be the ancestors of life on Earth.
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What’s the News: If you were to bring a glass of water to Mars, the liquid would instantly boil because the Red Planet’s carbon dioxide atmosphere is so thin: The vapor pressure of the water easily surpasses the weak atmospheric pressure, sending water molecules flying off quickly into the atmosphere. However, ancient shorelines and river-like features indicate that Mars had a watery past, leading researchers to wonder what happened to Mars’ once-thicker atmosphere. Now, data from the Mars Reconnaissance Orbiter has uncovered a massive deposit of solid CO2 at the south pole that could double the planet’s atmospheric pressure if it were released as gas. “If you double the amount of CO2 in the atmosphere, it’s quite possible that you could have liquid water,” planetary scientist Philip James of the Space Science Institute in Boulder told Scientific American. “People have suggested that this could happen, and now it looks like it could be possible.”
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Young. Old. Scalding hot. Icy cold. Terrestrial midgets. Gas giants. As the cavalcade of planets spotted beyond our solar system continues to grow, we get to see worlds of all sorts—and we get to speculate on the staggering number of exoplanets that might inhabit just our own galaxy.
Today’s first piece of otherworldly news involves baby exoplanets. Astronomer Christian Thalmann says his team may have spotted planets in the process of forming around three different stars, the first time scientists have spotted the process in action.
An infant star forms from a collapsing cloud of dust and gas and gathers a dense, flat disk of material that rotates with the star like a record album. The material in the disk will eventually clump up into nascent planets. Theoretical models of planet formation predicted that those protoplanets should suck up more gas and dust with their gravity, clearing a wide gap in the otherwise solid disk. [Wired]
Peering at young stars like T Chamaeleontis (T Cha) LkCa15 and AB Auriga, Thalmann and colleagues saw those telltale gaps in the dusty rings (their study is forthcoming in the Astrophysical Journal Letters). The stars are much like our own sun, so these pictures of infant solar systems could resemble what our own looked like as a baby. But though the stars are nearby in cosmic terms—T Cha lies just 350 light years away—the gaps are faint enough that it’s difficult to tell for certain if newly forming planets, and not the influence of binary stars or other objects, are creating them.
If Thalmann’s team is right, catching the birth of new worlds would be a great scientific coup. Our galaxy, however, isn’t exactly hurting for planets.
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You know the old routine in sci-fi: Aliens show up, people of Earth freak out. Whether we provoke aliens a la The Day the Earth Stood Still or they arrive foaming with blood lust like in Mars Attacks, storytellers’ general feeling is that the mass of humanity would not respond well to the real presence of extraterrestrial life. We need Will Smith and Tommy Lee Jones to keep ‘em separated from us.
In 2011—the year after we were supposed to make contact—are we humans still a backwater mob of talking apes who would crumble into pandemonium, or cosmic self-doubt, at the discovery of life beyond Earth? This week, a special issue of The Philosophical Transactions of the Royal Society addresses that question and more.
You’ve come a long way, baby
Albert Harrison, psychologist at the University of California, Davis, may live to regret saying nice things about humanity. But it’s nice to see somebody giving us a vote of confidence:
The Brookings Report warned in 1961 that the discovery of life beyond Earth could lead to social upheaval. But [Harrison] says “times have changed dramatically” since then. Even the discovery of intelligent aliens “may be far less startling for generations that have been brought up with word processors, electronic calculators, avatars and cell phones as compared with earlier generations used to typewriters, slide rules, pay phones and rag dolls,” Harrison writes in one of the papers. [MSNBC]
SETI (the Search for Extra-Terrestrial Intelligence) hasn’t been successful in its half-century hunt for alien civilizations, but it has ingrained into people the idea of looking for life beyond Earth. The continually increasing exoplanet count (one discovery was announced just today) is showing people just a small glimpse of the variety of worlds out there. Thus, Harrison says the people of Earth would respond to the discovery of alien life with “delight or indifference,” according to the Press Association.
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The Kepler space telescope, launched nearly two years ago, has already proven its worth as an exoplanet hunter many times over. But the discoveries keep on coming. NASA just announced that Kepler has found its first rocky planet–and that the rocky world is only 1.4 times the size of Earth, making it the smallest exoplanet ever found.
Phil Plait explains that this nearly Earth-sized isn’t actually Earth-like and habitable:
[I]t orbits extremely close in to its star, circling over the star’s surface at a distance of roughly 3 million kilometers (1.8 million miles) — amazingly, it takes less than an Earth day to make one circuit. But being that close to a star comes at a price: the surface temperature of the planet must be several thousand degrees!
The planet, Kepler-10b, may not be habitable to life as we know it, but Plait is still plenty excited. Get the rest of the story on how the planet was found and what its discovery means over at Bad Astronomy.
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80beats: After a Flawless Launch, Kepler Telescope Gets Ready for Planet Hunting
DISCOVER: How Long Until We Find a Second Earth?
The Martian rovers and orbiters have sent so much data back to Earth in the last few years that discoveries about Mars’ wet and active past come left and right. Yesterday we covered the story that the stuck Spirit rover may have found evidence of recent water right under its tracks. And another study this week, out in Nature Geoscience, pinpoints a spot by a Mars volcano that could contain evidence of a watery system more than 3 billion years old—and perhaps even life, too.
The finding came after the Mars Reconnaissance Orbiter observed a mineral called hydrated silica sitting on the flank of the extinct Syrtis Major volcano.
The mineral is transported and then concentrated by hot water or steam, suggesting the deposits were laid down in what was once a hydrothermal environment. Groundwater may have been heated by magma from the erupting volcano and vented to the surface as steam, says John Mustard of Brown University in Rhode Island, a member of the team that identified the mineral. [New Scientist]
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It’s just a lab experiment, but University of Arizona researcher Sarah Horst says that her team’s re-creation of the atmosphere on Saturn’s moon Titan showed that atmospheric reactions could produce some of life’s basic ingredients, and do it without the presence of liquid water.
Titan, which is larger than Mercury, boasts a thick atmosphere of mostly nitrogen with dashes of methane, carbon monoxide, and other trace ingredients (At -290 degrees Fahrenheit, Titan is a tad too frigid for liquid water). Horst brewed up an approximation of that mixture. She and her colleagues then blasted it with radio-frequency radiation, a lab stand-in for ultraviolet radiation from the sun.
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NASA’s next rendezvous with the Red Planet got the go-ahead this week. The space agency approved development of MAVEN, the Mars Atmosphere and Volatile Evolution mission, which is scheduled to launch in November 2013.
In the last decade, missions like the Phoenix Lander, the Spirit and Opportunity rovers, and the Mars Express have reinforced the case that our neighbor was once watery, and far more hospitable to life than the planet we see today. The ancient evidence of liquid water suggests that the planet once had a dense atmosphere, which is now long gone. MAVEN’s mission is to investigate the interaction between Mars’s now-thin atmosphere and the solar wind, and to look for clues to how and when the sun stripped away the planet’s thick atmosphere.
Many researchers think that Mars’s loss of its magnetic field billions of years ago started the process.
“Mars can’t protect itself from the solar wind because it no longer has a shield, the planet’s global magnetic field is dead,” said [lead investigator Bruce] Jakosky, describing how the magnetic field disappeared and the atmosphere then exposed to the punishing solar wind. [AFP]
For more details about MAVEN, check out our coverage from 2008, when NASA first announced the mission. The team’s critical design review will come next July, which could be the true make-or-break time for the mission.
Related Content:
80beats: NASA Announces Plan to Study Martian Climate Mystery
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80beats: Early Mars: Cold and Wet, But Potentially Still Full of Life
Image: NASA
From Ed Yong:
The origin of life is surely one of the most important questions in biology. How did inanimate molecules give rise to the “endless forms most beautiful” that we see today, and where did this event happen? Some of the most popular theories suggest that life began in a hellish setting, in rocky undersea vents that churn out superheated water from deep within the earth. But a new paper suggests an alternative backdrop, and one that seems like the polar opposite (pun intended) of the hot vents –ice.
Like the vents, frozen fields of ice seem like counter-intuitive locations for the origin of life – they’re hardly a hospitable environment today. But according to James Attwater form the University of Cambridge, ice has the right properties to fuel the rise of “replicator” molecules, which can make copies of themselves, change and evolve.
Read the rest of this post at Not Exactly Rocket Science. And for more about the possibly frigid origins of life—and the implications of that for finding life beyond Earth—check out the DISCOVER feature “Did Life Evolve in Ice?”
More Related Content:
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Image: Wikimedia Commons
We know that the Search for Extraterrestrial Intelligence (SETI) is often strapped for cash. But what if the aliens out there trying to reach us, rather than being far superior technologically and beaming signals in all directions, are actually starving scientists, too?
In a pair of papers in Astrobiology, three members of the Benford family—Gregory, an astrophysicist and sci-fi author; James, president of Microwave Sciences; and James’ son Dominic, of NASA—ponder the possibility of E.T. trying to reach us on a budget, and say that we might have to revise the way we hitherto have watched.
Aliens wishing to communicate would probably broadcast at frequencies between 1 and 10 gigahertz, where there is less astronomical background noise than in other wavebands. Most SETI projects tune in to the “cosmic water hole” waveband between 1.42 and 1.72 gigahertz. The reasoning goes that alien astronomers might expect earthly scientists to be looking there anyway as this is the frequency of radiation emitted by interstellar hydrogen and hydroxyl clouds [New Scientist].
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Want to know what early or extraterrestrial life might look like? You might try looking at Earth’s extremes: the coldest, highest, and deepest places on our planet. One unmanned research vehicle just tried the last of these strategies, and took samples from a hydrothermal vent plume 16,000 feet under the sea–about 2,000 feet deeper than the previous record-holding vent.
A research team led by Woods Hole Oceanographic Institution (WHOI) and including scientists at NASA’s Jet Propulsion Laboratory studied three hydrothermal vents, found along an underwater ridge in the Caribbean called the Mid-Cayman Rise. They published their findings yesterday in The Proceedings of the National Academy of Sciences.
Hydrothermal vents are usually found in spots where the Earth’s tectonic are moving away from each other, creating a weird zone of raw chemistry. A mixture of hot vent fluids and cold deep-ocean water form plumes, which can contain dissolved chemicals, minerals, and microbes. Instead of searching the entire 60-mile-long ridge with the vehicle, the team scouted for chemicals from the plume to zero-in on the vents.
“Every time you get a hydrothermal system, it’s wet and hot, and you get water and rocks interacting. Wherever this happens on the seafloor, life takes advantage,” said geophysicist Chris German of the Woods Hole Oceanographic Institute. “Every time you find seawater interacting with volcanic rock, there’s weird and wonderful life associated with it.” [Wired]
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If there were life on the Saturnian moon of Titan, the thinking goes, it would have to inhabit pools of methane or ethane at a cool -300 degrees Fahrenheit, and without the aid of water. While scientists don’t know just what that life would look like, they can predict what effects such tiny microbes would have on Titan’s atmosphere. That’s why researchers from the Cassini mission are excited now: They’ve found signatures that match those expectations. It’s far from proof of life on Titan, but it leaves the door wide open to the possibility.
In 2005, NASA’s Chris McKay put forth a possible scenario for life there: Critters could breathe the hydrogen gas that’s abundant on Titan, and consume a hydrocarbon called acetylene for energy. The first of two studies out recently, published in the journal Icarus, found that something—maybe life, but maybe something else—is using up the hydrogen that descends from Titan’s atmosphere to its surface:
“It’s as if you have a hose and you’re squirting hydrogen onto the ground, but it’s disappearing,” says Darrell Strobel, a Cassini interdisciplinary scientist based at Johns Hopkins University in Baltimore, Md., who authored a paper published in the journal Icarus [Popular Science].
Erring on the side of caution, the scientists suggest that life is but one explanation for this chemical oddity. Perhaps some unknown mineral on Titan acts as a catalyst to speed up the reaction of hydrogen and carbon to form methane, and that’s what accounts for the vanishing hydrogen. (Normally, the two wouldn’t combine fast enough under the cold conditions on Titan to account for the anomaly.) That would be pretty cool, though not as much of a jolt as Titanic life.
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In a half-century of hunting, the Search for Extra-Terrestrial Intelligence (SETI) has turned up nary a whisper from E.T. But for renowned physicist Stephen Hawking, the non-success of SETI and others who hope to contact alien life might be for the best: Aliens, he says, might not like us.
Hawking caused waves with this suggestion in his new Discovery Channel special, which debuted last night. He has long believed that extraterrestrial life exists, simply because of the sheer vastness of the universe. While much of what’s out there might be simple microbial life, there may indeed be new civilizations far more advanced than our own. But that doesn’t mean they’ll be friendly.
Said Hawking: “We only have to look at ourselves to see how intelligent life might develop into something we wouldn’t want to meet. I imagine they might exist in massive ships, having used up all the resources from their home planet. Such advanced aliens would perhaps become nomads, looking to conquer and colonise whatever planets they can reach” [The Times].
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