Posted on by Jason Major

Hunting for High Life: What Lives in Earth’s Stratosphere?

The Moon photographed through the layers of the atmosphere from the ISS in December 2003 (NASA/JSC)

What lives at the edge of space? Other than high-flying jet aircraft pilots (and the occasional daredevil skydiver) you wouldn’t expect to find many living things over 10 kilometers up — yet this is exactly where one NASA researcher is hunting for evidence of life.

Earth’s stratosphere is not a place you’d typically think of when considering hospitable environments. High, dry, and cold, the stratosphere is the layer just above where most weather occurs, extending from about 10 km to 50 km (6 to 31 miles) above Earth’s surface. Temperatures in the lowest layers average -56 C (-68 F) with jet stream winds blowing at a steady 100 mph. Atmospheric density is less than 10% that found at sea level and oxygen is found in the form of ozone, which shields life on the surface from harmful UV radiation but leaves anything above 32 km openly exposed.

Sounds like a great place to look for life, right? Biologist David Smith of the University of Washington thinks so… he and his team have found “microbes from every major domain” traveling within upper-atmospheric winds.

Smith, principal investigator with Kennedy Space Center’s Microorganisms in the Stratosphere (MIST) project, is working to take a census of life tens of thousands of feet above the ground. Using high-altitude weather balloons and samples gathered from Mt. Bachelor Observatory in central Oregon, Smith aims to find out what kinds of microbes are found high in the atmosphere, how many there are and where they may have come from.

“Life surviving at high altitudes challenges our notion of the biosphere boundary.”

– David Smith, Biologist, University of Washington in Seattle

Although reports of microorganisms existing as high as 77 km have been around since the 1930s, Smith doubts the validity of some of the old data… the microbes could have been brought up by the research vehicles themselves.

“Almost no controls for sterilization are reported in the papers,” he said.

But while some researchers have suggested that the microbes could have come from outer space, Smith thinks they are terrestrial in origin. Most of the microbes discovered so far are bacterial spores — extremely hardy organisms that can form a protective shell around themselves and thus survive the low temperatures, dry conditions and high levels of radiation found in the stratosphere. Dust storms or hurricanes could presumably deliver the bacteria into the atmosphere where they form spores and are transported across the globe.

If they land in a suitable environment they have the ability to reanimate themselves, continuing to survive and multiply.

Although collecting these high-flying organisms is difficult, Smith is confident that this research will show how such basic life can travel long distances and survive even the harshest environments — not only on Earth but possibly on other worlds as well, such as the dessicated soil of  Mars.

“We still have no idea where to draw the altitude boundary of the biosphere,” said Smith. This research will “address how long life can potentially remain in the stratosphere and what sorts of mutations it may inherit while aloft.”

Read more on Michael Schirber’s article for Astrobiology Magazine here, and watch David Smith’s seminar “The High Life: Airborne Microbes on the Edge of Space” held May 2012 at the University of Washington below:

Inset images – Top: layers of the atmosphere, via the Smithsonian/NMNH. Bottom: Scanning electron microscope image of atmospheric bacterial spores collected from Mt. Bachelor Observatory (NASA/KSC)

Posted on by Nancy Atkinson

Mars Sample Return Mission? Naaah… Just Beam Back Martian DNA

Artist concept of a Mars Sample Return mission. Credit: Wickman Spacecraft & Propulsion.

A Mars sample return mission has long been a dream and goal of many planetary scientists. Getting Martian soil samples back here on Earth would allow them to be studied in ways rovers and landers just can’t do. Of course, the big reason for getting samples of Mars back to Earth would be to really determine if there ever was – or is — life on Mars. But a sample return mission would be “hellishly difficult,” Steve Squyres of the MER mission once said.

But forget sending a lander, scooping up samples, putting them in a capsule and somehow rocketing them back to Earth. Human genome sequencer Craig Venter wants to send a DNA sequencing machine Mars, and beam back the DNA data to Earth. Not to be outdone, Jonathan Rothberg, founder the DNA sequencing company Ion Torrent, is working on getting his Personal Genome Machine to Mars and sending back the data.

In articles in the Los Angeles Times and MIT’s Technology Review this week the two biologists seem to be in a race, of sorts, to see who could send their DNA machines to Mars first. Venter was quoted as saying, “There will be life forms there,” Venter said, and wants to build a “biological teleporter.”

Rothberg is looking to be part of a NASA-funded project at Harvard and MIT called SET-G, or “the search for extraterrestrial genomes.”

An MIT researcher involved in the project, Christopher Carr, told Technology Review that his lab is working to shrink Ion Torrent’s machine from 30 kilograms down to just three kilograms so that it can fit on a NASA rover, and they are testing how well the device can withstand the heavy radiation it would encounter on the way to Mars.

With NASA’s current budget woes, a sample return mission likely couldn’t happen until around 2030. But another Mars rover mission may be slated for 2018, if all goes well, and a DNA sequencer could potentially be part of the mission, the two biologists said. And an in-situ DNA sequencer avoids the potential pitfalls of a sample return mission.

“People are worried about the Andromeda strain,” Venter said. “We can rebuild the Martians in a P-4 spacesuit lab instead of having them land in the ocean.”

Sources: Los Angeles Times, Technology Review

Posted on by Jason Major

Alien Life May Not Be So Alien – If It Exists At All

Our galaxy has exoplanets, organic compounds, liquid water -- even a nebula shaped like a DNA helix -- but is there life? (Image credit: M. Morris/UCLA)

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Are we too hopeful in our hunt for extraterrestrial life? Regardless of exoplanet counts, super-Earths and Goldilocks zones, the probability of life elsewhere in the Universe is still a moot point — to date, we still only know of one instance of it. But even if life does exist somehow, somewhere besides Earth, would it really be all that alien?

In a recent paper titled “Bit by Bit: the Darwinian Basis for Life” Gerald Joyce, Professor of Molecular Biology and Biochemistry at the Scripps Research Institute in La Jolla, CA discusses the nature of life as we know it in regards to its fundamental chemical building blocks — DNA, RNA — and how its ability to pass on the memory of its construction separates true biology from mere chemistry.

“Evolution is nothing more than chemistry plus history,” Joyce said during a Public Library of Science podcast.

The DNA structures that evolved here on Earth — the only place in the Universe we know for certain that life can thrive — have proven to be highly successful (obviously). So what’s to say that life elsewhere wouldn’t be based on the same basic building blocks? And if it is, is it really a “new” life form?

“Truly new ‘alternative life’ would be life of a different biology,” Joyce said. “It would not have the information in it that is part of the same heritage of our life form.”

To arise in the first place, according to Joyce, new life can take two possible routes. Either it begins as chemical connections that grow increasingly more complex until they begin to hold on to the memory of their specific “bit” structure, eventually “bit-flipping” — aka, mutating — into new structures that are either successful or unsuccessful, or it starts from a more “privileged” beginning as an offshoot of previous life, bringing bits into a totally new, immediately successful orientation.

With those two scenarios, anywhere besides Earth “there are no example of either of those conditions so far.”

That’s not saying that there’s no life elsewhere in the Universe… just that we have yet to identify any evidence of it. And without evidence, any discussion of its probability is still pure conjecture.

“In order to estimate probabilities, we need facts,” said Joyce. “The problem is, there is only one life form. And so it’s not possible to estimate probability of life elsewhere when you have only one example.”

Voyager included a golden record with images and sounds of Earthly life recorded on it... just in case. (NASA)

Even though exoplanets are being found on a nearly daily basis, and it’s only a matter of time before a rocky, Earthlike world with liquid water on its surface is confirmed orbiting another star, that’s no guarantee of the presence of alien life — despite what conclusions the headlines will surely jump to.

There could be a billion habitable planets in our galaxy. But what’s the relationship between habitable and inhabited?” Joyce asks. “We don’t know.”

Still, we will continue to search for life beyond our planet, be it truly alien in nature… or something slightly more familiar. Why?

“I think humans are lonely,” Joyce said. “I think humans are like Geppetto — we want to have a ‘real boy’ out there that we can point to, we want to find a Pinocchio living on some extrasolar planet… and then somehow we won’t be such a lonely life form.”

And who knows… if any aliens out there really are a lot like us, they may naturally be searching for evidence of our existence as well. If only to not be so lonely.

Listen to the full PLoS podcast here.

Posted on by Nancy Atkinson

We Really Hope ET is Out There, But There’s Not Enough Scientific Evidence, Researchers Say

This artist's illustration gives an impression of how common planets are around the stars in the Milky Way. Credit: NASA, ESA, and M. Kornmesser (ESO)

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For many of us who grew up listening to Carl Sagan, watching robotic spacecraft travel to other worlds, and indulging in science fiction books and movies, it’s a given: one day we’ll find life somewhere else in the solar system or Universe. But are we being too optimistic? Two researchers say that our hopes and expectations of finding ET might be based more on optimism than scientific evidence, and the recent discoveries of exoplanets that might be similar to Earth are probably getting everyone’s hopes up too high.

Astrophysicist Edwin Turner from Princeton and researcher David Spiegel from the Institute for Advanced Study say the idea that life has or could arise in an another Earth-like environment has only a small amount of supporting evidence, most of it extrapolated from what is known about abiogenesis, or the emergence of life, on early Earth. Their research says the expectations of life cropping up on exoplanets are largely based on the assumption that it would or will happen if the same conditions as Earth exist elsewhere.

Using a Bayesian analysis — which weighs how much of a scientific conclusion stems from actual data and how much comes from the prior assumptions of the scientist — the duo concluded that current knowledge about life on other planets suggests Earth might be a cosmic aberration, where life took shape unusually fast and furious. If so, then the chances of the average terrestrial planet hosting life would be low.

“Fossil evidence suggests that life began very early in Earth’s history and that has led people to determine that life might be quite common in the universe because it happened so quickly here, but the knowledge about life on Earth simply doesn’t reveal much about the actual probability of life on other planets,” Turner said.

So, if a scientist starts out assuming that the chances of life existing on another planet is as large as on Earth, then their scientific results will be presented in a way that supports that likelihood, Turner said.

“Information about that probability comes largely from the assumptions scientists have going in, and some of the most optimistic conclusions have been based almost entirely on those assumptions,” he said.

Therefore, with all the exoplanets being found, and as our discoveries have become more and more enticingly Earth-like, these planets have our knowledge of life on Earth projected onto them, the researchers said.

How does an exoplanet researcher feel about this? Turner and Spiegel found a sympathetic soul in Joshua Winn from the Massachusetts Institute of Technology, who said that the two cast convincing doubt on a prominent basis for expecting extraterrestrial life.

“There is a commonly heard argument that life must be common or else it would not have arisen so quickly after the surface of the Earth cooled,” Winn said. “This argument seems persuasive on its face, but Spiegel and Turner have shown it doesn’t stand up to a rigorous statistical examination — with a sample of only one life-bearing planet, one cannot even get a ballpark estimate of the abundance of life in the universe.

It is true that science is about facts — not about what your gut feelings are. But there’s a strong argument that we need inspiration to do the best, most engaging science. Writer Andrew Zimmerman Jones blogged today at PBS about how many scientists were spurred to follow their careers by reading science fiction when they were young.

“The finest science fiction is inspired by the same thing that has inspired the greatest science discoveries throughout the ages: optimism for the future,” wrote Jones.

And perhaps that is what is mostly behind our hopes for finding ET: optimism for the future of the human race, that we really could one day travel to other worlds, and find new friends — “to explore strange new worlds, to seek out new life and new civilizations, to boldly go where no one has gone before…”

Turner and Spiegel do say they are not making judgments, but just analyzing existing data that suggests the debate about the existence of life on other planets is framed largely by the prior assumptions of the participants.

“It could easily be that life came about on Earth one way, but came about on other planets in other ways, if it came about at all,” Turner said. “The best way to find out, of course, is to look. But I don’t think we’ll know by debating the process of how life came about on Earth.”

Read the team’s paper.

Sources: Princeton, PBS

Posted on by Nancy Atkinson

Intelligent Alien Dinosaurs?

I for one welcome our alien dinosaur overlords…maybe.

Dinosaurs once roamed and ruled the Earth. Is it possible that similar humongous creatures may have evolved on another planet – a world that DIDN’T get smacked by an asteroid – and later they developed to have human-like, intelligent brains? A recent paper discussing why the biochemical signature of life on Earth is so consistent in orientation somehow segued into the possibility that advanced versions of T. Rex and other dinosaurs may be the life forms that live on other worlds. The conclusion? “We would be better off not meeting them,” said scientist Ronald Breslow, author of the paper.

The building blocks of terrestrial amino acids, sugars, and the genetic materials DNA and RNA have two possible orientations, left or right, which mirror each other in what is called chirality. On Earth, with the exception of a few bacteria, amino acids have the left-handed orientation. Most sugars have a right-handed orientation. How did that homochirality happen?

If meteorites carried specific types of amino acids to Earth about 4 billion years, that could have set the pattern the left-handed chirality in terrestial proteins.

“Of course,” Breslow said in a press release, “showing that it could have happened this way is not the same as showing that it did. An implication from this work is that elsewhere in the universe there could be life forms based on D-amino acids and L-sugars. Such life forms could well be advanced versions of dinosaurs, if mammals did not have the good fortune to have the dinosaurs wiped out by an asteroidal collision, as on Earth.”

But not everyone was impressed with the notion of dinosaurs from space. “None of this has anything to do with dinosaurs,” wrote science author Brian Switek in the Smithsonian blog Dinosaur Tracking. “As much as I’m charmed by the idea of alien dinosaurs, Breslow’s conjecture makes my brain ache. Our planet’s fossil record has intricately detailed the fact that evolution is not a linear march of progress from one predestined waypoint to another. Dinosaurs were never destined to be. The history of life on earth has been greatly influenced by chance and contingency, and dinosaurs are a perfect example of this fact.”

For further reading:
American Chemical Society paper
ACS press release
Dinosaur Tracking blog

Posted on by Jason Major

Is This Proof of Life on Mars?

View of Mars from Viking 2 lander, September 1976. (NASA/JPL-Caltech)

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The Curiosity rover is currently on its way to Mars, scheduled to make a dramatic landing within Gale Crater in mid-August and begin its hunt for the geologic signatures of a watery, life-friendly past. Solid evidence that large volumes of water existed on Mars at some point would be a major step forward in the search for life on the Red Planet.

But… has it already been found? Some scientists say yes.

Researchers from universities in Los Angeles, California, Tempe, Arizona and Siena, Italy have published a paper in the International Journal of Aeronautical and Space Sciences (IJASS) citing the results of their work with data obtained by NASA’s Viking mission.

The twin Viking 1 and 2 landers launched in August and September of 1975 and successfully landed on Mars in July and September of the following year. Their principal mission was to search for life, which they did by digging into the ruddy Martian soil looking for signs of respiration — a signal of biological activity.

A six-inch-deep trench in the Martian soil dug by Viking 1 in February 1977. The goal was to reach a foot below the surface for sampling.

The results, although promising, were inconclusive.

Now, 35 years later, one team of researchers claims that the Viking landers did indeed detect life, and the data’s been there all along.

“Active soils exhibited rapid, substantial gas release,” the  team’s report states. “The gas was probably CO2 and, possibly, other radiocarbon-containing gases.”

By applying mathematical complexities to the Viking data for deeper analysis, the researchers found that the Martian samples behaved differently than a non-biological control group.

“Control responses that exhibit relatively low initial order rapidly devolve into near-random noise, while the active experiments exhibit higher initial order which decays only slowly,” the paper states. “This suggests a robust biological response.”

While some critics of the findings claim that such a process of identifying life has not yet been perfected — not even here on Earth — the results are certainly intriguing… enough to bolster support for further investigation into Viking data and perhaps re-evaluate the historic mission’s “inconclusive” findings.

The team’s paper can be found here.

Image credits: NASA/JPL-Caltech. Also, read more on Irene Klotz’s article on Discovery News.

Posted on by Nancy Atkinson

How Would Humans Respond to First Contact from an Alien World?

Artist concept of an exoplanet. Credit: David A. Hardy.

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According to Star Trek lore, it is only 51 years until humans encounter their first contact with an alien species. In the movie “Star Trek: First Contact,” on April 5, 2063, Vulcans pay a visit to an Earth recovering from a war-torn period (see the movie clip below.) But will such a planet-wide, history-changing event ever really take place? If you are logical, like Spock and his Vulcan species, science points towards the inevitability of first contact. This is according to journalist Marc Kaufman, who is a science writer for the Washington Post and author of the book “First Contact: Scientific Breakthroughs in the Hunt for life Beyond Earth.” He writes that from humanity’s point of view, first contact would be a “harbinger of a new frontier in a dramatically changed cosmos.”

What are some of the arguments for and against the likelihood of first contact ever taking place and what would the implications be?

“One argument against first contact is from those who say there is no other life in the Universe,” said Kaufman, speaking to Universe Today via phone, “and with that is the Fermi paradox, which says that if there is so much life out there, why hasn’t it visited us yet? That was first posited back in the 1950’s and with everything we’ve learned since then, it seems rather presumptuous and Earth-centric to say that because no one has come to Earth, there is no life out there.”

Kaufman argues the Universe is so vast, the number of exoplanets is so huge – with the number of exoplanets in habitable zones now gaining in numbers almost daily – and we now understand that all the makings for the building blocks of life are out in space, so it defies logic to argue there is no other life out there.

Another argument against first contact states there might be microbial life elsewhere in the Universe, but it is not intelligent. “This is where the Fermi paradox comes in even more,” Kaufman said. “It certainly is true — as far as we know — that no intelligent life has made contact with Earth. But when you look at the amount of time we’ve been a technologically advanced society, it has only been a few hundred years. In the vastness of time, that is a pitifully small amount of time – truly nothing.”

In the immensity of cosmological time, Kaufman said, it is quite possible that microbial life emerged and evolved a billion years ago on another world and we missed coinciding with it, as civilizations could have come and gone.

“But all the makings are there and unless we want to say that Earth was made through divine creation or only through an unbelievable set of circumstances this is the only place in the Universe where life began, it just seems hugely, hugely implausible,” Kaufman said.

So, Kaufman says, the best, most logical argument is that life exists beyond Earth and in some instances includes what we would consider intelligence.

“If you have microbial life and billions of planets in habitable zones, the logic says that some of them will advance like we did,” Kaufman said. “There’s no reason to say that evolution is exclusive to Earth. It feels very 14th or 15th century-Earth-centric to say that we are the only place where there is intelligent life.”

Our continued scientific understanding, and in particular, the recent ongoing finding of so many exoplanets, has been a real revolution in our understanding of the cosmos, Kaufman said, and it is a huge boost to the logic of finding life elsewhere.

“It was hypothesized for decades, if not centuries that other planets were out there,” he said. “Now that we are finding planets almost every day, from a scientific perspective, it shows us that if the science is pointing in a certain direction, you just need to have the technology and the knowledge catch up to that hypothesis.”

Kaufman says that like the surge in finding exoplanets, astrobiology is likely the next area of science where breakthroughs will happen.

“Scientists almost unanimously believe there is other life out there, but we just don’t have the technology to find it yet,” he said. “Even with the recent potential cuts in NASA’s budget for planetary missions, and even if NASA is not able to send up as many missions, there is a broad movement going on in college campuses and institutes – from working on synthetic life, to studies in cosmology, and astrochemistry — all of those things are moving forward because there is a real sense that something is within reach. This area of science is just going to blossom.”

So if tomorrow (or on April 5, 2063) a spaceship shows up, how would we respond?

“On one level, I’d hope there would be a huge amount of wonder and awe and a recognition of the vastness of the Universe. But I also imagine there would be a lot of defensiveness, as well,” said Kaufman, referring to some, like Stephen Hawking, who say we shouldn’t send messages out into space — because if a more technically advanced civilization comes to Earth, the outcome for the less advanced (us) would likely be bad.

But Kaufman has hope that Earthlings would welcome a visit.

“Look at the continuing fascination of Roswell or UFOs,” he said. “Throughout history, humans have looked to the skies and thought that we’ve experienced something ‘out there’ – be it angels or gods or spaceships. There is, I believe, a deep human craving that we aren’t alone, and that would be a significant part of our response.”

For more information see Kaufman’s book, and website,”Habitable Zones”

Posted on by Jason Major

“Tidal Venuses” May Have Been Wrung Out To Dry

Extreme heating from tidal stresses may render a "Tidal Venus" planet inhabitable

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Earth-sized exoplanets within a distant star’s habitable zone could still be very much uninhabitable, depending on potential tidal stresses — either past or present — that could have “squeezed out” all the water, leaving behind a bone-dry ball of rock.

New research by an international team of scientists suggests that even a moderately eccentric orbit within a star’s habitable zone could exert tidal stress on an Earth-sized planet, enough that the increased surface heating due to friction would boil off any liquid water via extreme greenhouse effect.

Such planets are dubbed “Tidal Venuses”, due to their resemblance to our own super-heated planetary neighbor. This evolutionary possibility could be a factor in determining the actual habitability of an exoplanet, regardless of how much solar heating (insolation) it receives from its star.

The research, led by Dr. Rory Barnes of the University of Washington in Seattle, states that even an exoplanet currently in a circular, stable orbit could have formed with a much more eccentric orbit, thus subjecting it to tidal forces. Any liquid water present after formation would then have been slowly but steadily evaporated and the necessary hydrogen atoms lost to space.

The risk of such a “desiccating greenhouse” effect would be much greater on exoplanets orbiting lower-luminosity stars, since any potential habitable zone would be closer in to the star and thus prone to stronger tidal forces.

And as far as such an effect working to create habitable zones further out in orbit than otherwise permissible by stellar radiation alone… well, that wouldn’t necessarily be the case.

Even if an exoplanetary version of, say, Europa, could be heated through tidal forces to maintain liquid water on or below its surface, a rocky world the size of Earth (or larger) would still likely end up being rather inhospitable.

“One couldn’t do it for an Earthlike planet — the tidal heating of the interior would likely make the surface covered by super-volcanoes,” Dr. Barnes told Universe Today.

So even though the right-sized exoplanets may be found in the so-called “Goldilocks zone” of their star, they may still not be “just right” for life as we know it.

The team’s full paper can be found here.

Posted on by Paul Scott Anderson

New Analysis of Clay Deposits in Ancient Martian Lakes

Map of 226 ancient lakes on Mars. Credit: Goudge, T.A., Head, J.W., Mustard, J.F. and Fassett, C.I./MOLA/NASA

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Mars was once a much wetter world than it is now, with hot springs, rivers, lakes and perhaps even oceans. Just how wet exactly, and for how long, is still a subject of considerable debate. One vital clue comes from clay mineral deposits and sediments left over after the water disappeared, but still visible now. They provide a valuable insight into what Mars used to be like, and why it is the cold, dry place we see today.

A team of scientists from Brown University has just completed a new study of ancient lake beds on Mars, specifically looking at the clay deposits within them, to try to determine how many of these lakes still contain such deposits and their composition. So what do they tell us about conditions on early Mars? How does this affect the search for evidence of life?

As it turns out, about a third of the lake beds examined still show evidence for clay deposits. A total of 79 lake beds out of 226 studied to be exact, indicating that they are less common on Mars than on Earth. The reason for this may be that the chemistry of the water was not ideal for preserving clays or that the lakes were relatively short-lived.

The paper was just published in Icarus on March 2, 2012.

From the abstract:

“These results indicate that hydrated and evaporite minerals are not as commonly associated with lacustrine deposits on Mars as they are on Earth. This suggests in situ alteration and mineral precipitation, a common source of such minerals in terrestrial lakes, was not a major process occurring in these paleolacustrine systems, and that the observed minerals are likely to be present as transported material within the lacustrine deposits. The lack of widespread in situ alteration also suggests that either the water chemistry in these paleolake systems was not conducive to aqueous alteration and mineral precipitation, or that the open-basin lake systems were relatively short-lived.”

Images for the study came from the Mars Reconnaissance Orbiter, Mars Odyssey and Mars Express spacecraft.

Clay deposits have become a primary focus of study by orbiters and rovers, as they could preserve fossil traces of early life, just as they do on Earth. Even if they are less common on Mars, the fact that they do exist there is exciting, and there is now much interest in exploring them further. Apart from underground, they are the best places to look for such evidence of life. It is also possible that additional deposits have been buried underground, waiting to be discovered.

The Opportunity rover is currently very close to a treasure trove of clays in Endeavour crater, and it is expected to head straight for them after its winter “hibernation” is over in the next few months. The Curiosity rover, en route to Mars right now, will land in Gale crater next July, where there are also clay deposits near the base of a mountainous peak within the crater. Gale crater is thought to be another site of a former Martian lake.

The abstract is available here (with full paper available for purchase).

Posted on by Paul Scott Anderson

Exciting New ‘Enceladus Explorer’ Mission Proposed to Search for Life

Water vapour geysers erupting from Enceladus' south pole. Credit: NASA/JPL

Water vapour geysers erupting from Enceladus' south pole. Credit: NASA/JPL

Along with Jupiter’s moon Europa, a tiny Saturnian moon, Enceladus, has become one of the most fascinating places in the solar system and a prime target in the search for extraterrestrial life. Its outward appearance is that of a small, frozen orb, but it revealed some surprises when the Cassini spacecraft gave us our first ever close-up look at this little world – huge geysers of water vapour spewing from its south pole. The implications were thought-provoking: Enceladus, like Europa, may have an ocean of liquid water below the surface. Unlike Europa however, the water is apparently able to make it up to the surface via fissures, erupting out into space as giant plumes.

Now, a new project sponsored by the German Aerospace Center, Enceladus Explorer, was launched on February 22, 2012, in an attempt to answer the question of whether there could be life on (or rather, inside) Enceladus. The project lays the groundwork for a new, ambitious mission being proposed for some time in the future.

Cassini was able to sample some of the plumes directly during its closest approaches to the moon, revealing that they contain water vapour, ice particles and organic molecules. If they originate from a reservoir of subsurface liquid water, as now thought by most scientists involved, it would indicate an environment which could be ideal for life to have started. The necessary ingredients for life (as we know it at least) are all there – water, heat and organic material. The fissures themselves generate much more heat relatively than the surrounding surface, suggesting that the conditions below the surface are much warmer. Maybe not “hot” per se, but warm enough, perhaps also with the aid of salts like in Earth’s oceans, to keep the water liquid.

But what is the best way to search for evidence of life there?  Follow-up missions have been proposed, to again sample the plumes, but with instruments able to look for life itself, which Cassini can’t do. This would seem ideal, as the water is being spewed out into space, with no drilling through the ice necessary. But the Enceladus Explorer project is proposing to do just that; the rationale is that any organisms (most likely microscopic) which may be in the water could easily be destroyed by the force of the ejection from the fissure. So then what is the best way to sample the water itself down below?

Enceladus Explorer would place a base station on the surface near one of the fissures; an ice drilling probe, the IceMole, would then melt its way through the ice crust to a depth of 100-200 metres until it reaches a liquid water reservoir. It would obtain samples of the water and examine them in situ for any traces of microorganisms. With no GPS system available, or external reference points to use, the probe would need to function autonomously, finding its own way through the ice to the water below.

The IceMole is already being tested here on Earth, and has successfully melted its way through the ice of the Morteratsch glacier in Switzerland. The next experiment will have it navigate its way through ice in the Antarctic, sampling completely uncontaminated water from a subsurface lake below the ice, much like the conditions found on Enceladus.

There is no timeframe yet for such a mission, especially given current budgets, but the Enceladus Explorer project has already shown that it is certainly technologically feasible and would provide an incredible look at an environment in the outer solar system which is amazingly Earth-like yet utterly alien at the same time.