Tag Archives: extraterrestrial

NASA Chief: We’ll find extraterrestrial life within the next decade

It seems almost unthinkable that out of an infinitely vast universe, there’s no one but us, occupying a small blue dot in a remote galaxy. So is anyone else looking towards us when we watch the stars at night? Or are we really the only ones? Now top NASA scientists are saying it’s almost certain that we’ve got company.

“I believe we are going to have strong indications of life beyond Earth in the next decade and definitive evidence in the next 10 to 20 years,” said Ellen Stofan, NASA’s chief scientist, during a public panel held in Washington on Tuesday.

“We know where to look, we know how to look, and in most cases we have the technology,” said Stofan.

Jeffery Newmark, the agency’s interim director of heliophysics put it in these terms: “It’s definitely not an if, it’s a when.”

Lest the headline made you imagine an INDEPENDENCE DAY scenario of alien invasion – you can rest easy. The same goes for any thoughts that the ancient Egyptians received intergalactic help with building the pyramids.

“We are not talking about little green men,” Stofan said to clarify any hyperbole. “We are talking about little microbes.”

Throughout the course of their hour-long presentation, NASA’s leaders described the numerous recent discoveries that indicate how never before in history have people been closer to uncovering extraterrestrial life – whether it happens to be in our own solar system, or on any number of Earth-like candidates spotted light years from home.

Among the examples, Jim Green, the director of planetary science for NASA, referenced a study analyzing the thin atmosphere just above the Martian polar ice caps, the remains of an era when nearly 50% of the planet’s northern hemisphere were covered with an ocean larger than the Arctic Sea – up to one mile deep, and for up to 1.2 billion years, it had liquid water, plenty of time to have allowed for lifeforms to develop, and possibly even for there to be fossils, compressed within the planet’s organic rocks.

“We think that long period of time is necessary for life to get more complex,” Stofan said.

Bringing teams of field geologists and also researchers within the burgeoning field of astrobiology to Mars would sharply increase the odds of discovering fossils of the past – potentially an intriguing story of survival that rivals the narrative that rocks on Earth tell us – a mass extinction event that may have ended life as we know it on the red planet.

Another recent study that made headlines not too long ago was referenced by Green. Measurements of the aurora occurring on Jupiter’s distant moon Ganymede may indicate that beneath its layers of ice, it may be concealing an immense liquid ocean.

These findings are examples of why we may have been casting our nets too far in the hunt for extraterrestrial life. Previous searches for life were almost analogous to finding a hospitable planet to inhabit – one whose conditions most closely resembled the Earth, a familiar environment to adapt to in terms of climate and gravity. Therefore, astronomers set their sights on “habitable zones,” planetary bodies close enough to a host star where temperatures made it possible for liquid water to exist on the surface, without freezing or vaporizing. There is, however, the possibility that life may be very different from our own – with beings that are based on composites of methane and nitrogen, rather than the organic carbon-based life forms found on Earth.

“We now recognize that habitable zones are not just around stars, they can be around giant planets too,” Green said. “We are finding out the solar system is really a soggy place.”

Among other exciting voyages coming up, NASA announced plans this winter to travel to another moon of Jupiter Europa, also thought to contain an ocean with hydrothermal vents.

“I don’t know what we are going to find there,” he said.

Newmark described how NASA’s own work here at home, which recently came under fire at a Senate hearing, is critical to exploring the possibilities of interplanetary life. Right now, NASA dedicates $1 billion annually to Earth science, and is engaged in studying how Earth’s magnetic field is instrumental in protecting the planet’s water and atmosphere against being carried off by solar wind, making it critical in enabling life on Earth to develop.

“Mars does not have a significant magnetic field, so it lets the wind strip away the water and atmosphere,” he said.

Paul Hertz, director of astrophysics at NASA also joined the panel discussion, where he spoke of the ways in which future telescopes already being planned will enable scientists to survey the atmospheres on large rocky planets, such as the Kepler discoveries found near distant stars, in a hope to find the chemical markers necessary for life.

“We are not just studying water and habitability in our solar system, but also looking for it in planets around other stars,” he said – something that could be advantageous in navigating the solar system and coming up with more efficient ways for space travel than what we currently have.

NASA associate administrator John Grunsfeld, said part of what excites him most about the search for life beyond our planet is to see what that life looks like.

“Once we get beyond Mars, which formed from the same stuff as Earth, the likelihood that life is similar to what we find on this planet is very low,” he said.

Grunsfeld maintains that researchers are very close to making strides in the search for extraterrestrial beings, and thinks that such a goal is within the grasp of an upcoming generation of scientists and space explorers. Green, however, hopes that the discoveries will be made much sooner. After all, the advances are coming at a faster pace than ever before. The Europa mission hopes to take off by the end of the decade.

“The science community is making enormous progress,” said Green. “And I’ve told my team I’m planning to be the director of planetary science when we discover life in the solar system.”

James Sullivan
James Sullivan is the assistant editor of Brain World Magazine and a contributor to Truth Is Cool and OMNI Reboot. He can usually be found on TVTropes or RationalWiki when not exploiting life and science stories for another blog article.

Is There Life Beneath the Tiger Stripes of Enceladus?

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While most people recognize Saturn from its nine immense rings, you’ve probably never heard of Enceladus, one of its lesser moons that hasn’t received nearly as much attention in the media lately as Titan. While researchers have proposed that life may exist on Titan, even non-carbon based life forms much different from any life as we know it on Earth, Enceladus is another likely candidate for maintaining lifeforms. It might even be a bit more inviting than Titan, where any submersible probes would have to be built to endure extreme cold. Although Enceladus contains an immense sea encrusted with ice, two recent studies have suggested that hydrothermal vents exist beneath it, allowing heat to enter and maintain life forms similar to those found on Earth. It’s an idea similar to what planetary scientists think may be happening on Jupiter’s nearby moon, Europa.

As interest in the search for extraterrestrial lifeforms has increased, and perhaps Enceladus may be among the first places to look.

“You have a habitat that could possibly harbor life,” said Linda Spilker, project scientist for NASA’s Cassini mission to Saturn in an interview with NBC News. “So it’d be very interesting to go back with a future mission to make the measurements to could tell you whether or not there might be life in Enceladus’ ocean.”

Hydrothermal vents are like the geysers of the ocean, present along mid ocean ridges, forming when underwater mountains like the Mid Atlantic Ridge shift in position. Ancient hydrothermal vents exist on Mars, where an ocean that was once larger than the Arctic Sea has been discovered. However, planetary scientists have yet to see any hydrothermal vents on Enceladus at work, much less any direct evidence of marine life. Enceladus’ warm water is concealed underneath an icy crust that’s 25 miles deep. However, the researchers believe that volcanic activity would be the best way to explain materials captured on the moon’s surface by the Cassini spacecraft.

Almost ten years ago, the Cassini researchers documented what appeared to be geysers of ice water leaping from the surface of Enceladus — evidence that there’s a liquid reservoir beneath the sheets of ice. In the following years, scientists made an in-depth analysis which determined that this ice encrusted sea happens to lie in a region adjacent to the moon’s south pole. Water emanates out of cracks within the ice known as “tiger stripes.”

Scientists also learned that the icy spray was partially responsible for Saturn’s faint E-ring. Using a Cosmic Dust Analyzer they looked closely at the contents of the spray. Along with naturally formed ice crystals, they discovered particles rich in silicon, about one nanometer in size – bits of dust made of silica, the same compound known for plugging up volcanoes on Earth. Along with the methane, this is a prominent sign of volcanic activity from hydrothermal vents. It is also likely that these mechanisms could support underwater life, just as silica and methane do in deep-sea settings on Earth.

“What we did first was just to know what these particles were, and by doing this, we started to think about how they formed,” said Hsiang-Wen Hsu, a researcher at the University of Colorado’s Laboratory for Atmospheric and Space Physics.

In order to replicate similar particles, the scientists learned the only way to make them from ordinary rocks was to have minerals interacting with alkaline water under temperature that were at least 194 degrees Fahrenheit. The water also had to contain salinity levels just under four percent. All of these conditions can be found in the hydrothermal vents beneath the Atlantic Ocean, a region called the Lost City, in which volcanically heated water permits the existence of some strange marine life, capable of thriving without sunlight. “That is a very good analog to what we have,” Hsu said.

The study, which was led by Hsu, was published in the journal Nature this week. An additional study has just been accepted for publication in Geophysical Research Letters, and gives further evidence to the hydrothermal hypothesis.

Alexis Bouquet of the Southwest Research Institute conducted the second study – giving an analysis of Enceladus’ water plumes. Gases in the plumes are consistent with Earth’s subglacial lakes, with higher levels of methane in the plumes than what was predicted.

It is possible that methane is escaping from Enceladus’ ice, but researchers have another explanation: Hydrothermal vents may be “compensating by adding methane into the ocean.”

Spilker, who works for NASA’s Jet Propulsion Laboratory, said that the methane study is a “nice, complementary part of the story.” While researchers had known of water rising out of the cracks in Enceladus’ ice, they weren’t sure if it was warm enough to sustain life.

“What’s really striking is that this is the first time we’ve seen active hydrothermal vents outside of the seafloor on Earth,” Spilker said.

This vent activity may be stimulated by a tidal pull from Saturn and its other moons, particularly Dione.

So far, Enceladus has been known to contain the “Big Three” criterion for life on Earth: the presence of liquid water, chemical building blocks essential to organic activity, and even energy sustenance in the form of hydrothermal heat. So is there life on Enceladus?

“That is the big question left to be answered,” said Hsu.

It is still possible to explain the observations made by Cassini through other means. “It is necessary to have a more systematic study to understand why this way works and the others do not,” Hsu said.

Even if Enceladus does contain these hydrothermal vents, they may not be active long enough to allow life to evolve. “For life, the conditions have to be stable for a long time. It’s most likely that the activity on Enceladus is episodic,” Hsu said.

Cassini will sample the moon’s water plumes again in October when it makes a close flyby — but it was not equipped to detect life. It will be some time before another expedition is made to Enceladus, as researchers are currently at work on an expedition to Europa, whose ocean is thought to be much larger than the one on Enceladus.

What Life On Titan Might Look Like

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Looking back at the stars, with the realization that we are looking at entire worlds distant from our own like so many grains of sand, we can’t help but imagine what may be staring back. A planned flyby of the moon Titan once again has drummed up interest in the possibility of extraterrestrial life, very different from our own. While this particular moon of Saturn, a point of interest due to its vast lakes of methane, contains no water, astronomers at Cornell University have proposed a picture of what creatures from Titan might be like – very different from the carbon based life forms that exist on Earth.

Using both the power of imagination and a prominent scientific vision, in the burgeoning proto-scientific field that is astrobiology, the study of potential life processes on other planets, this team of chemical engineers proposed a way in which cells that are methane based can reproduce and acquire nutrients without the need for oxygen – carrying out the same life processes that organisms do on Earth.

They modeled a cell membrane, made up of small organic nitrogen compounds which would be capable of replicating in liquid methane temperatures as low as 292 degrees below zero, what scientists estimate to be the temperature of Titan’s lakes. Their work was published in the journal Science Advances on Feb. 27. Paulette Clancy, who specializes in molecular chemical dynamics led the effort, alongside his first author James Stevenson, who is currently a graduate student in chemical engineering. The paper’s co-author was Jonathan Lunine, who serves as the David C. Duncan Professor in the Physical Sciences in the College of Arts and Sciences’ Department of Astronomy at Cornell, where past faculty members include the legendary science educator Carl Sagan, who himself dabbled in astrobiology.

Lunine’s field of interest is the moons of Saturn. He served as an interdisciplinary scientist on the Cassini-Huygens mission, the first mission to land on Titan, and discover its methane-ethane seas back in 2004. Fascinated with the prospect of methane-based lifeforms on Titan, he received a grant from the Templeton Foundation for studying non-aqueous life. Clancy and Lunine met after the latter sought help last year with chemical modeling from Cornell faculty members.

“We’re not biologists, and we’re not astronomers, but we had the right tools,” Clancy recalled. “Perhaps it helped, because we didn’t come in with any preconceptions about what should be in a membrane and what shouldn’t. We just worked with the compounds that we knew were there and asked, ‘If this was your palette, what can you make out of that?’”

On Earth, all life is dependent on the phospholipid bilayer membrane, a strong, yet highly permeable vesicle that is water-based and shelters the organic matter that defines the makeup of every cell. Out of these vesicles come liposomes. Until now, the majority of astronomers interested in the possibility of extraterrestrial life hunted for the circumstellar habitable zone of each system, a narrow band surrounding a star where temperatures would be ideal for liquid water. The Kepler telescope has singled out several thousand of these planets throughout the universe thought to bear similarities to conditions on Earth. Rarely have they considered the possibility of lifeforms based on other elements such as methane, which contains a substantially lower freezing point than water.

The new concept is called an “azotosome,” derived from “azote,” the French word for nitrogen, and a play on “liposome” – “soma” meaning the body.

Their azotosome bears components of nitrogen as well as carbon and hydrogen molecules which exist throughout the vast cryogenic seas of Titan, regions thought to contain waves and even islands that appear and disappear under the currents. So far, the working model exhibits a similar stability and flexibility to the liposome – a surprise as neither engineers involved with the project had had much familiarity with cellular stability, building the model in the way they worked on semiconductors.

In order to commence this new application of molecular dynamics, the researchers routinely did a search on potential compounds of methane that would allow for self-assembly into membrane-like structures. The best compound they were able to find is an acrylonitrile azotosome, which maintained good stability, as well as a strong barrier to decomposition, and also had considerable flexibility, allowing for fluid molecules to enter and exit its walls – just like phospholipid membranes on Earth, therefore making it possible for organelles to develop which would later lead to living beings. Acrylonitrile – which is an organic compound that is colorless and poisonous is routinely used to manufacture acrylic fibers, resins and thermoplastics – is present in Titan’s atmosphere.

Clancy, intrigued with the launch of their concept, has said that their next step will be to simulate an environment in which their model cells would interact in the way of breathing, eating, and reproducing within a methane environment. Meanwhile, Lunine is eagerly anticipating the next mission to Titan which should kick off some time by the 2020s, soon followed by ones that will successfully sample the lake material.