Simulation suggests non-water based life could exist on Saturn's moon Titan

July 5, 2016 by Bob Yirka report
An image of Titan's surface, as taken by the European Space Agency's Huygens probe as it plunged through the moon's thick, orange-brown atmosphere on Jan. 14, 2005. Today, Cornell scientists have chemical evidence that suggests prebiotic conditions may exist there. Credit: ESA/NASA/JPL-Caltech/Univ. of Arizona

(Phys.org)—A team of researchers at Cornell University has built and run a simulation that showed prebiotic reactions could possibly occur on the surface of one of Saturn's moons, Titan, suggesting the possibility of life evolving in a place where it is too cold for water to be a factor. In their paper published in Proceedings of the National Academy of Sciences, the team describes the simulation they created in response to the discovery (by the Huygens probe) that polymers such as polyimine might have already developed on the moon's surface.

As scientists continue to search for life on other planets, more and more they are beginning to concede that if it does exist, it may not necessarily exist in the Goldilocks, or habitable zone. Such planets are all the "right" distance from their star, and hopefully, also have water. But recent evidence has suggested that some could lead to types of where there is no water, which further suggests that it may exist outside of what is now considered the habitable zone.

For life to come about in such places, researchers reason, there would likely need to be some sort of action going on—and that is why there has been so much focus on Titan; it is the only object in our solar system, besides Earth, that has both rainfall and erosion due to liquid movement. But the water it has is locked far underground and the moon is too cold to support an impact by anyway. But, as the researchers with this new effort discovered after poring over data sent back by Huygens, the surface does have in its sediment, brought down from the atmosphere by methane and ethane rain.

It was those molecules that drove the design of the simulations—the team wanted to see if they could form the basis of reactions that could lead to the creation of polymers such as polyimine, which the team notes, are conducive to the formation of prebiotic reactions leading to a form of life. Their simulations showed that such reactions are possible and that the structures that came about were also able to absorb sunlight in the wavelengths present on the Titan surface.

The researchers suggest their work, and that done by others indicates that a return to the planet by a new probe might be in order, one able to test for a different form of , or at least its precursors.

Explore further: Life on other planets could be far more widespread, study finds

More information: Polymorphism and electronic structure of polyimine and its potential significance for prebiotic chemistry on Titan, PNAS, www.pnas.org/cgi/doi/10.1073/pnas.1606634113

Abstract

The chemistry of hydrogen cyanide (HCN) is believed to be central to the origin of life question. Contradictions between Cassini–Huygens mission measurements of the atmosphere and the surface of Saturn's moon Titan suggest that HCN-based polymers may have formed on the surface from products of atmospheric chemistry. This makes Titan a valuable "natural laboratory" for exploring potential nonterrestrial forms of prebiotic chemistry. We have used theoretical calculations to investigate the chain conformations of polyimine (pI), a polymer identified as one major component of polymerized HCN in laboratory experiments. Thanks to its flexible backbone, the polymer can exist in several different polymorphs, which are relatively close in energy. The electronic and structural variability among them is extraordinary. The band gap changes over a 3-eV range when moving from a planar sheet-like structure to increasingly coiled conformations. The primary photon absorption is predicted to occur in a window of relative transparency in Titan's atmosphere, indicating that pI could be photochemically active and drive chemistry on the surface. The thermodynamics for adding and removing HCN from pI under Titan conditions suggests that such dynamics is plausible, provided that catalysis or photochemistry is available to sufficiently lower reaction barriers. We speculate that the directionality of pI's intermolecular and intramolecular =N–H…N hydrogen bonds may drive the formation of partially ordered structures, some of which may synergize with photon absorption and act catalytically. Future detailed studies on proposed mechanisms and the solubility and density of the polymers will aid in the design of future missions to Titan.

Press release

Related Stories

Early Titan was a cold, hostile place for life

June 30, 2015

Titan is a mysterious orange-socked moon of Saturn that is exciting to astrobiologists because it has some of the same kinds of chemicals that were precursors to life on Earth. It also has a hydrological cycle that allows ...

What are the chances of life on another planet?

May 9, 2016

In an infinite universe, most scientists agree, the odds of life existing on a planet besides Earth are pretty high. It is unlikely, however, that familiar life forms will be found on any planet within our solar system. Life ...

Huygens mission: Ten years at Titan

January 14, 2015

Celebrating the 10th anniversary of the pioneering Huygens mission to Saturn's moon Titan, the first successful landing on an outer Solar System world.

Recommended for you

Discovered: Fast-growing galaxies from early universe

May 24, 2017

A team of astronomers including Carnegie's Eduardo Bañados and led by Roberto Decarli of the Max Planck Institute for Astronomy has discovered a new kind of galaxy which, although extremely old—formed less than a billion ...

9 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

Whydening Gyre
4.5 / 5 (4) Jul 05, 2016
They're still only considering CHO types of "life".
How bout other elemental combinations that might exhibit the same reactivity ratios?
Chris_Reeve
1 / 5 (8) Jul 05, 2016
The inferred methane seas are inferred in order to explain how methane can still be releasing into space from the atmosphere, in light of the fact that sunlight should immediately destroy it. The entire mystery relies upon an assumption that all of the planets must be billions of years old. But, TITAN LACKS A SINGLE CRATER. So, why do we hold to this assumption that it must be old? Seems like there are two possibilities here, as the moon could have simply been captured.
boc
1 / 5 (3) Jul 05, 2016
Scientists have finally acknowledged that there is no evidence that life needs water.
Uncle Ira
5 / 5 (12) Jul 05, 2016
But, TITAN LACKS A SINGLE CRATER.
Cher I don't think that is right. I could be wrong because it's been about year since I the book about the Cassini stuffs. But if I am remembering right, Titan got plenty of craters.

Most of them are pretty new though. They think the older ones don't show up so good because they are hard to detect because you can't just look at them like you can the moon here because it has a really thick smoggy atmosphere and because of heavy weathering the really old ones have been smoothed over like here.

TheGhostofOtto1923
5 / 5 (9) Jul 05, 2016
But, TITAN LACKS A SINGLE CRATER.
Cher I don't think that is right. I could be wrong because it's been about year since I the book about the Cassini stuffs. But if I am remembering right, Titan got plenty of craters.

Most of them are pretty new though. They think the older ones don't show up so good because they are hard to detect because you can't just look at them like you can the moon here because it has a really thick smoggy atmosphere and because of heavy weathering the really old ones have been smoothed over like here.

Yah heres 2
http://www.nasa.g...ver.html

Google search time - 10 sec
Andrew Palfreyman
2 / 5 (4) Jul 05, 2016
At such devastatingly low temperatures, I'd be surprised if any chemical reaction rate was distinguishable from zero!
Mark Thomas
4.7 / 5 (6) Jul 05, 2016
Just because a few prebiotic chemical reactions might still work on Titan does not suggest "non-water based life could exist on Saturn's moon Titan." This sounds more like click bait than science.
torbjorn_b_g_larsson
5 / 5 (6) Jul 05, 2016
The article bait-and-switch between ice moon ocean habitability and Titan - a unique body - habitability.

@WG: Carbon chemistry is the only useful game in town. E.g. Si wouldn't work, since SiO2 is solid, et cetera. "They" (scientists) have considered this all along, as seen in any astrobiology textbook if you open one.

@Chris: Methane seas are observed. The original methane source is still undetected (though the detection of an ammonia filled ocean is telling), but the atmosphere is not inconsistent with the current methane cycle.

@boc: No, they have not. There is plenty of evidence that life needs water, and it is highly likely *all* life needs it. These simple experiments are not enough to convince otherwise.
SCVGoodToGo
2.6 / 5 (5) Jul 06, 2016
arbon chemistry is the only useful game in town. E.g. Si wouldn't work, since SiO2 is solid, et cetera.


NO KILL I

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.