Saturn's weird, Earth-like moon just failed a key test for alien life

An image from NASA's Cassini probe, taken Sept. 23, 2006, shows a pair of hydrocarbon lakes on Titan.
An image from NASA's Cassini probe, taken Sept. 23, 2006, shows a pair of hydrocarbon lakes on Titan. (Image credit: NASA/JPL)

Saturn's most Earth-like moon looks a bit less likely to host life, thanks to quantum mechanics, the weird rules that govern subatomic particles.

Titan, the second largest moon in our solar system after Jupiter's Ganymede, is unique in two ways that have convinced some researchers that this moon might host extraterrestrial life: It's the only moon in our solar system with a dense atmosphere, and it's the only body in space, besides Earth, known to definitely have pools of liquid on its surface. In Titan's case, those pools are frigid lakes of hydrocarbons, closer to the gasoline in a car than the oceans on Earth. But some researchers have suggested that complex structures could arise in those pools: bubbles with special properties that mimic ingredients found to be necessary for life on our planet.

On Earth, lipid molecules (fatty acids) can spontaneously arrange themselves into bubble-shaped membranes that form the barriers around the cells of all known life-forms. Some researchers think this was the first necessary ingredient for life as it formed on Earth.

Related: 9 strange scientific excuses for why humans haven't found aliens yet 

On Titan, researchers have speculated in the past, an equivalent set of bubbles might have emerged, these consisting of nitrogen-based molecules called azotosomes.

But for those structures to arise naturally, the physics has to work just right in the conditions actually present on Titan: temperatures of about minus 300 degrees Fahrenheit (minus 185 degrees Celsius), without liquid water or atmospheric oxygen.

Previous studies, using molecular dynamics simulations — a technique often used to examine the chemistry of life — suggested that such bubble structures would arise and become common on a world like Titan. But a new paper, published Jan. 24 in the journal Science Advances, suggests that those earlier simulations were wrong.

Using more complex simulations involving quantum mechanics, the researchers in the new paper studied the structures in terms of their "thermodynamic viability."

Here's what that means: Put a ball at the top of a hill, and it's likely to end up at the bottom, a position of lower energy. Similarly, chemicals tend to arrange themseIves in the simplest, lowest-energy pattern. The researchers wanted to know whether the azotosomes would be the simplest, most efficient arrangement for those nitrogen-bearing molecules.

Titan represents a "strict test case for the limits of life," the researchers wrote in their paper. And in this role, the moon fails. Azotosomes, the simulation showed, just aren't thermodynamically viable on Titan.

This work, the researchers said in a statement, should help NASA figure out what experiments to include on its Dragonfly mission to Titan, planned for the 2030s. It's still theoretically possible that life emerged on Titan, the researchers said in the paper, but such life would likely not involve anything we'd recognize as a cell membrane.

Originally published on Live Science.

Rafi Letzter
Staff Writer
Rafi joined Live Science in 2017. He has a bachelor's degree in journalism from Northwestern University’s Medill School of journalism. You can find his past science reporting at Inverse, Business Insider and Popular Science, and his past photojournalism on the Flash90 wire service and in the pages of The Courier Post of southern New Jersey.
  • BB Brown
    admin said:
    Life on Earth likely began with the bubble-like membranes that surround our cells. Similar membranes probably wouldn't form on Titan, according to quantum mechanics.

    Saturn's weird, Earth-like moon just failed a key test for alien life : Read more
    These membranes are a long way from being cell membranes. Cell membranes are incredibly complex, requireing a complex code as a blueprint to construct them. In addition, the code is only the blueprint: the instructions for "how" the code is run is not well understood today because of its complexity. For an interesting viewpoint from a world-renowned scientist see: Dr. James Tour, The Origin of Life Has Not Been Explained. r4sP1E1Jd_YView: https://www.youtube.com/watch?v=r4sP1E1Jd_Y&vl=en
    Reply
  • BB Brown
    These membranes are a long way from being cell membranes. Cell membranes are incredibly complex, requireing a complex code as a blueprint to construct them. In addition, the code is only the blueprint: the instructions for "how" the code is run is not well understood today because of its complexity. For an interesting viewpoint from a world-renowned scientist see: Dr. James Tour, The Origin of Life Has Not Been Explained. r4sP1E1Jd_YView: https://www.youtube.com/watch?v=r4sP1E1Jd_Y&vl=en
    Reply
  • dk72
    BB Brown said:
    I see you're trying to push "intelligent design" viewpoints in overstating the complexity of the cell membrane needed for life to begin, and referring to "blueprints" for construction and complex coding, etc....followed up by video of an evolution denier....that has been demonstrated to not understand evolution. Early life would not have started out with a complex structure. Likely an early proto-cell would have a very simple lipid membrane, not the complex cellular membrane that you immediately jump to as if that would be the impossible starting point.

    First of all, no one has claimed that the origin of life has been explained, so it's a bit silly for Tour to feel the need to tell people that it has not, as if that is some great conclusion he came to. However, we know life exists, we know there are many organic precursors that share characteristics with the simplest life forms, and there are various possible pathways being explored, but even then, if one is found and proven, it may not even be the same exact pathway...or pathways...that led to the actual rise of life on earth. However, just because we don't have definitive answers, there is no basis for just playing the "oh geez, it's so complicated it must have been done by a god" fallback. The "god of the gaps" fallacy that is no more valid than early man thinking lightning was something magical from the sky gods.
    Reply
  • WhiteRobe
    BB Brown said:
    These membranes are a long way from being cell membranes. Cell membranes are incredibly complex, requireing a complex code as a blueprint to construct them. In addition, the code is only the blueprint: the instructions for "how" the code is run is not well understood today because of its complexity. For an interesting viewpoint from a world-renowned scientist see: Dr. James Tour, The Origin of Life Has Not Been Explained. r4sP1E1Jd_YView: https://www.youtube.com/watch?v=r4sP1E1Jd_Y&vl=en
    Very correct
    Reply