Titan is the largest moon and is covered in oceans of hydrocarbons, but there may be another surprise waiting on this massive satellite - alien life.
Methane-based lifeforms could be living on the distant world, swimming, crawling, or floating through the bizarre alien oceans.
Chemical processes forming life require heat in order to develop. Titan is far from the sun, receiving little thermal radiation from our parent star. However, as the satellite orbits around the second-largest planet in the solar system, tidal forces continually warp the moon. This stretching of land and ocean creates friction, producing heat that could drive chemical reactions, making life possible, researcher speculate. However, this warming still does not produce anything resembling a temperate climate - oceans on Titan average 282 degrees below zero Fahrenheit.
Water is a vital component for life on our home planet, but on Titan, liquid methane could serve a similar purpose. Oxygen would not be needed for metabolic processes in methane-based lifeforms. Instead, nitrogen compounds would fulfill those needs within cells.
Phospholipid bilayer membranes surrounding terrestrial cells hold together organic material. These liposomes are one of the reasons astrobiologists seek out alien worlds within the "habitable zone" around their suns, as water needs to remain liquid for the membranes to function properly. However, methane has a much lower freezing point than water, potentially making such membranes possible in alien cells.
Jonathan Lunine, of the College of Arts and Sciences, was a researcher on the Cassini-Huygens mission that discovered the oceans of Titan. Although he is one of the world's leading expert on the environment of Titan, he knew he needed someone familiar with chemical processes to study the possibility of alien life on the Saturn moon. He teamed with Paulette Clancy, of Cornell University, a professor of chemical and biomolecular engineering.
"We're not biologists, and we're not astronomers, but we had the right tools. 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?" Clancy said.
They found that such a membrane, which they call an azotosome, could develop from carbon, nitrogen and hydrogen known to exist on Titan. Furthermore, these structures would be just as strong and flexible as those on earth.
The research was inspired by a 1962 essay by Isaac Asimov on non-water-based alien life, titled "Not as We Know It."
Study of how methane-based lifeforms could exist in the oceans of Titan was published in the journal Science Advances.
