For many years, mankind has wondered about the existence of life in worlds outside the Earth. It is possible though that alien life may indeed exist but not as we know it.

A team of researchers from the Cornell University has modeled a new type of methane-based and oxygen-free life form that, similar to life forms on Earth, has the ability to metabolize and reproduce.

Albeit hypothetical, the cell membrane, which is made up of small organic nitrogen compounds, is able to function in extremely cold liquid methane temperatures, a necessity for worlds with harsh and cold environments such as the Titan, Saturn's giant moon, which could harbor methane-based and oxygen-free cells and has seas made of liquid methane.

The cell membrane is dubbed "azotosome." "Azote" is the French word for nitrogen. "Liposomes," on the other hand, is hailed from the Greek words "lipos" and "soma," which mean "lipid body" and thus "azotosome" means "nitrogen body." Azotosome is composed of carbon, nitrogen and hydrogen molecules known to exist in the cold seas of Titan but exhibit the same flexibility and stability of the analogous liposome on Earth.

Many astronomers look for signs of life in extraterrestrial worlds in the so-called circumstellar habitable zone, where liquid water can exist, basically because life on our planet is based on phospholipid bilayer membrane, the water-based vesicle, where the organic matter of each cell is housed. Researchers are exploring the idea of cells that are not based on water but on methane and have very low freezing point.

"Using molecular simulations, we demonstrate that these membranes in cryogenic solvent have an elasticity equal to that of lipid bilayers in water at room temperature," wrote James Stevenson from the School of Chemical and Biomolecular Engineering at Cornell University and his colleagues.

This study was published in Science Advances on Feb. 27:

"As a proof of concept, we also demonstrate that stable cryogenic membranes could arise from compounds observed in the atmosphere of Saturn's moon, Titan, known for the existence of seas of liquid methane on its surface."

With the initial proof of concept on hand, the researchers said that the next step would be to try to demonstrate how the cells would behave in a methane environment to see what would be equivalent to metabolism and reproduction in oxygen-free, methane-based cells.

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