New Life Form Discovered on Saturn's Moon Titan?
Well... not exactly*, but scientists have concluded that if one does exist, this would be what the new life would look like. Living on Saturn's moon Titan, it would have to metabolize and reproduce akin to life on Earth, strengthening the theory that Titan may be habitable, according to new research.
It is well known that water is a hallmark sign of life, but Titan does not have oceans with water. Rather, it boasts mysterious seas of methane. So how is life expected to survive in this harsh environment?
Reported in the journal Science Advances, the new life form suggests that Titan could harbor methane-based, oxygen-free cells composed of small organic nitrogen compounds, and capable of withstanding liquid methane temperatures of 292 degrees below zero.
"Ours is the first concrete blueprint of life not as we know it," first author James Stevenson from Cornell University said in a statement.
On Earth, life is based on a phospholipid bilayer membrane - the strong, permeable, water-based vesicle that houses the organic matter of every cell. A vesicle made from such a membrane is called a liposome. Liposomes are the reason why astronomers look for extraterrestrial life in what's called the circumstellar habitable zone - the narrow band around the Sun where liquid water can exist.
But, researchers have now determined that cells based on methane, which has a much lower freezing point than water, can also give rise to a life form. The hypothetical cell membrane has been named an azotosome.
The azotosome (meaning "nitrogen body") is made from nitrogen, carbon and hydrogen - molecules that are known to exist in Titan's seas. These molecules also show the same stability and flexibility that Earth's analogous liposome does.
"We're not biologists, and we're not astronomers, but we had the right tools," lead researcher Paulette Clancy said. "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?'"
If life could be based on methane, it would change any preconceived notions about what constitutes life and possibly how we search for habitable planets.
*[EDIT: The original version of this article mistakenly implied that the life form is real. To be clear, it is a concept. As in a proof-of-concept that life is at least possible under the laws that biologists believe dictate how cells function.]
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