Saturn’s largest moon Titan is often called an analogy to early Earth, with its thick, chemical-rich atmosphere and widespread system of flowing rivers and north polar lakes. But located almost a billion miles away from the Sun, everything on Titan is shifted into a completely different—and frigid—level of existence from that found on Earth. With surface temperatures of 300 degrees below zero F, the lakes are filled with liquid methane and what’s life-giving water here is literally solid rock there. Even the rain on Titan falls as oversized drops of ethane.
But even in this extreme cryo-environment it’s possible that life may right now exist…life relying on an entirely different chemistry than what’s possible on our planet.
Recently scientists have identified a molecule on Titan called vinyl cyanide, or acrylonitrile. To Earthly life acrylonitrile is toxic and carcinogenic; luckily for us it isn’t naturally-occurring here. But on Titan it is and apparently in quantity; it’s possible that vinyl cyanide, raining down from Titan’s atmosphere into its vast hydrocarbon lakes, could even help form methane-based cell structures in much the same way phospholipids do here.
The molecule (C2H3CN) has the ability to form membranes and, if found in liquid pools of hydrocarbons on Titan’s surface, it could form a kind of lipid-based cell membrane analog of living organisms on Earth. In other words, this molecule could stew in primordial pools of hydrocarbons and arrange itself in such a way to create a “protocell” that is “stable and flexible in liquid methane,” said Jonathan Lunine (Cornell University) who, in 2015, was a member of the team who modeled vinyl cyanide and found that it might form cell membranes.
Further evidence of life “not as we know it?” Read more on Ian O’Neill’s Astroengine blog here: Vinyl Cyanide Confirmed: Weird Form of Alien Life May Be Possible on Saturn’s Moon Titan and in a Gizmodo article by Maddie Stone here: Potential Building Block of Alien Life Spotted in Titan’s Atmosphere
New research on Jupiter’s ice-covered moon Europa indicates the presence of a subsurface lake buried beneath frozen mounds of huge jumbled chunks of ice. While it has long been believed that Europa’s ice lies atop a deep underground ocean, these new findings support the possibility of large pockets of liquid water being much closer to the moon’s surface — as well as energy from the Sun — and ultimately boosting the possibility that Europa could harbor life.
“Now we see evidence that it’s a thick ice shell that can mix vigorously, and new evidence for giant shallow lakes. That could make Europa and its ocean more habitable.”
– Britney Schmidt, Institute for Geophysics, University of Texas at Austin
There’s been a lot of buzz in the space news world recently about findings by NASA scientists that may indicate the possibility of some sort of biological activity on Saturn’s cloud-covered moon, Titan. This has been carried to many different levels of excitement, depending on the individual reporters…what has NOT been announced is anything definitive in the least about the discovery of life anywhere outside our planet, much less a frigid moon coated in liquid methane and hydrocarbon mud. Still, the findings are very intriguing to astrobiologists; namely that computer models have noted a lack of hydrogen and acetylene in Titan’s thick atmosphere – thicker than our own, in fact – where there should be plenty of both. There are theories as to what may be causing this absence of organic elements, ranging from as-of-yet unknown chemical processes occurring on the distant moon to being the result of biological activity – methane-based “cryo-organisms” that have evolved on the moon to take advantage of its abundance of liquid hydrocarbons, despite its incredibly cold environment.
And, of course, there’s always the very real possibility of simple computer error. Results will have to be somehow replicated to even be considered…thus is the scientific way. 🙂
To try to make some sense of the media noise the Cassini imaging team has posted a report by NASA astrobiologist Chris McKay, in which he clarifies the findings and what they may mean. Some of it waxes a bit technical to those who perhaps didn’t get an “A” in high school chemistry the first time around *ahem* but it’s great to have some insight into what is nonetheless a very intriguing concept. Are we on the verge of discovering living organisms on another world, on a moon in our own solar system no less? It’s hard to not get one’s hopes up, what with all that it would mean…but I can be patient, I suppose. [/lie]
After all, if there IS life on Titan, it’s been waiting a very long time for us to find it. We can make sure we know just how to say “hello” before barging in.
On Earth organisms (like humans) can react O2 with organic material to derive energy for life’s functions. On Titan organisms could react H2 with organic material to derive energy. The waste product of O2 metabolism on Earth is CO2 and H2O; on Titan the waste product of H2 metabolism would be CH4. As a result of the Cassini mission, there is now abundant evidence for CH4, even in liquid form, on Titan.
– Chris McKay, Astrobiologist, NASA Ames Research Center