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
One of the biggest clues to finding evidence of life on Mars – past or present – has been the existence of methane, an organic compound that is the principal component of natural gas here on Earth. Methane can arise via both biological and non-biological processes, but in both cases it can be used as “food” for living organisms (known as methanotrophs.) Methane has been detected on Mars today by both orbiting spacecraft and rovers on the ground, and now researchers have identified methane within meteorites found on Earth that originated from the Red Planet.
The concept of off-world habitation has been getting extra attention recently, especially with the announcement of 100 semi-finalists selected for the MarsOne “mission” (quotes because there’s more than a small amount of doubt that it will ever really take off – pun intended) and world-famous astronauts like Buzz Aldrin unabashedly telling us to “get our asses to Mars.” But even if we did manage to send a set of human derrières to the Red Planet, where would they call home? Building a safe habitation for humans for any sort of long term stay would be a time-intensive and expensive challenge, to say the least, and the environment of Mars – regardless of how much it might look like the deserts of Arizona or Utah in pictures – is harsh, unforgiving, and downright inhospitable for people. A lot of protection against the Martian elements would have to be built into modules for living and working, especially the extreme daily (and seasonal, depending on latitude) temperature changes and exposure to both solar and cosmic radiation. Protection equals mass, and mass equals fuel, and fuel equals more mass… and more money. What if there were a way for humans to set up base somewhere that radiation exposure and temperature variations could be mitigated? Somewhere like an easily-accessible cave where Mars itself could provide safe shelter to astronauts?
(Hey, it worked well for humans in the past.)
A great find from the NASA archives! This composite of three artists’ renderings from 1975 may have only been wish fulfillment for an unnamed JPL artist; however, the landscape and the rendered shapes took into account what was known about Mars at that time, a year before the first Viking landing.
“Life on Mars” was envisioned as low to the ground, symmetrical and simple. The artist drew silicon-based life forms, probably coached by others, perhaps scientists, who had thought about such possibilities. Peculiar saucer-like shapes stood only slightly above ground level, root-like structures reached outward for growth resources; a bundle of cones faced many directions for heat, light or food. Instead of reality, the images embodied the artist’s hope and anticipation of what future Martian exploration would find.
Hey, at least it’s not this.
Image Credit: NASA/JPL