Life with Hydrocarbons

You know that stuff making a mess of the Gulf of Mexico right now? How messy and destructive it is? Well, it just might be the source of life on another world. Oil is a hydrocarbon. Hydrocarbons are organic compounds consisting of hydrogen and carbon atoms. When mixed with oxygen, they burn. Your gas grills, lighters, and cars all use hydrocarbons. Many of our roads are paved with them, and just about every toy or gadget you own contains them in the form of plastics. But I’m not going to lecture you about how dependent our society is on hydrocarbons. I’m here to tell you that we might have the most compelling evidence for life on another world yet. That world it Titan.

The surface of Titan

As you know, I love writing about the possibility of alien life. Titan has been a prime candidate for finding life on another world; now it might be THE prime candidate. I’m going to go into a bit of science talk, so bear with me for a bit.

Titan’s atmosphere has lots of hydrocarbons. It has lakes of them too. They evaporate and form clouds. The methane on Titan is broken down into hydrogen by UV light. Hydrogen, being light and whimsical, should float around and distribute itself evenly in Titan’s atmosphere, eventually escaping into space. This doesn’t seem to be happening, not does it seem like it is being stored under the moon’s surface.

It’s as if you have a hose and you’re squirting hydrogen onto the ground, but it’s disappearing,” Strobel said. “I didn’t expect this result, because molecular hydrogen is extremely chemically inert in the atmosphere, very light and buoyant. It should ‘float’ to the top of the atmosphere and escape.”

Acetylene is also created, through various chemical reactions, in Titan’s atmosphere. The acetylene should sink to the surface and just kind of hang out there. The problem is that Cassini has not detected any acetylene on the surface of Titan. So there should be a bunch of stuff on Titan that isn’t there. Something is turning the hydrogen and acetylene back into methane.

How is this for a really freaking awesome explanation:

This lack of acetylene is important because that chemical would likely be the best energy source for a methane-based life on Titan, said Chris McKay, an astrobiologist at NASA Ames Research Center, Moffett Field, Calif., who proposed a set of conditions necessary for this kind of methane-based life on Titan in 2005. One interpretation of the acetylene data is that the hydrocarbon is being consumed as food. But McKay said the flow of hydrogen is even more critical because all of their proposed mechanisms involved the consumption of hydrogen. (emphasis mine)

It is not proof, but it is really compelling evidence. The best evidence yet.

This information comes from two different studies, one focusing on the hydrogen element (pun not initially intended, but when I realized it was a pun I decided to keep it) and the other looking at the surface acetylene.

Whether there is life there or not, there is still an unknown organic process going on there, and the voyage of discovery is an exciting one. It is incredible that we know as much about a moon orbiting another planet about 1.4 billion kilometers away from Earth.

And just in case you forgot how amazing Titan is:

In addition Cassini’s spectrometer detected an absence of water ice on the Titan surface, but loads of benzene and another material, which appears to be an organic compound that scientists have not yet been able to identify. The findings lead scientists to believe that the organic compounds are shellacking over the water ice that makes up Titan’s bedrock with a film of hydrocarbons at least a few millimeters to centimeters thick, but possibly much deeper in some places. The ice remains covered up even as liquid methane and ethane flow all over Titan’s surface and fill up lakes and seas much as liquid water does on Earth.

Water ice as “rocks”, hydrocarbon lakes, oceans, rivers, and a film of organics as dirt.

It is hard for me to keep my skeptic’s hat on when reading about stuff like this. I get so excited about the possibility of life on other worlds. It is important to remember that what we have are signs, just a bit of evidence, but not proof, that there could be life on Titan.

We need to do a lot more research to rule out all possibilities that this isn’t caused by living organisms before we can make any conclusions. This seems like the perfect reason to send another probe to Titan.

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