Hints of Life Found On Saturn's Moon Titan 227
Calopteryx writes "New Scientist reports that in 2005, researchers predicted two potential signatures of life on Titan. Now, thanks to research done with the help of the Cassini spacecraft, both have been seen, although non-biological chemical reactions could also be behind the observations. NASA's writeup has further details: 'One key finding comes from a paper online now in the journal Icarus [abstract] that shows hydrogen molecules flowing down through Titan's atmosphere and disappearing at the surface. Another paper online now in the Journal of Geophysical Research maps hydrocarbons on the Titan surface and finds a lack of acetylene. 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.'"
So, to sum up: Life possibly on Titan (Score:3, Informative)
Re:I wonder if Huygens contaminated things. (Score:2, Informative)
It sounded like it was referring to heretofore unknown kinds of life that use completely different chemical processes than we see on earth, with the possible exception of really weird stuff that you find at the bottom of the ocean. Nothing that would have gotten onto our probe, in any case.
Re:I smell a movie... (Score:5, Informative)
Re:I wonder if Huygens contaminated things. (Score:3, Informative)
The probe was sterilized, if I recall correctly. So it shouldn't be an issue.
Keep in mind that in the long history of the solar system it's likely that material blasted off the earth by an impact event or events has made its way to the surface of Titan. So Titan may have already been contaminated with life from earth.
Re:I wonder if Huygens contaminated things. (Score:3, Informative)
I have a pretty good suspicion that most life on Earth, even the extremophiles, would have a rather hard time living on Titan. The temperatures are extremely low, the solar energy and even Saturn's energy are much less combined than on Earth. The kind of biochemistry would be quite different than found here. I'm not saying it's entirely impossible, but I think a planet like Mars would be far more likely to be able to harbor certain hardy organisms from Earth than a place like Titan. My understanding is that on a world like Titan, the solvent would be something like ammonia or an ammonia-water mixture, so we'd see considerably different organic chemistry that would likely kill of anything we left behind in a really big hurry.
Re:So, to sum up: Life possibly on Titan (Score:5, Informative)
Re:Wasn't there an AC Clark book about this? (Score:3, Informative)
The original printing of the book 2001, they went to Saturn. In the film they went to Jupiter. After seeing the film Clarke thought that made more sense, so he wrote the sequel based on the film, not his book.
http://en.wikipedia.org/wiki/2001:_A_Space_Odyssey_(novel)#Differences_from_the_film [wikipedia.org]
As far as I care, it's fair game as long as it isn't Europa. We should attempt no landings there.
Re:Looks like I WIN! (Score:3, Informative)
I believe the term you are looking for is "Bazzinga"
Re:I wonder if Huygens contaminated things. (Score:5, Informative)
I must be misinterpreting your comment. Can you explain how crashing a probe into a celestial body has LESS contamination risk than just letting it drift off into the void?
Generally, they crash it into a celestial body that has no capability to support life and, such as the case of Jupiter, is hostile to the biological processes of what could possibly contaminate it.
No life from Earth will survive in Jupiter's atmosphere. The pressure is... extreme beyond that of the extreme on Earth.
The pressure there would be 10,000 times greater than the pressure at the deepest point in Earth's ocean. 10,000,000 Earth Atmospheres compared to 1,000 in the Marianas Trench.
Then you have the temperature. The hottest spot on Earth (the core) is about 7300K. On the liquid 'surface' of Jupiter, it is 10,000k. The most extreme of the thermophiles on Earth live in an area less than 400k. The core of Jupiter is hotter than the surface of the Sun.
If you find me something that can survive 10,000k temperatures and 10 million atmospheres I'd bow down to my new overlord.
Re:I wonder if Huygens contaminated things. (Score:4, Informative)
If it uses DNA or RNA (quite unlikely) then I guess that contamination is possible. But since we'd want to totally sequence whatever replicator molecule it used, it would be reasonably easy to determine whether contamination is even a reasonable hypothesis.
Remember, all life on this planet is related to a measurable degree. If it's related, then we can figure out what it's most closely related to, and how long ago it diverged. (Remember, when the proto-moon collided with the earth it quite likely emitted fragments that went that far. But we could measure even that distant a relationship, albeit with less certainty.)
But it's most likely that whatever molecule it uses for a replicator would be something not related to our nucleic acids. For one thing, the major solvents appear to be non-polar rather than polar, so anything water-based would be insoluble, where things that are lipid based would tend to be soluble. Also, the reaction rate is very temperature dependent, so it would be probable that the major chemicals of life on Titan would be unstable at STP (standard temperature and pressure).