From our email list comes this link to a Stanford iTunes U course, Astrobiology and Space Exploration. These are movies; there are no separate accompanying audio files. It’s listed under Lynn Rothschild, but there’s a whole lineup of speakers including Frank Drake and Chris McKay.
We had a great meeting today with another large turnout. Judit Szulágyi gave a presentation about habitability zones. We discussed a recent article on arxiv.org about detecting life with microbial fuel cells. Then we capped off the hour with a lengthy review of the recent papers that lend evidence to Titan having methane-based life.
Here is the original press release, “What is Consuming Hydrogen and Acetylene on Titan?” and Chris McKay’s response from earlier this week to the furor it kicked up. And here are the four papers referenced in the discussion today:
- The abundances of constituents of Titan’s atmosphere from the GCMS instrument on the Huygens probe
- Possibilities for methanogenic life in liquid methane on the surface of Titan
- Molecular hydrogen in Titan’s atmosphere: Implications of the measured tropospheric and thermospheric mole fractions
- Detection and Mapping of Hydrocarbon Deposits on Titan
A recent paper by Johns Hopkins own Darrell Strobel has been making the rounds. His paper, “Molecular hydrogen in Titan’s atmosphere: Implications of the measured tropospheric and thermospheric mole fractions,” in conjunction with results from a VIMS study soon to be published in the Journal of Geophysical Research, has renewed interest in a 2005 paper by Chris McKay and Heather Smith about methane-based life. From a JPL press release:
One key finding comes from a paper online now in the journal Icarus 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.
“We suggested hydrogen consumption because it’s the obvious gas for life to consume on Titan, similar to the way we consume oxygen on Earth,” McKay said. “If these signs do turn out to be a sign of life, it would be doubly exciting because it would represent a second form of life independent from water-based life on Earth.”
Cheers to Johns Hopkins for being on the cutting edge of astrobiology research!