[LINK] "Keeping an Eye on Io"
Jun. 22nd, 2010 06:38 pm![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
rfmcdonaldCentauri Dreams' Paul Gilster shared a novel idea with his readership today. It's been imagined for decades, and considered a serious possibility, that there might be life and entire ecosystems in the outer solar system, in the subsurface water oceans of moons like Jupiter's Europa and Saturn's Enceladus. Today's the first time that I heard serious speculation as to the possibility that Io, a Moon-sized rocky body with the closest orbit orbit to Jupiter of that giant's four planet-sized moons and not coincidentally the most volcanically active body known in the solar system, might harbour life.
Underground microbial life on Io would, then, be protected from low temperatures and shielded from radiation, in an environment with both trapped moisture and nutrients like sulfide and hydrogen sulfide. Schulze-Makuch speculates that sulfur could play a large role here as a potential building block of life, noting that there is no evidence to this point for any organic molecules on Io and little hint of carbon of any kind. But it’s also worth keeping in mind that any organic molecules would be extremely difficult to find in Io’s atmosphere — they wouldn’t last long given the radiation environment at the surface. Energy, of course, is plentiful, and the author studies the possibility of chemical and magnetic energy’s role in astrobiology.
Dirk Schulze-Makuch (Washington State University) made the case for astrobiology on the seemingly hostile world in a paper last year in the Journal of Cosmology. Io’s plasma particle interactions with Jupiter, its lack of a substantial atmosphere and its extreme temperature gradients all argue against life there. Nor do we see impact craters, indicating a malleable surface that is being constantly reformed.
But there is this to be said about the place: It formed in a part of the Solar System where water ice is plentiful and geothermal heat could have made the origin of life possible. We can imagine a scenario where water was lost on the surface and life went deep underground, where both water and carbon dioxide may still be plentiful. Schulze-Makuch’s view:
Geothermal activity and reduced sulfur compounds could still provide microbial life with sufficient energy sources. Particularly, hydrogen sulfide is probably a common compound in Io’s subsurface…. Volcanic activity is prevalent on Io and lava tubes resulting from that activity could present a favorable habitable environment. Microbial growth is common in lava tubes on Earth, independent of location and climate, from ice-volcano interactions in Iceland to hot sand-floored lava tubes in Saudi Arabia. Lava tubes also are the most plausible cave environment for life on Mars… and caves in general are a great model for potential subsurface ecosystems.
Underground microbial life on Io would, then, be protected from low temperatures and shielded from radiation, in an environment with both trapped moisture and nutrients like sulfide and hydrogen sulfide. Schulze-Makuch speculates that sulfur could play a large role here as a potential building block of life, noting that there is no evidence to this point for any organic molecules on Io and little hint of carbon of any kind. But it’s also worth keeping in mind that any organic molecules would be extremely difficult to find in Io’s atmosphere — they wouldn’t last long given the radiation environment at the surface. Energy, of course, is plentiful, and the author studies the possibility of chemical and magnetic energy’s role in astrobiology.
