'Worms From Hell' Unearth Possibilities For Extraterrestrial Life

An anonymously submitted article says, "For the first time, scientists have found complex, multi-celled creatures living a mile and more below the planet’s surface, raising new possibilities about the spread of life on Earth and potential subsurface life on other planets and moons (abstract). ... The research is likely to trigger scientific challenges and cause some controversy because it places far more complex life in an environment where researchers have generally held it should not, or even cannot, exist."

Comments

Re:Rules for life

[Mindcontrolled]

The potentially arsenic-"based" bacteria are still carbon based. Only the phosphate links in the sugar-phosphate backbone of their DNA are possible replaced by arsenate links, possible the phosphates in their ATP or GTP, too. This is interesting, but not too surprising, as arsenic is chemically quite close to phosphorus.

I am not arguing that earth-like conditions are a necessity, but that there are hard limits on conditions. If you want to have life you need a chemistry that is sufficiently complex to store information and to build structures. With that, you are down to carbon. Nothing else (with the very, very low possibility of silicon being an exception) makes a sufficiently complex chemistry. You need metabolism, so you need some kind of energy gradient and therefor chemical dynamics on a timescale that makes exploiting that gradient possible. Another hard limit. Those limits are not given by taking earth as a standard, this is basic thermodynamics, in the end.

I'm wary of this theory.

[wcrowe]

My question is this: just because you find life in extreme conditions, does not mean it can develop in those conditions. It seems more likely to me that life develops in more ideal conditions, then migrates to areas where conditions are more harsh. Am I being too skeptical or pessimistic?