'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."

Re:Rules for life

[Mindcontrolled]

I wouldn't say that we generally assume conditions to be necessarily earth-like for life to arise. However, there are hard constraints on conditions that allow complex chemistry to happen - and those limit the habitable range. Basically, the only reasonably complex chemistry happens with carbon - so you are automatically limited to conditions where carbon compounds are stable. That sets an upper bound for temperatures, for example. On the other hand, you want some reactivity - life has to be dynamic, after all. That gives you a lower bound for temperatures. Earth happens to be in the middle there, but there are quite some deviations from earth-like conditions where life would be possible, biochemically.

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?

life probably orginated in extreme conditions

[peter303]

Many biological reactions at surface pressures and temperatures require catalysts called enzymes to proceed. Protein synthesis and the citric cycle are two basic examples. These do not require catalysts at high temperature and pressures according to work Robert Hazen of Carnegie Institute.

After life began it evolved enzymes to expand into other ecological niches. For example, the ocean surface is an energy rich area with solar radiation.

Re:I'm wary of this theory.

[danlip]

I agree with you, but this still has implications for the possibility of extraterrestrial life. Mars used to be much warmer and wetter, so it is possible that life developed under more ideal conditions and continued to survive under harsh conditions.

But my doubts come because TFA says the worms were "found in water flowing from a borehole about one mile below the surface". That seems like plenty of opportunity for contamination. I'd be very skeptical that there are worms one mile below the surface of the earth in locations not touched by human activity. If you found them in a freshly drilled borehole with no water flowing that would be much more interesting.