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believe we have to prepare for serious
re-thinking on "life" unless we restrict ourselves to the wet Earth.
Nature's recent article (excerpts
only):
Titanic life may bloom without waterPhilip Ball
...does life depend on water? Or could it
be that Earth life has evolved to suit its watery home? Anything we might
recognize as life probably needs a liquid solvent to transport molecules and
bring them together. But who says the solvent must be water?
...Benner
and his colleagues argue (Organisms should be comfortable in a hydrocarbon
ocean) in Current Opinion in Chemical Biology that water-free
environments on other worlds might fulfil
the conditions for life1. (Benner S. A.,
Ricardo A. & Carrigan M. A. Curr. Opin. Chem. Biol., 8. 672 -
689 (2004).
...Titan looks like the best candidate for non-aqueous
life. It seems to have rivers and oceans (of hydro-carbons), and its sticky
surface is apparently made partly from organic molecules. (reactive
nitrils).
...So it's not obvious
that water is special, apart from the fact that it exists in large quantities on
Earth.
*
Nasa restricted its plans
to bodies with water for life.
Our ways of thinking about
biology seem to need a rather fundamental
refurbishing.
John
M
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