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On 29/08/2013 04:52 PM, James Holsenback wrote:
> http://www.bbc.co.uk/news/science-environment-23872765
Interesting how they say "Mars had more oxygen", as if that's a basic
requirement for all living organisms.
There are, in fact, many organisms on Earth to whom oxygen is a deadly
toxin. Presumably these organisms date from the time when Earth's
atmosphere was reducing rather than oxidising. It was supposedly the
spread of photosynthetic organisms to a level where they could affect
the atmosphere on a global scale which led to the "oxygen catastrophy"
and the resulting iron oxide deposits that stripe the oldest rocks...
...not sure how all of that fits in with a Mars origin for life. I'm
also not sure how life supposedly got from Mars to Earth. On a stellar
scale, our blue planet is a pretty small target to hit.
Also, since water appears to be the fundamental solvent of life, the
fact that Mars lacks it seems to make it *less* likely as an origin.
(Although whether talking about Mars or Earth, I think it's safe to
assume that different regions may have different local conditions. Life
probably arose in just one specific such region - whichever planet that
was on...)
Really, if people want to suggest that life travelled here from another
planet, they're going to need some pretty impressive data to back that up.
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Orchid Win7 v1 <voi### [at] dev null> wrote:
> Interesting how they say "Mars had more oxygen", as if that's a basic
> requirement for all living organisms.
AFAIK oxygen is pretty much required for multicellular organisms.
It's about the only molecule that has the properties just right so that
it can act as a "fuel" for multicellular metabolism.
For unicellular organisms, not so much. Life on Earth almost died
completely because some organisms started to produce oxygen as a
by-product they didn't need.
--
- Warp
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