Lars Henrik Mathiesen> > Date: Thu, 29 Nov 2001 02:11:05 -0500
> > From: Andreas Johansson <[log in to unmask]>
> > Nik Taylor wrote:
> > >They're adapted to hot climates. Their planet is quite a bit warmer
> > >than ours. They would find our tropics to be comfortable, and
> > >subtropics to be bearable, but would not venture into more temperate
> > >climates, were they to visit Earth. Their planet's atmosphere also has
> > >more oxygen and more carbon dioxide. I'm estimating ~23.2% oxygen.
> > >Atmospheric pressure is around 1.2 atmospheres.
> > That'd ought to land us on a oxygene partial pressure of about .28
> > atmospheres, which'd make fires extremely rapid and difficult to
> > (I've seen claims that an oxygene pressure of .23 would make the Earth's
> > continents effectively uninhabitable due to making forrest fires and
> > flashfires effectively unextinguishable). Do the birdheads use fire at
> > I hope lightning is uncommon on their planet ...
>I'm sure that's true if you took plants that have evolved *here*
>(oxygen partial pressure about 210 hPa) and populated the continents
>of a 230 hPa world with them. But I'm also sure evolution would come
>up with a way to avoid burning off whole continents every September.
The claim was that if the Earth's atmosphere's oxygene partial pressure
rose, the continents would become uninhabitable to higher animals and
plants. With life's manifest ability to adapt to very different
surroundings, I have little doubt that life could thrive on a planet with
However, assuming a biochemistry reasonably similar to what we see on Earth,
it's hardly avoidable that many biological substances are highly
inflameable, so Im quite convinced that fire becomes a greater danger when
the oxygen partial pressure increases. It's also worth noticing that
technological development will face an additional problem as more metals
become inflameable - I think that iron would burn at .28 atmospheres of
oxygen, and aluminium would likely be unuseable (it burns a .21 atmospheres
of oxygen, which evidently is a big problem for people who construct
high-speed military vehicles - it's no good if the first glancing hit causes
your torpedo boat to catch fire!).
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