On 11/11/2011 10:06, Tim Streater wrote:
In article op.v4q2hny7ytk5n5@i7-940, "Lieutenant Scott"
wrote:

On Thu, 10 Nov 2011 21:13:09 -0000, Tim Streater
wrote:

In article op.v4qziypkytk5n5@i7-940, "Lieutenant Scott"
wrote:

On Wed, 09 Nov 2011 19:57:20 -0000, Gib Bogle
wrote:

Depends where is space you are. Equilibrium temperature at Earth's
distance from the Sun is -15C. The fact that the Earth's average
temperature is +15C is a bit of a clue that there is life here.

By space I clearly meant away from here! In the middle of nowhere!

If you mean in inter-galactic space, you'll cool down to 3K or whatever
the temp of the background radiation is. I think you don't actually
explode but fizz, rather.


Not sure what you mean by the clue about life though - are you
suggesting that life increases it be 30C?

Yes. The atmosphere is full of oxygen, a poisonous and extremely
reactive gas. And don't say it isn't poisonous, because although we need
it for life, life takes good care to ship it round the body extremely
carefully, bound up in small packets inside haemoglobin. If you took
away all the life processes that produce it, it's reckoned that it would
all disappear within about a million years or so - the Earth would
"rust", essentially.

Photosynthesis actually works *against* the greenhouse effect CO2 is
triatomic and a potent greenhouse gas whereas O2 is diatomic and is not.
The very first plants by stripping the atmosphere of CO2 and CH4 made
the planet cooler (and the original higher CO2/CH4 concentrations in
part compensated for a weaker young sun). The oxygen pollution they
produced initially forced soluble iron out of solution leading to some
of the exteremely red oldest sedimentary rocks (and also mineable iron
ore bodies).

So the Earth is far away from the equilibrium state that you would
expect (wrong average temp, lots of a very reactive gas in the atmos).
Clues to life.

This is very true. Finding O2 and CH4 in the same planetary atmosphere
advertises interesting non-equilibrium chemistry (ie. possibly life).

Which is in fact why you don't need probes to land on Mars to look for
life. Atmos: neutral gases like carbon dioxide. Average temp: what a
black body's equilibrium temp would be at that distance from the Sun.

That's what James Lovelock says, anyway. [1]

He could well be wrong though. Methane emissions have now been observed
in the Martian summers which is a big surprise when the surface is
covered in superoxides and peroxides and illuminated by hard UV. It is
now also known that dig down a bit and you find water and dry ice too.

http://www.nasa.gov/mission_pages/ma...rsmethane.html

I don't think there is any way to resolve it without sending probes. It
is unlikely to be more than a few microbes eking out a living in the
permafrost. But wherever we have looked on Earth there have been some
extremophiles living there albeit growing very slowly and hard to spot.

--
Regards,
Martin Brown