[extropy-chat] Water Marks the Asthenosphere

[Technotranscendence]

On Friday, January 26, 2007 4:57 AM Eugen Leitl eugen at leitl.org wrote:
>> Reading this, I'm wondering if a lot of water on
>> other words might be integrated into the mantle
>> or other strata... Perhaps Mars has lots of
>
> There seems to be lots of ice under the surface,
> with even occasional surface melts.

Yes.  I was wondering about the absolute amounts...  On another list, I
wrote:  "Of course, this doesn't mean that, e.g., you might be able to
easily use or release this water.  My first thought was, of course,
imagine flushing it out [on a body like Mars].  But my quick follow-up
was: how and what would that do to the mantle?"

>> water, but it's all part of a mineral matrix deep
>> below the surface.  What about Luna?
>
> Most of it was baked out during formation,

Yes, that might be so, but what if it's not?  Is there enough data on
the lunar interior to know?  If large amounts of water can be
incorporated into Earth's mantle and not baked out, might not something
similar be true about Luna?  Of course, it could be that the water in
Earth's mantle can't be baked out because the only place it has to go -- 
up -- has been saturated with water -- and also because there are
processes to add water to the mantle (so that if there's a loss, there's
some balance that maintains a stable equilibrium or the loss is so low
that huge amounts still remain).

> but it might have recaptured enough volatiles in
> the polar cryotraps from impacts, which are now
> most  likely tightly bound by alumosilicates (rather
> like concrete).

I've read about something like this a few years ago in _American
Scientist_.  However, it remains speculative and the process mentioned
could happen anywhere on the Moon -- not just in the polar regions.  If
the mixing were sufficient to put water lower enough or the mineral
binding tight enough (olivine would capture lots of water, wouldn't it)
so that the temperatures it's likely to experience later on wouldn't be
able to get it out, it might be there in lots of places -- not just the
poles.  I think the article set some limits on the degree to which this
would happen and set a depth of about a meter or so for such mixes.
This would be easy to test.

> Baking this out by putting the material in the focus
> of a large elliptic mirror (made from aluminized mylar)
> and recapturing it is rather trivial. Provided, your
> protons are really there, of course.

Since you mention protons, wasn't there also talking about recovering
solar wind hydrogen, though the amounts would be very small, from lunar
regolith?

> It is also arguable why one would need volatiles on
> the Moon, unless one considers pressurizing a lava
> tube or excavating an artificial cavity to build a habitat
> for primates. This only makes sense at a very late state
> of the game, which primary stages are driven by
> remotely operated and autonomous automata.

Colonization or for industrial and other processes that need water.

> By the time you're done, people might look sufficiently
> different (or be succeeded by their automata) so that
> heavy life support based on volatiles could look quaint,
> or completely obsolete.

This is possible, though I would prefer to hedge my bets.  Some here
argued against sending a probe to Pluto because, by 2015, better, faster
craft would beat it there.  Well, 2015 hasn't arrived yet, but what if
2015 looks a lot like 2007 -- save for higher storage hard drives, a few
more genomes being mapped, and nanotube TVs?

Regards,

Dan