>From what I've been reading on Supercritical Co2
http://p2library.nfesc.navy.mil/P2_Opportunity_Handbook/5_17.html,
it is an excellent organic solvent, but I don't know
how well it would do on the types of deposits the
rovers have been finding
Then you missed the point of Gary's contribution.
Water is a good solvent
for salts (things that carry
positive and negative ionic charges) , liquid
CO2 is not.
To try and put things more succinctly still (I'm getting bored by
this off-message debate with no data to sustain it):
The recent reports from the Mars rovers are for rocks that (1)
appear to have been deposited from liquid fluid flow (as
opposed to wind-like atmospheric fluid flow) and (2) had salts crystallised out in them.
If you want a single explanation for both the above then a
liquid that can evaporate and leave behind
previously-dissolved salts
argues more for water than CO2.
I agree that, of course, this only relates directly to those
outcrops that the rovers have visited on Mars. One can speculate
further on what else happens elsewhere on Mars where no equivalent
data exist to test the hypotheses - but can't those that are
interested do so on a Mars mailing list?
Unless we think there is an important role for liquid CO2 as an
organic solvent on Europa, that nobody has mentioned thus far, I
recommend we stop now - or at least start those messages off:
"Mars CO2" in the subject line?
Otherwise I may just subscribe to "Mars debate" and see
what's new with Europa...
best wishes, Chris
PS Meantime - thanks to Larry K for alerting about the
Astrobiology Mag. Vol.3 issue - that IS what I subscribe for!
--
_____________________
Prof. Chris German, MBE
Southampton Oceanography Centre
Tel: +44 (0)2380
596542
Southampton Oceanography Centre
European Way, Southampton, SO14
3ZH Fax: +44 (0)2380
596554
http://www.soc.soton.ac.uk/CHD/chemgrp/index.html
