> On Sat, Mar 27, 2004 at 08:24:37PM +0900, Michael Turner wrote: > > > So I'm still holding out for a possible CO2 sea/ocean/lake as an explanation > > for features that we, on our water planet, associate only with bodies of > > water. That doesn't mean that there haven't *also* been bodies of water on > > Mars, just that it doesn't look like the case is closed yet. Unless I've > > missed something.
And Eugene Leitl replied: > I'm unfamiliar with early Mars models which propose a surface pressure larger > than 5.11 atm at temperatures above -56.4 deg C Hoffman's site is back up, so munch away on this (admittedly under "speculative concepts.") http://www.earthsci.unimelb.edu.au/mars/Lakes.html As I remembered: he hypothesizes that such conditions could be created by impact events. Impact events? On Mars? I *think* I can dimly discern evidence of those .... but the eye and the imagination can play tricks, you know. ;-) > Plus, the "also" part doesn't mix very well with respective phase diagrams: > http://onsager.bd.psu.edu/~jircitano/phase.html Only if you interpret "also" as "simultaneous" - I certainly didn't mean to imply any such thing, though Hoffman at least entertains the possibility, even if he finds it distinctly unlikely. If there was surface liquid CO2, it might not be able to easily coexist with liquid H2O in the same time or place, but that doesn't mean it didn't coexist elsewhere, or that there weren't bodies of water after the some collision cooling-off period. If anything, it might take a collision event to first warm up the planet enough (more atmospheric CO2 and more greenhouse effect) to make water flow and pool on the surface. So bodies of water, if they existed, might have required precisely the same preconditions as bodies of liquid CO2, just later in the cycle of impact after-effects (and there might have been many such cycles.) > Maybe elsewhere, but not on Mars. No sustained presence of liquid CO2 on > planetary surface, sorry. I am deeply touched by your faith (oh, I mean "absence of data"), Eugene. ;-) -michael turner [EMAIL PROTECTED] == You are subscribed to the Europa Icepick mailing list: [EMAIL PROTECTED] Project information and list (un)subscribe info: http://klx.com/europa/
