SETI bioastro: Fw: Could Mars Have Ever Supported Life?

From: Larry Klaes (lklaes@bbn.com)
Date: Wed May 03 2000 - 08:44:43 PDT


From: "Bruce Moomaw" <moomaw@jps.net>
To: "Europa Icepick Group" <europa@klx.com>
Subject: Fw: Could Mars Have Ever Supported Life?
Date: Tue, 2 May 2000 20:12:30 -0700
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-----Original Message-----
From: Clements, Robert <Robert.Clements@dva.gov.au>
To: 'europa@klx.com' <europa@klx.com>
Date: Tuesday, May 02, 2000 7:06 PM
Subject: RE: Could Mars Have Ever Supported Life?

>
>This is one of wildest (in the colloquial, extreme, sense; not in the
>scientific, highly implausible, sense) scientific speculations on
>contemporary Martian life to emerge in years. Has anyone had the chance to
>confirm Haberle's calculations?; & are any planned orbiter instruments
>capable of detecting such permadamp areas if they exist?
>
>All the best,
>Robert Clements <Robert.Clements@dva.gov.au>
>
>
>> -----Original Message-----
>> From: Larry Klaes [SMTP:lklaes@bbn.com]
>> Sent: Wednesday, May 03, 2000 5:20 am
>> To: carlsagan@craigerware.avalon.net; META@egroups.com;
>> acc-list@clarke.lac.usp.br; setitalk@klx.com; europa@klx.com;
>> zia-discuss@world.std.com
>> Cc: David Grinspoon; Andrew LePage; Fractenna@aol.com; Dr. Stuart A.
>> Kingsley; Elaine Mullen; sstride@jpl.nasa.gov; Philip Plait
>> Subject: Could Mars Have Ever Supported Life?
>>
>> Could Mars Have Ever Supported Life?
>> by Bruce Moomaw
>>
>> Hellas is interesting for another reason as well. Robert
>> Haberle pointed out in his talk that the common belief that Mars' air
>> pressure is too low for liquid water to exist anywhere on its surface
>> today is not quite true -- there are still a few lowlands where the
>> air pressure is just high enough for it to exist briefly. He
>> identified seven such regions where the temperature is high enough,
>> for at least a few weeks each year, for liquid water to exist, but the
>> air pressure is still so low that it evaporates after only a few
>> minutes, which means that it would have to be replenished from some
>> groundwater source. Five of these lowlands are in the equatorial
>> regions and have long since dried out, but two others -- the huge
>> Hellas and Elysium craters -- are in the far south and may still have
>> a substantial amount of ground ice mixed into their soil (originally
>> poured into them by runoff from those valley networks created by the
>> heat of the giant impacts that formed the basins). If their soil is
>> actually moist, even for a few weeks a year, it might allow live
>> microbes to thaw out and carry out their reproductive cycle before
>> refreezing. Addition evidence suggests that at least a few big
>> Martian craters, including Hellas, were still filled by lakes of
>> liquid water (probably covered by a layer of ice) as recently as a few
>> hundred million years ago.
>>
>==

In fact, Gerald Soffen -- who was connected with the water vapor mapper
experiment on the Viking Orbiters -- pointed out that their results had
showed some areas of relatively high humidity, and asked Dan McCleese after
his Conference talk whether any more sensitive orbital search is planned
that could tell whether such any such areas were due to actual groundwater
supplies (rather than just weather patterns). McCleese (the principal
experimenter for the ill-fated PMIRR experiment on Mars Observer and Mars
Climate Orbiter) said that his instrument could have done so -- and while it
won't be flown again, detailed planning is already underway for miniaturized
IR and microwave mappers that could do the same thing. And -- as Benjamin
Weiss would have suggested in his cancelled Conference talk, and as other
scientists have also suggested -- orbital searches for local concentrations
of other trace gases may be very useful in looking both for volcanic areas
that might be hospitable to microbes, and for actual gas emissions from
living Martian microbes.

                                                    Bruce Moomaw

==
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