Date: 24 Jun 1993 14:59:04 GMT
From: "Geoffrey A. Landis" <LANDIS#M#_GEOFFREY@LIMS-A1.LERC.NASA.GOV>
Subject: Life on Mars
Newsgroups: sci.astro,sci.space,sci.bio

For information on Viking scientific results, try
: _Scientific Results of the Viking Project_, 
American Geophysical Union 1978, Library of Congress
number TL789.8; NASA CR-155560 or NTIS number N78-16078;
reprinted from _Journal of Geophysical Research_, 
Vol. 82, No. 28 (Sept. 30, 1977).  The Viking biology 
experiment results are the last four papers (page 
4569-4680), but it's got a lot of other good data on 
Mars as well.

Just for reference, almost nobody in the Mars science 
community believes that the Viking result indicated life.  
It is pretty much universally accepted that the evolution 
of oxygen from the wetted soil indicates that the soil 
contains peroxides or superoxides.  Note that when the 
wetted soil has dried out and was wet a second time, 
no oxygen was evolved.  (But it is important to test 
this hypothesis with an actual measurement, of course!)

I was just talking to a chemist who works here the other 
day about what happened to the primordial nitrogen in the 
Mars atmosphere.  I suggested that maybe it is present 
in the form of nitrates in the soil.  He said, well, 
considering the UV available, it could also be in the 
form of cyanates or azides.

!!!

I can just imagine the excitement of the Mars expedition now.  
First they are all poisoned.  Then they blow up.

Geoffrey A. Landis

Newsgroups: sci.astro,alt.sci.planetary,rec.arts.sf.science
From: henry@spsystems.net (Henry Spencer)
Subject: Re: Mars is going to Europe.
Date: Sat, 19 Jun 1999 06:22:02 GMT

In article <376A3FC3.EEC87BF3@ix.netcom.com>,
Bruce Sterling Woodcock  <sirbruce@ix.netcom.com> wrote:
>> >There's carbon all over the place.  An estimated 10^5 kg of organic
>> >carbon gets rained on Mars from space every year.
>> Correct... and the Viking GCMS should have seen some of it.  The fact that
>> *none* showed up is fairly strong proof that there is some process on the
>> surface which actively destroys carbon compounds...
>
>Read the post.  The GCMS wasn't sensitive enough.

Do your research a bit more carefully, and pay better attention to what
I'm saying.  The GCMS was not sensitive enough to detect organics at the
level arguably found by the LR experiment.  It *was* sensitive enough to
detect them at the level expected for meteoritic organics in the regolith.
Finding *no* organics startled people for reasons well beyond the seeming
inconsistency with the life-detection experiments.

>Furthermore, even if
>someone destroys some of the carbon on the surface, it can still survive
>beneath the surface.

Only well below the surface, since the immediate surface layer is turned
over by wind erosion and meteorite impacts.  (Some of the Viking samples
came from circa 10cm down.)  Besides, what you're claiming to be positive
life-detection results did come from the surface.

>> More to the point, what would more funny-looking-weakly-positive results
>> from LR-like experiments prove?  There simply is no point...
>
>Because LR-like experiments could, properly designed, do other tests for
>carbon and chiralty and so on and disprove the other alternate explanations
>provided so far.

Just how many experiments are we talking about flying here?  Remember,
there are not that many landers headed for Mars, and they are quite small
compared to the Vikings.

It would take a lot of such experiments to settle the question to
everybody's satisfaction (not just Gil Levin's).  I question whether that
many would get flown within any reasonable time even if they were made a
high priority.  What is needed, to get people to take the idea seriously,
is at least tentative confirmation from a *different* type of experiment,
preferably a more direct one that *unquestionably* isn't subject to false
alarms from active surface chemistry.  ("Unquestionably" means it has to
be good enough to convince skeptics, not just true believers.)
--
The good old days                   |  Henry Spencer   henry@spsystems.net
weren't.                            |      (aka henry@zoo.toronto.edu)

From: gherbert@crl3.crl.com (George Herbert)
Newsgroups: sci.astro,alt.sci.planetary,rec.arts.sf.science
Subject: Re: Mars is going to Europe.
Date: 20 Jun 1999 10:11:25 -0700

Bruce Sterling Woodcock  <sirbruce@ix.netcom.com> wrote:
>Henry Spencer wrote:
>> Only well below the surface, since the immediate surface layer is turned
>> over by wind erosion and meteorite impacts.  (Some of the Viking samples
>> came from circa 10cm down.)  Besides, what you're claiming to be positive
>> life-detection results did come from the surface.
>
>I disagree.  You're postulating that it must be "well below the surface",
>but you haven't shown that.  It depends on the theoretical organic-destroying
>process.  You do realize that the H2O2 theories don't hold up anymore, right?
>So another mechanism must be invoked.

They were never "H2O2" theories; they were peroxides, not *hydrogen* peroxide.
And they have not been refuted, in fact UV exposure of simulated mars surface
samples in simulated mars atmospheric conditions generated the inorganic
peroxides in the soil that had previously been hypothesized to explain
the various Viking results.  Unless there are other processes in play,
given the Mars surface, atmosphere, and solar UV flux there *have* to be
the inorganic peroxides there.


-george william herbert
gherbert@crl.com