[meteorite-list] Mars life concerns

From: Marc Fries <m.fries_at_meteoritecentral.com>
Date: Tue Jul 19 13:44:23 2005
Message-ID: <1340.10.17.14.1.1121795058.squirrel_at_webmail.ciw.edu>

To borrow from Jim Carrey, "Alrighty then!" We'll go one at a time here...

> 1. What you seemed to be emphasizing in your first post was the
> probability
> that the astronauts contaminated specifically the (apparently virgin)
> part of
> the camera insulation during there journey back to earth.

1) The camera was not a "virgin" sample. Not even close. See Baalke's
posts.

> 2. A typical sneeze has, what, 50,000 diverse microbe individuals? A
> typical human hand, how many, 100,000,000 diverse individuals (95% under
> the
> fingernails)?
> 3. And now you would expect me to believe using "an iota of horse sense"
> that all 100 organisms being identical are the result of a someone
> "sneezing on
> a lab bench", adding that you are reasonably sure there were other
> microbes
> there, too that went undetected and blame it on unknown errors and your
> view

2,3) Again, the culturing methods used in 1969 were very clumsy. See the
following as one of many examples:

http://www.genex2.dri.edu/research/microzoo.htm

    Note especially the comment, "we can cultivate 0.01 -0.1 % of the
total organisms from seawater samples". That is very typical for
culturing. When you choose a growth medium it will be optimized for a
class of microbes. Most other microbes won't grow very well or at all
in it. Ergo, you miss the vast majority of microbes in a sample this
way. If you use a medium "tuned" for bacilli then you'll miss all the
fungi and what-not. All hail the mighty god of horse sense.
   As a sort-of aside, that's why NASA will never launch another
Viking-type life detection instrument again. When you rely on
culturing microbes then you automatically cut your chance of detection
by 90-95% or more. It also assumes that whatever lives "out there"
would actually grow on a Terran growth medium.

> of limitations in analysis? You could be right, of course, we'll never
> know.
> Because in the end you just have a series of assumptions you are making
> regarding an analysis done by a technician before you were born, in which
> you
> impose own pet biases as well.

   We do know, actually - quite well. See above, and the other posts in
this thread outlining the handling of the camera.
    And these points I raise aren't "pet biases". They are known
limitations of the techniques used in the 1960's. Data taken with
what are today outdated techniques are not useless, BUT you have to
interpret them using what is known about the technique for good and
for bad. For example, when Raman discovered the type of spectroscopy
that is named after him, his light source was the sun and his detector
was his own eyes (both of them, indeed). His discovery is still valid
today, but there was no way that he could collect the kind of
information that I can get from my brand-new, expensive confocal Raman
imager.

> 4. You also agreed with my pirated statement from the NASA website
> pointing
> out the apparent fact that none of the other rocks or camera parts were
> contaminated (detected as such), but say this only further proves it was
> contamination because it wasn't repeated? That is uncommon horse sense.
> My sense
> tell me there would have been at least one more "false positive" setting
> off
> bells and whistles in all those rocks that were handled in a similar
> manner by
> the astronauts regarding the possibility of contamination.

    You do realize that your entire argument hinges on that one, singular
measurement, yes? Never mind the hundreds or thousands of other
measurements that they took that said otherwise... I repeat: good
measurements are repeatable measurements.

> 5. I don't know why the positive result was specific to exactly one
> species
> and 50-100 dormant individuals of this species -and only this species-
> were
> detected and somehow subsequently cultured at the CDC. I do believe it

   Repeat of argument 2/3. See above for refutation.

> The plot thickens
> aimlessly...

   No, it tells a story. A story about a single measurement of a common
contaminant on a sample that was not handled in an aseptic fashion.
I'm not "revising results" or exaggerating problems with the
methodology of the times. If anything, I'm impressed that those folks
only came up with a single instance (that I'm aware of) of microbes
where they logically shouldn't be found. That says to me that their
study was careful and thorough. However, microbes are everywhere, even
in NASA's clean rooms:

http://ijs.sgmjournals.org/cgi/content/full/53/1/165

   This is not an open controversy - it's actually very straightforward
instance of laboratory contamination, and a cautionary tale about
letting your hopes make a fool of your reason.

Cheers,
MDF

-- 
Marc Fries
Postdoctoral Research Associate
Carnegie Institution of Washington
Geophysical Laboratory
5251 Broad Branch Rd. NW
Washington, DC 20015
PH:  202 478 7970
FAX: 202 478 8901
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Received on Tue 19 Jul 2005 01:44:18 PM PDT