Life On Mars..?

[Keith A Henderson]

Damon ponders....

>
> 1) Someone finds a meteorite.  I'll accept a scientist's ability to tell
> a meteorite from some other rock.  "Look, a big hole in the ground!  And
> a rock right in the middle of it! [scratches chin]"  But then another
> scientist must've looked at it and said, "Oh, it must come from Mars.
> *Everything* comes from Mars."  Seriously, though, of all the places this
> rock could've come from, how in the world does a person figure it out
> exactly?
>
> 2) Possible answer:  chemical makeup.  OK.  The rocks on Mars are (I
> could be wrong on this) about 95% iron oxide and 5% other stuff, right?
> Well, most asteroids are made of the same stuff, except it's iron instead
> of iron oxide.  Well, when a big chunk of iron sits in the great outdoors
> (or indoors, for that matter) for 100,000 years (is that the figure?), it
> tends to, um, oxidize.  And meanwhile, couldn't bacteria have grown on
> the rock sometime between now and then?

Chemical makeup is right on.  I just attended this past spring a lecture given
by astronaut/geologist Harrison Schmitt (the last person to walk on the moon,
or I should say the 'most recent').  Anyway, his talk was more about asteroids
and meteorites and what we can learn about the solar system from them.

BTW, metallic meteorites and 'stony' meteorites are both common.

And each planet has a very, very, very characteristic fingerprint of the
composition of 'trace' elements (unusual things like Rhenium, Thallium, Osmium,
Iridium most likely).....so characteristic that it is absolutely impossible to
get it wrong.  I can't remember exactly how they knew what that planetary
signature was beforehand (it was something pretty ingenious), but once they
were able to pin down what Mars' signature is, identifying meteorites on Earth
as originating from Mars is cake now.

And these days, 90% (or probably more) of meteorites are found in Antarctica.
Obviously, it's really easy to spot one sitting in a zillion square miles of
ice (well it's easy to spot just about anything, and sometimes even things that
aren't there :) ), and there are regions of Antarctica (called 'blue ice'
zones) where heavy ablation concentrates foreign matter.  Some of my colleagues
(and one of my committee members) make it a general practice to go hunting for
meteorites on 'bad weather days' when it's impossible to do any other work.
There are like 7 or 8 thousand Antarctic meteorites now catalogued, and less
than 10 thousand total discovered I believe.  They now have enough to have a
statistically viable sample (not biased according to ease of finding on land
(dirt)), such that we don't really need any more in order to learn about the
bulk composition of the proto-solar system, etc.  But there are some very rare
types (can't remember exactly what they were called) that are odd and difficult
to explain.  Plus the 6 or 7 (?) that have been identified as "martian".

I don't know about the bacteria issue...there is certainly some bacteria/life
in Antarctica, although buried in the ice there's probably very little.  But I
wouldn't count this out as a contamination problem.  But I assume (or would
hope) that these researchers have some clue that these organic molecules come
from deep enough within the crystalline structure as to be authentic.  We'll
have to wait and see.

Interesting news....hope it's not another cold fusion.  :)

Keith H. (FAA)