Wee Beasties on Mars [NOISE]

[Jim McCoy]

> > schryver at radiks.net:
>
> > > NBC News at Sunrise has just announced the discovery of alien life on the
> > > planet Mars.  The lifeform that became extinct more than 2 billion years
> > > ago was found as a fossil in a meteor that originated from mars and landed
> > > on earth.  The fossil found was a primitive germ life form.
>
> NASA is holding a news conference today to discuss the find.  I must
> admit I am curious as to how they determined the meteor's origin.
> Most material in the solar system is similar in composition.

Using the same methods that geologists use to determine whether or not
certain meteorites are from the moon, by chemical composition.  Material from
within the solar system actually has varied composition mainly determined by
the distance of the body from the Sun (there are various theories as to why
this is, an intro cosmology book will describe them all in detail), the
actual percentages of various elements and compounds can be used to make a
reasonable guess as to whether or not a particular meteorite was knocked off
of a planet or moon to which we have sent a probe.  For example, it is
possible to buy fragments of "moon rocks" which are not actually samples
returned from Apollo missions (which are all owned by the U.S. government)
but are from meteorites which match the exact chemical and physical
composition of the returned lunar samples.  Such determinations are a lot
easier for planets/moons which do not have active vulcanism or other events
which significantly mix up the composition of the planet.

At the news conference given this afternoon the fact that the meteorite was
Martian in origin was probably the least controversial.  It seems that
exobiology may no longer be a field without a subject :)  If the results are
confirmed what I think will end up being the most interesting fallout of this
will be in the creationism/evolution debate.  It seems that life may have
been independantly generated at multiple locations, barring a "space seed"
debate flaring up again, and the "impossible odds" argument has become pretty
weak...

jim