[meteorite-list] Mars magnetite purpose

From: Matson, Robert <ROBERT.D.MATSON_at_meteoritecentral.com>
Date: Thu Apr 22 09:44:44 2004
Message-ID: <AF564D2B9D91D411B9FE00508BF1C8692C607B_at_US-Torrance.mail.saic.com>

Greetings Everett and List,

> Because every investigator accepts the fact that the magnetites
> were produced on Mars, the unique truncated hexa-octahedral
> magnetites are a true biosignature and probably constitute evidence
> of the oldest life (i.e. 3.9 billion years old) yet found and that life
> resided on Mars!

However, list member E.L. Jones brought up an interesting
argument: why would there be an (exo-Darwinian) evolutionary
advantage to bioengineering and orienting magnetite on a planet
that has a current dipole moment no more than 1/10000th that
of earth? Granted, it was probably substantially higher in
the past, but even when Mars first formed, it probably had
no more than 1/10th the strength of earth's dynamo. So one
question would be: at what level of dipole moment does
bacterial orienteering by magnetite become possible?

Cheers,
Rob Matson
Received on Thu 29 Mar 2001 09:14:27 PM PST