QUESTION:
Suppose a dead body (human or animal) is buried in Martian soil, so that it
does not get damaged by meteors or blown away by wind. Will it remain
undecayed forever, or will it start some life on the planet, as the bacteria
in the body can evolve, using CO2 and water in the planet?

ANSWER from Jack Farmer on July 22, 1997:
You present an interesting scenario for a long-term Exobiology experiment on
Mars. I can only speculate about the outcome of your experiment based on
what I know about 1) the present surface environment of Mars and 2) the way
that organic materials behave under comparable conditions on Earth.

We believe that the Martian soil is loaded with strongly oxidizing
compounds, and this probably accounts for the lack of organic compounds in
the soil. The Viking landers carried instruments that could have detected
one organic compound in a billion, but even with this high sensitivity,
nothing was found. Indications are that the organics in the Martian soil
have been stripped away chemically by powerful oxidants like peroxides. So,
my guess is the buried organic material would be rapidly oxidized and lost
during your Mars experiment.

We also know that at present Martian soils contain no liquid water. The
atmospheric density is so low on Mars (~1/100 that on Earth) that water can
only exist as ice and vapor. No liquid water is possible. So, my guess is
that the microbes introduced into the soil by the burial experiment you
propose would not be able to live or grow due to the lack of liquid water.

Jack D. Farmer, PhD.
NASA Ames Research Center
http://exobiology.arc.nasa.gov