[extropy-chat] ET is a Bacterium was Dark Matter and ET

[Amara Graps]

>      That bacteria could survive long enough in space
>to colonize other worlds is pretty well documented.

millions of years ? (the traveling time in space of the Martian
meteorites span years to millions of years).

This is a still relatively new research area.
  Horneck (below) says

[begin quote]
Viable transfer from one planet to another requires that life,
probably of microbial nature, survives the following three steps:
1) the escape process, i.e. ejection into space, e.g. caused by a
large impact on the parent planet; (ii) the journey through space,
i.e. time scales in space comparable with those experienced by
the Martian meteorites (approximately 1-15 Ma); and (iii) the
landing process, i.e. non-destructive deposition of the biological
material on another planet.
[end quote]

There is a large range of conditions to test for these three
steps. Many aspects look feasible, but results are along ways
away to support your first sentence.

>Any of the rod shaped bacilli of the type that contain
>Anthrax as a representative species can form
>super-resistant endospores. These spores can survive
>in a near inanimate state without food or water for
>indeterminately long periods of time in very harsh
>conditions including hard vacuum, ionizing radiation,
>and extremes of heat and cold. It seems that such
>spores could be easily disseminated by asteroid and
>comet strikes or possibly even by supernovae.

See the chapter: Viable Transfer of Microorganisms in the Solar System
and Beyond by Gerda Horneck, et al. in _Astrobiology: The Quest for
the Conditions of Life_ by Springer 2002.

It is an extremely comprehensive report, detailing the conditions that
they have tested bacteria and the conditions that they still need to
test.

Amara


-- 

Amara Graps, PhD
Istituto di Fisica dello Spazio Interplanetario (IFSI)
Istituto Nazionale di Astrofisica (INAF),
Adjunct Assistant Professor Astronomy, AUR,
Roma, ITALIA     Amara.Graps at ifsi.rm.cnr.it