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

[The Avantguardian]

--- Mike Lorrey <mlorrey at yahoo.com> wrote:

> The problem is that extremophiles tend to not
> survive extremes they
> aren't built for. A high pressure, high temp
> extremophile doesn't do
> well at low pressure/no pressure low temperature and
> vice versa. Bugs
> evolved for cold just die as their protiens
> precipitate out of solution
> when temps get too high. Hot, high pressure bugs see
> their protiens
> contract so tight that they tear themselves apart.

Endospores get around all these problems. They really
are remarkable adaptations. 

> Another problem is transfer. Given that astronomical
> bodies tend to hit
> each other at velocities in excess of 20,000 mph,
> the impact temps and
> pressures of such collisions are too excessive for
> any life, even high
> temp, high pressure bacteria, to survive. You are
> going to have to find
> a bug that lives and thrives in lava to solve that
> missing link.

Not necessarily. See the following excerpt from the
paper that I posted the link for earlier:

"Deposition of Spores from Space to a Planet

Assuming that spores trapped inside ejecta survive
launch and transit through space, they must be
captured by the gravity of a recipient planet and
survive entry. Our current understanding of what
happens to a rock fragment upon reentry is generally
good, thanks to years of study of natural meteors and
the reentry of spacecraft (24, 108, 147). It turns out
that planets with atmospheres are almost ideal
recipients of life-bearing rock fragments. Although
small (0.001 to 1 kg) fragments may burn up entirely
in Earth's atmosphere, larger fragments are slowed
dramatically upon reentry to a terminal velocity of a
few hundred meters per second. Because the entire
reentry process, from first encounter with the
atmosphere to impact, takes only about 1 min or so,
the interior of the meteorite (except for a few
millimeters of ablation crust at the surface) is not
heated significantly above its in-space temperature.
This accounts for the well-documented phenomenon that
recently landed meteorites are cold to the touch.
Aerodynamic drag forces often disaggregate the rock in
the lower atmosphere, and the resulting fragments
strike Earth's surface in the characteristic pattern
of a strewn field (147). Upon impact, these fragments
are further shattered and mixed with the surface
material of the destination planet. It is therefore
possible for endolithic microbes not only to survive
reentry embedded in a meteorite, but actually to be
effectively inoculated into the recipient planet's
crust, thereby encountering an environment potentially
conductive to growth." 



The Avantguardian 
is 
Stuart LaForge
alt email: stuart"AT"ucla.edu

"The surest sign of intelligent life in the universe is that they haven't attempted to contact us." 
-Bill Watterson


		
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