[ExI] NASA tease on SETI find

[Rafal Smigrodzki]

On Thu, Dec 2, 2010 at 9:42 PM, spike <spike66 at att.net> wrote:

 This opens up possibilities for the panspermia notion,

### How so? Remember, these are garden-variety gamma-proteobacteria,
not anything that fell from the sky, unless you already believe that
all life on Earth did.

as well
> as causing me personally to increase my own estimate of the number of star
> systems that support life.

### Trivially, yes, in the sense that our estimate of the probability
that worlds with unusually high metallicity (and therefore high levels
of arsenic) could harbor DNA and protein-based life should now be
higher - but we have no reasons to believe that high metallicity is a
significant issue on most otherwise habitable planets. Personally, I
never thought that metallicity is a problem anyway - the only reason
why metals are poisonous to most terrestrial life is not their
intrinsic badness but rather rarity - and rare chemicals are more
likely to be problematic when encountered, since normally there is no
pressure to evolve good uses for them.

For me a more astrobiologically significant finding was the discovery
of gamma-ray eating molds inside the Chernobyl sarcophagus. If an
eukaryote can develop the ability to feed on gamma rays after a few
years inside a little piece of Hell, then a hundred million years in
that place could perhaps yield some very, very tough creatures,
capable of breezing through millions of years of space travel. Of
course, the Ruskis still aren't good at propaganda, so the black mold
of Chernobyl hardly made headlines.

Rafal