Re: life test for planets

From: Eugene Leitl (
Date: Mon Jan 28 2002 - 12:55:05 MST

On Mon, 28 Jan 2002, Amara Graps wrote:

> What ?
> Interstellar dust/micrometeoroids is absolutely detected in the
> inner Solar System, to, at least, near Earth. Some of it falls to Earth.
> On the flip side, a tiny portion of our Solar System dust escapes
> the Solar System.
> 'We' are not isolated bubbles. Other nearby stars are not isolated
> from 'Us', either.
> Did I misunderstand your above statement, Eugene?

Yes. What I meant that shortest impact ejecta travel Mars->Earth duration
is about half a year (worst case several MYrs, which is beginning to be
problematic for spores), while the "pebbles" are very macroscopic, and at
no point does their core temperature rise over 40 C. So, they both travel
short, and are well shielded by the bulk of the specimen.

Interstellar dust streams are relatively slow (60..80 km/s? I forget), and
they're merely micron sized. The transit over few LYrs takes basically
forever, and there is no shielding, so it is very very tough conditions
for life to make it. The organics does probably fine, but in absence of
self repair due to absence of metabolism does probably sterilize about

Thank you for the great abstracts you gathered, much appreciated.

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