[ExI] Life must be everywhere!

[Kelly Anderson]

On Sat, Apr 14, 2012 at 3:00 PM, Tomasz Rola <rtomek at ceti.pl> wrote:
> Knowing is silver but learning is golden :-).

I'll second that one!!

> Applying this to the impact calculator doesn't change much, however. A 1km
> piece of ice falling down at 42km/s is going to burn me alive anyway.

Depends on how far away from you it hit, I suppose...

> Ten times slower speed required only means ten times longer exposure to
> life killing factors.

But there could be a sweet spot in there somewhere... Life might take
breaks along the way too... stop and reproduce on one rock before
progressing to the next...

> Again, in m/s - a speed comparable to fastest cars. So, whatever gets this
> far is likely to be able to get away from the Sun, either directly or as
> side effect of relatively benign asteroid clashes.

Even asteroid pass by could throw you out of the solar system... think
of a little rock rotating clockwise, and a bigger rock going
counterclockwise with a slightly larger radius. Upon crossing, the big
rock has a slightly more elliptical orbit, and the small rock is
ejected from the system entirely. No physical 'collision' is actually
necessary, just an encounter.

> So, it seems that indeed a big number of rocks can travel between the
> stars. The problem is, can they sustain life for a very long time periods.
> Millions years, maybe billions. Everything can happen during such journey.

Sure.

> Again, I don't think a natural panspermia is very likely to occur. And if
> it does, then it's on a very limited scale. Still, a nice idea to think
> about.

It would only have to happen once in a hundred million years for it to
be the source of life's blueprint... Deep time changes the probability
equations very much, making crazy seeming schemes like natural
selection and panspermia actually seem quite a bit less crazy.

-Kelly