[ExI] Panbiogenesis

Anders Sandberg anders at aleph.se
Thu Jan 26 00:09:20 UTC 2012

On 25/01/2012 19:45, BillK wrote:
> On Wed, Jan 25, 2012 at 6:10 PM, Anders Sandberg  wrote:
>> I wonder if anybody has run a hydrocode on what happens to a terrestrial
>> planet subjected to its sun going supernova? It would be interesting to see
>> if any material is ejected that is not subjected to extreme heating and
>> radiation. ...
> But they can eject whole planets from their system and push some
> planets out to larger orbits. Though those planets still exist, I
> expect they are pretty crisply toasted.

Yes. I found this paper when looking for the answer to my question: 
http://arxiv.org/abs/1107.1239 "The Great Escape: How Exoplanets and 
Smaller Bodies Desert Dying Stars" - apparently quite a lot of planets 
and smaller bodies can escape a system where the star is undergoing mass 
loss or supernovas.

Even more intriguing is
"Can a Planetary System Survive a Host Star Supernova Explosion?"
where the abstract (the only thing available, it seems) says:

> Our calculations show that even a small Earth-like planet is not 
> destroyed mechanically nor thermally in such an explosion (and larger 
> planets are even more stable). Nor is a planet kicked out of its orbit 
> due to the momentum of exploding star shell or of due to star's 
> radiation pressure. In some cases even a portion of a planetary 
> biosphere (deep in planet's crust) can survive. 

So there is likely some chance of supernovae seeding space with 
thrown-off pieces of rock, or old terrestrials drifting around with 
frozen subsurface biospheres. Good news for panspermia.

Anders Sandberg,
Future of Humanity Institute
Philosophy Faculty of Oxford University

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