Re: >H Re: The Great Filter
Forrest Bishop (forrestb@ix.netcom.com)
Mon, 10 Mar 1997 14:33:16 -0600 (CST)
You wrote:
>
>Forrest Bishop writes (on the transhuman list):
>>Colliding binary neutron stars may provide a hefty element of the
>>"Great Filter". An article in the April, 1997 issue of *Astronomy*
>>magazine reports astrophysicists theorise that these events produce
>>the gamma ray bursters, and goes on to say that "in Milky Way-like
>>galaxies, such explosions would destroy advanced life on every nearby
>>Earth-like planet on the average every 100 million years." Nearby is
>>implied to be between 1500 and 3000 light years.
This might explain the 'hard step' between unicellular and
multi-cellular life: single-cell life is relatively 'easy', given
autocatalysis and self assembling vesicles, and is fairly radiation
resistant. Multicells are much less resistant, and need several hundred
million years of radiation-quiet time to evolve.
On Earth, single cells arose quite early- before the crust even cooled,
but it took several billion years before multicell life. Perhaps
these occasional massive radiation events kept bombing us back to
single cell forms during this period, and then we got lucky.
Forrest