In a message dated 8/1/99 19:02:45, jonkc@worldnet.att.net wrote:
> CurtAdams@aol.com Wrote:
>
>>But even by your figures, a 100 kg mass would expect 2 x 10^7 hits
>>from a supernova 2 ly away. In a body of many billions of cells,
>>that's quite trivial. Only about 1 cell in a 1000 will take a hit,
>>and the vast majority of hits don't do anything significant.
>
>An Alpha particle will kill or mutate any cell it hits, a rare neutrino that
hits
>would be almost as deadly.
Well, I looked up some of these numbers.
A supernova neutrino has an energy of 5 to 40 MeV.
An ev is 1.6 x 10^-12 ergs, so a sn neutrino is up to 6.4 x 10^-5 ergs.
The rate under discussion yields 200 neutrinos absorbed/gram, or
1.3 x 10^2 ergs/gram, which is 1.3 x 10^-4 rads. (0.00013)
A 50% lethal dose at Hiroshima was about 400 rads. Alpha particles
are more hazardous and a 50% lethal dose would be about 20 rads.
The radiation dose from the 2 ly-away supernova is thus less than
1/100000th of a 50% lethal dose, even if neutrino energy is a damaging