[ExI] Gamma Ray Bursts (was: The void left by deleting religion)

[John K Clark]

"Damien Broderick" <thespike at satx.rr.com>

> Which gamma ray burst explanation are you thinking of?

There are lots of theories but I don't believe any gamma ray burst
explanation is yet entirely satisfactory.

> I've read about a whole variety.

It seems you can group them into 2 categories, those that last between a
tenth of a second and 2 seconds and those that last about 100 seconds. They
don't last long but in that short time they produce about a thousand times
as much energy as the sun will in it's entire 6 billion year history. They
are the most energetic things in the known universe.

>You mean that they're extragalactic?

Yes, they are at cosmological distances, and it's a good think too, if one
blew up anywhere in our galaxy we'd be dead meat. Fortunately that is
unlikely, the precursors seem to be huge metal poor stars and the universe
hasn't made stars like that for billions of years, so they're all billions
of light years away. Modern stars have traces of metal in them and this
greatly accelerates the solar wind so when a large star reaches the end of
its life it has already lost a substantial percentage of its mass; ancient
stars had little or no metal and thus kept most of their mass until the very
end when they blew up.

> Jets?

Probably, otherwise they'd have to be even more energetic to be as bright as
they are over such huge distances. A few years ago one was so bright it
damaged some satellites and had a detectable effect on the upper atmosphere,
and this from halfway across the universe. We only see the ones with the 
jets
pointing our way.

   John K Clark