Re: galactic EMP

Date: Sun Jan 14 2001 - 09:58:14 MST

Chuck Kuecker wrote:
> If the blast from galactic center is intense enough to scorch bodies in our

Scorched is said too much: the primordial stuff out there at the periphery
has usually never seen anything hotter than few 10 K. (It gets downright
cooked whenever a body gets flung solwards; see comets). You don't need at
all much to denaturate that, even after brief exposure. If you have a piece
of certified urgunk with a few-billion year old surface, and that surface
shows signs of being subject to sudden flashes, and you can date when
the flash came, due to subsequent microimpact erosion, it could be
interesting. This would also help with estimating frequency of nasty bright
events like supernova and gamma flashes, because the record must be out
there. Also, the primeordial debris cloud seems to end rather sharply,
being possibly stripped off some rather violent event. There might be still
traces of that possible event buried out there. We'd be stupid not
too look at that record at the earliest opportunity.

> solar system, you don't have to worry about present day military gear
> surviving. More to the point - would our atmosphere provide enough
> shielding to allow life to remain on the surface, or even in the first 100
> yards of the surface?

The amount of EMP necessary to fry the electronics should be invisible
to an uninstrumented human. If it's dark, you might see really bright
aurora, but that's about it. It's just like a global NEMP nuke without
the fireball (because the source is somewhere at the galactic center).
> I take it the "EMP" will be caused by heavy particles traveling at sublight
> speeds. If it's pure radiation, the first warning we get will also be the
> last thing we ever see...

It can't be photonic radiation, but it has to be pretty relativistic, so
there would be not much warning coming. A wave of this should be shocking
interstellar medium and anything denser than that, though, so you should
see the neighbourhood lighting up as it passes. If a wave is still travelling
out there (since there's no point in looking at megayear windows due to
low probability that such a thing is about to hit us, other risks must
have higher priorities), you should be able to map it by looking as it lits
gas and dust clouds.

The point is still: are there hints that such a thing exists, or was the
warning I read utter bogus? Amara? Anybody else?

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