The shockwave isn't the problem. It's hard radiation from the supernova that kills. And that travels, of course, at the speed of light. We'd only know about it as it happens. There'd be no warning, no time for anxiety or futile efforts to save ourselves.

The Universe is cruel, but takes pleasure in small mercies.

Originally posted by RFBurns
Well the thing about is that it is 8 billion light years away. That means that it occured 8 billion years ago. So that star went supernova a very long time ago...in a galaxy far far away...

Nothing to worry about. If Hubble picks up a supernova in our own galaxy, it is not going to affect us....unless it just so happens to be that one star we all depend on...called Sol.
Cheers!!!!

This is not true.

Gamma ray bursts are thought to result from a super-massive star going supernova before becoming a black hole, or from the merger of neutron stars -- and if one of those happens even 500 lightyears away from us, we could all be killed by gamma radiation. Some scientists think that a large supernova -- or hypernova -- that occurs even 1000 light years from us could cause mass extinctions (maybe even humans) due to radiation.

So, like the OP said, it is possible that a Supernova, hypernova, or gamma ray burst 500 lightyears away could have already happened 450 years ago (but the light hasn't even reached us yet) and the inevitable radiation wave of destruction is already on its way to destroy life on Earth.

Cheerful thought, isn't it

[edit on 1/20/2009 by Soylent Green Is People]