[Moltke]

Authorities describe recent cosmic activity from a type of super-dense star that has released a burst of gamma rays. This massive electromagnetic storm is heading toward Earth...

Well, that's where it falls flat on its face, isn't it? You cannot know about "a burst of gamma rays" until it's actually here (i.e., no warning). That's the nature of electromagnetic radiation and what allows us to look into the past by looking at galaxies far, far away...

[surfer]

Well you are assuming this movie is based on current technology...what if they had invented a detection technology at the time of this movie :)

[Joe Brower]

Moltke is correct -- EM from cataclysmic events like supernova (which produce objects like neutron stars, pulsars, etc.) would propagate through the void at light speed, meaning you would have no way of having any sort of advance warning. It would be on you and that's when you'd know. Even if you had outposts that could broadcast a warning via laser beam, it could only follow behind the EM wave.

This fact alone makes this an interesting sort of threat. That, and the fact that a supernova cooking off within 20-30 light-years away from us does have the potential to cook us pretty good, as in extinct. And like I said, there's absolutely nothing to do for it.

So I think I'll just go and have a beer... $:-)