It's the directed by man behind 28 Days Later, but its a sci-fi (no zombies sorry).
Thing is it was released with little to no advertising here etc, but I personally think it's one of the best films this year (even though I've just seen Transformers which I loved). Go read up on this movie and give it a chance. One thing I've seen in most of the reviews is the plot device - ie the reason why their out there - you just have to let it go and buy into it a little - if you can do that you'll have a good movie on your hands. Even I had to say to myself 'ok the so Sun is dying and their going to do something about it... what is this Armageddon?!?' but it's really not that kind of film at all.
Go do some reading and make some time to go see it, from what I understand it's just been released in the US (I think the UK have had it already)... that said this movie probably wont last long against Transformers.