[DoctorDoom]

Sustainability is relative:

http://www.cnn.com/2006/TECH/space/07/0 ... index.html

A low-tech society wouldn't have a chance against an asteroid strike. Neither does ours if we stagnate at present technology levels. We don't need to worry about how long the sun's going to shine; odds are something like this would wipe out civilization much much sooner. Unless, of course, we keep advancing.

[Novus]

A high tech society wouldn't have a chance against that astoroid either. Here it is in 2006 and a massive asteroid could slam into the earth and we would never see it comming. It just be booom you are all dead.

[emailking]

It's possible to deflect such asteroids (slowly, over time) if one knows years in advance that it will hit. It is also possible to see all such asteroids if one sets up enough automated telescopes to look (on the moon for example).

So yes, a sufficiently advanced society could stop such strikes.