[drzaiusapelord]

The resources and practically to gently shoving a comet or asteroid out of the way are probably a billion less than building self-sustaining colonies elsewhere. Worse, now we have two planets to defend, not one.

I don't see the "we must migrate now" types saying "lets put migration away for a while so we can better build anti-asteroid solutions and detection systems."

Arguably, we're just a couple launches and deployments of mass drivers away from fixing this issue. This is all known tech that could be deployed relatively quickly. A self-sustaining Martian colony is probably hundreds of years away considering the work it would take to terraform the planet.

[Dove]

The resources involved in preventing a GRB from hitting us, on the other hand, are . . .

. . . actually I have absolutely no idea how you would practically do that at all.