“If it comes that close every two years it’s bound to hit any century. How about we blow it up now?”
regardless of what Nasa wants you to believe, we do not have the capability do do anything like that at this point in time.
besides I printed up a bunch of Giant Meteor 2024 bumper stickers
https://www.ibtimes.sg/nasa-asteroid-warning-dangerous-space-rock-may-hit-earth-2024-33943
We certainly have the capability to rendezvous a spacecraft with comets and asteroids; we’ve already done it a few times. We’ve just never sent up a nuke (as far as we the common people know). The only problem I see is that blowing up a big rock will just turn it into thousands of smaller rocks with greater likelihood to hit us.
With no air in space there would be no shockwave, even from a nuke. Any force exerted against an asteroid would have to come from the direct impact of bomb shrapnel, and that’s not likely to do much. I wonder if the radiant heat from a nuclear explosion, if directed at a specific side of an asteroid, could produce enough of an opposite force to gently nudge it onto a different path on some future close pass. It certainly wouldn’t work in the short term, but maybe it could have a longer term effect.