unless we're currently able to destroy earth-threatening meteorites and no one told me.

Well, we do have the technological means to build something to counter one of them, if we were to learn about it tomorrow and it had ETA 2-3 years. Assuming the threat is taken seriously and more resources and effort are put into this than they were / are in killing militant toddlers in the middle-east using drones, that is.

But if one shows up now and it's about to hit Earth on the prophecy-filled turn of the Mayan calendar? Nope, GG.