In case one prefers not to get astronomical news from "Business Insider":<p><a href="http://www.space.com/35265-newfound-asteroid-buzzes-earth-2017-ag13.html" rel="nofollow">http://www.space.com/35265-newfound-asteroid-buzzes-earth-20...</a>
My favorite proposed method of asteroid deflection: <a href="http://www.planetary.org/explore/projects/laser-bees/" rel="nofollow">http://www.planetary.org/explore/projects/laser-bees/</a><p>The idea is to ablate material off of one side of the asteroid using lasers and/or mirroring sunlight to redirect its trajectory. This is better than using a nuclear bomb which risks fragmenting the asteroid. If you intercept early enough it doesn't take much of a change in trajectory to miss Earth.
There are whoppers out there capable of resetting civilisation. Do we have to have a small city destroyed before we design and build the technology to avert all future impacts?
FYI, my understanding is that all the asteroids capable of posing an existential threat to humanity are known and tracked. Smaller asteroids like this one are not, but there is an upper bound on the possible damage they can do, and the damage is pretty small in expectation (i.e., when weighted by the chance of a collision).<p>On the other hand, it's still possible that a long-period comet or rogue planet could come out of nowhere and wipe humanity out. Presumably the odds are extremely remote, judging by the rarity of extinction-level events in the geological record.