Asteroid 2007 WD5 was only discovered 2 months ago. Had it been heading towards Earth, we would have been utterly helpless to respond.
On January 30th, there is a 3.9% chance that a 160-foot-diameter asteroid will smash into Mars, possibly creating a crater about a kilometer wide. While this is incredibly cool for scientists, and on some level for the rest of us, it’s also a little terrifying. If something like that were headed for, say, Washington, DC, things would be a little more interesting to the average American.
I don’t know how big an area we’d have to evacuate if one was heading for us.
The uncertainty region during the Mars encounter now extends over 400,000 km along a very narrow ellipsoid that is only 600 km wide.
Since 400,000 km is much more than the diameter of Mars, that region must extend well into space. So I don’t really know how big a spot on Mars is actually in danger of being hit, or how far away one would have to be to avoid it (Assuming one could survive on Mars otherwise).
In any event, I hope we have something taking video of Mars when it happens. That would be pretty sweet.