Originally posted by avalanchethecat
It's only a tiddler, wouldn't be much more than fireworks if it did hit.
Correct at least compared to the OP threat.
"So It Won’t Hit. But What If It Did?
Ah, you’re one of those people who enjoys scaring the crap out of yourself. OK, let’s think about what would happen if DA14’s path actually did intersect ours.
We have some decent comparisons. There is a crater in Arizona called, oddly enough, Meteor Crater, that’s about 1.2 kilometers (0.75 miles) across. It was created 50,000 years ago or so by an asteroid roughly the size of DA14, which upon impact probably detonated with an explosion equivalent to a 20 megaton nuclear weapon going off.
That asteroid was metallic, so it could make it through the Earth’s atmosphere and hit the ground. We now know many asteroids are much less sturdy, and probably would explode high in the atmosphere, disintegrating under the excruciating pressures of screaming through the air at Mach 20. That happened in Siberia in 1908 in the famous Tunguska event. Again, a DA14-sized rock came in, but this time blew up high over the Earth’s surface.
Not that this was any blessing. Trees were knocked down and set aflame for hundreds of square kilometers, and anyone within probably 10 kilometers wouldn’t have lived to tell the tale.
So we really don’t want rocks like this hitting us. They won’t cause a global extinction, but it doesn’t take something ten kilometers across (like the one that did in the dinosaurs) to have a catastrophic effect. Anything the size of DA14 would be able to take out a city. And it doesn’t even have to hit over populated land; just having one come in over the United States could trigger a global economic collapse. Remember, it only took a handful of people flying a couple of planes into buildings to do that. An asteroid impact, especially one that comes in without warning, could be a lot worse."