Sunday, June 17, 2012
It probably won't, but it should. An asteroid called 2012 LZ1 just flew by us two days ago at a distance 14 times that of that from the Earth to the moon, which would not otherwise be news except for two things: 1) this asteroid was just discovered less than two weeks before closest approach, and 2) the asteroid is some 500 metres in diameter. That's the size of 2005 YU55 which made so many headlines back in November. Most of the asteroids we don't know about until a few days before they fly by are very small, perhaps 10 or so metres in diameter, but this one would have made a crater about 5 km in diameter (along with a number of other effects such as earthquakes and thermal radiation) if it were to have hit us.
I often hope to see the Earth hit by an asteroid that we discover about a week before impact, but only one about 10 metres in diameter (such an asteroid would make headlines and then break up in the atmosphere). Something as large as 2012 LZ1 is a much scarier prospect. Even if it landed in the ocean (which it most likely would), the tsunami created by it would be nothing to sneeze at. As this article states:
Astronomy Magazine analyst Bob Berman added during the webcast that the event was "scary" and a bit of a wake-up call for astronomers, who only discovered the LZ1 this week.
"The word space certainly means there's room up there, but now it's almost like we're dodging bullets here and there," he said. "We thought things like this size, we'd easily detect more than just a few days before they zoom past us. This one is a little bit worse that we could see something the size of a city block and not detect it until just three days beforehand."