Last night, the news announced we’d have a close encounter with an asteroid about half an hour from now. As it turns out, not one, but TWO asteroids were heading towards Earth, and one of them has already Russia! The other is still headed this way.
Here’s essentially what’s happening:
Asteroids often clump together due to microgravity. They’ll stay clumps, so long as there are no collisions or they do not encounter a gravitational gradient large enough to pull them apart, like what happened with Shoemaker-Levy9 that impacted Jupiter in a string of chunks.
So, here’s the original story, as of 5 hours ago. No changes from what we watched on the news last night. The size was reported as being half a football field (about 150 ft).
Here’s another story, picked up by Yahoo, as of 3 hours ago, covering the arrival and impact as caught from several different camera angles. They say it was about the size of a bus.
Here’s a third story, created by Associated Press, as of 30 minutes ago.
I suspect the asteroid that was reported last night was actually a clump of two or more, which separated by Earth’s gravitation gradient as the clump approached Earth. This could have been as far away as several times the distance between here and the Moon. The larger one was picked up on video and tracked, and , while the smaller one escaped notice and hit the Earth.
Meanwhile, here’s NASA’s live-stream tracker, which has already been updated to note the Russian explosion.