Space is a dirty place. There’s all sorts of interstellar junk flying around at breakneck speed. In our solar system Jupiter, the largest planet with the strongest gravity, gets hit most often.
Still, in terms relative to the age of our planet, the Earth gets hit all the time. Just the random dust and specks burning out in the upper reaches of our atmosphere add a few hundred million pounds of additional mass to Earth every day!
Sometimes the incoming rocks are large.
We don’t see much evidence because water and weather gradually heal our wounds. The pock marked surface of the atmosphere free Moon gives a more realistic impression of what really happens.
I mention this because a reasonably significant rock came pretty close to hitting the Earth a few weeks ago. I’m only hearing about it now–and I’m usually pretty up on these things.
Here’s NASA’s dispassionate reporting:
The Jakarta Globe said the explosion was loud enough that, “Locals at first thought it was an earthquake and ran out of their homes in panic.”
Well, yeah. A hundred thousand pounds of TNT would make quite a rumble.
No one saw this bad boy coming. Not NASA. Not the Air Force. Surprise! It was the size of a small house and we had no warning at all.
What little we do know of this incident comes because we monitor atmospheric noise while searching for nuclear tests. Again, it’s a surprise to me, but there is a network of “infrasound stations” associated with the Comprehensive Nuclear-Test-Ban Treaty Organization and they pinned it down.
In writing about this incident NASA scientists mention “an average impact velocity for NEAs of 20.3 km/s.” In other words, near Earth asteroids hit the Earth’s atmosphere at around 45,000 mph! That’s New York to Los Angeles in under four minutes!
Bottom line, those scary movies where asteroids plunge to Earth causing death and destruction… maybe they’re more science and less fiction than we think.