Chelyabinsk-Sized Asteroid Impacts May Be More Common Than We Thought

The Bad Astronomer writes "Using data from the Feb. 15, 2013 asteroid impact over Russia, scientists have determined that we may be hit by objects in this size range (10 — 50 meters across) more often than we previously thought, something like once every 20 years (abstract). They also found the Chelyabinsk asteroid was likely a single rock about 19 meters (60 feet) across, had a mass of 12,000 tons, and was criss-crossed with internal fractures which aided in its breakup as it rammed through the Earth's atmosphere."

Comments

Friction versus increasing pressure

[mc6809e]

It's nice to see that the author didn't buy into the myth that it's friction which causes the increase in temperature as a fast moving body move through the atmosphere.

"As this main mass plummeted through our atmosphere at a speed of 20 kilometers per second â" dozens of times faster than a rifle bullet â" the huge pressure it generated compressed the air in front of it, heating it up."

That kind of journalistic competency it worth noting.

Re:Friction versus increasing pressure

[Charliemopps]

Well the reason there is a pressure wave in front of the asteroid at all is due to friction. If it were frictionless it would simply pass through the atmosphere without disturbing it. This is more semantics with the english language than making any scientific point.