Chelyabinsk-Sized Asteroid Impacts May Be More Common Than We Thought 50
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."
Re:quite dense (Score:3, Interesting)
I have a small piece of Chelyabinsk in my meteorite collection, It's a stony, not an iron, although it does have enough iron-nickel chondrules in it to be attracted by a magnet.
Yeah, density of about 3.4 gm/cm^3 is about right. (My piece, at just over 10gms, is about 3 cc.)
A 60-foot diameter iron is about what carved out the mile-wide Barringer (aka Meteor) Crater in Arizona. Irons tend not to airburst, or if they do, do it lower down in the atmosphere. It may also have been travelling faster.