Was Siberian meteor blast a warning of things to come?
Feb 15, 2013 | Richard A. Kerr | ScienceNow
The 10-meter-diameter chunk of rock that exploded over western Siberia
yesterday had nothing to do with the 45-meter asteroid whizzing close by
Earth today, scientists say. But it does provide a more dramatic
reminder of the incessant rain of cosmic debris that the planet endures.
Such a meteoric detonation tens of kilometers high
happens on average every 10 years or so. This one just happened to
strike over a populated area, injuring several hundred people, mostly by
sending window glass flying. That pales beside the destruction wreaked
by the detonation of a 40-meter asteroid over an unpopulated part of
Siberia in 1908; that so-called Tunguska event leveled 2000 square kilometers of forest.
The object's energy - it was traveling at thousands of kilometers per
hour - was released in an explosion when it shattered and atmospheric
friction burned up the bits in a moment. Airbursts of Tunguska size
probably happen every 1200 years on average somewhere on a mostly empty
Earth. One of these days, a bigger bit of cosmic debris will make it to
the ground intact.
No comments:
Post a Comment