Infrasonic detection of a near-Earth object impact over Indonesia on 8 October 2009


Chronological Encyclopedia of Discoveries in Space cover

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From a paper published on Saturday in Geophysical Research Letters, scientists describe the after the fact detection of the impact of a near-Earth object about 6 to 10 yards in diameter over Indonesia in 2009. From the abstract:

We present analysis of infrasonic signals produced by a large Earth-impacting fireball, believed to be among the most energetic instrumentally recorded during the last century that occurred on 8 October, 2009 over Indonesia. This extraordinary event, detected by 17 infrasonic stations of the global International Monitoring Network, generated stratospherically ducted infrasound returns at distances up to 17 500 km, the greatest range at which infrasound from a fireball has been detected since the 1908 Tunguska explosion. From these infrasonic records, we find the total source energy for this bolide as 8–67 kilotons of TNT equivalent explosive yield, with the favored best estimate near ∼50 kt. Global impact events of such energy are expected only once per decade and study of their impact effects can provide insight into the impactor threshold levels for ground damage and climate perturbations.

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