On October 8, 2009 about 03:00 Greenwich time, an atmospheric fireball blast was observed and recorded over an island region of Indonesia.
The blast is thought to be due to the atmospheric entry of a small asteroid about 10 meters in diameter that, due to atmospheric pressure, detonated in the atmosphere with an energy of about 50 kilotons (the equivalent of 50,000 pounds of TNT explosives).
The blast was recorded visually and reported upon by local media representatives.
A report from Elizabeth Silber and Peter Brown at the University of Western Ontario indicates that several international very-long wavelength infrasound detectors recorded the blast and fixed the position near the coastal city of Bone in South Sulawesi, island of Sulewesi. They note that the blast was in the 10 to 50 kT range with the higher end of this range being more likely.
Assuming an estimated size of about 5-10 meters in diameter, we would expect a fireball event of this magnitude about once every 2 to 12 years on average. As a rule, the most common types of stony asteroids would not be expected to cause ground damage unless their diameters were about 25 meters in diameter or larger.
Don Yeomans, Paul Chodas, Steve Chesley, NASA/JPL Near-Earth Object Program Office
