At about 11:00 a.m. local time (300 Universal Time, UT) on October 8, 2009, people around the town of Bone, in the province of South Sulawesi, island of Sulewesi, in Indonesia saw a very bright fireball in the late morning sky.
Experts now say it was a meteor hitting the atmosphere of Earth, and exploding with the energy of approximately 40,000 to 50,000 tons (40 to 50 kilotons) of TNT.
According to a Sky and Telescope article, the blast was “… about three times the energy of the nuclear bomb dropped on Hiroshima in 1945.” [Sky and Telescope (10/25/09): “Cosmic Blast Rattles Indonesia”]
In the October 23, 2009 NASA/JPL Near Earth Object (NEO) Program article “Asteroid Impactor Reported over Indonesia,” it states that “… energy of about 50 kilotons (the equivalent of 100,000 pounds of TNT explosives) occurred.”
A video taken by an amateur photographer, along with commentary by a TV station, appears on the YouTube website “Benda Mirip Meteor Jatuh di Bone, Sulawesi Utara -- MAPer1ck9 Files”
The analysis of the event, by Elizabeth Silber and Peter Brown, both of the Meteor Infrasound Group, Department of Physics and Astronomy, University of Western Ontario (London, Ontario), state that the explosion was registered at low-frequency atmospheric waves on instruments at several very-long wavelength infrasound stations.
The stations are are maintained by the Comprehensive Nuclear-Test Ban Treaty Organization (CTBTO).
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The location of the meteor explosion was centered at 4.5 degrees South latitude, 120 degrees East longitude. The object was probably about 20 to 30 feet (5 to 10 meters) in length.
According to the Sky and Telescope article, “… this was the most powerful meteoric blast since 1994, when a "mini-Tunguska," nearly as bright as the Sun, exploded over the tiny Pacific island of Kosrae.”
The meteor explosion is not an unusual or rare event on Earth. Silber and Brown state that such explosions occur about once every two to twelve years.
NASA's NEO office states, "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."
The report released by Silber and Brown on October 19, 2009, appears at the bottom of the NASA/JPL website earlier referenced. It is titled “Summary of Preliminary Infrasonic Analysis of the Oct 8, 2009 Indonesian Superbolide.”