The Bone airburst, 2009
A daytime blast over a populated area that many took for a plane crash.
Key facts
- When
- 8 October 2009, late morning local time
- Where
- Over Bone, South Sulawesi, Indonesia
- What hit
- about 10 m across
- Era
- The sensor age, 2000 onwards
- Location
- 4.50° S, 120.00° E
Roughly 30 to 50 kilotons of TNT, released about 20 to 25 km up.
Two to three Hiroshima bombs.
What happened
On the morning of 8 October 2009 people near the town of Watampone in South Sulawesi heard a tremendous explosion and saw a smoke trail in the sky. Some thought a plane had crashed, others that it was an earthquake.
Infrasound stations around the Pacific recorded the blast, and analysis showed it was a small asteroid, perhaps 10 m across, exploding high in the atmosphere. At about 30 to 50 kilotons it was one of the most powerful airbursts recorded in the first decade of this century.
Videos made by residents showed the trail breaking up into twisted shapes.
Effects
The explosion was loud enough to frighten people, but no serious damage was reported, because the energy was released so high.
The evidence
Infrasound from many stations, satellite data and residents' videos and accounts. No meteorites are known.
Did you know?
Without the worldwide infrasound network, this event might have been dismissed as an unexplained boom.
The asteroid is thought to have been travelling at about 20 km per second.
Related pages
How is impact energy measured? See energy explained, or try the impact calculator.