(meteorobs) News of recent Indonesian asteroid strike

Thomas Ashcraft ashcraft at heliotown.com
Tue Oct 27 23:00:16 EDT 2009



http://neo.jpl.nasa.gov/news/news165.html

::


 From the Telegraph (UK):

 

http://www.telegraph.co.uk/science/space/6444895/Asteroid-explosion-over-Indonesia-raises-fears-about-Earths-defences.html

 


  *Asteroid explosion over Indonesia raises fears about Earth's defences*


    *An asteroid that exploded in the Earth's atmosphere with the energy
    of three Hiroshima bombs this month has reignited fears about our
    planet's defences against space impacts.*

By Tom Chivers
Published: 10:23AM GMT 27 Oct 2009

 

On 8 October, the rock crashed into the atmosphere above South Sulawesi, 
Indonesia <http://www.telegraph.co.uk/news/worldnews/asia/indonesia>. 
The blast was heard by monitoring stations 10,000 miles away, according 
to a report by scientists at the University of Western Ontario 
<http://neo.jpl.nasa.gov/news/news165.html>.
Scientists are concerned that it was not spotted by any telescopes, and 
that had it been larger it could have caused a disaster.
The asteroid <http://www.telegraph.co.uk/science/space>, estimated to 
have been around 10 metres (30ft) across, hit the atmosphere at an 
estimated 45,000mph. The sudden deceleration caused it to heat up 
rapidly and explode with the force of 50,000 tons of TNT.
Luckily, due to the height of the explosion -- estimated at between 15 
and 20 km (nine to 12 miles) above sea level -- no damage was caused on 
the ground.
However, if the object had been slightly larger -- 20 to 30 metres (60 
to 90ft) across -- it could easily have caused extensive damage and loss 
of life, say researchers.
Very few objects smaller than 100 meters (300ft) across have been 
spotted and catalogued by astronomers.
Tim Spahr, director of the Minor Planet Center 
<http://www.cfa.harvard.edu/iau/mpc.html> in Cambridge, Massachusetts, 
warned that it was inevitable that minor asteroids would go unnoticed. 
He said: "If you want to find the smallest objects you have to build 
more, larger telescopes.
"A survey that finds all of the 20-metre objects will cost probably 
multiple billions of dollars."
The fireball was spotted by locals in Indonesia, and a YouTube video 
taken that day <http://www.youtube.com/watch?v=yeQBzTkJNhs> "appears to 
show a large dust cloud consistent with a bright, daylight fireball", 
according to the Ontario researchers.
An asteroid or comet fragment around 60 meters across is believed to 
have been behind the Tunguska Event 
<http://en.wikipedia.org/wiki/Tunguska_event>, a powerful explosion that 
took place over Russia in 1908. The blast has been estimated at 
equivalent to 10-15 million tons of TNT -- enough to destroy a large city.
The White House 
<http://www.telegraph.co.uk/news/worldnews/northamerica/usa/barackobama/> 
is to develop a policy on the space object impact threat by October next 
year.





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