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Asteroids pose war risk
04/10/2002 08:23 - (SA)
Washington - Asteroids regularly explode over the Earth with the intensity of a nuclear bomb and there is a chance the explosions could be mistaken for a nuclear attack, possibly triggering an atomic war, an Air Force general said on Thursday.
At least 30 times a year, a space rock slashes into the atmosphere and explodes, releasing energy
equal to that of an atomic bomb, Air Force general Simon P.
Worden told members of a House Science subcommittee.
Worden, deputy director for operations of the US Strategic
Command, said the United States has satellite instruments that
determine within a minute if the explosion is a nuclear weapon or a natural explosion from an asteroid.
But no one else has such technology, he said, and without it,
some countries could conclude the explosions came from a nuclear
bomb and could launch an atomic attack against an enemy.
For instance, Worden said Pakistan and India, both of which have
the atomic bomb, were at full alert in August, poised for war.
Not far away, a few weeks before, Worden said, US satellites
detected over the Mediterranean an atmospheric flash that indicated "an energy release comparable to the Hiroshima burst". Air Force instruments quickly determined it was caused by an asteroid 4.5 metres to nine metres wide.
"Had you been situated on a vessel directly underneath, the
intensely bright flash would have been followed by a shock wave
that would have rattled the entire ship, and possibly caused minor damage," Worden said in his testimony.
The explosion received little or no notice, the general said,
but it possibly could have caused a major human conflict had it
occurred over India or Pakistan while those countries were on high alert.
"The resulting panic in the nuclear-armed and hair-triggered
opposing forces could have been the spark that ignited a nuclear
horror we have avoided for over a half-century," he said.
Worden said the Air Force's early warning satellites in 1996
detected an asteroid burst over Greenland that released energy
equal to about 100 000 tons of explosives. He said similar events
are thought to have occurred in 1908 over Siberia, in the 1940s
over Central Asia and over the Amazon basin in the 1930s.
"Had any of these struck over a populated area, thousands and perhaps hundreds of thousands might have perished," he said.
Detecting asteroid bursts
Worden said the current generation of early warning satellites
do a good job of detecting asteroid bursts in the atmosphere and
that new equipment will be even better. He said the Air Force is
working on an asteroid alert programme that would quickly send
information from the satellites to interested nations.
He said the Air Force is studying the establishment of what he
called a Natural Impact Warning Clearinghouse that would be part of the North American Aerospace Defence Command communications centre in Cheyenne Mountain near Colorado Springs.
Nasa is in the midst of a 10-year programme to find and assess of
every asteroid one kilometre or more in size that could pass close to the Earth and might pose a danger to the planet.
Such asteroids or comets are called near earth objects. If an
asteroid one kilometre in size struck the planet it could wipe out whole countries. An asteroid one mile across could snuff out
civilisations, while one that is three miles across could cause human extinction, experts say.
Edward Weiler, head of Nasa's office of space science, told the House committee that his agency has detected 619 near earth objects and is finding about 100 new ones each year. None poses a danger to the Earth.
One kilometre asteroids are relatively rare, but Worden and
others said that smaller asteroids also can be destructive. For
instance, if an asteroid the size of a cruise ship smashed into the ocean it could cause huge waves, called tsunamis, capable of
drowning coastal cities on two continents.
Worden called for a system of instruments and telescopes on land
and in space that could scan the sky to find asteroids down to the size of 90 metres. He said telescopes and instruments weighing less than 67.5 kilograms could easily be launched to establish an observing network. - Sapa/AP
- SAPA
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