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BRITAIN PLANS £25m SHIELD TO PREVENT ASTEROID COLLISIONS
From The Sunday Times, 17 September 2000
http://www.sunday-times.co.uk
By Jonathan Leake, Science Editor
A GOVERNMENT team is to propose spending up to £25m on a plan
that would
safeguard Britain and the world from devastation by a giant
asteroid or
comet.
The Spaceguard initiative, expected to be announced tomorrow by
Lord
Sainsbury of Turville, the science minister, could see Britain
using a
chain of telescopes to detect and monitor "near-Earth
objects".
A report, from a commission appointed by Sainsbury, says that
Earth
faces a tiny but definite risk of being struck one day by an
asteroid -
a large lump of stone or metals travelling at tens of miles a
second.
This kind of impact is believed to have wiped out the dinosaurs
65m
years ago.
A monitoring station, possibly based at Armagh in Northern
Ireland and
linked to telescopes around the world, would be the first stage
in a
programme that would also investigate ways of knocking any
approaching
asteroid off a collision course with Earth.
One option could be to fire a nuclear missile that would explode
close
to the incoming rock and deflect it.
At least two big impacts were recorded during the last century
alone.
The first, at Tunguska in Siberia in 1908, devastated an area the
size
of greater London. The other, in Brazil in 1947, left several
huge
craters. Both fell in unpopulated areas and nobody was killed.
Last week astronomers announced that a huge asteroid would cross
Earth's
orbit today at a range of 2.6m miles. In astronomical terms this
is a
tiny distance - and others will come much closer.
In 2027, a rock measuring half a mile in diameter, travelling at
50
miles per second and known as 1999 AN10, will hurtle past Earth
at a
distance of just 200,000 miles. It will pass close by several
more times
- with nobody yet able to predict whether it will hit the planet.
The British commission includes Professor Harry Atkinson, who has
worked
for the European Space Agency and other international bodies, and
Sir
Crispin Tickell, the former British ambassador to the United
Nations. It
was set up in January.
The threat is already taken seriously by America and Japan, which
have
established their own Spaceguard projects. Nasa has said it plans
by
2006 to track all asteroids with diameters greater than 1km that
will
cross the path of Earth.
An asteroid that size would wipe out most life and there would
have been
many such events early in Earth's 4.6 billion-year history. Now,
however, the risk is much lower because most potential collisions
have
already happened. The last big asteroid, about six miles in
diameter,
was the one that wiped out the dinosaurs.
The commission's report says Britain's role could be to find
smaller
objects, between 50 yards and about half a mile in diameter, of
which
there are many thousands.
Up to six telescopes would have to be built - some designed to
detect
near-Earth objects, others to track them continually and a third
group
to analyse the light they reflect in order to find out what they
are
made of.
The aim of Spaceguard would be to ensure that Earth had
sufficient
advance warning - hopefully decades - to investigate and then
take
preventive action.
A Whitehall source said: "We accept there is a risk and want
Britain to
take a leading role in dealing with it."
Sainsbury wants other European countries to help finance the
network,
which would be computerised and would enable astronomers to build
up a
huge database from which they could predict which objects
presented a
threat.
Mark Bailey, director of the Armagh Observatory, a world-renowned
centre
for the study of asteroids and comets, where the project would
probably
be based, believes the world is now so heavily populated that
even a
small impact could kill millions. "Asteroid and comet
impacts have
changed human history in the past and it could happen
again," he said.
The biggest risk to Earth is from comets that appear at random
from the
Oort Cloud - a huge sphere of icy rubble that surrounds the solar
system. They move very fast and could reach Earth within months
of being
spotted.
Dr Bill Napier, an astronomer who specialises in comets and
asteroids,
believes the only solution is to set up a fleet of rockets
carrying
nuclear bombs that could be detonated half a mile from any
threatening
object.
"You would only have to nudge them a few metres to send them
safely past
Earth to avoid Armageddon," he said.
Copyright 2000, Times Newspapers Ltd.
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