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TARGET EARTH! The bad news - a huge asteroid is heading for us at 75,000mph

Posted on: Thursday, 4 September 2003, 06:00 CDT

NOW is probably not the time to be planning your wardrobe for March 21, 2014, but you might consider wearing a hard hat or possibly carrying a large airbag.

Because that is the date scientists have earmarked for Armageddon - or at least for the possibility of an asteroid striking the Earth.

The giant rock in question - with the less-than-catchy name of Asteroid 2003 QQ47 - was first spotted millions of miles out in space by scientists in Socorro, New Mexico, on August 24. It will be visible from Earth by telescope for the next two months.

It measures a whopping threequarters of a mile in diameter (4,000ft), has a mass of 2,600 million tons (the equivalent of 8,000 Empire State Buildings) and is travelling at a speed of 75,000mph.

And if it hits the Earth it would do so with 350,000 megatons of energy - that's the same explosive force as the simultaneous detonation of 23 million Hiroshima bombs - leaving a crater 12 to 18 miles wide.

Hardly surprisingly, the impact would be great enough to destroy virtually an entire continent, or, if it lands in water, to trigger a giant tidal wave.

Scientists say the initial impact would be localised but the knock- on effects would be global. The Earth would be plunged into a nuclear winter and humanity blasted to the verge of extinction.

A spokesman for the Near Earth Objects (NEO) Information Centre in Leicester, which is monitoring the progress of the asteroid, said yesterday: 'So much dust and matter would be thrown up that the whole world climate would be affected. All sorts of gases would be trapped in the atmosphere, and sunlight would be blocked out, causing crops to fail across the globe.' BUT BEFORE you start booking a one-way ticket to Mars, it is worth noting that the asteroid is a safe 46.6 million miles away - half as far away as the Sun.

Oh yes, and the probability of it hitting Earth is one in 909,000.

Kevin Yates, project manager of the NEO Information Centre, says: 'Objects of about half a mile wide hit Earth at a rate of one every few hundred thousand years, but as more observations are made over the coming months and the uncertainties about it decrease, Asteroid 2003 QQ47 is likely to drop down the risk scale.' It looks like a lucky escape this time, but what exactly do we know about asteroids - and what are the chances of a direct hit in the future?

Asteroids are chunks of rock left over from the formation of the solar system around 4.5 billion years ago. Most remain a safe distance from Earth in the asteroid belt between the orbits of Mars and Jupiter.

However, the force of collisions between them and the gravitational pull of Jupiter can nudge the asteroids out of these safe orbits and send them into the Earth's orbit.

The Government set up the NEO Information Centre at the National Space Centre in Leicester almost two years ago to monitor the hundreds of potentially hazardous objects in space and analyse the probability of a direct hit by any of them. So we can spot trouble - but then what?

In the Bruce Willis blockbuster Armageddon, nuclear missiles were launched to blow apart an asteroid hurtling disastrously close to Earth.

In real life such a solution would be unlikely because it would mean producing a nuclear weapon so large that, if anything went wrong, it could destroy the entire Earth.

Also, experts fear the explosion would simply result in a proliferation of thousands of smaller asteroids tumbling to Earth.

A more plausible option, according to scientists, would be to send a spacecraft into the atmosphere to paint an area of the asteroid white, using special paint. The power of the Sun reflecting off the painted area would, in theory, create enough energy to force the asteroid away from the Earth's orbit.

The other most commonly considered option is to send a satellite into space to attach a 'solar sail' to the asteroid. The sail would capture photons (particles of radiation) to drive it just as a conventional sail on a boat is driven by the wind.

Nasa scientists are considering another proposal, by Professor Hermann Burchard of Oklahoma State University, to deploy giant airbags - yes, seriously - to nudge a perilous asteroid off course. The devices, carried on spacecraft, could be inflated with gas next to an asteroid as it hurtles towards us and would be used to steer it off course.

It's far from convincing and, of course, any such mission would take at least a decade to plan, and would be highly risky.

Some scientists believe the ancient Egyptians had their own method of protection from asteroids. Professor Chandra Wickramasinghe, from the Centre of Astrobiology at Cardiff University, claims the Egyptians may have designed the pyramids as shelters for the leaders against cosmic showers of objects.

An interesting theory which, of course, cannot be proven, but what we do know is that asteroid attacks are nothing new.

The oldest known asteroid struck South Africa 2,000 million years ago, leaving a 190-mile scar at the Vredefort Dome, southwest of Johannesburg.

More recently, about 250 million years ago, an asteroid collided with Australia causing an 80-mile wide crater at Wolf Creek, western Australia, and, it is believed, the extinction of whatever life there was on Earth.

Probably the most famous direct hit, however, was on the Yucatan peninsula in Mexico 65 million years ago, which caused a massive nuclear winter leading to the extinction of the dinosaurs.

That asteroid is thought to have been six miles wide, compared with Asteroid 2003 QQ47, which is 'just' three-quarters of a mile.

JUST over two million years ago, a half-mile wide asteroid caused a 300ft global tidal wave when it plunged into the South-East Pacific. At around the same time an asteroid hit Quebec in north- east Canada, and debris from that hit was recently found in a cliff face in Bristol.

Scientists believe the explosion - 40 million times more powerful than the atomic bomb dropped on Hiroshima - sent a supersonic shockwave and a cloud of whitehot marble- sized fragments of molten rock and glass sweeping across what is now Britain.

In modern times there have been a couple of worrying near misses too. In 1908 an object exploded over Siberia, at an altitude of five miles, flattening 780 square miles of forest and sparking a swathe of fires.

Then, in 1995, a 40ft object exploded in the atmosphere above New York. No damage was caused on the ground.

But if you're still worried about Asteroid 2003 QQ47, here's a comforting thought: you are more likely to be struck by lightning than become the victim of an asteroid hit. Each of us has a one in 600,000 chance of that happening.

And there's as much chance of...

SCIENTISTS estimate that Asteroid 2003 QQ47 has a 909,000-to-1 chance of colliding with Earth.

Now bookies William Hill have compiled a list of other events that, statistically, have odds of 909,000-to-1 of happening before March 21, 2014: DAVID BECKHAM to be England manager and win the World Cup, with Brooklyn scoring the winning goal and Romeo as substitute.

TOPLESS model Jordan to marry Prince Harry and become Queen.

UK temperature to hit 100F on Christmas Day.

PRINCE CHARLES to wed Camilla, renounce his right to the throne and become an MP for the Green Party.

ARNOLD Schwarzenegger to become U.S. President and introduce compulsory bodybuilding and German lessons in schools.

A MANNED expedition to Mars to discover the Loch Ness Monster there.

MICHAEL JACKSON to have a head transplant and say he should be known as Elvis.

PREVIOUS HITS

2,000m years ago South Africa: Oldest known crater on Earth, left 190-mile scar

250m years ago Australia: 80-mile crater. Thought to have caused extinction of almost all life on Earth

65m years ago Yucatan peninsula: 100-mile scar made by six-mile wide asteroid. Blast rendered dinosaurs extinct

2.15m years ago South-East Pacific: Halfmile wide asteroid caused 300ft global tidal wave

1908 Siberia, Russia: 200ft object explodes at 5-mile altitude, flattening 780 square miles of forest

1995 New York City: 40ft object explodes in atmosphere, no damage

Ideas to divert the asteroid have included using airbags or huge sails.

Another brainwave is to paint it white to use the Sun's rays to reflect off the surface and move it out of the Earth's orbit

THE IMPACT

The asteroid would crash into the Earth with the same force as 23 million Hiroshima bombs The crater would be 18 miles across, but the global effect would cause a nuclear winter and the extinction of humanity

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