News Search Search this site or the web powered by FreeFind Site search Web search Story archive		25-7-2002 Scotsman The odds and all the ends By Gethin Chamberlain Staring at their results from the Linear Observatory's automated sky survey programme in New Mexico three weeks ago, US astronomers noticed something which prompted them to put down their cups of Starbucks' finest, sit up and pay attention. Lurking among the reams of data they had spotted a small - by the standards of an infinite universe - lump of rock, barely two kilometres across. Compared with the quasars, supernovas and black holes which make the life of an astronomer so exciting, it had little to recommend it as an object worthy of another moment's thought, apart from one small detail ... it appeared to be travelling uncomfortably close to the Earth. Reaching for their computers, they did some quick calculations. The asteroid - which they christened 2002 NT7 - appeared to circle the Sun every 837 days, travelling in a tilted orbit from roughly the same distance as Mars to just within the Earth's orbit. According to the figures which the computer was churning out, there was every chance that asteroid and planet would one day meet. On 1 February 2019, the computer suggested. Probably. The astronomers considered the data and rechecked it. The results were the same. As long as they had remembered to carry all the decimal points and any number of other imponderables did not intervene to send it spinning off harmlessly into space, 2002 NT7 was going to make an awful mess. Travelling at 28km a second, it could easily wipe out a continent, alter the global climate and kill hundreds of millions of people. Far from being horrified, scientists were delighted at the news, not a response likely to be shared by those living on the continent - as yet undetermined - which would be hosting the impact. Most of those in the firing line, however, are not looking for funding for new telescopes and research projects. Astronomers are, and telescopes all over the world were quickly trained on the little rock as those with an eye for the sort of publicity a good end of the world story can generate began to mentally tot up the potential windfall. "This asteroid has now become the most threatening object in the short history of asteroid detection," says Dr Benny Peiser, an asteroid expert at Liverpool John Moore's University. "Objects of this size only hit the Earth every one or two million years. In the worst case scenario, a disaster of this size would be global in its extent, would create a meltdown of our economic and social life, and would reduce us to Dark Age conditions." If asteroids are threatening the Earth, few are faster out of the blocks than Lembit Opik, the Liberal Democrat MP for Montgomeryshire and a strong voice behind the formation of Spaceguard UK. Under Major Jay Tate, Spaceguard UK was set up to track objects in space which could collide with the Earth, and to raise awareness of how to deal with them. Spaceguard - and Opik - have long campaigned for a British-funded telescope to keep an eye out for incoming asteroids. The news from America had Opik all but rubbing his hands in glee: "I have said for years that the chances of this asteroid having an impact which could wipe out most of the human race is 100 per cent," he says. "It does sound like a science fiction story and I may sound like one of these guys who walks up and down with a sandwich board saying the end of the world is nigh, but the end is nigh." And then he made his play: "We only actually track one in every five of every object that could result in a serious global collision," he warns, ominously. "If this object hits the Earth it will probably set back civilisation by many years - there is no way of under-selling the danger." Can we survive? Of course - but we better start buying those telescopes now: "Seventeen years is not a long time to divert it, if it really is coming our way," he adds. Never underestimate the ability of a scientist or politician in search of funding for research into big glowing rocks hurtling around the solar system to come up with an impending disaster. Or scientists working in almost any field capable of generating widespread panic, come to think of it. And never, ever, underestimate the ability of people who believe everything they are told by men in white coats to be alarmed at the infinite number of ways they could meet their end. In recent years - usually during the summer months when real news is thin on the ground and scientists' thoughts turn to how to fund their next big project - there has been no shortage of stories predicting the end of the world as we know it. Comet X is going to hit the Earth a week on Tuesday; volcano Y is going to erupt "sometime soon", triggering a giant tidal wave which will sweep away everyone living anywhere short of the slopes of Mount Everest. Even plagues of giant bullfrogs have been cited as a threat to life as we know it. For those of a nervous disposition - and those who control the purse strings for funding for scientific research into subjects they don't really understand but which sound important - the crucial thing to remember is that in general, the bigger the threat, the less likely it is to happen. According to the statistics offered up by the astronomers, you are more likely to be killed by an asteroid than you are to die in a plane crash. But statistics can be adjusted to say almost anything and while people die in plane crashes almost every day, death by asteroid is a rather less familiar autopsy result. Astronomers have given the object a rating on the Palermo technical scale of threat of 0.06, making NT7 the first object to be given a positive value. NASA's Near Earth Object programme gives the asteroid a rating of one on the Torino impact hazard scale. Unless you are an astronomer, this will mean nothing to you whatsoever. What is helpful to know is that, according to Dr Donald Yeomans, of the NASA's Jet Propulsion Laboratory in California: "The error in our knowledge of where NT7 will be on 1 February, 2019, is large, several tens of millions of kilometres." So the chances are it will come nowhere near Earth. "This thing is the highest threat that has been catalogued but the scale in terms of the threat keeps changing," says Peter Bond, spokesman for the Royal Astronomical Society. "If it did hit the Earth it would cause a continental-size explosion but it is a fairly remote possibility." A remote possibility is all some scientists need. Earlier this month, US scientists suggested we all stop worrying about asteroids and start trembling at the prospect of the eruption of a super-volcano. One exists, they explained, under Yellowstone National Park. Millions could die if it explods, with shock waves flattening everything for thousands of square miles. An explosion is overdue, they suggested, although when it might arrive is not known. More research is needed to save the planet. In June, it was asteroids again. Air Force Brigadier General Simon Worden, from the US Space Command, claimed that a small asteroid could accidentally trigger a nuclear war if mistaken for a missile strike. The danger, he pointed out, was that about 30 small asteroids pierce the Earth's atmosphere every year, unleashing as much energy as the nuclear bomb dropped on Hiroshima. Such an explosion over India or Pakistan could unleash nuclear war, he reasoned. The answer, of course, was for governments to hand over cash for the scientists to build a new warning centre to gather information on asteroid explosions. Then there was CU11. There was a one in 100,000 chance of this 800m-wide space rock hitting the Earth in 2049. Then someone rechecked and decided it would miss. In January, scientists let it be known that the Earth had just survived a cosmic close shave as an asteroid hurtled past 390,000 miles away. Had the 300m-wide lump of rock arrived four hours earlier, it would have scored a direct hit, they claimed, causing global devastation. It didn't take Spaceguard UK too long to suggest that for a mere £35 million, Britain could have an improved early warning system. Last August, it was tidal waves. Scientists warned that the Cumbre Vieja volcano on La Palma could explode catastrophically, sending a large part of the Canary Islands sliding into the sea and triggering a tsunami 330ft high and travelling at more than 500mph. Death and destruction would follow, they pointed out, although when and if this disaster would occur were details which were uncertain. It would almost certainly need a lot more study in the not unpleasant surroundings of the Canary Islands. Ah, but this time, say the scientists, this is the big one. Research has shown that large asteroids do hit the Earth, with impacts once every 100,000 to every million years, depending on the size of the object. And just think what might have happened if we had missed this one. Give us money now and we'll be able to spot five times as many of these things and worry you all to death. The lump of rock which has caused the latest consternation is due to rendezvous with Earth - or miss completely - in 17 years time. Astronomers will spend the next few months closely studying asteroid 2002 NT7, which is bright enough to be tracked even by small telescopes, to decide whether it really is on an Earth-intersecting trajectory. The orbit of 2002 NT7 is recalculated once a day in three different areas across the globe to give the most accurate calculations possible. "Today calculations show a one in 60,000 chance that the asteroid will strike Earth. But with tomorrow's observations this will change" admitts Dr Alan Fitzsimmons, astronomer at Queens University Belfast and scientist for the Near Earth Objects Information Centre at the National Space Centre. For example, earlier this year the probability of asteroid 2002 CU11 hitting Earth was calculated as a one in 9,000 chance on one day, and we now know the probability of this rock hitting us in the next 100 years is zero. The trouble is that even if you know they are out there - and they certainly are - there is not an awful lot you can do about it. Joining a cult and assembling on a mountain top to watch the spectacle is always an option, but the drawback is that you do look pretty foolish sitting there in your saffron robes when night falls again and the most momentous incident of the day is that someone's trousers have fallen down in Big Brother 16. The same goes for telling your boss to stick his job and jetting off to Vegas to blow all your money on gambling and loose women - it's all very well until the end fails to arrive and you are left to hitchhike home. Build a Star Wars defence system to blow the asteroid off course with nuclear missiles? Fly out to meet it and attach booster rockets to the rock to guide it away to safety? Cover the planet in giant elastic bands to fling the offending item back into space? Some people believe the first two options at least are realistic. According to Dr Roderick Willstrop, of the Institute of Astronomy at Cambridge University, the answer may indeed sound like something out of a science-fiction movie. "The only way to deal with it is to give yourself enough time and launch rockets to stage an explosion in space which will deflect the asteroid sufficiently off course to avoid us," he said recently. The only drawback is that even with 100 telescopes combing the sky and every nuclear missile pointing at the stars, there is always the chance that something is going to get through. And when the survivors climb out of the rubble, there is bound to be at least one scientist or politician among their number with a smug grin on their face telling whoever will listen: "See - I told you so. If you had just listened to me and built that 101st telescope, this would never have happened. Probably "
		................................................................................................................. Copyright ©2004 Gethin Chamberlain. All rights reserved.