aainkoria: Finding dangerous asteroids, before they find us

শুক্রবার, ১৪ ডিসেম্বর, ২০১২

Finding dangerous asteroids, before they find us

Marcus Chown, consultant

Science Picture Co/Science Faction/Corbis

Near-Earth Objects: Finding them before they find us by Donald Yeomans is a fascinating tour guide of the asteroids we should worry about

IN Arthur C. Clarke's 1972 novel, Rendezvous with Rama, a telescope network for detecting Earth-threatening asteroids inadvertently nets an incoming extraterrestrial vehicle. The network, created after a space rock destroys the Italian cities of Padua and Verona and sinks Venice on 9/11 2077, is called Spaceguard. In 1998, in a classic case of science imitating science fiction, NASA set up a programme to reach its Spaceguard goal of tracking 90 per cent of dangerous asteroids.

The programme's manager, Donald Yeomans, is the author of this slim but totally fascinating book about his work (incidentally, he also has his own asteroid - 2956 Yeomans). By early 2012, he says, 8800 near-Earth asteroids, or NEOs - objects that orbit the sun nearer than 1.3 times the Earth's orbital distance - had been logged.

NEOs are scientifically fascinating because they are the leftover builders' rubble from the formation of the solar system and record the conditions of their birth 4.55 billion years ago. They are also crucial to humanity because they probably delivered the water to Earth that is essential to life. In the future they may provide a critical source of minerals when we use up those down here.

But, in addition to being life-bringers, NEOs are of course potential life-destroyers. According to Yeomans, the 10 kilometre asteroid that wiped out the dinosaurs 65 million years ago had the energy of 50 million megatonnes of TNT - the equivalent of a million of the biggest H-bombs ever exploded. Some asteroids have our names on them, says Yeomans. It is crucial that we find them, before they find us.