AS GOVERNMENTS around the world prepare to spend millions studying the threat
of nearby asteroids hitting the Earth, an astronomer in Northern Ireland is
warning that comets might pose a greater danger. “We may be looking for a swarm
of bees while standing on a railway line with the train coming,” says Bill
Napier of the Armagh Observatory.
Icy comets with their tails of gas and dust are much rarer than rocky
asteroids, but they don’t even have to hit the Earth to do damage. A giant comet
evaporating under the Sun’s glare would release billions of tonnes of dust…
