Asteroid close call

Interesting under-reported news item from the BBC: bq. Astronomers have revealed how they came within minutes of alerting the world to a potential asteroid strike last month. bq. Some scientists believed on 13 January that a 30m object, later designated 2004 AS1, had a one-in-four chance of hitting the planet within 36 hours. bq. It could have caused local devastation and the researchers contemplated a call to President Bush before new data finally showed there was no danger. And more: bq. ...word reached the astronomical community of an asteroid that had just been discovered by the twin optical telescopes of the Linear automated sky survey in New Mexico. bq. The object was expected to grow 40-times brighter in the next day - a possible sign that it was getting closer, very rapidly. bq. But with data from just four observations available, the uncertainties were large. There were many possible orbits the object could be on, and the majority of them did not threaten the Earth. We have been hit before and will be hit again.