A 20 million ton asteroid is currently hurtling through space at 23,000 miles per hour, on a collision course with Earth.

"When Paul Chodas and Steve Chesley arrived at Nasa’s Jet Propulsion Laboratory, in a valley beneath the slopes of California’s San Gabriel Mountains, on October 6 2008, they assumed it would be a normal day. But it would prove to be anything but. The scientists worked for the space administration’s Near Earth Object (NEO) programme, a team tasked with identifying comets, asteroids and meteors that potentially pose a threat to Earth. A normal day meant scanning their screens for small white dots in our solar system — the vast majority of which were either too far away to ever be a problem or so small they would burn up in our atmosphere long before they could ever do any serious damage. On that Monday morning, however, Chodas noticed an asteroid about the size of a truck beyond the moon’s orbit. It was on a collision course with Earth."

  By Alex Hannaford / Telegraph / more