Large space rock flies past Earth

12 January BBC

A 300 metre-wide asteroid is making a close pass to the Earth.Apophis named after the Egyptian demon of destruction and darkness has been put on a watch list by scientists.They have calculated that in 2036 there is a very small chance it could collide with our planet.

However, its current fly-by is at a safe distance of about 14 million km but this is close enough for astronomers to study the space rock and assess its future risk.Apophis will not be visible with the naked eye, but space enthusiasts can watch it online via the Slooh space camera's website.

The large rocky mass was first discovered in 2004. At the time, it raised alarm when scientists calculated that it had a one in 45,000 chance of smashing into the Earth in 2029.Later revisions, lifted this threat; instead on the Friday 13 April 2029, it will make a close pass at a distance of about 30,000km.

However, astronomers say there is still a one in 200,000 chance that it could strike Earth in 2036.Professor Alan Fitzsimmons, an astronomer at Queen's University Belfast, UK, said: "In 2029, it will pass so close to us that Earth's gravity will change its orbit.Most of the potential orbits it will end up on will mean we are safe for the next 100 years.

But there is a small region of space - something we call a keyhole and if it passes through that keyhole in 2029, it will come back and hit us on 13 April in 2036.If this happened, it would strike the Earth with 100 times the energy in our largest nuclear bombs, said Prof Fitzsimmons.