Apophilypse Now

It's called Apophis. It's 390m wide. And it could hit Earth in 31 years time

In Egyptian myth, Apophis was the ancient spirit of evil and destruction, a demon that was determined to plunge the world into eternal darkness.A fitting name, astronomers reasoned, for a menace now hurtling towards Earth from outerspace. Scientists are monitoring the progress of a 390-metre wide asteroid discovered last year that is potentially on a collision course with the planet, and are imploring governments to decide on a strategy for dealing with it.

Nasa has estimated that an impact from Apophis, which has an outside chance of hitting the Earth in 2036, would release more than 100,000 times the energy released in the nuclear blast over Hiroshima. Thousands of square kilometres would be directly affected by the blast but the whole of the Earth would see the effects of the dust released into the atmosphere.

'Space tractor' to avert asteroid ArmageddonOnline

No need to send Bruce Willis into space with a nuclear bomb: The best way to deal with a killer asteroid hurtling towards Earth could be a 'gravity tractor'.

Two NASA astronauts, gently mocking the solution offered in the Hollywood blockbuster Armageddon have come up with a deceptively simple plan to pull asteroids off course.

Dr Edward Lu and Dr Stanley Love propose in today's issue of the journal Nature that a rocket be launched into space, effectively to act as a giant magnet.

Landing on an asteroid, which is no more than a spinning pile of rubble, is very difficult to achieve.

Instead, the gravity tractor would hover alongside the asteroid, with its thrusters pointing outwards so the exhaust does not affect the surface.

The tractor would then gradually pull the asteroid off course, using nothing more than the gravitational pull between the two bodies.

'This saves you from having to land on the asteroid and then trying to stabilise yourself on a flying pile of rock and debris which is spinning all the time,' Dr Love said.

In Armageddon, a doomsday asteroid is on a collision course with Earth and the only way to knock it off course is to drill into its surface and detonate a nuclear bomb.

Instead, the scientists calculate that, with sufficient warning, a 20-tonne gravity tractor could safely deflect an asteroid 200 metres across in about a year of towing.

I doubt the Guardian's derivation of the name. There is more than one Apophis around and about the time of an unofficial push to name 2003 UB313, the putative tenth planet and its moon Xena and Gabrielle the discoverers named the asteroid formerly known as 99942 after an Apophis, apocryphal or not.

Still, demon of the ancient world or Goauld system lord, it's a relief we won't need Bruce Willis to save us.