2004 vd17

[Boddie]

An asteroid that threatens to pass perilously close to the Earth has been upgraded in the threat it poses by scientists monitoring it.

The space rock, 2004 VD17, measuring in at about 500 metres in length, has a mass of nearly one billion tonnes, according to reports on the ABC News Web site.

Any collision with Earth would release more than 10,000 megatonnes of energy - In context this is comparable to all the world's combined nuclear arsenals, according to a report by NASA near-Earth object (NEO) expert Dr David Morrison.

The asteroid was first spotted in November 2004 and identified as a "potential threat", with odds of a collision initially estimated at one in 3,000. Those odds have now been shortened to less than one in 1,000 following further observations, ABC report.

"The risk of an impact within the next century - specifically on May 4, 2102 - is higher than that of any other known asteroid," said Dr Morrison.

"Fortunately, it is nearly a century before the 2102 possible hazard from NEA 2004 VD17. This should provide ample time to refine the orbit and, most probably, determine that the asteroid will miss the Earth."

The asteroid has been upgraded to yellow on the Torino impact risk scale for near-earth objects, meaning it warrants attention, ABC report.

There are two more grades beyond this - orange for a close encounter, and red for a certain collision.

[SteveA]

Hey Boddie, it's easier to provide a link to the story rather than rewriting it.

A background paragraph to introduce the story is fine but I'd rather see what related stories and facts there are on, or linked from, the originating page; like where ABC got their story from, for instance.

Could you post the URL please?