News in Science

Rare meteorite find in Australian outback

Scientists have discovered a rare kind of meteorite in outback Western Australia, which could hold clues about the origin of our solar system.

The findings are published in today's edition of the journal Science.

Planetary scientist Dr Philip Bland, of Imperial College London, says they tracked the meteor as it travelled through the atmosphere and then plotted where it landed on Earth.

Bland says the meteorite was found within 100 metres of the predicted site of the fall.

The meteorite, called Bunburra Rockhole, is a melted basalt, which is the size of a cricket ball, he says.

Bland says they tracked the meteor using a network of observatories across the Nullarbor Plain, which stretches across southern Australia.

The observatories are part of a trial experiment that records images of the night sky and track falling objects such as meteors.

First find

The Bunburra Rockhole was the first meteorite find for the camera network.

CSIRO Exploration and Mining scientist and co-author Dr Rob Hough, of says the search for the meteorite was helped by the fact the Nullarbor Plain is marked by white limestone rocks.

"A dark meteorite on the white surface is easier to find, however it's very tiny, so the discovery is still quite amazing," says Hough.

Bland says because they can trace the meteor's orbit, they can calculate not only where they land, but also where they came from.

He says only a handfull of meteorites found on Earth have had their orbit's traced.

According to Bland most meteors come from the asteroid belt - a region between the orbits of Mars and Jupiter.

The asteroid belt contains a mixture of rocks, ranging in size from dust-like particles through to miniature-planets, which orbit around the Sun, he says.

"It's rubble that didn't accrete into a planet."

Not from Vesta

Bland says most basalt meteorites, like the one found in the Nullarbor, originate from a large asteroid called Vesta. But the Bunburra Rockhole meteorite is different.

"Our little guy can't be from Vesta, the composition is all wrong," he says.

Bland says his colleague, Bill Bottke of the Southwest Research Institute in Colorado, developed a computer model to identify where in the asteroid belt different meteorites come from.

Bottke's model suggests that when the solar system was forming the objects in the inner region of the solar system would have melted at some point. Over time, these objects slowly migrated further away from the Sun.

"But there was a lot of other stuff out there at the time and these melted objects got battered around," says Bland, with only the survivors of this battering making it into the asteroid belt.

Bottke's model predicts that these survivors should be in the inner-most part of the asteroid belt, he says.

"That's exactly where our little guy comes from."

Bland says the find is really exciting because it gives clues about the early solar system.

The researchers are currently analysing the meteorite to more accurately detemine its age.

Bland believes the meteorite might also provide additional clues on how the inner planets formed.

"There might be other processes that went into making planets like the Earth, Mars and Venus," he says.