Mars rock to fetch astronomical sum

A DESERT prospector is set to become a millionaire as British scientists prepare to announce today that a meteorite found in the Sahara desert came from Mars.

The announcement will make the 2.2kg (4.8lb) rock only the 13th ever confirmed as coming from the Red Planet, out of 20,000 extra-terrestrial rocks collected worldwide. The rarity and scientific value of such finds has pushed their auction price up to roughly $1000 (pounds 620) per gram - making this one worth about pounds 1.2m.

The find will also help to fuel the debate over whether life ever arose on our nearest planetary neighbour, and provide extra impetus for a fresh space mission to it.

The Planetary Sciences Research Institute, a British team specialising in meteorite chemistry, has been examining tiny fragments taken from the 2.2kg (4.8lb) meteorite at the Open University over the past few days. "There is global scientific interest in the test results," said an Open University spokesman, who said the confirmation could help to "unlock the secrets of Martian climatic history and provide evidence of conditions capable of supporting life."

Professor Colin Pillinger, the university's expert in the field, has led the investigation, which analyses the ratios of isotopes - chemicals with the same atomic constituents but different weights - in the samples. This provides a characteristic "fingerprint" of the rock's source.

Meteorites fall to Earth from beyond the atmosphere, but can originate from any part of the solar system or even beyond it. The other Mars meteorites were knocked off that planet millions of years ago, probably by a glancing asteroid impact. They then drifted in space before being pulled to Earth by gravity.

Only by checking their isotopic composition can scientists determine where they came from.