Meteorites `may have kick-started life on Earth`
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Last Updated: Thursday, March 11, 2010, 16:33
  
London: Life on Earth may have been kick- started by meteorites which bombarded our planet four billion years ago, a new study has suggested.

Previously planetary scientists thought that nothing could have survived the "heavy bombardment".

But, now a team at Aberdeen University has claimed that microbes -- the primitive forms of life -- survived the massive barrage of impacts by taking refuge deep underground -- and actually thrived on the temperatures generated.

For their study, the researchers analysed a mineral called pyrite, in a crater on Devon Island, a wilderness in the Canadian High Arctic, which were deposited by a type of microbe which likes heat and is also capable of withstanding temperatures close to boiling point.

According to them, hyperthermophiles had colonised all of the Haughton Crater - over 12 miles across and at least 200 metres below the Earth's surface, indicating they would have been able to live deep underground in the darkness known as the "deep biosphere", 'The Daily Telegraph' reported.

"When the Earth was young, over four billion years ago it was repeatedly hit by large meteorites which would have shocked and melted the planet's surface. Until now scientists have imagined that primitive life would not have been able to withstand this pummelling.

"But our analysis of the mineral told us that this ancient microbe could have been able to survive meteorite bombardment through a combination of living underground and reinvading the surface rock while it was still very hot.

"So the asteroid bombardment may well have led to the primitive lifeforms flourishing rather than wiping them out.

"Our findings add to a growing body of evidence that there is much life on our planet that lives deep below out of sight and that this is where early life on Earth may have started.

"Similar meteorite craters with similar minerals occur on Mars, and this work highlights an approach that could help us look for evidence of life there," Prof Parnell, who led the team, wrote in the 'Geology' journal.

PTI


First Published: Thursday, March 11, 2010, 16:33


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