Moon craters reveal history of 4-bln yr old asteroid bombardment in solar system

March 14th, 2009 - 12:34 pm ICT by ANI  

London, March 14 (ANI): A scientist is analyzing the age of craters found on the Moon in the 1990s to find out if they are the same age as the others, which would support the idea that asteroids bombarded the inner solar system about 4 billion years ago.

Most surveys of lunar impact craters have used photos, but Herbert Frey of NASAs Goddard Space Flight Center in Greenbelt, Maryland, wanted to know if there were any old craters buried beneath younger ones.

So, he studied elevation mapping data from the Clementine mission in the 1990s.

He also used simulations to identify impact signatures, such as a roughly circular crater with a thin crust and a thicker rim.

This approach uncovered 150 craters more than 300 kilometres wide instead of 45.

Frey is now trying to work out the age of the newly found craters. If they are the same age as the others, this would support the idea that asteroids bombarded the inner solar system for a particularly intense period about 4 billion years ago.

Some researchers think that life may have existed before this bombardment, but if so, its survival now seems less likely, said Andrew Valley of the University of Wisconsin, Madison.

The probability that early primitive life, if it existed, could find refuge, even in sediments beneath the ocean would be reduced, he added.

Other researchers, however, disagree, arguing that life could have survived the barrage of impacts deep underground.

Frey, who will present the work at the Lunar and Planetary Science Conference in Woodlands, Texas, later this month, expects more subtle features to be discovered when the Asian lunar probes release further data and NASAs Lunar Reconnaissance Orbiter launches in May. (ANI)

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