Instrument on board Chandrayaan-1 finds deepest crater on moon

The US Space agency's Moon Mineralogy Mapper (M3) detected the enormous crater -- the South Pole-Aitken basin -- that was created when an asteroid smacked into moon's southern hemisphere shortly after the formation of earth's only natural satellite.

"This is the biggest and deepest crater on the moon -- an abyss that could engulf the United States from the East Coast through Texas," said lead researcher Noah Petro of NASA's Goddard Space Flight Center in Greenbelt.

According to Petro, who had presented his result on Thursday at the Lunar and Planetary Science meeting in this city in Texas, "The impact of the asteroid collison punched  into the layers of the lunar crust, scattering that material  across the moon and into space".
"The tremendous heat of the impact also melted part of the floor of the crater, turning it into a sea of molten rock," NASA said.

That was just an opening shot. Asteroid bombardment over billions of years has left the lunar surface pockmarked with craters of all sizes, and covered with solidified lava, rubble, and dust, it added.Moon Mineralogy Mapper was one of 11 instruments onboard Chandrayaan-I.

Glimpses of the original lunar surface, or crust, are rare and views into the deep crust are still rarer, NASA said.

However, it said a crater on the edge of the South Pole-Aitken (SPA) basin may provide such a view. It is called the Apollo Basin, formed by the later impact of a smaller asteroid, and still measures a respectable 300 miles across.

"We believe the central part of the Apollo Basin may expose a portion of the Moon's lower crust. If correct, this may be one of just a few places on the Moon where we have a view into the deep lunar crust, because it's not covered by volcanic material as many other such deep areas are," Petro said.

"Just as geologists can reconstruct Earth's history by analysing a cross-section of rock layers exposed by a canyon or a road cut, we can begin to understand the early lunar history by studying what's being revealed in Apollo."

Both SPA and Apollo are estimated to be among the oldest lunar craters, based on the large number of smaller craters superimposed on top of them, NASA said."The Apollo and SPA basins give us a window into the earliest history of the Moon, and the Moon gives us a window into the violent youth of Earth," said Petro.