"Since time immemorial, humanity has looked up and wondered what made the man in the Moon," Maria Zuber, GRAIL principal investigator from the Massachusetts Institute of Technology in Cambridge, said.
"We know the dark splotches are large, lava-filled, impact basins that were created by asteroid impacts about four billion years ago. GRAIL data indicate that both the near side and the far side of the Moon were bombarded by similarly large impactors, but they reacted to them much differently," she said.
Understanding lunar impact basins has been hampered by the simple fact that there is a lack of consensus on their size. Most of the largest impact basins on the near side of the Moon (the Moon's face) have been filled with lava flows, which hide important clues about the shape of the land that could be used for determining their dimensions.
The GRAIL mission measured the internal structure of the Moon in unprecedented detail for nine months in 2012. With the data, GRAIL scientists have redefined the sizes of massive impact basins on the Moon.
Maps of crustal thickness generated by GRAIL revealed more large impact basins on the near-side hemisphere of the Moon than on the far side.
The new GRAIL research is also helping redefine the concept of the late heavy bombardment, a proposed spike in the rate of crater creation by impacts about 4 billion years ago.
The findings are published in the journal Science.
--ANI (Posted on 08-11-2013)