Researchers have a new explanation for the origin of moon's crust.

Previous studies conducted on lunar rocks brought by Apollo astronauts led to the assumption that molten moon gradually cooled to form a global crust. A latest study on lunar meteorites challenges this idea. The researchers say that the crust formation of the moon was a more complex event than previously considered.

Lunaites or lunar meteorites are rocks that were ejected from the moon's surface - possibly by an asteroid impact or passing comet - and landed on Earth's surface.

Natural History Museum researchers, who conducted the present study, said that the lunar rocks present a simplistic picture of the moon's surface as they were obtained from the near side of the moon (the side that always faces the earth). Lunar meteorites found on earth are a more accurate representation of the moon as they come from the other side of the satellite.

"This very careful and detailed study of two meteorites has given clear evidence that the elegant older model of how much of the Moon's crust formed is much too simplistic," said Museum co-author Anton Kearsley.

The scientists analyzed the lunar crust preserved in the meteorites. The researchers found that there were subtle yet significant differences in the composition of lunar rocks and meteorites. The study suggests that the lunar surface is more complex than previously imagined.

"This strongly suggests that the Moon's pale crust developed by the addition of new material and the reworking of old material, over a much longer time than we used to think," said Kearsley in a news release.

The researchers say that instead of one huge magma ocean, the moon might have had a series of melting events that created similar, but not identical, materials. Also, the satellite might have had several small melting spots created by bombardments of asteroids.

The study is published in the journal Philosophical Transactions of the Royal Society A.

The origin of our closest cosmic neighbor remains a mystery. A recent study had found that Moon was formed roughly 100 million years after Solar System's birth.