Composite image of the Moon's south polar region, captured by NASA's Clementine probe over two lunar days. Permanently shadowed areas could harbour water ice. A new study suggests that a large part of this water came from comets.
Credit: NASA
PARIS: Water on the Moon came in large part from comets which bombarded the lunar surface in its infancy, a new study suggests.
For decades, the Moon was thought to have been as dry as it was void of life and atmosphere. This assumption, though, has been revisited after findings by NASA last year of significant traces of frozen water in a permanently shadowed crater.
A team of astrophysicists led by James Greenwood of Wesleyan University in Connecticut, U.S., analysed rock samples collected during the Apollo expeditions, looking in particular at variations in hydrogen isotopes in a water-loving mineral called apatite.
Frozen water reservoirs in orbit
The signature, they say, points to three potential sources: from the sub-surface lunar mantle, from protons brought by the ‘solar wind’ of particles blasted from the Sun - and from comets.
The isotope measurements in the apatite were similar to those previously found in three well-known comets: Hale-Bopp, Hyakutake and Halley.
Comets have been described as frozen reservoirs of water orbiting the Sun, for they contain vast quantities of ice in their heads.
Did comets provide Earth with its first water?
Under a ‘giant impact’ theory dating back to the 1970s, the Moon was formed from part of Earth, after our planet collided with a space rock or planet some 4.5 billion years ago.
‘Significant delivery’ of cometary water occurred after the Moon-forming event, suggests Greenwood's team.
Comets also provided Earth with some of its lavish endowment of water as well as key chemicals to kickstart life, according to some hypotheses. The paper is published online by the journal Nature Geoscience.
Moon Water
It is a bit absurd and a very interesting study, anyways, it is only a suggestion, but if these were actually true we might as well think that what if these sickness or bacteria on our planet Earth which are sometimes incurable came from comets.. Such comets even reached the smaller moon, it may also have reached us here and brought unknown bacteria!