Water on moon originated from comets: Study

Researchers at the University of Tennessee have suggested that lunar water may have originated from comets smashing into the moon soon after it formed.

Larry Taylor, a distinguished professor in the department of earth and planetary sciences, was the one last year to discover trace amounts of water on the moon.

This discovery debunked beliefs held since the return of the first Apollo rocks that the moon was bone-dry.

Taylor and his fellow researchers conducted their study by analyzing rocks brought back from the Apollo mission.

Using secondary ion mass spectrometry, the researchers measured the samples' 'water signatures', which tell the possible origin of the water-and made the surprising discovery that the water on the Earth and moon are different.

"This discovery forces us to go back to square one on the whole formation of the Earth and moon. Before our research, we thought the Earth and moon had the same volatiles after the Giant Impact, just at greatly different quantities. Our work brings to light another component in the formation that we had not anticipated-comets," said Taylor.

Scientists believe the moon formed by a giant impact of the nascent Earth with a Mars-sized object called Theia, which caused a great explosion throwing materials outward to aggregate and create the moon.

Taylor's article theorises that at this time, there was a great flux of comets, or "dirty icebergs," hitting both the Earth and moon systems. The Earth already having lots of water and other volatiles did not change much. However, the moon, being bone-dry, acquired much of its water supply from these comets.

Taylor's research has shown that water has been present throughout all of the moon's history-some water being supplied externally by solar winds and post-formation comets and the other internally during the moon's original formation.

To be precise, the lunar water he has found does not consist of "water"- the molecule H2O-as we know it on Earth. Rather, it contains the ingredients for water-hydrogen and oxygen-that when the rocks are heated up, will be liberated to create water.

The findings were reported in the journal Nature Geoscience.