Paris - An instrument aboard an Indian space probe has boosted a hypothesis that the Moon generates water thanks to collisions between solar particles and lunar dust, the European Space Agency (ESA) said on Thursday.
Observations by three probes, published on September 23, showed that water exists on the Moon, a finding that swept away the satellite's stereotype as an utterly arid place.
Data sent back by a European-Indian instrument aboard India's Chandrayaan-1 probe have now bolstered a theory as to how this water is created, ESA said in a press release.
Protons spewed out by the Sun - also known as solar wind - collide with the thick, loose layers of dust, called regolith, which carpets the Moon's surface, according to the theory.
Some of the debris grains contain oxygen. The interaction of the protons with this dust produces water, as well as small hydrogen-oxygen molecules called hydroxyl.
An instrument aboard Chandrayaan-1 called SARA (Sub-keV Atom Reflecting Analyser) confirmed the absorption of protons by the regolith, ESA said.
"The Moon is a big sponge that absorbs electrically-charged particles given out by the Sun. These particles interact with the oxygen grains on the lunar surface, producing water," ESA said.
SARA found, though, that only 80 percent of the protons are absorbed by the regolith.
One in five bounces back into space, and in so doing teams up with an electron to become a hydrogen atom.
The findings will be published in a specialist journal, Planetary and Space Science.
On September 23, the US journal Science reported data from three probes - Nasa's Cassini and Deep Impact, and from Chandrayaan-1 - to aver that water particles had been found on the Moon.
Every ton of lunar soil consists of 25 percent water, according to this estimate.
The instrument aboard Chandrayaan-1 which spotted the water molecules is the Moon Mineralogy Mapper (M3), like SARA an instrument jointly built by European and Indian scientists. - AFP