Suddenly, water is becoming more common in the solar system, and perhaps the universe, than we thought. Large deposits of nearly pur water-ice have now been suggested by new images taken by Nasa’s Mars Reconnaissance Orbiter. Last week’s discovery of water in the topsoil of the Moon triggered a renewed interest in the Earth’s satellite.

Finding water on the Moon has long been called the holy grail for lunar scientists, and explorations towards this have been on for the last 40 plus years. The puzzle may have finally been cracked by Nasa and the Indian Space Research Organisation (ISRO). Instruments on board the Indian space agency’s Chandrayaan-1 spacecraft including Nasa's Moon Mineralogy Mapper (M3) and ISRO’s own Moon Impact Probe (MIP) have found signatures of water on the Moon surface.

The findings was revealed after analysis of M3 data by a joint team of scientists from US and India led by Carle Pieters, principal investigator from Brown University, USA and J N Goswami, principal scientist, Chandrayaan-1 from Physical Research Laboratory of India`s Department of Space. Pieters said, “We are not talking about lakes, oceans or even puddles. Water on the moon means molecules of water and hydroxyl that interact with molecules of rock and dust specifically in the top millimeters of the moon's surface.’’

Goswami said “we first saw traces in 3-4 places in March this year. We shared the data and Nasa got data from its Cassini spacecraft, and the spectrometer on Epoxi spacecraft to help confirm the finding.’’ The Epoxi mission flew past the moon in June 2009 on its way to a November 2010 encounter with comet Hartley 2. The observations were further strengthened by results obtained from the analysis of archived data of lunar observation in 1999 by Cassini on its way to Saturn.

The new findings, detailed in the September 25 issue of Science, come in the wake of further evidence of lunar polar water ice by Nasa’s lunar reconnaissance orbiter and just days before the planned lunar impact of Nasa’s Lcross satellite, which will hit one of the permanently shadowed craters at the moon's south pole on October 9 in hope of churning up evidence of water ice deposits.

Even Apollo astronauts may have returned with evidence of water on the moon 40 years ago when they brought back samples of lunar rocks. Trace amounts of water were detected in the rocks, but these were assumed to be contamination from the Earth because the rock containers had leaked. “The isotopes of oxygen that exist on the moon are the same as those that exist on the Earth, so it was difficult if not impossible to tell the difference,” said Larry Taylor of the University of Tennessee, Knoxville, who is a member of one of the Nasa-built instrument teams for India's Chandrayaan-1 satellite and has studied the moon since the Apollo missions.

So, why is discovery of water on moon so important? Well, for one, water supports life as we know it. Without it, we cannot conceive of a living being—from the smallest virus to the giant sequoia tree or the African bush elephant. That opens up the exciting possibility of life existing somewhere else. Second, it’s also important if man is to colonise or use the Moon as a stepping stone to other worlds.

But the discovery must be put in perspective. “Even the driest deserts on the Earth have more water than are there at the poles and surfaces of the Moon,” Nasa scientist Jim Green told the media.

The water on the Moon could have come from the impact of comets or radiation from the sun. The second, endogenic source, is thought to possibly come from the interaction of the solar wind with moon rocks and soils. The lunar rocks are about 45 per cent oxygen (combined with other elements as mostly silicate minerals). The constant stream of charged particles emitted by the sun are mostly protons, or positively charged hydrogen atoms. If these atoms hit the lunar surface with enough force, they break apart oxygen bonds in soil materials, some of which might form water, If this theory holds true, we should water on other planets of our solar system too.

So what comes next? Experts suggest that this is just an initial discovery and lot more analysis is needed to provide evidence of water. U R Rao, renowned space scientist and former ISRO chairman said, “We will have to wait for more data analysis, especially from the high energy X-ray spectrometer being studied in ISRO’s Ahmedabad centre.’’ Adds Prof Goswami, “The volume of data collected from Chandrayaan-1 is phenomenal. It may take six months to three years to analyse it.”

The discovery will also decide what new instruments are needed on board Chandrayaan-II scheduled to be launched in 2013. ISRO chairman G Madhavan Nair has indicated that the agency would look at a mid-course correction of the Chandrayaan-II mission objective because of the new find.

If water can be collected on the Moon, it will help the plans of several countries, including US and Russia, to build habitats on the Earth’s satellite. Rao says the discovery could help space-faring countries to utilise the moon as a base for deeper space exploration of the solar system, especially Mars.

Varun Dutt is knowledge editor at Financial Chronicle and a doctoral scholar at Carnegie Mellon University, PA