The Brown Daily Herald
Thirty-seven years ago, Apollo 15 brought back 170 pounds of surface material from its lunar mission. But recently a Brown professor found something unexpected in the samples - water.
In a presentation to the 38th Lunar and Planetary Science Conference earlier this month, Assistant Professor of Geological Sciences Alberto Saal announced his discovery of trace amounts of water - about 30 parts per million - in a sample of basalt recovered by the 1971 Apollo 15 mission.
To date, no one had found any conclusive evidence of water in the samples.
"They thought it was stupid," Saal said of his proposal to reexamine the basalt. "It took me three years to get it funded."
Saal said the advantage he had over previous examiners was a technique created by Erik Hauri, a researcher at the Carnegie Institution for Science's Department of Terrestrial Magnetism. The new technique allowed Saal to achieve a level of precision that was not possible for previous researchers.
Saal said that with the older technology, it had been difficult to differentiate the planetary component of the sample from terrestrial contamination. But with Hauri's new method, Saal was able to examine the basalt with as much as two orders of magnitude more precision.
The basalt isn't exactly dripping with water, but the discovery provides support for one theory on how the moon came to exist.
"In some sense, it's expected," said Ian Dell'Antonio, associate professor of physics. He explained that the water, based on beads of glass brought from the moon's core to its surface by volcanic eruptions, helps to explain the creation of the moon by providing evidence on the composition of its core. He said the discovery verifies the common theory that the moon was created more than 4 billion years ago when an object the size of Mars impacted the Earth.
Dell'Antonio added that, while this verifies one theory about the existence of water on the moon, it does very little for another, more controversial theory that postulates impacting meteroids posited water in the form of ice on the surface of the moon after its creation.
According to NASA's National Space Science Data Center, it is in this second type of water - surface ice embedded in craters situated at the moon's north and south poles - that future exploration would look for.
"Deposits of ice on the Moon would have many practical aspects for future manned lunar exploration," the Web site states, citing the ice as a possible source of water and oxygen for future explorers.
After attempts by the Clementine probe in 1994 and the Lunar Prospector in 1998 to discover such surface ice on the moon, NASA plan to launch another craft, the Lunar Reconnaissance Orbiter, equipped with new technology, to continue the search in October.
