The lunar glasses

New Delhi, July 9: Tiny beads of lunar volcanic glasses brought by the Apollo astronauts more than 35 years ago have now yielded the first evidence of water deep in the Moon’s interior.

A team of US scientists studying the geological souvenirs from the Apollo missions has used sophisticated instruments — not available in the Apollo era — and discovered chemical residues that point to water.

“This is the first sign that the Moon’s deep mantle may hold water,” geologist Alberto Saal, a team member at Brown University, told The Telegraph. The findings will be described in the journal Nature tomorrow.

Scientists believe the Moon was created when a Mars-sized object collided with Earth about 4.5 billion years ago. The intense heat generated by the impact melted or vaporised most of the light elements, according to the theory of the Moon’s origin. Researchers believe the Moon lost virtually all its hydrogen in its catastrophic creation.

“The volcanic glass beads now tell us that the impact was not enough to rid Moon of all the hydrogen,” Saal said.

Over the past four decades, researchers have repeatedly analysed samples of rocks and other material from the Moon. But in all that time, the limit for detecting water was about 50 parts per million (ppm).

“We developed a way to detect as little as 5ppm of water,” said Eric Hauri, a scientist at the Carnegie Institution for Science. “We were surprised to find a great deal more in these glass beads, up to 46ppm.”

The scientists analysed volcanic glass beads formed during magma eruptions on the Moon about 3.5 billion years ago. Their calculations suggest that at the time of these eruptions, the magma had about 745ppm of water. “It suggests that the Moon’s interior might have had as much water as the Earth’s upper mantle,” Hauri said.