Silver found on the Moon

Scientists who blasted a spent rocket into a lunar crater last year say they have discovered traces of silver. However, the levels are far too low to make it worth opening a lunar silver mine.

More importantly from the point of view of space exploration, large amounts of water have been discovered at the bottom of a crater pointing the way to future manned missions.

However, less welcome has been the detection of surprisingly high levels of mercury in the soil, posing a potential risk to explorers.

The Lunar Crater Remote Observation and Sensing Satellite mission involved deliberately crashing a spent rocket into a crater near the Moon's south pole.

Material thrown up by the impact was then analysed by instruments on the American space agency Nasa's Lunar Reconnaissance Orbiter probe.

The target studied was the Cabeus crater, which lies in a permanently shaded region of the Moon where temperatures fall as low as 35 Kelvin (minus 238C).