Space age research: lunar dust reveals moon may be 40m years older than thought

It has shone down upon the dinosaurs, inspired the greatest poets, and been explored by intrepid astronauts. But despite its enduring presence, quite when the moon came into being has remained a matter of debate.

- Nicola Davis 

Now researchers say the Earth's satellite is 40m years older than previously thought.

Scientists made their discovery by studying crystals within lunar dust that was brought back in 1972 as part of the Apollo 17 mission - the last time astronauts set foot on the moon.

"It's amazing being able to have proof that the rock you're holding is the oldest bit of the moon we've found so far. It's an anchor point for so many questions about the Earth.

When you know how old something is, you can better understand what has happened to it in its history," said Dr Jennika Greer of the University of Glasgow, the study's lead author.

About 100m years after the formation of the solar system, when the planets had already formed, it is thought a Mars-size body struck Earth, ejecting a large mass of material that eventually became the moon. The energy involved in the impact meant its surface was initially molten, but as the lunar magma ocean cooled the material solidified.