How old is the Moon?

Since man first stepped on the Moon in 1969, experts have been studying the precious rocks the astronauts brought back.

One of their big goals has been to work out just how old the Moon is.

And finding that out is not as easy as looking at its birth certificate!

Previously scientists thought the Moon was around 4.35 billion years old, however a new study suggests that it could be millions of years older than that.

Scientists have studied samples of the moon which were gathered in 1969

Professor Francis Nimmo from the University of California Santa Cruz in the US and his colleagues were behind one of the latest studies.

Samples that have been used to date the Moon come from its surface.

But the team suggest that the Moon's surface may have actually "remelted" 4.35 billion years ago - meaning older samples are hidden away underneath.

The team looked at things like craters on the Moon and the age of some minerals and suggested that the Moon could be up to 4.51 billion years old, more than 150 million years older than previous estimations - that's quite a difference!

The Moon is believed to have formed during the solar system's chaotic early start, when a Mars-sized object called Theia collided with the newly-formed Earth.

This blasted magma - hot molten rock - out into space, which formed a ring of debris, orbiting our planet.

This clumped together to eventually form the Moon.

The team behind the new study believe the Moon heated up and cooled down over a long period of time, causing its surface to melt, remelt and reform.

They say their research could help explain why there aren't many more craters on the Moon's surface, despite it being hit by asteroids around 4 billion years ago.