The Moon is 40 million years older than previously thought, lunar crystals brought back by the Apollo astronauts have shown.

Scientists from the University of Glasgow and the Field Museum, in Chicago, have been studying samples collected during the last Moon landing by Nasa in 1972.

They discovered that the zircon crystals are 4.46 billion years old, meaning that the Moon must be at least that age.

Experts believe that the Moon formed when a giant object the size of Mars crashed into the early Earth, knocking off a huge chunk, which would have taken millions of years to cool before the crystals could form.

It means that the Earth and the Moon have been locked together for much longer than previously thought – from about 150 million years after the Earth formed 4.6 billion years ago.