A collision between the Earth and a Mars-sized body led to the creation of our planet's natural satellite - Moon, a new study by scientists from the Universities of Gottingen, Cologne and Munster in Germany suggested.

The researchers made a precise analysis of the Apollo rocks that were brought to the Earth by astronauts nearly four decades ago, and found that the rocks had a slightly different composition than they would have expected of the terrestrial samples.

It was the first study to point out a difference in isotopes between rocks collected from the Moon and Earth.

They detected that the lunar samples had an O-17 to O-16 ratio, which was twelve parts per million higher than the sample rocks obtained from Earth's mantle.

The researchers concluded that 30 per cent to 50 per cent of the sample Apollo rocks was similar to that of Theia, a planetary object that collided with earth nearly 4.5 billion years ago.

Sharing the findings of the study, lead researcher Daniel Herwartz said, "The differences are small and difficult to detect, but they are there. This means two things; firstly we can now be reasonably sure that the giant collision took place. Secondly, it gives us an idea of the geochemistry of Theia."

The Moon rock samples were brought back to earth by the National Aeronautics & Space Administration's (NASA's) Apollo missions between 1969 and 1972.