The Earth contains mysteries that are yet to be unravelled. They focus on how Earth formed, and what is at its centre. A recent study has clues as to what shaped our planet at the beginning of the solar system. Scientists have evidence that vast amounts of a rare, primordial form of the gas helium may be trapped inside Earth. It is called helium-3. Scientists believe this helium-3 is from a giant cloud of gas and dust that gelled to create different planets. The gas has remained locked inside Earth's core for billions of years. It is occasionally released in volcanic eruptions.

The research has created great excitement among planetary geologists. They believe large amounts of helium-3 could unlock secrets of the Big Bang. The scientists are speculating that the presence of helium-3 could mean that Earth was created much more quickly than we thought. A geophysicist in the USA shed light on the possible speed of Earth's creation. He said: "There is evidence that has been interpreted to say the Earth formed very slowly, requiring 100 million years. [However], you wouldn't get much helium deep in the Earth if the Earth formed that slowly."