Mystery element in Earth's core found to be silicon

In a discovery that could help scientists uncover the secrets of the universe, Japanese scientists have found that silicon is likely the mystery element in the Earth's inner core.

Scientists have had a long-held consensus about the centre of the planet being composed of about 85 per cent iron and 10 per cent nickel. Sulphur, oxygen and silicon have been the prime candidates for the remaining five per cent.

But whether it is sulphur, oxygen or silicone was something that scientists were not sure about. Now a team led by geophysicist Eiji Ohtani at Tohoku University in northern Japan has claimed that the remaining 5 per cent is most likely composed of silicon.

To arrive at this conclusion, Ohtani's team subjected iron-nickel alloys mixed with silicon to the kinds of high temperatures and pressure found in the inner core. And it discovered that when observed with X-rays, the data for the mixed material matched the seismic data obtained for the inner core.

"Our latest experiments suggest that the remaining five percent of the inner core is composed mostly of silicon," Japan Today quoted Ohtani.

This experiment will also help in ascertaining whether the Earth's surface was rich in oxygen in its early formation before photosynthesis began or not. Although Ohtani also cautioned that the subject needs more research before it could be ascertained that silicon is the missing element.

Scientists are divided on the opinion whether the Earth's inner core contains silicon or oxygen.

Ohtani's findings, if ascertained, can also confirm whether the Earth was oxygen rich in the beginning or not.

But Ohtani also said that it is unlikely that oxygen would exist in the inner core, as it is difficult for silicon and oxygen to co-exist in the same place.

"But it doesn't necessarily mean the rest of the planet was oxygen rich because there is a possibility that oxygen did not exist as an element of the Earth at its formation in the first place." Ohtani told Japan Today.

The research was presented at a meeting of the American Geophysical Union in San Francisco held in December. This will now be presented as a research paper to a peer-reviewed scientific journal.