Earth is similar to Sun but with less volatile elements

ANU scientists have learned that Earth is made of the same elements as the Sun. However, our planet has less volatile elements like oxygen, helium, nitrogen, and hydrogen.

Haiyang Wang, the lead author of the study, said the team estimated the composition of Earth and the Sun with an aim to create a new tool to measure the elemental composition of other stars and planets that orbit them.

"The composition of a rocky planet is one of the most important missing pieces in our efforts to find out whether a planet is habitable or not," said Wang from the ANU Research School of Astronomy and Astrophysics (RSAA).

Other rocky planets in the universe are also less volatile versions of their prime stars, just like Earth. Co-author and RSAA colleague Associate Professor Charley Lineweaver believes every star has some kind of planetary system in orbit around it.

"The majority of stars probably have rocky planets in or near the habitable zone," he said.
"This comparison yields a wealth of information about the way the Earth formed. There is a remarkably linear volatility trend that can be used as a baseline to understand the relationships between meteorite, planet, and stellar compositions," said co-author Professor Trevor Ireland, from the ANU Research School of Earth Sciences.