Discovery shakes beliefs of Earth to the core

For a century, scientists have assumed that the Earth has same chemical make-up as the sun. But this belief has been challenged by scientists at The Australian National University. Professors Ian Campbell and Hugh O'Neill from the Research School of Earth Sciences at ANU said their research shakes up our understanding of the Earth's chemistry - right to the core. "For decades it has been assumed that the Earth had the same composition as the Sun, as long the most volatile elements like hydrogen are excluded. This theory is based on the idea that everything in the solar system in general has the same composition. Since the sun comprises 99 per cent of the solar system, this composition is essentially that of the sun," Professor O'Neill said. As it is easier to measure the chemical make-up of chondritic meteorites, planetary geologists have long used these to more precisely determine the sun's composition - and therefore the composition of the Earth.