article_snippet: Such conditions prevent geophysicists from visiting Earth's mantle, so 'we know a lot more about the surface of Mars than we do Earth's interior,' according to Dr Lowell MiyagiDr Lowell Miyagi. '
article_snippet: Earth has many layers, like an onion,’ said Dr Lowell MiyagiDr Lowell Miyagi.
article_snippet: ‘Most layers are defined by the minerals that are present.
article_snippet: a new layer in the Earth isn't defined by the minerals present, but by the strength of the minerals present.