Scientists have long wondered what lies at the very center of the Earth, and the latest research ... which the study reports is likely a 400-mile-wide (644-kilometer-wide) ball of metal ...

The Grand Canyon is a gigantic geological library, with rocky layers that tell much of the story of Earth’s history. Curiously though, a sizeable layer representing anywhere from 250 million ...

Scientists have long wondered what lies at the very center of the Earth, and the latest research ... which the study reports is likely a 400-mile-wide (644-kilometer-wide) ball of metal ...