Ever wondered why Earth looks flat even though it's a sphere? The planet's massive size makes its curvature nearly impossible ...

The Indian Ocean "gravity hole" is a region where Earth's mass is reduced, leading to weak gravitational pull, lower-than-average sea levels and a puzzle scientists have only just begun to solve.

Scientists at Yale and in Singapore have devised what may be the ultimate acid test—a comprehensive model for estimating the origins of Earth's habitability, based in part on ocean acidity.