Earth, in most renderings, is a smooth sphere with a glossy complexion—a blue marble, as pictures snapped from space have shown us. Earth scientists know that’s not exactly true. Earth, in fact, is an ...

[UPDATE (April 5, 2011): It turns out some of the descriptions I used below to describe a geoid were not accurate. I refer you to this page at the University of Oklahoma for a good description. I’ve ...

Learn how we know the Earth is round, and the science behind the shape of our gravitational field.

The Earth’s geoid is the shape the planet would assume if its surface were made of water. Naturally, there’s little dispute over the shape of the geoid over the oceans, where it varies by only 100 ...

Credit: International Centre for Global Earth Models (ICGEM) / E. S., Barthelmes, F., Reißland, S., Elger, Like all scientific mysteries, the Indian Ocean geoid low (IOGL) — also known as the Indian ...

The region of lower gravity, discovered in 1948, manifests as a vast depression in the ocean's surface that reaches some 348 feet deep at its greatest extent. A mysterious “gravity hole” in the Indian ...

The Indian Ocean Geoid Low (IOGL), a significant gravitational anomaly, has puzzled scientists for decades. Research suggests it formed due to interactions between tectonic plates and mantle plumes ...

The ground beneath your feet may feel solid, but Earth is constantly shifting. While we have mapped the surface in detail, its deep interior remains a mystery. Even with modern technology, no probe ...

For over seventy years, a mysterious gravitational depression beneath the Indian Ocean has baffled scientists. Known as the Indian Ocean Geoid Low (IOGL), it marks the deepest point in Earth’s gravity ...