When the Earth is naked and stripped free of tides and currents, it's not really all that round. According to gravity data, the Earth is a bit more potato shaped.
At a workshop in Germany, scientists showed off a stunning image of a geoid. The model exposes the surface of the ocean. The blue areas are regions with the weakest gravitational pull and the areas in yellow have the strongest.
European Space Agency's GOCE satellite mapped this image of Earth's gravity. It is the most accurate model of a geoid ever produced.
The one-tonne satellite uses an ion engine to counteract drag. Watch an animation of it in action.
Gravity data will be important for understanding phenomenon such as ocean circulation and ice dynamics. It will help scientists discover how the Earth works.
Perhaps knowing more about the gravitational forces on Earth could help predict events such as the earthquake that shook Japan. While the earthquake was caused by tectonic plate movement under the ocean, movements deep under the ocean can't be seen from space. Earthquakes do leave behind a gravity signature. This information could improve climate change models.
As the Earth warms, gravity data could be useful in understanding changes associated with sea level, ocean currents and ice flows.