New results from Europe's Goce satellite has rendered a highly detailed map of how gravity varies across the Earth. These kind of measures are important for understanding how gravity shapes some key processes on Earth.
"Chief among these new insights is a clearer view of how the oceans are moving and how they redistribute the heat from the Sun around the world - information that is paramount to climate studies.
Those interested in earthquakes are also poring over the Goce results. The giant jolts that struck Japan last month and Chile last year occurred because huge masses of rock suddenly moved. Goce should reveal a three-dimensional view of what was going on inside the Earth."
The article describing the work, from the BBC, also includes a nice discussion of the concept of the geoid.