Earth may be round, but not its gravitational field! After two years in orbit, the European Space Agency's Gravity Field and Steady-State Ocean Circulation Explorer satellite has revealed the clearest picture of earth's gravity-field map:
The geoid is the surface of an ideal global ocean in the absence of tides and currents, shaped only by gravity. It is a crucial reference for measuring ocean circulation, sea-level change and ice dynamics – all affected by climate change.
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