The BBC has an article on the European Space Agency’s GOCE satellite being used to map the variations in gravity. What! You thought that gravity was just 9.8 meters/sec²? That was the value we used in all of our engineering classes (unless we had to use English units and use 32.2 ft/sec²). Actually, gravity varies from 9.78 meters/sec² at the equator to 9.83 meters/sec² at the poles. (The newest weight loss regimen will be to move to one of the dark blue areas, I suppose.)
Launched in 2009, the sleek satellite flies pole to pole at an altitude of just 254.9km – the lowest orbit of any research satellite in operation today.
The spacecraft carries three pairs of precision-built platinum blocks inside its gradiometer instrument that sense accelerations which are as small as 1 part in 10,000,000,000,000 of the gravity experienced on Earth.
This has allowed it to map the almost imperceptible differences in the pull exerted by the mass of the planet from one place to the next – from the great mountain ranges to the deepest ocean trenches.
via BBC News – Goce satellite views Earth’s gravity in high definition.
