'Earth Explorer' Mapping Planet Inside Out From Space

The most accurate gravity map of Earth ever is being recorded - from space, of course. The Gravity Field and Steady-State Ocean Explorer (GOCE) was launched by the European Space Agency (ESA) this fall to explore Earth inside and out like never before.

GOCE is equipped with a triple-accelerometer gradiometer, accurate to within one part in one hundred trillion of standard Earth gravity. Don't pretend you understand that - a one hundred trillionth is beyond the human minds ability to usefully picture. For reference, it's the size of a virus compared to a sixteen wheeler truck.

The GOCE is the first in a series of Earth Exploring satellites - it's companions will be CRYOSAT, SMOS, AEOLUS and the excellently-named SWARM. Five satellites in orbit with names like that - the ESA have not confirmed that the quintuplet will merge to form a giant alien-battling robot in times of distress, but only because it's so obvious it doesn't need to be said.

The image above provides a global model of the Earth's gravity field and of the geoid. The geoid (the surface of equal gravitational potential of a hypothetical ocean at rest) serves as the classical reference for all topographical features -important for studies of Earth interior processes, ocean circulation, ice motion and sea-level change.

The five hundred million dollar satellite is expected to survive for 20 months - at twenty-five million a month that makes it even higher maintenance than Paris Hilton, but infinitely more useful. Data provided by the satellite will map everything from ocean depths to the magma core of the planet, providing data of unprecedented accuracy for everything from climate physics to geophysics.

In an interesting coincidence, GOCE was launched on the same day the Large Hadron Collider was supposed to power up. Project leader Kal-El urges readers not to pay too much attention to this, nor ask why the nose cone seems to be full of diapers and a red cape.

Posted by Luke McKinney.

GOCE homepage http://www.esa.int/SPECIALS/GOCE/index.html