This Geoid Is The Most Sophisticated Map Of Earth's Gravity Yet

GOCE's 'Potato Earth' View

Yellow areas show the highest gravity, blue the lowest.ESA/HPF/DLR

Since 2009 the European Space Agency's Gravity field and steady-state Ocean Circulation Explorer (GOCE) has been mapping the Earth's gravitational field, and today the agency released its most detailed model of the geoid to date. More potato-shaped than spherical, this latest model shows just how different gravity can be at different points on our planet.

The geoid is, roughly speaking, a model of the earth that doesn't follow the surface of the crust but rather the average ocean surface if the oceans were at equilibrium and extended through the continents--in other words, the shape the earth would take based on its existing gravitational field if the tides, currents, and crust features didn't distort things. It's an idea that's been around for well more than a century but only recently has been modeled precisely, largely thanks to GOCE.

Today's new geoid marks the most precise model to date. In the above image, yellow indicates the strongest gravitational pull while blue indicates the lowest. And while we experience these differences in gravity as negligible, they have a big impact on ocean dynamics and the movement of heat around the planet--key to understanding atmospheric conditions and climate change.

The geoid also informs geology, a field of study recently punctuated in no small degree by the string of earthquakes in and around Japan that have wrought serious devastation. Researchers hope that GOCE's data--more of which will be made available this fall--will help explain and define these big movements in the Earth's crust.

Click the BBC link below for a full 360-degree view of Earth through GOCE's eyes.

Ion-Propelled Gradiometer

GOCE must remain in stable free fall at low orbit, so an electric ion propulsion engine constantly provides small bursts of thrusts to counteract any air resistance the craft encounters.ESA - AOES Medialab