Antarctica is famously a continent capped with ice, but as Earth’s climate changes and the polar regions get warmer, its ancient ice is beginning to melt. The immediate consequence of the melting is the growing instability of ice shelves, places where the ice covering extends into the ocean. However, if we really want to know how quickly Antarctica is losing ice, we need a way of measuring that loss in terms of total mass.
In that mission, scientists are aided by gravity. As Antarctic ice melts, it shifts mass from the continent into the oceans, slightly changing Earth’s gravitational field in that part of the world. We wouldn’t notice it, but orbiting observatories like the Gravity Field and Steady State Ocean Circulation Explorer (GOCE, which is more an abbreviation than acronym) can measure small fluctuations in gravity compared with other spots on our planet.