Monday, October 20, 2014

Melting Antarctic Ice is Changing the Earth's Gravitational Field

Antarctic ice is ancient but it is being lost at a precipitous rate. According to recent research, three Antarctic glaciers, are losing approximately 185 billion metric tons (204 billion US tons) of ice each year. In fact, so much ice is being lost at the bottom of the world that it is reportedly changing Earth’s 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. Mass is the source of gravity, so if the crust is thicker in one place than another the thicker part will exert a slightly higher gravitational pull.

As reported in Geophysical Research Letters, the impact on the Earth's gravity field has been documented by orbiting observatories like the Steady State Ocean Circulation Explorer (GOCE), and the twin Gravity Recovery and Climate Experiment (GRACE).

These Gravity measurements are corroborated by other studies like the CryoSat experiment, which measures the height of ice through a method known as altimetry. Another method involves measuring the brightness of light reflected off the ice.

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