Ice Loss Leading to a Dip in Gravity?!

Here's something a little stunning. A veteran European Space Agency (ESA) satellite that measures the intensity of the Earth's gravity has found that ice loss in West Antarctica has actually led to subtle dips in local gravity.

However, moving to Antarctica won't exactly be the next popular weight loss program any time soon. Despite the fact that the ESA's Gravity field and Steady-state Ocean Explorer (GOCE) has certainly identified a dip in gravity strength between 2009 and 2012 that practically mirrors Antarctica's shrinking volume, experts are quick to add that this isn't exactly the kind of gravity shift you'd feel.

"The strength of gravity at Earth's surface varies subtly from place to place owing to factors such as the planet's rotation and the position of mountains and ocean trenches. Changes in the mass of large ice sheets can also cause small local variations in gravity," the ESA reports.

In the case of Antarctica, measurements from the ESA's CryoSat satellite has shown that since 2009 the rate at which icemelt has shortened (in altitude) the West Antarctic Ice Sheet every year has increased nearly threefold. And between 2011 and 2014, Antarctica as a whole has been shrinking in volume by more than 77 cubic miles (125 km) a year.

This data was compared with data from GOCE's high-resolution measurements and NASA's Grace satellite - designed to measure changes over time - to make what researchers are calling one of the most comprehensive gravity change models of the Earth ever made. However, so far the West Antarctic has been the only region analyzed in detail.

"We are now working in an interdisciplinary team to extend the analysis of GOCE's data to all of Antarctica," Johannes Bouman, from the German Geodetic Research Institute, said in a recent statement. "This will help us gain further comparison with results from CryoSat for an even more reliable picture of actual changes in ice mass."

[Credit: ESA/DGFI/Planetary visions]