Our Chubby Earth

July 28, 2011

Brit Trogen


When you picture the Earth, an image of a perfect, blue-green sphere probably comes to mind. If you have a really accurate imagination, you may add the slight bulge in the middle that occurs due to the Earth's spin, which prevents it from being perfectly round, with water gathering more densely at the equator. But you probably don't put much thought into the growing pains Earth's been going through over the last 22,000 years or so. The "awkward phase," if you will. Earth, to put it bluntly, has been packing on the pudge.


Over the last few decades these changes have become pretty apparent. There's a measurable increase of 0.28 of bulge happening per decade, and while that might not sound like much, add it on to the 13 miles of spare tire that already exists relative to the poles, and... let's just say every little inch counts (amiright ladies?!) Thanks to precise data collected by satellites from the Gravity Recovery and Climate Experiment (GRACE), we're starting to have a pretty good idea of the reasons behind this widening.


The GRACE satellites make their conclusions in an ingenious fashion: by measuring gravity fields above the earth, they're able to determine the mass of ice on the Earth's surface (since gravity is dependent on mass.) Using snapshots of Earth taken every 30 days in conjunction with these gravitational measurements, researchers at the University of Colorado were able to test (and tentatively confirm) a theory on the culprit for Earth's pudge problem: melting glaciers in Greenland and Antarctica. As a result of ice loss, and the gathering of water at the equator, slowly but steadily, the Earth's shape is changing. And it's worth mentioning that this is yet more evidence of that pesky global phenomenon known as "warming."


So, looks like there's more than one reason for Earth to go on a diet. And it couldn't hurt our chances with Venus much, either. 



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