RENO, Nev. - A Reno scientist and his team of researchers have uncovered the mystery of why the Earth wobbles on its axis as it spins through space. Geoff Blewitt, a geophysicist at the University of Nevada, Reno, said the discovery provides scientists with another means to determine whether Earth is undergoing global warming.



Researchers have used models and global positioning system (GPS) technology for more than a decade to track the movement of water from melting ice masses, the oceans and the atmosphere that cause the Earth to bulge at its equator and the North Pole to shift slightly, he told the Reno Gazette-Journal.


In recent years, however, Blewitt and his colleagues developed computer software that analyzes GPS signals more precisely, allowing them to measure changes in the shape of the Earth within a few millimeters, or about three-twentieths of an inch.


"So instead of using models, we actually observe bulges in the Earth's shape directly and relate it to the wobble," Blewitt said.


Blewitt and his fellow researchers, Richard Gross of the Jet Propulsion Laboratory and Peter Clarke and David Lavallee of the University of Newcastle-upon-Tyne, England, have published their findings in an article published in the April 1 edition of Geophysical Research Letters.


Blewitt will present his groups findings Thursday at an international science conference in Montreal.

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