Scientists: Earth not getting fatter

A NASA-led research team says it's laid to rest a recurrent rumor that Earth has a weight problem, reporting that the planet is not getting fatter after all. Scientists have long speculated that the solid Earth might be expanding or contracting, proposing various theories to back up their contention about one or the other. A NASA study, published in Geophysical Research Letters, has essentially settled the argument. Using a battery of space measurement tools and a new data calculation technique, researchers detected no statistically significant expansion of the solid Earth, a release by the space agency said Tuesday.An international group of scientists led by Xiaoping Wu of NASA's Jet Propulsion Laboratory in Pasadena, Calif.-- and including participants from the Institut Geographique National, Champs-sur-Marne in France, and Delft University of Technology in The Netherlands -- set out to evaluate the accuracy of the measurements.After analysis, they estimated the average change in Earth's radius to be 0.004 inches per year, or about the thickness of a human hair, a rate considered statistically insignificant."Our study provides an independent confirmation that the solid Earth is not getting larger at present, within current measurement uncertainties," Wu said.