Aceh quake may have made Earth wobble

Earth takes one on the chin:

The deadly Asian earthquake may have permanently accelerated the Earth's rotation -- shortening days by a fraction of a second -- and caused the planet to wobble on its axis, U.S. scientists said Tuesday.

Richard Gross, a geophysicist with NASA's Jet Propulsion Laboratory in California, theorized that a shift of mass toward the Earth's center during the quake Sunday caused the planet to spin 3 microseconds, or one millionth of a second, faster and to tilt about an inch on its axis.

When one huge tectonic plate beneath the Indian Ocean was forced below the edge of another "it had the effect of making the Earth more compact and spinning faster," Gross said.