An earthquake can make earth rotate faster by nudging some of its mass closer to the planet's axis, just as ice skaters can speed up their spins by pulling in their arms.

The earthquake that struck Chile on Saturday may have shifted the earth's axis and created shorter days, according to scientists at Nasa.

Gross said that even though the Chilean earthquake is much smaller than the Sumatran quake, it is predicted to have changed the position of the figure axis by a bit more for two reasons.