Each day should be 1.26 microseconds shorter

(CNN) -- The massive earthquake that struck Chile on Saturday may have shifted the Earth's axis and created shorter days, scientists at NASA say.

The change is negligible, but permanent: Each day should be 1.26 microseconds shorter, according to preliminary calculations. A microsecond is one-millionth of a second.

A large quake shifts massive amounts of rock and alters the distribution of mass on the planet.

When that distribution changes, it changes the rate at which the planet rotates. And the rotation rate determines the length of a day.

... determined that the quake should have moved the Earth's figure axis about 3 inches (8 centimeters). The figure axis is one around which the Earth's mass is balanced. That shift in axis is what may have shortened days.

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