Skip to: Content
Skip to: Site Navigation
Skip to: Search


Chile earthquake shortened Earth's day? NASA thinks so.

NASA says if the day has shortened any, you can look to Chile. Earthquake over the weekend could have altered the Earth's axis.

By Malcolm RitterAssociated Press / March 3, 2010

Has the day shortened because of the Chile earthquake? NASA seems to think so.



Earth's days may have gotten a little bit shorter since the massive earthquake in Chile, but don't feel bad if you haven't noticed.

Skip to next paragraph

Recent posts

The difference would be only about one-millionth of a second.

Richard Gross, a scientist at NASA's Jet Propulsion Laboratory in Pasadena, Calif., and colleagues calculated that Saturday's quake shortened the day by 1.26 microseconds. A microsecond is one-millionth of a second.

IN PICTURES: Images from the magnitude-8.8 earthquake in Chile

The length of a day is the time it takes for the planet to complete one rotation — 86,400 seconds or 24 hours.

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. Conversely, a quake can slow the rotation and lengthen the day if it redistributes mass away from that axis, Gross said Tuesday.

Gross said the calculated changes in length of the day are permanent. So a bunch of big quakes could add up to make the day shorter, "but these changes are very, very small."

So small, in fact, that scientists can't record them directly. Gross said actual observations of the length of the day are accurate to five-millionths of a second. His estimate of the effect of the Chile quake is only a quarter of that span.

"I'll certainly look at the observations when they come in," Gross said, but "I doubt I'll see anything."

IN PICTURES: Images from the magnitude-8.8 earthquake in Chile


Read Comments

View reader comments | Comment on this story