For two weeks in November 2009, ocean currents flowing around Antarctica changed noticeably enough to temporarily speed up the planet's spin by about one ten-thousandth of a second. Scientists precisely monitor the length of Earth's day through space geodetic techniques, such as counting how long it takes laser light to travel from Earth to a mirror on the moon and back again. Big changes in how mass is distributed across the planet--such as changes in the atmosphere, or a monster earthquake--can alter the pace of rotation. The 2009 shift in Antarctica marks the first time such a shift has been traced to a short-term pattern in the oceans, scientists from NASA's Jet Propulsion Laboratory in Pasadena, Calif., and Paris Diderot University in France report February 28 in Geophysical Research Letters.
|Printer friendly Cite/link Email Feedback|
|Title Annotation:||SCIENCE NOTEBOOK|
|Article Type:||Brief article|
|Date:||Apr 7, 2012|
|Previous Article:||Say what?|
|Next Article:||Icy isolation may have led to new human species: cold-climate refuges possibly influenced Homo evolution.|