Scientists determine extent of Earth's wobbling
Scientists determine extent of Earth's wobbling
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Tuesday, 27, Jun 2006 03:04
New technologies have enabled scientists to measure short-term variations in the Earth's axis of rotation, or wobbles, more accurately than ever before.
Although longer-term wobbles, such as the Chandler wobble of 433 days and the annual wobble, have been well charted, shorter wobbles are more difficult to monitor as they are often overshadowed by their larger counterparts.
However, scientists from the Royal Observatory in Belgium and the Paris Observatory have tracked short-term wobbles by taking advantage of the Global Positioning System and a period in which the annual wobble and Chandler wobble effectively cancel each other out (November 2005 to February 2006).
During this period, short-term wobbles ranged from the size of an A4 sheet of paper to a mobile phone, and remained within one metre square.
The results, which will be published in Geophysical Research Letters, revealed that weather patterns in the northern hemisphere have a significant effect on the extent of the earth's wobble.
"Both the location of high - or low-pressure centres - for example, over Asia or northern Europe - and the relationship of these weather systems to each other played a measurable role in creating, or 'exciting', small, short-term wobbles," commented the American Geophysical Union.
Other factors affecting the Earth's wobble identified by the researchers include oceanic and atmospheric pressures.