Fluctuation in Earth`s spin changes length of day
Thrice in the past 10 years, Earth`s spin has missed a beat, which caused the planet`s days to stretch and shrink temporarily.
London: Thrice in the past 10 years, Earth`s spin has missed a beat, which caused the planet`s days to stretch and shrink temporarily.
The oceans` and the atmosphere`s push and tug on Earth`s spin cause it to fluctuate; these everyday variations hide longer-term patterns, some of which are known and, some are not, New Scientist reported.
University of Liverpool researcher, Richard Holme, took a look at half a decade of GPS and astronomical data to see how the length of the day varied.
The phenomenon causes days to lengthen by a few milliseconds over ten years, then shrink them back again.
Then there is a 5.9-year cycle to contend with, which happens due to a continuous tremble between the fluid outer core and the surrounding mantle, which changes length of the day by fractions of milliseconds every year.
After eliminating both the regular cycles, Holme found sudden unexpected jumps in the length of the day materialized from his computation.
Thrice in recent years - namely in 2003, 2004, and 2007 - Earth`s spin fluctuated; the jumps broke up the longer-term change by a fraction of a millisecond, and many months before they go back to normal.
Satellite readings of Earth`s magnetic field over the past 2 decades have showed that the field also experience sudden jerks, and Holme found that jumps in the Earth`s spin coincided with them.