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Monday, August 13, 2012

Polar Motion Animation 1973-2012




This graphic shows the current state of polar motion of Earth’s rotational axis. The point at which the white axes cross in the middle of the image represent the geodetic North Pole. Each day the Earth’s actual rotational axis moves anywhere from a few centimeters to over a meter. Each tick mark on the white axes represents a distance of 10 feet.
This animation illustrates the motion of the Earth’s polar axis over time in 30 day increments. The length of the animation covers between 4 and 5 years of polar movement. The velocity of the motion can be estimated by the length of the aqua line as it fades to gray. The longer that that segment is the faster the pole is moving. Thus the acceleration of the poles motion can be deduced from the change in the segment’s length.
By comparing the current motion to the historic motion of the poles one can see that the historic motion of Chandler’s Wobble follows a very constrained path. Should the Earth’s axis begin to shift we expect to see very early signs of it in these animations.