Earth Is Smaller than Previously Thought!

No, the world does not fit into your hands, but is smaller than people believed when they previously measured it. The discrepancy is minute, but the team of geodesists from the University of Bonn says it is significant. They have remeasured the size of the Earth, as part of a long lasting international cooperation project.

Their final results show that blue Earth is some millimeters smaller, a fact that can result important, for example, in proving a climate contingent rise in the sea level. The German team employed a system of measurement based on radiowaves that are transmitted into space from punctiform sources, named Quasars. A terrestrial network of over 70 radio telescopes worldwide picks up these waves. As the gaging stations are so far apart from one another, the radio signals are detected with a little time-lag, as the technique is called VLBI (Very Long Baseline Interferometry).

"From this difference we can measure the distance between the radio telescopes-and to the preciseness of two millimeters per 1,000 kilometers," explained lead researcher Dr. Axel Nothnagel, of the Geodesy Institute of the University of Bonn.
VLBI proved, for example, that Europe and North America are going away from each other at a speed of about 18 millimeters yearly.

The distance of the gaging stations from one another permits the measurement of the Earth size or of the precise location of the center of the Earth.

"We have analyzed the measurements and calculations from 34 partners in 17 countries. A combination of GPS and satellite laser measurements will enable the availability of the coordinates from almost 400 points on the surface of the Earth with unparalleled exactness." explained Nothnagel.

This new system would allow, for example, tracking down the so-called Altimeter-Satellites within just a few millimeters precision. These satellites measure their distance over the Earth's surface and can record the slightest rise in sea level, but deviations from the flight path can lead to wrong data. If the satellite flies over the expected distance, the sea level will appear lower than in reality.