The Earth is smaller than assumed: German researchers

Jul 05, 2007
Earth
German researchers at the University of Bonn said that the world is smaller than first thought.

Although the discrepancy is not large, it is significant: Geodesists from the University of Bonn have remeasured the size of the Earth in a long lasting international cooperation project. The blue planet is accordingly some millimeters smaller than previously assumed.

The results are important, for example, to be able to demonstrate a climate contingent rise in sea level. The results have now appeared in the renowned Journal of Geodesy.

The system of measurement used by the Bonn Geodesists is invisible. It consists of radiowaves that are transmitted into space from punctiform sources, the so-called Quasars. A network of more than 70 radio telescopes worldwide receives these waves. Because the gaging stations are so far apart from each other, the radio signals are received with a slight time-lag.

"From this difference we can measure the distance betwen the radio telescopes—and to the preciseness of two millimeters per 1,000 kilometers ", explained Dr. Axel Nothnagel, reasearch group leader for the Geodesy Institute of the University of Bonn.

The procedure is called VLBI, which stands for "Very Long Baseline Interferometry". The technique can be used, for example, to demonstrate that Europe and North America are distancing from each other at a rate of about 18 millimeters annually. The distance of the gaging stations from each other allows the the size of the Earth or the exact location of the center of the Earth to be determined.

"We have analyzed the measurements and calculations from 34 partners in 17 countries",explained Nothnagel. "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."

The results are the basis for a new coordinate system for the planet. With this system it would be possible, for example, to determine the track of so-called Altimeter-Satellites within a few millimeters precision. Altimeter-Satellites measure their altitude over the Earth’s surface and can, for example, register a rise in sea level. Deviations from the flight path, however, falsify the result. If the satellite flies higher than expected, the distance to the surface of the Earth differentiates from what is recorded—the sea level appears lower than it really is.

Source: University of Bonn

Explore further: NASA balloons begin flying in Antarctica for 2014 campaign

add to favorites email to friend print save as pdf

Related Stories

Geologists discover ancient buried canyon in South Tibet

Nov 20, 2014

A team of researchers from Caltech and the China Earthquake Administration has discovered an ancient, deep canyon buried along the Yarlung Tsangpo River in south Tibet, north of the eastern end of the Himalayas. ...

52-million-year-old amber preserves 'ant-loving' beetle

Oct 02, 2014

Scientists have uncovered the fossil of a 52-million-year old beetle that likely was able to live alongside ants—preying on their eggs and usurping resources—within the comfort of their nest. The fossil, ...

Scientific instruments of Rosetta's Philae lander

Sep 23, 2014

When traveling to far off lands, one packs carefully. What you carry must be comprehensive but not so much that it is a burden. And once you arrive, you must be prepared to do something extraordinary to make ...

Recommended for you

Scientists make strides in tsunami warning since 2004

21 hours ago

The 2004 tsunami led to greater global cooperation and improved techniques for detecting waves that could reach faraway shores, even though scientists still cannot predict when an earthquake will strike.

Trade winds ventilate the tropical oceans

22 hours ago

Long-term observations indicate that the oxygen minimum zones in the tropical oceans have expanded in recent decades. The reason is still unknown. Now scientists at the GEOMAR Helmholtz Centre for Ocean Research ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.