The Earth is smaller than assumed: German researchers

July 5, 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: Claims about new planets that turned out to be wrong—and why 'Planet Nine' may be different

Related Stories

Antarctic microbes hold clue to Earth's oxygen

January 20, 2016

At the bottom of an icy Antarctic lake, a thin, slimy layer of bright green microbes is generating a tiny oasis of oxygen that might give a picture of what early Earth looked like before oxygen became common in the atmosphere. ...

What are the Earth's layers?

December 7, 2015

There is more to the Earth than what we can see on the surface. In fact, if you were able to hold the Earth in your hand and slice it in half, you'd see that it has multiple layers. But of course, the interior of our world ...

Cool, dim dwarf star is magnetic powerhouse

November 19, 2015

Astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) have discovered that a dim, cool dwarf star is generating a surprisingly powerful magnetic field, one that rivals the most intense magnetic regions ...

Birth of high mass stars and the origin of life

December 29, 2015

Takeshi Sakai, Assistant Professor, Graduate School of Informatics and Engineering, discusses recent work. "I am using the Atacama Large Millimeter/Submillimeter Array (ALMA) facilities in Chile to study the formation of ...

ALMA spots monstrous baby galaxies cradled in dark matter

December 4, 2015

Astronomers discovered a nest of monstrous baby galaxies 11.5 billion light-years away using the Atacama Large Millimeter/submillimeter Array (ALMA). The young galaxies seem to reside at the junction of gigantic filaments ...

Recommended for you

Long-term picture offers little solace on climate change

February 8, 2016

Climate change projections that look ahead one or two centuries show a rapid rise in temperature and sea level, but say little about the longer picture. Today (Feb. 8, 2016), a study published in Nature Climate Change looks ...

0 comments

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.