View of the Earth as seen by the Apollo 17 crew traveling toward the moon. (Credit: Image courtesy of NASA/Johnson Space Center)
Posted on 07/07/2007 3:14:06 AM PDT by neverdem
Science Daily — 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 up to now assumed. The results are important, for example, to be able to demonstrate a climate contingent rise in sea level.
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, research 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.
The results are published in the Journal of Geodesy.
Note: This story has been adapted from a news release issued by University of Bonn.
EEEEEAHHH!! We're all gonna die!!
Al was right—the Earth is shrinking like a slice of bacon in a frying pan!
No wonder it took me less time to get to work today...
Fossil DNA Proves Greenland Once Had Lush Forests; Ice Sheet Is Surprisingly Stable
FReepmail me if you want on or off my health and science ping list.
It’s a small world, after all.
The myth of Global Warming has become the center of gravity around which all scientific work must now rotate.
This is scary. IIRC, Al Gore took two undergraduate courses in science at Harvard. The grades that he earned were a B and a C. Please, am I wrong?
Still wouldn't want to paint it.
Yep. In the meantime, they are going to make us pump all the oil back in and swell it up again...
I was reading an article once that said the mass of earths atmosphere is 5000 TRILLION metric tons. I mean just think about that, it`s not one trillion, not two, not three, but FIVE THOUSAND trillion!! Maybe Al Gore and his boy Leo DiCaprio can tell me how cow farts and a Chevy can affect that.
D’oh!!
You beat me to it!
Heck, everybody knows that. I’ve been hearing it all my life.
sorry - bigger
The article seems to assume that the diminsions are constant.
Fact is, the surface is in continuous change making the measurements variiable withn the limits of very small tolerances.
The article seems to assume that the diminsions are constant.
Fact is, the surface is in continuous change making the measurements variiable withn the limits of very small tolerances.
How can you measure the earth down to a few millimeters? I mean, where does the earth stop. The earth’s land is pretty much covered with sand or dirt, and this stuff moves around. And the oceans move significantly due to tidal forces. So when someone says the earth is a few millimeters smaller, what the hell does that mean, and why should I care?
LLS
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