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Doru Dragan

16 Noi 2009 16:23



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Pe acelasi topic, DH spune:
"To Abel Cavaši and Polestar101: Both of you are in violation of this site's rules.

To everyone else: These two are crackpots.

Abel Cavaši does not understand how precession arises. The Earth obviously is not a spinning top on some surface. Some model other than a spinning top is needed to explain how planetary precession occurs. The correct model is to use gravity gradient torque.

Polestar101 is quoting the IAU out of context. Several organizations, including the IAU, the IERS, NASA, and the US Naval Observatory, are involved in a never-ending effort to improve the reference frames used in the sciences. Two of the most important (to us) reference frames are inertial and Earth-fixed reference frames. Accurately knowing and predicting the relationship between these frames is the subject of precession/nutation theory.

Note very well: The error in Earth orientation is now known to within 300 micro arcseconds, RMS, with an error growth rate of about 30 micro arcseconds per year. (About those numbers: For a circle the size of the Earth, the arc length subtended by a 300 micro arcsecond angle from the center of the Earth represents about 1 centimeter at the Earth's surface.)

Note very very well: No new science was needed to create a model of this precision. Scientists have a very good model of what causes precession."