On the Behaviour of Atomic Clocks during the 1999 Solar Eclipse over Central Europe

Previous reports on detected influences of solar eclipses on atomic clocks and the movement of pendulums have brought up speculations that some yet undetected gravitational shielding effect exists. We have compared the relative pace of three types of atomic clocks, based on the ground state hyperfine transitions of hydrogen, rubidium and cesium during the total solar eclipse on 11th of August 1999 over central Europe. In our experiment, no anomalous changes in the relative clock rates correlated with the eclipse were found, at a level much smaller than previously reported.

Thomas Udem, Jörg Reichert, Ronald Holzwarth, and Theodor Hänsch
Max-Planck-Institut für Quantenoptik (MPQ) , Laser Spectroscopy Division

Rainer Krämer, Jörg Hahn, and Jens Hammesfahr
Deutsches Zentrum für Luft und Raumfahrt (DLR), Institut für Hochfrequenztechnik

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Last modfied 13.12.1999