It's been more than four decades since the last eclipse was visible from Europe. But on Aug. 11, when the earth, moon, and sun align perfectly in the sky, two NASA scientists will get their last chance this millennium to solve a 50-year-old enigma.
During the full eclipses of 1954 and 1959, the Nobel laureate Maurice Allais noticed anomalies in the movement of a Foucault pendulum. Devised by a French physicist, it's a simple pendulum with a heavy bob attached to a long wire. The earth's rotation causes the plane of the pendulum's swing to turn.
Next week's total-solar eclipse over Europe, Turkey, northern Iraq, southern Iran, and across Pakistan and India may hold the answer to Allais's highly questionable observation.
Researchers at the Marshall Space Flight Center in Huntsville, Ala., hope to exactly reproduce Allais's experiments with pendulums. "If something strange is happening to Foucault pendulums during solar eclipses, then it's a real mystery. Is it some gravitational effect, a peculiar manifestation of tides, or something else entirely?" asks researcher David Noever at the Huntsville center. "It's unlikely, but Allais could have stumbled onto something."
(c) Copyright 1999. The Christian Science Publishing Society