Solar eclipse image taken aboard Gemini 12.
Click on image for full size
Courtesy of NASA

Can an Eclipse Change Gravity?
News story originally written on July 6, 1999

A question more than four decades old will be answered soon. The last solar eclipse of the millennium was used by scientists around the world to test a theory first developed in 1954. A French economist named Maurice Allais believes that during an eclipse, Earth's gravitational pull slighty increases.

Allais tested his theory during two total solar eclipses, one in 1954, and another in 1959. He used an instrument called a Foucault pendulum. This special tool swings in the same direction while the Earth turns underneath it. If his theory holds true, everything we know about gravity is false. Through the past 40+ years, no one has been able to duplicate Allais' experiment with any success.

David Doever of NASA's Marshall Space Flight Centre in Huntsville decided to put the experiment to the test. Doever doesn't expect to find proof to support Allais, but believes such an theory must be investigated.

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