Fine Structure

The 22nd of July will bring a total solar eclipse to parts of Asia and some scientists are taking this opportunity to examine the effects of the eclipse on gravity at the surface of the Earth.

It all started with an eclipse on June 30th, 1954. Maurice Allais was conducting research on pendulums which happened to coincide with an eclipse in Paris. Allais reported that his pendulum abruptly changed rotation direction when the eclipse was right overhead and resumed normal course after it had passed. Ever since then scientists have tried to reproduce or explain the effects with varying degrees of success. This eclipse will be watched by a variety of sensitive gravity detectors in different locations in an attempt to foil any coincidences that might effect the measurements.

Gravity is still fairly mysterious so it's always fascinating to watch how these experiments turn out and what it can teach us, even if the idea of the moon "blocking" gravity is generally seen as a far-fetched idea.