Above: Clicking on this image will launch an animated global map of the July 22nd eclipse. Regional animations of India and China are also available. Credit: Larry Koehn of ShadowAndSubstance.com.  07/20/09

Not only will today’s solar eclipse be the longest predicted for the 21st century (about six and a half minutes), it is also providing scientists around the world a chance to hopefully determine whether or not the Earth’s gravity is affected by an eclipse.

The possibility of changes in the Earth’s gravity was first raised in 1954 when a scientist in Paris, conducting experiments in his lab with a pendulum, noticed that during a solar eclipse the pendulum slowed, indicating a change in gravity.  While the scientist, Maurice Allais, was able to repeat the experiment during a later eclipse with the same result, many scientists have not been so lucky.

Today NASA, along with scientists around the world, will be repeating Maurice Allais’ experiment.  When all the results are correlated, we may learn something today which will greatly enhance our understanding of the nature of gravity.

Read more here http://science.nasa.gov/headlines/y2009/20jul_longestsolareclipse

and here http://allais.maurice.free.fr/English/Science.htm.