Foucault's Pendulum + Solar Eclipses

[f36c]

Was it ever determined if solar eclipses effect changes in Foucault Pendulum rotation? I can find no definitive answer to this question despite the fact that I am pretty sure NASA had a big program to determine the answer a few years ago.

Here is an except describing the question more fully from

Mathematical mysteries: Foucault's pendulum and the eclipse

“The rate of rotation of Foucault’s pendulum is pretty constant at any particular location, but in 1954, during an experiment with one, a physicist named Maurice Allais got a surprise. His experiment lasted for 30 days, and one of those days happened to be the day of a total solar eclipse. Instead of rotating at the usual rate, as it did for the other 29 days, his pendulum turned through an angle of 13.5 degrees within the space of just 14 minutes. This was particularly surprising as the experiment was conducted indoors, away from the sunlight, so there should have been no way the eclipse could affect it! But in 1959, when there was another eclipse, Allais saw exactly the same effect.”

[Misery_Loves_Co]

This was particularly surprising as the experiment was conducted indoors, away from the sunlight, so there should have been no way the eclipse could affect it!

I’m sorry that I have nothing to add to the OP, but this sentence struck me as extremely silly - if an eclipse could have this effect it would certainly not be due to the amount or quality of light striking the pendulum, otherwise every time you shut the lights out in the building the pendulum would jump.

Carry on . . .

[chukhung]

Maurice Allais is probably better known in the field of economics in which he won the Nobel prize in 1988. From the Nobel site, his autobiographical sketch on this page, http://www.nobel.se/economics/laureates/1988/allais-autobio.html, says

On the experimental level, and as a by-product of this theoretical research, I conducted, from 1952 to 1960, experiments on the anomalies of the paraconical pendulum (a short pendulum, about one meter long, suspended by a steel ball), anomalies the existence of which I proved. For these experiments I received the 1959 Galabert Prize of the French Astronautical Society, and I was laureate in 1959 of the United States Gravity Research Foundation.

My main idea at the start was that a link could be established between magnetism and gravitation by observing the movements of a pendulum consisting of a glass ball oscillating in a magnetic field. Of all the observations made in 1952 and 1953 I was not able to draw any definitive conclusion. Through certain experimental devices, I obtained positive effects, but with other devices I obtained no effect whatsoever. A much stronger magnetic field would have been necessary, but it was unrealizable in my laboratory with the available means.

But in the absence of any magnetic field other than that of the earth, I observed, in the course of continuous observations, pursued over periods of about one month from 1954 to 1960, very remarkable anomalies in the movement of the paraconical pendulum, to wit essentially the existence of a significant periodicity of the order of 24 hrs 50 min. Identical results were found in June-July 1958 in two laboratories, some 6 km away from each other, one in a basement, the other in an underground quarry.

At the same time, I observed in the second half of July 1958 a correspondence between the anomalies in the movement of the paraconical pendulum and the anomalies observed in the optical sightings on a fixed sighting mark through a fixed telescope.

Finally during the total eclipses of the sun on June 30, 1954, and October 22, 1959, quite analogous deviations of the plane of oscillation of the paraconical pendulum were observed.

Further information on this phenomenon and recent efforts to reproduce Allais’s results can be found on this page, http://abcnews.go.com/sections/science/DyeHard/dye990915.html

Many scientists have trouble taking Allais’ claims seriously because, quite frankly, none of it makes much sense. There’s a near total eclipse once a month when Earth, the moon and the sun are nearly aligned at the time of a new moon, so a similar effect should be present then.

NASA has a very detailed page about this effect and efforts to test it during an eclipse in 1999 here, http://science.nasa.gov/newhome/headlines/ast06aug99_1.htm.

There are also a number of very interesting links (few of which I’ve had a chance to look at) on this page, http://naturalscience.com/ns/letters/ns_let23.html

[f36c]

But if you follow those links they are either written before the eclipse or just after before data had been assembled. No links to publication or anything. Plenty of interest beforehand, ABC, NBC, BBC etc and a paucity of links afterword.