[Renfield]

This is a very silly post. The Allais effect is only puzzling to someone who fails to view the Earth, the moon, and the sun as a single system.

All objects with mass exhibit gravitational force. The force of gravitational attraction between 2 objects is inversely proportional to the square of the distance between those two objects, so the farther away the objects are from each other, the weaker the attraction is, but it is still there. The Earth, for example, has a gravitational attraction for Pluto, and vice-versa, even though they are billions of miles apart. So, the gravitional force that an observer measures is related to his distance from the center of mass of all those objects that are exhibiting gravitational force on him.

When the moon is on the opposite side of the earth from the sun, the center of mass of that system is slightly farther away from the observer on the surface of the earth, than if the moon is in line between the earth and the sun. When the moon eclipses the sun, it is directly in line between the earth and the sun, so the center of mass (and the center of gravitational attraction) will have its maximum shift sunward along a line stretching between the earth and the sun...and near which the observer of the eclipse will be. (I am ignoring the effects of variations in the moon's orbital radius). The pendulum swings faster because it is closer to the center of gravitational attraction of the system, making gravity ever-so-slightly greater.

[KarlInOhio]

If that were the cause, there would be a gradual change during the day as the point of measurement changed distance from the center of mass. The maximum and minimum times would change as the location of the moon changed during the month. However the paper the article references shows a definite spike during the eclipse. If the measurements are correct, something stranger is going on.

[Physicist]

The pendulum swings faster because it is closer to the center of gravitational attraction of the system, making gravity ever-so-slightly greater.

That doesn't work, because the Earth is in free-fall with respect to the combined sun-moon system. The only part that doesn't cancel is the gravitational gradient, AKA the tidal force, and this definitely is greater during an eclipse.

[SauronOfMordor]

When the moon eclipses the sun, it is directly in line between the earth and the sun, so the center of mass (and the center of gravitational attraction) will have its maximum shift sunward along a line stretching between the earth and the sun...and near which the observer of the eclipse will be.

If so, then the effect should also be observed whenever the moon is more-or-less in line with the sun (ie, once every month), rather than exclusively being seen during an eclipse

[boris]

Someone said, "If you cannot say it in numbers you don't understand it," or words to that effect.

So let's see some equations and confirming calculations, please--otherwise you are blowing hot air.

--Boris

[aruanan]

This is a very silly post. The Allais effect is only puzzling to someone who fails to view the Earth, the moon, and the sun as a single system.

When the moon is on the opposite side of the earth from the sun, the center of mass of that system is slightly farther away from the observer on the surface of the earth, than if the moon is in line between the earth and the sun.

And you're saying this about astronomers and physicists. Ha ha ha. You're comparing the gravitational attraction of the moon on an object on earth with relationship to the sun, the object being either between the sun and the moon or the moon being between the object and the sun. This difference in gravitational pull isn't what the difference noted in the Allais effect is talking about. The Allais effect is a change in the period of the pendulum that is observed during the period of totality and only within the zone of totality. The change begins and ends with that short period of totality.