The history of viewing gravity-related phenomena when solar eclipses occur is lengthy, and the narratives surrounding an eclipse’s “totality” are even more substantial.
When the moon comes between the earth and the sun, there occurs a phenomenon, known as solar eclipse. In 2026, it is predicted that there will be at least 5 eclipses occurs, but there are only two eclipses which are true total eclipses. But total eclipses are rarely seen on the earth.
Original caption from NASA: "S103-E-5037 (21 December 1999)--- Astronauts aboard the Space Shuttle Discovery recorded this rarely seen phenomenon of the full Moon partially obscured by the atmosphere of Earth. The image was recorded with an electronic still camera at 15:15:15 GMT, Dec. 21, 1999.".
The Effect of the Sun
On this image the following are also depicted: the synchronous rotation of the Moon, the motion of the Earth around the common center of mass, the difference between the sidereal and synodical month (green mark), the Earth's axial tilt.
The sun can be viewed even if it is under the horizon due to the effect of atmospheric refractions. Before the actual sunrise and after the actual sunset, we can see the sun but in a specified location only. When partial or total eclipse occurs, the sky seems dark even when there is the sun.
The Period of Saros
Pendule de Foucault du Panthéon de Paris
Lunar effects occur every 177 days in which brief cycles of eclipses reiterate. These are temporary cycles which are known as sets and these cycles exist for three to four years. It happens in places where the moon’s orbit rises or falls. There is a stoppage of cycles when the moon’s orbit misses the earth, i.e. there is an intersection of the moon’s shadow with the end of north or South Pole of the earth. After every 18 years, there are five different sets which are known as Saros period.
The Effect of Movement
Animation of a fictitious pendulum of Foucault of 67 meters released at a distance of 50,25 meters (3/4 its length) in the east with a null speed.
The solar corona becomes visible when the moon eclipsing the sun. Since, the corona is not dark as the sun so it is visible only when the sun is set. The transparent photograph was taken by Bernard Leon Foucault with Armand Fizean, a physicist in 1845.
But there is confusion with a solar eclipse and its consequences on the Foucault pendulum. In 1954 and 1959, Maurice Allaise found that the movements of Foucault pendulum were strange so they could not explain when a solar eclipse occurs. This is just a hypothesis. But the movements which Maurice Allaise hypothesized did not fall under the category of Foucault phenomenon. So this effect termed as Allaise effect. There were also other changes which occur when the torsion pendulum move and the movements are called Saxl effect.
Example of solar coronal loops observed by the Transition Region And Coronal Explorer (TRACE), 171 Å filter. These loops have a temperature of approximately 106 K.
The length of the day is extended to 2.3 milliseconds per century due to the rate of rotation of earth. This effect is so small but over long terms its effect cannot be ignored. The rotational rate of earth gets minimized by 40 seconds in each century. But it is increased by 1 hour in a millennium. The time difference is measured by a quantity known as Delta-T. Many phenomenons have done in predicting the precise value of delta-t both in past and future. These are climatic effects like global warming, polar ice caps etc.