Talk about the process of solar eclipse.

The principle of lunar eclipse. On the fifteenth and sixteenth days of the lunar calendar, the moon runs in the opposite direction to the sun. At this time, if the centers of the earth and the moon are roughly on the same straight line, the moon will enter the umbra of the earth and produce a total lunar eclipse. If only a part of the moon enters the umbra of the earth, a partial lunar eclipse will occur. When the moon enters the penumbra of the earth, it should be a penumbral eclipse, but it is not called an eclipse because the brightness drops very little, so there are only two kinds of eclipses: total eclipse and partial eclipse.

Eclipses always occur in sight (full moon), but not every time, which is the same as not every new moon has an eclipse. Under normal circumstances, the moon either passes above the Earth's umbra or leaves under the Earth's umbra, and rarely or partially passes through the Earth's umbra, so an eclipse will not occur under normal circumstances. Eclipses occur up to three times a year, and sometimes they never happen at all.

Lunar eclipse formation map

The process of lunar eclipse

The process of an eclipse can be divided into five stages: first loss, eating, eating, giving birth to light and last contact.

First loss: The moon has just touched the umbra of the earth, marking the beginning of the eclipse.

Eclipse: The western edge of the moon is inscribed with the western edge of the Earth's umbra, and the moon just enters the Earth's umbra.

Eclipse: The center of the moon is closest to the center of the Earth's umbra.

Luminescence: the eastern edge of the moon is inscribed with the eastern edge of the umbra of the earth, and the total solar eclipse phase ends at this time.

Final contact: the western edge of the moon is tangent to the eastern edge of the umbra of the earth. At this time, the whole eclipse was over.

The degree of eclipse is called "eclipse", which is equal to the ratio of the farthest distance from the edge of the moon wheel to the umbra of the earth and the meridian of the moon when the eclipse is serious.

In ancient times, people did not understand the scientific truth of solar eclipse, and the fear of solar eclipse was no less than that of solar eclipse. It is said in foreign countries that Columbus sailed to Jamaica in South America at the beginning of the16th century, and there was a conflict with the local aborigines. Columbus and his sailors were trapped in a corner, without food and water. The situation is very critical. Knowing that there would be a total lunar eclipse that night, Columbus, who knew something about astronomy, shouted to the natives, "No food, no moonlight!" " In the evening, Columbus's words came true, and there was no moonlight. When the natives saw this scene, they were afraid, so they quickly made peace with Columbus.

The solar eclipse in Mesopotamia in 2283 BC was the earliest in the world, followed by that in China in 1 136 BC. Eclipses have been promoting the development of human understanding. As early as 188 1 years ago, Zhang Heng, an astronomer in Han Dynasty in China, made clear the principle of lunar eclipse. In the 4th century BC, Aristotle saw that the shadow of the earth was round from the solar eclipse, but inferred that the earth was spherical. Alistair, an ancient Greek astronomer in the 3rd century BC, and Hipparchus in the 2nd century BC both proposed to measure the relative size of the Sun-Earth-Moon system through solar eclipse. Iba Valley also proposed to observe the lunar eclipse in two distant places at the same time to measure the geographical longitude. In the 2nd century AD, Ptolemy used the ancient lunar eclipse records to study the movement of the moon, and this method has continued to this day. Before the appearance of rockets and artificial earth satellites, scientists have been exploring the atmospheric structure of the earth by observing eclipses.