How are solar and lunar eclipses formed?

The formation principle of solar eclipse and lunar eclipse is due to the linear propagation of light.

First, the formation of the solar eclipse

Solar eclipse is a special astronomical phenomenon. When the moon moves to the shadow of the earth, the area between the moon and the earth will be blocked by the earth because of sunlight, and the moon will be missing.

At this time, the sun, the earth and the moon are exactly (or almost) on the same straight line. Eclipses can be divided into three types: partial eclipse, total eclipse and penumbral eclipse.

Second, the formation of the solar eclipse

A solar eclipse, also known as an eclipse, is when the moon moves between the sun and the earth. If the three are in a straight line, the moon will block the light from the sun to the earth, and the shadow behind the moon will just fall on the earth. At this time, the solar eclipse happened.

Extended data:

When the moon moves between the sun and the earth, it is not always like this. When a lunar eclipse occurs, two conditions need to be met.

First of all, the solar eclipse always happens on the first day of the lunar calendar. Not all eclipses will happen on the first day of the lunar calendar, because the orbit of the moon (ecliptic) and the orbit of the earth (ecliptic) are not on the same plane. There is an included angle of 59 between the ecliptic plane and the ecliptic plane.

Secondly, both the sun and the moon move near the intersection of the ecliptic and the ecliptic, and the sun forms a certain angle with the intersection (eclipse limit).

Because the orbits of the moon and the earth are not perfect circles, and the distance between the sun and the moon is near or far, the shadow formed by the sun being blocked by the moon can be divided into umbra, pseudo-umbra (formed when the moon is far away from the earth) and penumbra on the earth. The observer can see the total solar eclipse in the umbra; Annular eclipse can be seen in the range of pseudoumbra; Only a partial solar eclipse can be seen in the penumbra.

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