The Changing Process of the Moon in Mid-Autumn Festival

The order of moon phase change is: new moon-waning moon-first quarter moon-convex moon-full moon-convex moon-second quarter moon-waning moon-new moon, and so on. The moon phase changes periodically, with a period of about one month.

The period of the moon phase is 29.53 days, which is called the new moon. It is the source of calendar months and weeks.

This time is longer than the moon's revolution (sidereal moon), because the moon revolves around the earth at the same time, and the moon will revolve around it for a lunar month (360+360 * 29.53/365.24) = 389.438+01degree (revolution only revolves around 360 degrees). So a sidereal month is about 29.53 * 360/389.11= 27.32 days.

Reason:

Because the moon itself is not luminous and opaque, under the sunlight, half of the sphere facing the sun is bright and the other half is dark (blocked by itself). Because the position of the moon relative to the earth and the sun has changed, the side irradiated by the sun sometimes faces the earth and sometimes faces away from it; Sometimes the bright part facing the earth is larger, and sometimes it is smaller, so there are different moon phases.

Can be simply summarized as two:

1, the moon is not luminous and opaque.

2. It is related to the relative positions of the moon, the earth and the sun.