Moon phase, an astronomical term, refers to the different images of the moon illuminated by sunlight seen on earth. Moon phase is the name in astronomy for the part of the moon illuminated by the sun seen on earth. As the moon moves a long distance from east to West in the starry sky every day, its shape is constantly changing. This is the phase change of the moon, which is called the phase of the moon.
Moon phase refers to the name of the moon illuminated by the sun seen on the earth in celestial literature. The movement of the moon around the earth makes the relative positions of the sun, the earth and the moon change regularly in a month. Because the moon itself does not emit light and is opaque, the visible part of the moon is the part that reflects sunlight. Only the part of the moon that is directly illuminated by the sun can reflect sunlight. We can see the part of the moon directly illuminated by the sun from different angles, which is the source of the moon phase.