The moon is sometimes round and sometimes curved, mainly because the positions of the earth and the moon are changing.
The moon is the floorboard of the moon and the satellite of the earth. It doesn't shine by itself, but its light reflects the sun. The moon is the fifth largest satellite in the solar system, with an average radius of about 1737. 10 km, equivalent to 0.273 times that of radius of the earth. The mass is close to 7.342× 1022 kg, which is 0.0 123 times that of the earth [1]. The surface of the moon is covered with craters, which may be formed by the impact of small celestial bodies. The average distance between the moon and the earth is about 384,400 kilometers, which is about 30 times the diameter of the earth.