Why does the moon only have day and night, but not four seasons?

This article answers the question of why there are only day and night on the moon, but no seasons. It explains that the alternation of day and night on celestial bodies results from the difference in their periods of rotation and revolution. The moon, which revolves around the Earth and the Sun with a period of one year and a period of one month for its rotation, experiences an alternation of day and night with half a month of daylight and half a month of night, accompanied by extreme temperature differences. At the same time, it shows that for celestial bodies to have seasons, they must simultaneously meet two conditions: orbiting the Sun and having a certain inclination between the plane of their rotation axis and that of their revolution orbit. Since the rotation axis of the moon is nearly perpendicular to the plane of the Earth's revolution orbit, it does not have seasons.

Why does the moon only have day and night, but not four seasons?

All planets orbiting stars, or satellites of planets, will experience day and night alternation on their surfaces if their rotation periods differ from their orbital periods around stars. Day represents light, and night represents darkness. The word "time" used to describe the passage of time originates from this. The moon takes a year to orbit the Earth around the Sun, while its rotation period is one month. Therefore, the moon experiences day and night alternation, with half a month being daytime and half a month being nighttime. During the day, it's extremely hot, with temperatures reaching up to 127°C; at night, it's extremely cold, with temperatures dropping as low as -183°C.

The reason why planets or satellites have seasons is firstly due to their orbital motion around the Sun, and secondly because the axis of their rotation is not perpendicular to the plane of their orbital path. For example, the Earth's axis of rotation is tilted at an angle of about 23.5°. From June to September, sunlight directly shines on the Northern Hemisphere, so the Northern Hemisphere experiences longer days and shorter nights, with hot weather; while from December to March, sunlight directly shines on the Southern Hemisphere, and the Northern Hemisphere experiences shorter days and longer nights, with cold weather. The situation is reversed in the Southern Hemisphere. If the Earth's axis of rotation were not tilted, even if it orbited the Sun, there would be no change in the seasons. Although people could measure the orbital period based on the changes in the stars, they would not experience the alternation of seasons, the passage of time, or the monotonous cycle of day and night. Mars, Saturn, and Neptune are similar to the Earth in this regard. Mercury, Venus, and Jupiter have almost no tilt in their axes of rotation, so they also do not experience seasons. The moon's axis of rotation is nearly perpendicular to the plane of its orbital path around the Earth, so the moon also experiences day and night alternation, but there is no change in seasons even though it takes a year to orbit the Earth.