Why don't lunar and solar eclipses happen every month?

Lunar and solar eclipses do not occur every month primarily because the Moon's orbit is tilted relative to the Earth’s orbit around the Sun. The tilt, which is about 5 degrees, means that during most months, when the Moon is new (for a solar eclipse) or full (for a lunar eclipse), it is usually above or below the direct line of sight between the Earth and the Sun.

For an eclipse to happen, the Sun, Earth, and Moon must be aligned in a straight line. Given the tilt of the Moon's orbit, this perfect alignment only occurs during specific times known as eclipse seasons, which happen approximately every six months. Therefore, even though the Moon completes its orbit around the Earth roughly every 29.5 days, the tilt prevents eclipses from occurring every month.

Understanding the role of the orbital tilt helps clarify why these events are relatively rare, emphasizing the importance of orbital geometry in celestial mechanics.