What would have to happen for a lunar and solar eclipse to happen every month?

Answer 1

First, you have to understand that the Moon has a tilt in its orbit. Its tilt is large enough to miss the Earth's shadow or the Sun's main stream of light. The Moon has to remove its orbital tilt for solar and lunar eclipses to happen every month. But eventually, the Moon will be far enough that it does not block enough sunlight for a solar eclipse to occur (this is because the moon is moving away from Earth because it orbits the Earth slower than the Earth rotates).

Answer 2

For a lunar eclipse to happen every month, the Moon would need to be in its full moon phase during every new moon, aligning perfectly with the Earth and Sun. For a solar eclipse to occur every month, the Moon would need to be perfectly aligned between the Earth and Sun during every full moon phase. However, this scenario is not possible due to the slight tilt in the Moon's orbit relative to Earth's orbit around the Sun.

Answer 3

In order to have regular eclipses visible from the earth's surface, the plane of the moon's orbit would have to be a lot closer to the plane of the ecliptic than it is now. The plane of the moon's orbit is inclined about 5.5 degrees to the plane of the earth's orbit. The result is that on most of the occasions when the sun, moon, and earth line up ... whether the moon is behind earth or in front of it ... the moon is usually far enough above or below the plane of the earth's orbit that nobody's shadow falls on anybody else ... the moon's shadow misses earth, or earth's shadow misses the moon, and there is no eclipse visible from earth. If the inclination of the moon's orbit were reduced to anything less than about 1/2 degree with respect to the ecliptic plane, then there would be at least partial lunar and solar eclipses every month. If the moon's orbit were exactly in the ecliptic plane, then all of the eclipses would be total.