Finally, the Moon appears to tilt back and forth like a metronome. The tilt of the Moon’s orbit contributes to this, but it’s mostly due to the tilt of our Earth. Earth has a tilt of 23.5 degrees on its axis, which means that when we observe the Moon from Earth, it’s a little like we’re standing sideways on a ramp. If you look left, the ramp slopes up. If you look right, the ramp slopes down. In front of you, the horizon looks higher on the right and lower on the left. If you turn around, the horizon appears to tilt the opposite way.
