Why aren the lunar apogee and perigee distances the same from month to month?
First, an obvious point. The reason that the Moon (full or otherwise) appears to be larger at perigee is that it is closer. What is not obvious, though, is that a full Moon does not always occur at perigee or apogee. The Moon’s orbit is stable, having only very slight variations. The reason for the differing size of the moon at each full Moon has to do with the orbit of the Moon in relationship to the Earth’s position around the Sun. At some times, the moon is full at perigee, at others, at apogee. If you were to take a picture of the moon each night from one new moon to the next and measure the diameter of the moon in each, you would have one picture where the moon is close to perigee and its diameter is close to the maximum we see, and one picture where the moon is close to apogee and its diameter is close to the minimum we see. This happens every month. Do this. Take a sheet of notebook or printer paper. Put a dot in the middle of the paper to represent the Sun. Now draw a large cir
