How much does the phase and position of the moon affect the weight of an object on the surface of the earth? For example, if a person at the equator on the equinox weighs 80 kg at noon when the moon is new, how much does he or she weigh at midnight that day? Conceptually, it would seem that it would have to be significant; otherwise, the height of the tides would not be significant. Also conceptually, it would seem that it would have to be non-zero, otherwise Lagrangian points wouldn’t work. On the other hand, if it is significant, how come it doessn’t come into play when jockeys and wrestlers try to make their weight?