Reb Eliezer,
“According to Newton and Ptolemy’s view as every heavenly body has a gravitational pull based on its size, so why does not the enormous gravitational pull of the sun dislodge the earth from being stationary in the center?”
If we choose our position on Earth to be a stationary frame of reference, which is a valid thing to do, then the sun is not stationary within that frame of reference. However, when constructing Newton’s Laws using Earth as a stationary frame of reference, we find some interesting forces that we must account for, such as a Coriolis Force that increases with latitude, centrifugal force, etc. These “fictitious” forces are why many people whine about Earth not being a true stationary frame of reference. A stationary Earth surface is useful for terrestrial-based calculations, such as weather models, flight paths, etc. But when launching a rocket to the Moon or Mars, or tracking asteriods and comets, it might be more useful to pick a different frame of reference.