I see what you mean, I think. But aren't you forgetting that the direction of the earth's gravity will swap direction, and start to decrease as you move along the moon-earth axis from the moon and pass through earth?
Originally Posted by Ken G
I have a feeling I'm completely missing your point, Ken G , maybe this'll at least clarify how I'm going wrong. This is how I pictured it. Each number is the gravity vector pointing left and decreases linearly from each body. The first line is the moon's; second, the earth's; and third, the net g.
As you can see, three units from the earth's center we have vectors pointing towards the earth's center but one has a magnitude of 9 and the other 19. What we do get, though, is a constant difference in magnitude of 10 between the near and far side, is that what you meant?
M 10 9 8 7 6 5 4 3 2 1 0 -1?
-15 -16 -17 -18 -19 E 19 18 17 16 15
g -5 -7 -9 -11 -13 23 21 19 17 15