Why there is tides on opposite sides of moon and Sun on the earth?
This link describes it very well: http://en.wikipedia.org/wiki/Tide It is probably not intuitive that there will be a tidal bulge opposite the moon. But it comes out of the solution of Newton’s laws of motion for the system. One way to think of it is that because the moon’s gravity decreases with distance, the side of the Earth away from the moon experiences less gravity than that close to it and combined with the centripetal force of the rotating Earth this causes the ocean to slop around to that side, as well as being pulled towards the moon on the closest side.
