Earth always has two surrounding gravitational forces, one proceeding from the moon and one from the sun.
The sun's pull, despite the fact our sun is further then the moon, is stronger and creates the high tide, and the moon the low tide. But as we know our earth moves, now exposing the other side to the sun which in turn leaves the other side of earth with the high tides and the other with the low tides. Tides never move, what moves is earth.
