If the gravitational effect of the moon influences tidal forces on earth, doesn't that violate the 2nd law of thermodynamics? If gravity is a force and not energy, and only forms of energy can convert into other forms of energy. Then how can gravity create tidal forces, which are kinetic energy??? Kinetic energy from tidal forces can then be converted into electrical energy here on earth. So you have a situation where gravity is being converted into "work" and dare I say "perpetual motion". Remember according to physics only energy can convert energy. Oh I forgot, the planets revolving is kinetic energy of corse, but what made them revolve? Oh the force of gravity, right. So we are back to gravity again. If there was no gravity there would be no "kinetic" energy. Yet how can a force create or convert energy? If someone mentions the sun in all this, then it's just another example of gravity acting on the planets and not solar energy. Tidal forces have little to do with solar energy, it's gravity that are responsible for high and low tides.