Perpetual Mobile and Gravitation I have fundamental question about what is called the “law of conservation of energy”.
We all hear about the tidal power stations which using the tidal power. The source of the tidal power came from the changes in the gravity field between the moon and the earth. Allegedly, because of the law of conservation of energy this influence must cause to some energy lose in the moon or the earth. And indeed we know that the moon orbit get longer and slower over time. My question is, are we really must say that the energy of the tide and the loss of the kinetic energy of the moon are equal? 
According to the general relativity theory the gravitation is the time space curve effect of a big object. This curve is not “energy consuming”, which means basically - two objects can spin around each other in space forever even that such a spin is a change in momentum that should consume energy according to the classic theory. The question is did the tidal effects caused by that “miracle” eternity momentum changes are indeed “energy consuming”?
Let's imagine that instead of the moon, there is black hole and the earth is spinning around it. This can cause to tidal power effects exactly like happen by the moon. This energy coming from the black hole which means that the black hole mass must be reduce according to the equation of $E=mc^2$. This is against what we know about black holes which are never losing any mass. 
But if the answer is “no” that mean in other words that the tidal power stations are kind of “Perpetuum Mobile” - creating energy from nothing. This is of course a weirder conclusion.
 A: My question is, are we really must say that the energy of the tide and the loss of the kinetic energy of the moon are equal?


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*The answer is obviously "YES." It must be so. I would refer at this point these words;


Nature is relentless and unchangeable, and it is indifferent as to whether its hidden reasons and actions are understandable to man or not.- Galileo Galilei
Because the answer I have in my desk right now is (not yet) "Mainstream Physics", quite similarily as the thoughts of Galileo's wasn't either. You ask further; 
The question is did the tidal effects caused by that “miracle” eternity momentum changes are indeed “energy consuming”?


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*Still; YES. Yet, the building of Tidal power stations shouldn't have any impact to this energy consumption. The very same energy would only be transferred to heat on viscous losses of water. So there is no need to argue against tidal power.


There is no Perpetual Mobile, but one; the whole universe. And the existence of this "Perpetual Mobile" is proved by many. But no, Though two objects could theoretically spin in space forever, in reality they wont. They are loosing matter and thus also energy all the time. Slow but sure, down to the drain. Gas, fluid or solid, it doesn't matter. It all comes to an end. And this is the only thing that ever aloud the new start, and thus -development.
Ps. The only thing which made Galileo's physics as a not Mainstream physics was the fact that he was at that point actually the only one who had very detailed observed certain phenomenons. I ie. encourage you to calculate the time which is needed to stop the rotation, if tides looses only 1% of their energy per shift, or 0.01%. Or what ever number which makes them different from a Perpetual mobile. After doing this I encourage you to look more details. If interest; contact me and I send you few hints to start with. The smallest detail can cause the turn even of the greatest mainstream.    
