einherjer

could the orbits not be be situated, perhaps by additional orbits of "moons" or something to keep the orbit from decay, or would you not be able to get a favorable EROEI? I would think it would be possible (theoretically, at least) to get a perfect "non-decaying orbit" if it was possible to crunch all the numbers with enough accuracy to where the orbiters neither moved further or nearer with each orbit.

@Lemur: I'm not sure what that had to do with my question, or what significant contribution it had to the thread beyond what was already stated.

First time poster, and I have no formal education; however, I do have a question. Regarding gravity as a power source: The planet Europa orbits Jupiter within it's immense gravitational field. Europa also feels gravitational effects from other Jovian moons, which creates heat energy. I understand that Einstein said "There ain't no such thing as a free lunch" or something to that effect with regards to energy, but where's the x-factor? Why couldn't infinite energy be harnessed out of 2 objects with an appreciable amount of gravity not orbit some massive, stellar hunk of magnet and copper wire and get an infinite supply of energy from it?