A prediction of the general relativity is that any moving mass produces fluctuation in the space-time fabric, commonly referred as Gravitational-Wave.
This prediction was recently confirmed by the LIGO experiment.
The generation of such gravitational waves requires energy, as stated on the wiki article linked above:
Water waves, sound waves, and electromagnetic waves are able to carry energy, momentum, and angular momentum and by doing so they carry those away from the source. Gravitational waves perform the same function. Thus, for example, a binary system loses angular momentum as the two orbiting objects spiral towards each other—the angular momentum is radiated away by gravitational waves.
The first law of thermodynamics states that:
The first law of thermodynamics, also known as Law of Conservation of Energy, states that energy can neither be created nor destroyed
Given that, one can imply that any moving object having a mass would create gravitational waves - even ever so tiny -, thus having a drag.
How does a system, for instance earth-moon orbit, can be stable and not decaying over time over the model of the general relativity? (Where does the energy comes from?)
Is this question solved?