According to this idea, an observer can not tell the difference between free falling in a gravitational field and floating in deep space. (sciencedaily.com)
The point is that none of the molecules in the system ever climb up in the gravitational field in equilibrium. (wattsupwiththat.com)
The moon, in contrast, stores much less of its energy in its gravitational field, so its gravitational field will make a much smaller contribution to its motion toward the sun. (sciencemag.org)