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Jim, you're still making the Earth's frame of reference privileged. The Earth is not the center of anything.

The gravitational field at any point results from all the mass in the universe, not just the Earth's.

If the lab is on the Earth's surface but the observer doesn't know it -- all that the observer can see is an accelerated astronaut -- the observer in the lab cannot distinguish between these two options regarding the scale reading: (1) it results from a gravitational field "g" in the downward direction; (2) it results from being in an accelerated frame of reference with acceleration "g" in the upward direction. (Actually, there are an infinite number of other options, combinations of gravity and acceleration yielding the same net result.)

Jim's comments are a perfect illustration of how hard it is to give up the notion of a privileged frame of reference.

Even Copernicus, who was willing to give up Earth's centrality, assumed that the Sun was the center of everything. So Jim is in excellent company.

Fred Bortz -- Science and technology books for young readers (www.fredbortz.com) and Science book reviews (www.scienceshelf.com)