Geocentrism and Relativity

Wiccan_Child said:

You question makes no sense: the Earth orbits the Sun, and the Sun orbits the Earth. We simply choose for conveniance to consider the Sun as motionless, and the planets fall into elegance around it. We could, for instance, consider the Earth to be motionless, in which case the Sun orbits around the Earth. Of course, the other planets would then orbit the Sun. Hence why it is natural to consider the Sun, not the Earth, as one of the focal points of orbit.

Also consider the notion of binary stars: does star A orbit star B, or vice versa? The answer is neither: they both orbit each other around a common center. Since the Sun doesn't have a sister star to dance with, it becomes a single massive point around which most (if not all) solar planets orbits (depending on which frame you're looking in, of course).

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BrainHertz said:

One important question about the binary star example: why not consider the possibility that they are not orbiting at all, but it is the rest of the universe (including us) that is rotating about them, with both stars simply hanging in space for some reason and not falling in towards each other?

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Wiccan_Child said:

Because this would require the rejection of gravity That said, the entire universe (the binary stars included) could be rotating around a the center of mass of the binary system.
Of course, this model falls folly to the usual geocentrism flaw: it requires that very distant particles (from galaxies to interstellar dust) have an angular velocity far exceeding the speed of light. Unless you're willing to throw out special relativity (which I don't recommend! ), this simply doesn't happen.

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