"Mmmm, I've heard of it. Isn't that the theory, once held by people on earth, that the Earth was the center of all creation, and the sun revolved around it, not vice-versa?"
"That is the one. Now, though your race believed it to be a false theory—"
"It is false!" I protested.
"For Earth, yes. But not, you see, for Mars. This place where you now stand, this brief liaison-point between our dimension and yours, is the center of your physical universe."
"You're crazy," I said. "Why, the sun alone is too massive to swing about this planet, let alone everything else! It'd be like a small boy trying to twirl a ten-ton boulder on the end of a rope; even if he managed, somehow, to get it started in motion, within ten seconds it'd be swinging him!"
"And if this small boy had another ten-ton boulder on the other side of him?"
"Well—uh ..."
"And another one above, and below, and in all directions from him? What then?"
I thought it over. "He'd be a mighty tired boy."
"That is not funny."