An Alternate History Science Fiction / Fantasy novel by Richard Garfinkle, published in 1996. Unlike our world, the universe of Celestial Matters obeys Ptolemaic astronomy, Aristotelian physics and Chinese Taoist alchemy. The earth is the center of the universe, with all the planets as well as the sun and moon revolving around it, set in a fixed sphere of stars. The timeline of this world also diverged from ours; the empire of Alexander the Great never collapsed, but grew and encompassed half the world.