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During Tycho Brahe's era of the late 1500's, society was struggling between the Aristotelian and Copernican models of the universe. The conservatives supported the Aristotelian theory, even though the views were becoming out of date, and the radicals or current scientists supported Copernicus' theory of the earth revolving around the sun.
Tycho developed a system that combined the best of both worlds, though still incorrect. He kept the Earth in the center of the universe, so that he could retain Aristotelian physics (the only physics available). The Moon and Sun revolved about the Earth, and the shell of the fixed stars was centered on the Earth. But Mercury, Venus, Mars, Jupiter, and Saturn revolved about the Sun. He put the (circular) path of the comet of 1577 that he had discoverd between Venus and Mars. This Tychonic world system became popular early in the seventeenth century among those who felt forced to reject the Ptolemaic arrangement of the planets (in which the Earth was the center of all motions) but who, for various reasons, could not accept the Copernican alternative.