Geocentric model coelestium" ("On the Revolutions of the Heavenly Spheres"), which posited that the Earth and the other planets instead revolved around the Sun. The geocentric system was still held for many years afterwards, as at the time the Copernican system did not offer better predictions than the geocentric system, and it posed problems for both natural philosophy and scripture. The Copernican system was no more accurate than Ptolemy's system, because it still used circular orbits. This was not altered until Johannes Kepler postulated that they were elliptical (Kepler's first law of planetary motion). With the invention of the telescope in 1609,
Trading Places He explains that this axiom asserts its importance not in the fact that "our time" sees an increased expectation of new operas being developed but, rather, in the fact that there is an increased expectation of "new productions of operas." Cavell draws a comparison of themes between "Trading Places" and the opera "The Marriage of Figaro", stating that "what "Trading Places" wants from its reference to "Figaro" is mostly the idea of resourceful and sociable young and poor overcoming with various disguises the conniving of the unsociable old and rich but with no sense that the old may be redeemed