| Chapter 1: | The New Astronomy |
detect if the Earth were to revolve about the Sun, rather than if it were merely to rotate on its axis, because the Earth's orbit is necessarily larger than the Earth itself.
No one observed the parallax effect either daily or annually, implying either that the stars were extremely distant or that the Earth was stationary. Aristotle dismissed the first possibility because there would have to be a huge volume of space separating the Ancient Planets from Earth if the stars were so far away. He believed that this contradicted the doctrine of Final Cause, which held that creation was purposeful and everything in the Universe served a function. To him, “place” was a location where something should reside, so he argued that an intelligent Creator would not construct a Universe that was largely empty.
Figure 1.3. (a) (Upper) If circle AB represents the Earth's orbit, an observer moving from A to B will detect a larger angle AOB when object O is closer. By convention, one-half of angle AOB is the parallax angle. (b) (Lower) Two objects “O” lying on the Firmament (the supposed eighth sphere of the stars) appear farther apart when the Earth is closer (angle ObO) than when it is more distant (angle OaO).
