Suppose one tries to explain Rømer's measurements in the Ptolemaic model (adding the Galilean moons) with circular orbits and Earth in the center of the system. How could the differences in eclipse times be explained?
A) The later times would still occur when Jupiter is at conjunction and the earlier times when Jupiter is at opposition.
B) The later times would occur when Jupiter is moving westward with respect to the stars and the earlier times when Jupiter is moving eastward with respect to the stars.
C) The later times would occur when Jupiter is moving eastward with respect to the stars and the earlier times when Jupiter is moving westward with respect to the stars.
D) Jupiter in this model is the same distance from Earth at all times so no explanation is possible.

Question

Quizplus · Accepted Answer

In the Ptolemaic model, the later times would be explained by Jupiter moving eastward with respect to the stars, as this would imply that Earth is on the opposite side of its orbit around the Sun, increasing the distance light has to travel. The earlier times would occur when Jupiter is moving westward, indicating Earth and Jupiter are on the same side of the Sun, reducing the distance and thus the time it takes for light from Jupiter's moons' eclipses to reach Earth.

Suppose One Tries to Explain Rømer's Measurements in the Ptolemaic