Question

Which contributions did Johannes Kepler make? Select three options.

He revived Aristotle’s model of the solar system.
He solved Ptolemy’s model by proving elliptical orbits.
He proved Galileo’s calculations were incorrect.
He determined that planets move faster when closer to the Sun.
He discovered laws of planetary motion.

Answer 1

Correct choices:
- He solved Ptolemy’s model by proving elliptical orbits.
- He determined that planets move faster when closer to the Sun.
- He discovered laws of planetary motion.

Brief why:
- Kepler replaced the older Ptolemaic/circular-epicycle picture by showing planetary orbits are ellipses (first law).
- His second law (equal areas in equal times) implies planets travel faster when nearer the Sun.
- Together with his third law (harmonic law) these are the three Keplerian laws of planetary motion.

Why the others are wrong:
- He did not revive Aristotle’s geocentric model — he advanced heliocentrism.
- He did not “prove Galileo’s calculations were incorrect”; Kepler generally supported telescopic discoveries and derived complementary laws of motion.