Question

Imagine another solar system, with a star of the same mass as the Sun. Imagine the planets are just like those of our system, but are placed in the reverse order: going outward from the star there is Neptune, Uranus, Saturn, Jupiter, Mars, Earth and Venus. The distances remain the same. E.g., in the new system, Neptune is located the same distance from the star as our Mercury is from our Sun, etc. How would the orbital periods of each planet change?

A) The orbital periods would increase for all planets.
B) The orbital periods would decrease for all planets.
C) The orbital periods would remain the same.
D) The orbital periods would change in a non-uniform manner for different planets.

Answer 1

The orbital periods of the planets in the imagined solar system with a reverse order arrangement would remain the same as our solar system since the distances from their star are unchanged.

Step-by-step explanation:

If we imagine another solar system with planets placed in reverse order of our own system but maintaining the same distances from their star, the orbital periods of each planet would not change. According to Kepler's third law of planetary motion, the orbital period of a planet around its star is determined by the size of its orbit - specifically, by the semi-major axis of the ellipse that constitutes the orbit. Since the masses of the planets and the star, as well as their distances (semi-major axes), remain the same, the orbital periods will also remain the same. Therefore, the answer to the student's question is C) The orbital periods would remain the same.