Kepler determined that planets change their speed as they travel around the sun. This happens due to all of the following EXCEPT
A). The sun's gravity makes the planets slow as they get closer
B). The sun's gravity pulls against the planet's inertia in some places
C). The sun's gravity pulls with the planet's inertia in some places
D). The planets' orbits are elliptical
A). The sun's gravity makes the planets slow as they get closer
The correct answer is A) The sun's gravity makes the planets slow as they get closer.
To determine the correct answer to this question, we need to analyze the options provided. Kepler's laws of planetary motion describe the motion of planets around the sun. Let's go through each option and eliminate the incorrect ones.
Option A states that the sun's gravity makes the planets slow down as they get closer. This aligns with Kepler's first law, which states that planets move faster when they are closer to the sun. Therefore, Option A is incorrect.
Option B suggests that the sun's gravity pulls against the planet's inertia in some places. This is in line with Kepler's second law, also known as the law of equal areas. It states that a line connecting a planet to the sun sweeps out equal areas in equal intervals of time. This implies that planets are faster in regions closer to the sun and slower in regions farther away. Therefore, Option B is incorrect.
Option C states that the sun's gravity pulls with the planet's inertia in some places. This is consistent with Kepler's second law, as explained above. Therefore, Option C is correct.
Option D states that the planets' orbits are elliptical. This is Kepler's third law, also known as the law of harmonies. It states that planets move in elliptical orbits with the sun at one of the foci. While this statement is true, it is not an exception to the statement that planets change their speed as they travel around the sun. Therefore, Option D is incorrect.
In conclusion, the correct answer is Option C. The sun's gravity pulls with the planet's inertia in some places.