Question

Which did Kepler notice about planetary motion that caused him to propose Kepler’s first law of orbital motion?

Answer 1

Kepler noticed that the orbits of the planets were ellipses, leading to Kepler's first law of orbital motion.

Step-by-step explanation:

Kepler noticed that the orbits of the planets were not perfect circles, as previously believed, but were actually ellipses. This observation led him to propose Kepler's first law of orbital motion, which states that each planet moves around the Sun in an orbit that is an ellipse, with the Sun at one focus of the ellipse.

Answer 2

The motions of the planets in the solar system made Keppler propose the laws of planetary motion.

Step-by-step explanation:

• The motions of the planets in the solar system made Keppler propose the laws of planetary motion.
• In simple words, Kepler's first law can be defined as all planets moved around the sun in the elliptical orbit having the sun as one of the foci.
• Kepler’s first law means that planets move throughout the Sun in elliptical orbits. An ellipse is a shape that follows a levelled circle.