Question

What did Kepler prove?

Answer 1

Kepler's law

1. He was the first to describe the planetary motion correctly.

Kepler's Laws of Planetary Motion

1. First law -
   
   All the planets revolve around the Sun in elliptical orbits with the sun as one of the foci.
2. Second Law-
   
   The radius vector that runs from the sun to the planet sweeps out the same amount of area in the same amount of time.
3. Third Law - The cube of a planet's semi-major axis is directly proportional to the square of its time period of revolution around the sun in an elliptical orbit.
   Mathematical expression for Kepler's third law.
   ${\mathrm{T}}^2\propto {\mathrm{a}}^3$
   Where, $\mathrm{a}$ represents the planet's semi-major axis .
   $\mathrm{T}$ represents time period of revolution around the sun.