The three rules of planetary motion that Kepler proposed can be rephrased as follows: (1) The orbits of all planets around the sun are elliptical, with the sun serving as one of the foci of the ellipse. (2) A radius vector that connects any planet to the sun will cover the same amount of territory in the same amount of time.

## How did Kepler change the heliocentric theory?

Johannes Kepler published his laws of planetary motion between the years 1609 and 1619.These laws are used in the field of astronomy to define the paths the planets take around the sun.The rules improved Nicolaus Copernicus’s heliocentric theory by explaning how planetary velocities might change and by replacing circular orbits and epicycles with elliptical trajectories.

- This was accomplished by replacing the circular orbits and epicycles with elliptical paths.

## What is the area form of Kepler’s Second Law?

‘ (But when he saw that it didn’t agree at all with observations, he modified his thinking, and he claimed that a line, which represents a planet’s genuine motion, sweeps out equal regions of an ellipse in equal periods of time:) ‘ ^ Wilbur Applebaum (2000).