In what frame(s) of reference are Kepler’s laws valid? Are Kepler’s laws purely descriptive, or do they contain causal information?

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Kepler’s 1st law states that the sun in the center of an elliptical orbit is at focus.

Kepler’s 2nd law states that the planet in the orbit moves as the line drawn from the sun is equal to times and area.

Kepler’s 3rd law states that is the ratio of squares of any two planet around the sun is equal to the ratio of cubes and the average distance from sun.