Question

The statements in the table summarize what Johannes Kepler stated in the early 1600s about the motion of planets.

Kepler’s Statements
The orbit of a planet around the sun is an ellipse.
As a planet orbits the sun, a line between the planet and the sun sweeps out equal areas during equal periods of time.
There is a mathematical relationship between the time it takes a planet to orbit the sun and the average distance the planet is from the sun.
Over the last four hundred years, predictions based on his statements have proven true. Which best describes Kepler’s statements?

hypothesis
theory
law
explanation

Answer 1

law

Kepler’s three statements describe consistent, predictable relationships observed in planetary motion (empirical rules now called Kepler’s laws). A "law" summarizes observed regularities; a "theory" would explain why those regularities occur (e.g., Newton’s theory of gravitation explains Kepler’s laws).