Kepler's Laws:
* Kepler's First Law (1609): Planets orbit the Sun in elliptical paths with the Sun at one focus.
* Kepler's Second Law (1609): A line joining a planet to the Sun sweeps out equal areas in equal times.
* Kepler's Third Law (1619): The square of a planet's orbital period is proportional to the cube of its average distance from the Sun.
Newton's Contribution:
* Law of Universal Gravitation (1687): Newton showed that every object in the universe attracts every other object with a force proportional to the product of their masses and inversely proportional to the square of the distance between them. This law provided the physical basis for Kepler's observations.
* Mathematical Derivation of Kepler's Laws: Newton used his laws of motion and universal gravitation to mathematically derive Kepler's laws, explaining them as a consequence of gravity. He showed that elliptical orbits are a natural consequence of the inverse square law of gravity.
* Explaining Orbits Beyond the Sun: Newton's work was not limited to the solar system. His laws could be applied to any two bodies in the universe, explaining the motion of moons around planets, stars in binary systems, and galaxies.
Summary:
* Kepler described how planets move, providing empirical laws based on observations.
* Newton explained why planets move the way they do, providing a physical explanation based on the force of gravity.
Newton's work provided a more fundamental understanding of planetary motion, extending its application beyond the solar system. It unified the seemingly separate laws of celestial mechanics and terrestrial motion, demonstrating the universality of gravity.
