Frank L. H. Wolfs
Department of Physics and Astronomy, University of Rochester, Slide 19
Sir Isaac Newton, a portrait by Kneller in 1702.
National Portrait Gallery in London.
Before Einstein:
Newton's laws of motion and gravity.
¥Using Newton's laws of motion, physicists could explain many phenomena in astronomy:

¥The orbits of planets around the sun.

¥The orbits of the moons around the planets.

¥The tides.

¥The existence of undiscovered planets and moons (such as Uranus, Neptune, and Pluto).