-
Calculated the circumference of the Earth without leaving Egypt. His measurement was off by only 211 miles from the true measurement.
-
His first major astronomical work, the Almagest, contains reports of astronomical observations that he had made over the preceding quarter of a century.
-
He completed his manuscript telling how he came up with the heliocentric system, this put the Sun (helio) at the center of the solar system.
-
He published a small book, De nova stella, thereby coining the term nova for a "new" star. This is classified as a supernova and we know that it is 7500 light-years from Earth.
-
He founded the three laws of planetary motion. Based on his information, he knew the moon's gravity controls the tides.
-
Published his work sharing his three universal laws of motion.
-
He applied the general theory of relativity to the structure of the universe as a whole.