PtolemyLived 87-150 AD
Geocentric Model: Ptolemy thought that the planets orbited the Earth in this order: Mercury, Venus, Sun, Mars, Jupiter, Saturn because no one felt the Earth moving and because the other planets, the Sun, and the stars seemed to be moving around the Earth.
Feb 19, 1473
Nicholas CopernicusLived 1473-1543
Heliocentric model: Copernicus thought that the planets orbited the Sun, not the Earth because of the rising and setting of the Sun, Moon, and stars and because the other planets rotated so he thought Earth did too.
Feb 15, 1564
Galileo GalileiLived February 15th, 1564-January 8th,1642
Galileo explained how to make the telescope have a wider range and work better so that he could see Jupiter's monns and the Moon's rough surface.
Dec 27, 1571
Johannes KeplerLived 1571-1630
Elliptical orbits: Kepler discovered that the orbits of the planets were not flattened circles but ellipses
Sir Isaac NewtonLived December 25th,1642-March 20th,1727
Universal Law of Gravity and Inertia: Newton explained That... Law of Gravity: Every object in the universe attracts every other with a force directed along the line of centers for the two objects that is proportional to the product of their masses and inversely proportional to the square of the separation between the two objects. Law of Inertia: A body will preserve its velocity and direct so long as no force in its motion's direction acts on it.