Our Understanding of the Universe

Ptolemy

100

Birth: 100 AD, Alexandria, Egypt
Death: 168 AD, Alexandria, Egypt
Discoveries: Ptolemy was an astronomer and mathematician. The word for earth in Greek is geo, so he called this idea a "geocentric" theory. He believed that the Earth was the center of the Universe.
Influence:

Copernicus

1473

Born: 19 February 1473, Toruń, Poland
Died: 24 May 1543, Frombork, Poland
Discoveries: Nicolaus Copernicus was a Polish astronomer who put forth the theory that the Sun is at rest near the center of the Universe, and that the Earth, spinning on its axis once daily, revolves annually around the Sun. This is called the heliocentric, or Sun-centered, system.

Kepler

1571

Born: 27 December 1571, Weil der Stadt, Germany
Died: 15 November 1630, Regensburg, Germany
Discover: German astronomer who discovered three major laws of planetary motion