 Greek  Believed the universe is spherical and finite  Planets center around the Earth  His theory that the sun and planets revolve and are centered around the Earth is called Geocentric  Successfully explained the phases of the moon and eclipses

 Greek  Wrote a book stating that he also believed Aristotle's theory  Also thought that the Earth was the center of the universe (geocentric)  Thought the order started with the Earth which he said was the center. Then Mercury, Venus, Sun, Mars, Jupiter, and then Saturn  This theory was accepted for 1500 years

 Polish  First to say that the sun was the center of the universe  His theory stated that Earth and all planets revolve around the sun in a circular path.  He was correct except that the planets revolve in an ellipse (oval) path not circular discovered by Kepler (German).  The theory that the planets are centered around the sun is called heliocentric. We still believe this theory today.

 Italian  Agreed with Copernicus’s heliocentric theory and improved the telescope  Observed the moon’s surface and discovered that our moon has craters  Observed Jupiter's moon

 German  Three laws of motion explained how the planets circled the sun  Planets revolve around the sun in an ellipse (oval) path

 English  Created a new and improved telescope  Suggested that gravity determined the planet’s orbits around the sun.

 American  Invented the Hubble Space Telescope  Observed hundreds of billions of galaxies

 Revolution- A planets orbit around the sun  Rotation- The spinning of a planet on it’s imaginary axis.  Gravity- The force of attraction between two bodies.  Atmosphere- The gaseous mass surrounding a planet.

 Located inside the asteroid belt-  Mercury, Venus, Earth, and Mars  Rocky planets are sometimes called terrestrials

 Located outside the asteroid belt-  Jupiter, Saturn, Uranus, Neptune, and Pluto  Also known as the gas giants except Pluto.  Pluto is closer to the rocky inner planets in composition.