1. Observing the Solar System Mrs. Davis Earth Science

2. Solar System in Order My – Mercury Very – Venus Educated – Earth Mother – Mars Just – Jupiter Served – Saturn Us – Uranus Nine – Neptune Pickles - Pluto

3. Wandering Stars ► The Greeks noticed that the stars had a pattern that did not change but they noticed that there seemed to be five points of light that wandered among the stars. ► They called these objects planets which means “wandering star”. ► These planets were Mercury, Venus, Mars, Jupiter, and Saturn.

4. Greek Ideas: Earth at the Center ► Aristotle Believed that the universe is perfect and finite and that Earth is stationary at its center. Geo – means Earth Geo centric system – Earth is at the center of the revolving planets.

6. Ptolemy ► He thought that Earth is at the center of the system of planets. The moon, Mercury, Venus, the sun, Mars, Jupiter, and Saturn revolve around Earth. ► The planets move in little circles that move in bigger circles.

7. Nicolas Copernicus ► Thought that the sun was the center of the universe. ► His sun-system is called “heliocentric” for the sun. Earth and other planets revolve around the sun.

9. Galileo ► Italian astronomer who was the first scientist to use a telescope to look at objects in the sky. ► He saw fours moons revolving around Jupiter. ► He discovered that Venus goes though phases like Earth’s moon.

10. Tycho Brahe ► Danish astronomer who observed the positions of the planets for about 20 years.

11. Johannes Kepler ► German mathematician who discovered that the orbit of each planet is an ellipse. ► An ellipse is an elongated circle, or oval shape.

12. Isaac Newton ► Newton concluded that two factors – inertia and gravity-combine to keep the planets in orbit. ► Inertia means that a moving object will continue to move in a straight line or a stationary object will remain in plain until some force acts to stop its motion. ► Gravity pulls the moon towards Earth.