1. Observing the Solar System
Chapter 9 Section 1

2. Today we call the planets by the names given to them by the Romans.
‘planets’ in Greek
means wanderers
Today we call the planets by the names given to them by the Romans.
Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto
Yes, Pluto is no longer considered a planet but don’t worry class we will get to that in this chapter.

3. Greek’s once believed that Earth was in the center of the solar system
This was known as a GEOCENTRIC SYSTEM.
‘Geo’ = Earth
‘Centric’ = Center
Geocentric System: Earth is at the center of the revolving planets and stars

4. Ptolemy’s model Greek Astronomer
Created a model that represented the Geocentric System
Model was incorrect (it showed the planets moving in tiny circles along the path of a bigger circle around Earth)
Was believed to be true nearly 1500 yrs after his death

5. Sun Centered System ‘Helios’ = Sun
Heliocentric System: Earth and other planets
revolve around the sun
I’m in the middle!!!

6. Which one is which?

7. Copernican revolution
Copernicus (Polish Scientist) was able to work out the arrangement of the known planets and how they move around the sun
It was not until Galileo (Italian Scientist) collected more evidence with a telescope that the Heliocentric Revolution was believed as fact.

8. Kepler-Danish Astronomer
Kepler noticed that the orbit of planets was not a circle but an ellipse
Ellipse: oval shape, maybe elongated or nearly circular

9. ‘Sol’ = Sun…called Solar System because it revolves around the sun.
Today we know that the solar system consists of the sun, eight planets and their moons, and several kinds of smaller objects that revolve around the sun.
The end