1. Big Bang

2. What is a theory?

3. Theories of Celestial Objects
Geocentric
“Earth” centered
Thought everything revolved around the Earth
Aristotle and Ptolemy
Heliocentric
“Sun” centered
Everything revolves around the Sun…Earth and planets
First suggested by Copernicus
Confirmed by Galileo
With the help of a telescope

4. 19)The “Big Bang” is a theory of how the universe began.
21)The Big Bang Theory states that the universe formed about billion years ago through a huge explosion.

5. 22)The universe continues to expand rapidly.
28)The Big Bang Theory states the solar system is about 4.6 billion years old.

6. Review Big Bang Theory Theory on how the universe formed
Happened about billion years ago through a huge explosion
Says the universe expanded from a size smaller than a speck of dust to its current size!

7. The Solar System

8. Review Geocentric means Heliocentric means
Everything revolves around the Earth
Heliocentric means
Everything revolves around the Sun
T/F Scientists think the solar system was once smaller than a speck of dust.
TRUE! Then the Big Bang happened!