1. OGT: Chapter Eight  Origins Of The Universe

2. Astronomy  Study of stars and planets Aristotle  Earth is center of the universe (geocentric). Sun, planets and stars rotated around the earth.  Copernicus  proved planets revolve around Earth (heliocentric).  **Science discovery is based on the knowledge you have at the time

3. Telescopes Add To Knowledge 1600’s  Allowed scientists to view motion  Sir Isaac Newton had the idea (hypothesis) that objects attract each other by a natural force (gravity). Force pulls objects to ground Force attracts bodies across space Gravity decreases with distance Gravity increases with mass

4. Gravity is proportional  Increase mass, increase gravity  Decrease distance, decrease gravity

5. Newton’s Laws  Added math to science  Work showed that the movement of planets, asteroids and comets are all determined by gravity  Moon has less mass which=less gravity=the moon has 1/6 the gravity of the earth.  If you weighed 180 pounds on earth, how much would you weigh on the moon?

6. A Star Is Born  Telescopes help measure the light rays to determine composition  Most stars are made up of H and He  Nuclear Fusion creates the star (atoms are slammed together and create energy in the form of heat and light)

7. Nebula  Star “factory”  Gravity pulls dust and gas together  Increased “glob” of dust and gas begins to spin  Pressure causes fusion (see above)  Energy is released

8. Types of Stars  Red Giant—older star (sun)  Supernova—core is hot enough to create iron helium, hydrogen and carbon Explosion occurs when core collapses—only a few have been seen (chance) As cools becomes dwarf or black hole

9. The Big Bang  Theory about the beginning of the universe Stars and planets emit light (spectra)—it shows that the universe is expanding (red shift) 13-15 billion years ago One huge explosion hurled things into space Cooling of material allowed H and He to combine and form first atoms

10. Milky Way  Our galaxy (there are millions)  There are spiral galaxies, bar galaxies, and elliptical galaxies