1. Our Place in the Universe Drew Smith

2. Important Principles The Cosmological Principle ▫The universe is isotropic and homogenous (it “looks” the same in all directions.) The Copernican Principle ▫Humans are not special observers of the universe. No place was the “starting point” of the universe.

3. What is the Universe? The observable universe contains nearly a septillion stars (1 X 10 24 ). ▫This is more than the number of grains of sand on earth. These stars are located in at least 80 billion galaxies. ▫These galaxies are then clustered, and superclustered.

4. Where do we fit? Solar System

5. Where do we fit? Interstellar Neighborhood

6. Where do we fit? Milky Way Galaxy

7. Where do we fit? Local Group

8. Where do we fit? Supercluster

9. Where do we fit? Local Clusters

10. Where do we fit? Observable Universe

11. The Universe is EXPANDING Each object increased in distance by double, which means the rate of expansion is constant across the universe. However, the object that began 10 cm away travelled 10 cm in the same time that the closer object travelled 5 cm. It was twice as far away, so its recession velocity was twice as great.

12. Any Questions? Assignment: ▫Write a story about the origin of earth, the solar system, the galaxy, the universe, or all of the above.