1. The Big Bang

2.  Cosmology – The study of the structure and evolution of the universe.  Big Bang Theory – The universe was very hot and small. Billions of years ago it violently exploded and has been expanding and cooling ever since.  Astronomers estimate the universe to be about 13.7 billion years old.

3. The Big Bang Proving the Big Bang: 1. Moving Galaxies: Galaxies are moving away from each other.  Hubble’s Law – The farther away the galaxy is, the faster it is moving away from us. This supports the Big Bang. 2. Cosmic background Radiation – Mysterious energy glow picked from a telescope in 1965. Turns out it was leftover thermal energy from the Big Bang.

4. The Big Bang  This glow seemed to come from all directions like it came from a central source. 3. Age of the Universe – Astronomers can measure approximately how fast the universe is expanding.  Between measuring the movement of galaxies and cosmic background radiation astronomers can estimate the age of the universe to be 13.7 billion years old.

5. The Big Bang Formation of the Solar System:  Solar Nebula – large cloud of dust and gas that formed our solar system.(about 5 billion years ago)  As it spun, it flattened like a disk and gravity pulled the solar nebula together to form our sun.

6. The Big Bang  Gas and dust gathered together in the outer parts of the rotating disk to form planetisimals.  Over time, these planetisimals formed the planets

7. The Big Bang

8. Galaxies: Group of stars, star systems, star clusters, dust, and gas bound together by gravity.  Spiral – Bulge in the middle with arms that curve outward. Most new stars are found in the arms.  Elliptical – A round flattened ball. Contains mostly old stars.  Irregular – No certain shape. Contain many bright young stars and much dust and gas.

10. The Big Bang The Future of the Universe :  No one knows for sure what will happen to the universe.  It seems to be in constant motion  Astronomers think it will continue to expand.

11. The Big Bang  Dark matter – does not give off light so can not be seen. Makes up 23% of the universe  Galaxies seem to be moving apart faster than they used to. Astronomers think this is because of dark energy. Most of the universe is made up of dark matter and dark energy

12. The Big Bang