1. Birth of a Theory Chapter 30.4

2. The Universe & Beyond -Cosmology – study of origin, structure, & future of the universe. Why? -to study how the universe was formed; and to gain a better understanding of how it may be affected in the future.

3. Hubble’s Contributions… -End of the 1920’s…Hubble found that the spectra of most galaxies shifted toward the red end of the spectrum. Significance? Examining the amount of red shift can determine the speed the galaxies are moving away from Earth. -From this, Hubble determined the universe is expanding!

4. A Theory Emerges: -Many theories on the creation of the universe have been proposed. -Most commonly accepted is: “The Big Bang” -Billions of years ago all the matter in the universe was compacted into one small volume. -About 14 billion years ago, all of this matter exploded outward in all directions in an event called the Big Bang. -The cloud of matter expanded and parts of it began to clump together and formed galaxies. -The universe has continued to expand. (red shift)

5. Evidence for the Big Bang Theory: 1. Background Radiation: Throughout the universe low level energy is distributed evenly. Formed shortly after the Big Bang. 2. Ripples --- Irregularities in the cosmic background radiation; caused by small fluctuations in the distribution of matter in the early universe; the ripples might also indicate the 1 st stages in the formation of the universe’s 1 st galaxy.

6. What else is out there…? -Looking at the ‘ripples’…scientists have determined that Dark Matter – Matter in the universe that doesn’t give off light but has detectable gravity makes up close to 23% of the universe! -Dark Energy – Most of the universe is made up of something we know nothing about; acts as a force that opposes gravity. (73%) -What is the other 4%?