1. The Big Bang Theory
Picture is a gamma burst—there are obviously no pictures of the Big Bang, but we can imagine what it looked like.

2. What is a theory? In Science
Solid, logical explanation based on all available evidence.
Withstands repeated testing with experiments.
Can be revised or replaced as new evidence is discovered.
Never “proven” just made stronger.
Ex: Big Bang, Evolution, Plate Tectonics, Gravity, Cell, Germ, Atom

3. What is a theory? Outside of Science Guess Opinion Belief Idea
Explanation
Not proven

4. What is the Big Bang Theory?
Well tested and supported, widely accepted scientific theory on how the universe came to be

5. What does the Big Bang Theory say?
Our universe began with an incredibly hot, singular expansion of energy roughly BILLION years ago.
Universe has been expanding and cooling ever since.

6. What evidence do we have for the Big Bang Theory?
Red Shift
Cosmic Background Radiation
Einstein’s E=mc2
Hubble’s Law

7. Red Shift An object that appears “red” has a longer wave length
Objects that move away from another are seen to have longer wavelengths
Doppler Effect--sound and light change as they move closer to or further from a source.
Ex: sound increases in pitch as approaches and then deepens as gets further away--speeding crotch rocket
Ex: Light shifts to the red end as it gets further away, blue as it gets closer

8. Doppler Effect (Red Shift)
Doppler Effect--sound and light change as they move closer to or further from a source.
Ex: sound increases in pitch as approaches and then deepens as gets further away (ambulance as it moves past you)

9. Cosmic Background Radiation
Leftover heat from the big bang
Uniformly cool across the universe
Shows us that before the “bang” the universe cooled slightly and formed the parts of atoms we now know
In 1965, two young radio astronomers, Arno Penzias and Robert Wilson, almost accidentally discovered the CMB using a small, well-calibrated horn antenna. It was soon determined that the radiation was diffuse, emanated uniformly from all directions in the sky, and had a temperature of approximately 2.7 Kelvin (ie 2.7 degrees above absolute zero). Initially, they could find no satisfactory explanation for their observations, and considered the possibility that their signal may have been due to some undetermined systematic noise. They even considered the possibility that it was due to "a white dielectric substance" (ie pigeon droppings) in their horn! However, it soon came to their attention through Robert Dicke and Jim Peebles of Princeton that this background radiation had in fact been predicted years earlier by George Gamow as a relic of the evolution of the early Universe. This background of microwaves was in fact the cooled remnant of the primeval fireball - an echo of the Big Bang.

10. Einstein’s E=mc2 Energy can move so fast that it can turn into matter
Energy contained within the Big Bang expanded so quickly that it created matter
This matter is what makes up the physical parts of our universe
Matter can also move so fast that it turns to energy
Atomic bomb  or nuclear fission
4th period

11. Hubble’s Law The universe is expanding!
If the universe is expanding now then at some point it was very small
Further away galaxies are moving faster away from the center (more red shift).