1. The Big Bang Theory
This lesson aims at explaining the origin and evolution of the universe backed up by evidence
Welcome the Barenaked Ladies:

2. Big Bang theory: An explanation for the origin of the universe
Hubble was one of the first astronomers to study galaxies
Hubble’s Ideas:
1) Many other galaxies exist (not just the Milky way).
2) All galaxies are getting farther apart from each other (2 evidence support this theory). This means that the universe is expanding and this was most likely caused by the big bang.

3. Hubble’s ideas were the foundation to the Big Bang Theory (BBT):
BBT: states that the universe formed when an infinitely dense point suddenly and rapidly expanded in a single point. All the matter and energy that exists today were created during the early minutes of that hot, rapid, expansion.
The universe formed 13.7 billion years ago.
Show:

4. Evidence for BBT 1) Red spectral shifting
2) Cosmic background radiation

5. Recall- The Wave Nature of Light
Light is electromagnetic radiation (ER).
ER that we can see is called visible light.
Other forms of light that we cannot see also exist (ex: UV).
Longer wavelength carries less energy
Shorter wavelength carries more energy
White light is made of: ROYGBIV
Red light has a long wavelength
Blue light has a short wavelength

6. 1) Red spectral shifting
A spectroscope is an optical device that separates white light into its colour spectrum.
Spectral lines: Each element produces its own bar code when it emits visible light (dark lines in the spectrum).
Hubble studied the light of stars and determined which elements they contain by analyzing their spectral lines.
Show the diffraction goggles and spectroscopes

8. Blue wavelengths are shorter than red wavelengths
Spectral Shifting: The change in position of spectral lines to the left or the right of where they normally are in the spectrum of a light source that is NOT moving.
Draw red spectral shifting and blue spectral shifting….
Blue wavelengths are shorter than red wavelengths

9. Hear it from Sheldon
Doodle science:

10. 1) Red spectral shifting
If the lines shift toward the red portion, then wavelengths are getting longer.
This means that they are moving away from us and each other.
Great Video to show:
Simple video and to the point:
Hubble used a spectroscope to analyze the spectra of other galaxies. For each of these galaxies he noticed that the spectra were red shifted. This means that the galaxies are moving away from us. This is evidence that the Earth is expanding.
-What would Hubble have concluded if he saw blue-shifting occurring?

11. 2) Cosmic Background Radiation
The Big Bang is though to have released large amounts of energy.
Thought to be the left over low energy waves (microwaves) from the original expansion
Show this video: very good
The snow you see on your TV or the “static” you hear on your radio are some of this background radiation.

12. Expansion of the Universe: galaxies are moving away from us at an ever faster rate.
Galaxy A
Galaxy B
It is not the galaxies or celestial objects that are moving. It is literally the space in between them that continues to expand (think back to the balloon).

13. The Andromeda galaxy
The Andromeda galaxy is said to collide with ours (not in your lifetime).
What kind of shift will we observe from this galaxy upon inspection with a spectroscope? Explain.
Andromeda galaxy: 2.5 million light-years away from Earth? Solar system sun?
Collision predicted for 4 billion years now

14. The Big Bang Theory Recap