The Expanding Universe

The Doppler Effect

Relative motion affects wavelength

Cars Trains

Stars! Galaxies!

Galactic Observations

Edwin Hubble (1889-1953) He observed that galaxies outside

the Local Group were all red shifted Galaxies are moving away from us! Galaxies farther away are moving

faster – Hubble Expansion

The universe is expanding!

QUESTION

If all the galaxies around us are moving away from Earth, does this mean that the Milky Way is at the center?

Write your own prediction based on what we’ve learned in this unit

ACTIVITYModel the Expansion of the Universe

Analyze & Interpret

What pattern do you see in the five sets of measurements you took as you inflated the balloon?

Does this model help you answer the question and verify the prediction? Why or why not?

The Center of the Universe

If the Milky Way is not at the center of the Universe…

Where is the center ?

Demo (1D) – Elastic band universe Demo (2D) – Balloon Example 3D … Our Universe

The Big Bang (pg 374-375)

The Big Bang (t >= 0)

t = 0 … ENERGY t = 1 to 10000 seconds

• Light elements (H, He, …) t = 400 million years

• The first stars and galaxies form t = 4 billion years

• Milky Way galaxy t = 14 billion years…TODAY!

The Big Bang (t < 0)

NSA

“No Such Animal”… not a valid question