1. The Amazing Expanding Universe

2. Age of the Universe
The universe is about
12-15 billion years old.

3. Three Theories Steady-state: The universe is not expanding.
Oscillating Model: The universe expands and then contracts.
Expanding: The universe has been expanding since its beginning.
Evidence supports the Expanding Theory

4. Which Hubble?
Edwin Hubble
Hubble Telescope

5. Doppler Effect
Moving Away = Red Shift
Moving Closer = Blue Shift

6. Expanding Universe
Hubble discovered that virtually everything in the universe gave a red shift.
So, the universe is expanding.

7. The Start The Big Bang = a very dense ball exploding.
The universe has been expanding ever since.

8. Expanding
After less than a second, the universe was 2,000 times the size of the sun.
At 1 second, the universe was a dense swirling group of particles.
Material began to clump together.
After 1 billion years, the first star was born.
After billion years, humans showed up.

9. Going Back In Time
Because the universe is so large, it takes light waves a long time to travel to earth.
Most of the stars we see at night are from stars that have died long ago.