1. Topic 3: Earth in the Universe
Astronomy

2. Origin and Age of the Universe
Universe means everything that exists in any place – all the space, matter, and energy in existence.
The estimated age of the Universe is 13.7 billion years old.

3. The Big Bang
Big Bang Theory- states that all matter and energy started out concentrated in a small area and after a gigantic explosion, matter began to organize into subatomic particles and atoms.
Majority of the earliest atoms were hydrogen and helium.
The universe is constantly expanding.
Let me demonstrate!

4. Evidence for the Big Bang
Background Radiation- energy created by the explosion should be found in all parts of the universe in the form of radiation.

5. More Evidence for The Big Bang
Doppler Effect- Stars and celestial objects omit electromagnetic energy in the form of visible light. When there is a shift to either the shorter (blue end) or longer (red end) wavelengths, we identify this as a Doppler effect.
This is caused by the relative movement between Earth and other celestial objects.
If Earth and another celestial object are coming closer together this results in a blue shift Doppler effect.
If Earth and another celestial object are moving apart, this causes a red shift Doppler effect.

6. Doppler effect blue & red shifts
Galaxy A- is moving toward Earth
Galaxy B- is not moving towards or away from Earth.
Galaxy C- is moving away from Earth

7. Doppler effect Continued
With the exception of a few galaxies that are close to Earth, all galaxies are shifted to the red end of the spectrum.
A red shift indicates that the universe is expanding in all directions.
Lets Check It Out!