1. Astronomy

2. How our Universe Formed
Big Bang Theory – that states how the universe formed from a massive expansion approximately 14 bya
The Universe is expanding and the visible edge is about 13.7 billion light years away

3. Note: Our solar system is part of a bigger system called a galaxy and our galaxy (Milky Way) is part of a bigger system called the universe
Milky Way Galaxy…spiral shaped!

4. So, how did our Solar System form?
The Nebular Theory – explains that solar system was formed from a rotating disk of dust and gas
Formed ~4.6 bya

5. Kepler’s Laws
Earth orbits the Sun following Kepler’s 3 laws of planetary motion
The path of each planet around the Sun is an ellipse
Equal areas are covered in equal times
The length of time it takes a planet to orbit the Sun is proportional to its distance from the Sun

6. Kepler (1571-1630) came up with these scientific laws and they are still used in Astronomy today!

7. 1st Law: Law of Ellipses
The path of the planets around the sun are elliptical in shape with the center of the sun being located at one focus
The shape of the ellipse is determined by the location of the two focus points!

8. 2nd Law: Law of Equal Areas
This law states that an imaginary line from the sun to a planet sweeps out equal areas in equal time intervals

9. 3rd Law: The Law of Periods

10. Sun consumes 600 million tons of H each second!
The Sun
Our Sun and all other stars produce their energy by a process called nuclear fusion
Fusion is when hydrogen atoms collide to make a Helium atom; this releases lots of energy
Sun consumes 600 million tons of H each second!

11. What is the Difference between Fusion and Fission?
Fission is the opposite idea…instead of building bigger atoms, you are breaking atoms apart
Nuclear Power Plants like McGuire Nuclear Station in Huntersville do this with Uranium

12. Energy Produced by the Sun
Most of what astronomers know about our universe is from studying the light emitted from distant sources

13. Electromagnetic Spectrum
Visible light is just a small portion of the energy emitted by stars…what else is there?

14. Gamma rays are produced by violent nuclear explosions in space and are absorbed by our atmosphere…good thing, they are deadly to human cells!
X- rays are also absorbed by Earth’s atmosphere, so NASA has to put x-ray telescopes into space
UV rays are mostly blocked by the ozone layer, but some can get through and cause sunburns!
Infrared rays cause the heat we feel from sunlight
Microwaves easily move through atmosphere and are used in with satellites and GPS
Radio waves are used with huge telescopes to learn about the structure, composition, and motion of objects in space

15. Let’s Draw the Electromagnetic Spectrum