1. Astronomy Mr. Coyle Earth Space Science Harwood Union H.S.
S. Duxbury, VT
USA
Planet Earth

2. Organization of the Universe

3. The Big Bang Theory
The universe formed in an enormous explosion about 13.7 billion years ago
All matter or “stuff” in the universe was condensed into a tiny volume

4. Evidence of the Big Bang
Red Shift- when objects travel away from an observer their light “shifts” to the red end of the spectrum
Cosmic Background Radiation- energy that is leftover from the Big Bang and is evenly distributed throughout the universe

6. KABOOM!! Gas and dust spread throughout space
Matter separated into galaxies, which contain hundreds of billions of stars

7. Spiral Galaxy

8. The Nebular Theory
About 5 billion years ago, a nebula, or a giant cloud of gas and dust collapsed
This occurred within the Milky Way, which is our galaxy
Where there was once only cold, dark gas and dust a Solar System was about to form..

9. How did it happen? Slowly the nebula shrank to form a spinning disk
Gravity pulled some of the gas into the center of the disk
The gas became hot and dense
Nuclear fusion began and the Sun was born

10. What is nuclear fusion? Fusion means to “come to or to fuse together”
In Nuclear Fusion hydrogen (H) atoms join together to form helium (He)
This releases a LARGE amount of heat energy

11. Meanwhile… Gas and dust formed planetesimals or small bodies of matter
Collisions occurred, gravity pulled these small pieces of matter together and protoplanets, or tiny planets were formed

12. Gravity Gravity is a force of attraction between two objects
The larger the object, the stronger the force of gravity
Protoplanets, were like magnets pulling in planetesimals from the nebula
Eventually they formed planets and moons

14. The Inner Planets
Mercury, Venus, Earth and Mars are closest to the sun
They contain high amounts of Iron (Fe)
Iron is heavy and didn’t travel as far as some other elements
It makes up the core of these planets which are called terrestrial, because they are solid

16. The Outer Planets
The Outer Planets, or Gas Giants, formed where it was cold, far away from the sun
Very little of the heavy elements traveled this far
Gas Giants are made of helium, hydrogen, and other frozen gases
Some are thought to have solid cores
They became HUGE

18. Still to come… How do stars form? What different kinds of stars exist?
What happens when stars die?
What is a black hole?
What else is “out there” in the universe?