What is the Universe

1
What is the Universe?

• The Universe is most commonly defined as
  everything that physically exists!
• It is comprised of billions of galaxies. What
  are galaxies?

2
The Universe

• Even though the stars look close together in
  space. Space is relatively empty. If a dozen
  tennis balls was spread out across the USA, they
  would be more crowded than most stars in Universe.

3
What are Galaxies?

• Galaxies are large systems of stars and
  interstellar matter(planets, moons, asteroids,
  etc.) typically containing several million to
  trillions of stars.
• They are held together by gravity!
• Most galaxies are several thousand light years in
  width

4
Galaxy Clips
5
Types of Galaxies

• Elliptical Galaxies
• are oval to round in shape
• most are made up of a few million stars.
• More common than irregular but less common than
  spiral
• They contain the oldest stars with very little
  dust and gas.

6
Types of Galaxies

• 2. Spiral Galaxies
• Contain between a billion and a trillion stars.
• They typically have two main spiral arms curling
  out of a bulging center.
• They contain many middle-aged stars along with
  gas and dust.
• Most common type of galaxy
• The Milky Way is a spiral galaxy.

7
Types of Galaxies

• 3. Irregular Galaxies
• Do not fit into the spiral or elliptical groups.
  
• Their shapes are undefined.
• Least common type of galaxy
• Most irregular galaxies contain young stars, and
  much gas and dust..

8
Milky Way Galaxy

• It is a spiral galaxy
• Contains between 200 to 400 billion stars. Maybe
  even a trillion!
• Its width is 100 million light years
• It takes the solar system 240 million years to
  make one full orbit

You are here
9
The Milky Way Galaxy!

• The Core of Milky Way Galaxy

Milky way
10
My Universal Address!

• Jeremy Arend
• 109 Tar Heel Drive
• Delaware, OH 43035
• United States
• Earth
• Solar System
• Milky Way Galaxy
• Universe

Where do you live?