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

Galaxy Clips

Types of Galaxies1. 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 (nebula).

Types of Galaxies2. 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 nebula.

• Most common type of galaxy

• The Milky Way is a spiral galaxy.

Types of Galaxies3. 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 nebula..

Milky Way Galaxy• It is a spiral galaxy• Contains between 200

to 400 billion stars…. Maybe even a trillion!

• Middle aged• It’s width is 100

thousand light years• It takes the solar

system 240 million years to make one full orbit

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The Milky Way Galaxy!

• The Core of Milky Way Galaxy Milky way

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?

The UniverseEven though the stars look close

together in space. Space is relatively empty. If a dozen tennis balls were

spread out across the USA, they would be more crowded than most

stars in Universe.

My Universal Address!Jeremy Arend109 Tar Heel DriveDelaware, OH 43035United StatesEarthSolar SystemMilky Way GalaxyUniverse

Where do

you live?