Galaxies

Galaxies

What is a Galaxy?

A huge collection of:

- Gas

- Space Dust

- Millions to trillions of stars and any planets surrounding them

- "Rogue Planets"

Galactic Info

• Galaxies spin, similar to the objects in our solar system

• We don't know how many there are.

• Current estimates are at more than 2 trillion

Multiple Choice

Galaxies spin, similar to how our solar system spins.

• True

• False

Open Ended

What are galaxies made up of?

3 Main Types (based on shape)

- Spiral

- Elliptical

- Irregular

Spiral Galaxies

• Called this because they appear to form a spiral shape

• Stars are still forming in these types of galaxies

• One of the more common types of galaxies

Elliptical Galaxies

• Seem to be older

• Stars formation is no longer occuring

• Lack dust and gas

• Might be the result of galaxies colliding

Irregular

• Usually smaller

• Believed to form for 2 reasons - too small to form into a structure, or a massive collision caused them to lose their structure

Galaxies in Transition

• Kind of a 4th category for Galaxies

• Weirdly shaped, but with a clear structure

• Normally the result of galaxies colliding

Multiple Choice

Galaxies can collide with each other

• True

• False

Multiple Choice

This type of galaxy is generally considered to be older and is no longer forming stars.

• Spiral

• Irregular

• Elliptical

• Transition Galaxies

Multiple Choice

One of the more common types of galaxies which have stars still forming within them are...

• Elliptical

• Spiral

• Irregular

• Transition

Milky Way Galaxy

• The Galaxy we are within

• Spiral Galaxy

• About 100,000 light years wide

Dark Matter - a Brief Intro

- Something is strange about the spin of many galaxies, going against the laws of Kepler.

- Based on this, it was proposed that a large % of matter within galaxies, including our own, is invisible.

- This matter helps hold galaxies together and effects the movement objects within the galaxy

Multiple Choice

What type of galaxy is the Milky Way?

• Spiral

• Elliptical

• Irregular

• Transition

Open Ended

Briefly summarize how we know dark matter exists.