Galaxies: The Basics
Spiral Galaxies
Barred Spiral Galaxies
Elliptical Galaxies
Irregular Galaxies
100
What is a galaxy?
A collection of millions to billions of stars, gas, and dust
100

What is a spiral galaxy?

A galaxy that is shaped like a disc with spiraling arms

100
What is a barred spiral galaxy?
A spiral galaxy with well-defined bars at the center of the galaxy
100
What is an elliptical galaxy?
A galaxy that is usually egg-shaped and relatively featureless
100
What is an irregular galaxy?
A galaxy that cannot be classified as any other type of galaxy
200
No two galaxies can ever be the ________.
Same
200
The galaxy we live in now, the ________, is a spiral galaxy.
Milky Way
200
A barred spiral galaxy is almost the same as what type of galaxy?
Spiral Galaxy
200
What shape does an elliptical galaxy resemble? (Hint: not a circle or sphere)
An ellipse
200
What thing do irregular galaxies lack?
Symmetry
300
How many types of galaxies are there?
Four
300
What does the bulge of a spiral galaxy contain?
Stars, gas, and dust
300
About _____ of all known spiral galaxies are considered barred spiral galaxies.
1/2
300
What is the smallest type of elliptical galaxy called?
A dwarf elliptical galaxy
300
Irregular galaxies can fall under many _________.
Subcategories
400

What are 2 things a galaxy contains?

Stars, gas, dust, solar systems, planets, or black holes

400
What percentage of observed galaxies in our universe are spiral galaxies?
77%
400
What are two famous barred spiral galaxies?
Messier 91 and Messier 95
400
An elliptical galaxy will be created when which two galaxies collide?
The Milky Way and Andromeda
400
Irregular galaxies are typically very _________.
Bright
500
What are galaxies classified by?
Their shape and characteristics
500
What do spiral galaxies have outside of the bulge?
A thin disk of stars
500
How are barred spiral galaxies classified?
SBa, SBb, SBc, etc.
500
How are elliptical galaxies classified?
"Almost Circular (E0)" to "Quite Elliptical (E6)"
500
What two things are irregular galaxies filled with? (Hint: these things affect the brightness of the galaxy)
Gas and dust
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