Download Galaxy Characteristics

Galaxies
Quick Write
In this chapter, you will learn about
galaxies and their characteristics.
Write down these questions and
answer them in complete sentences.
1. How many galaxies in the universe
do you think exist?
2. What shape is the MW galaxy?
1. How did the MW begin
to form?
The globular clusters in
the halo are old – so we
think they formed first.
2. What shape was it
first?
They believe it was
spherical when it
began to form.
3. Why are there spiral arms?
Gravitational attractions
from other galaxies and
supernovae cause spiral arms.
4. Shapes of galaxies?
•Spiral
•Elliptical
•Irregular
5. Are galaxies clustered?
Yes, superclusters.
6. Radio galaxy?
Extremely bright
galaxies that have more
energy in radio waves
than visible light.
7. Active galactic nuclei?
Centers of galaxies that emit
(give off) more energy than the
rest of the galaxy combined.
Check for Understanding
The MW galaxy began as a ______ shape,
but now is a ______ shape.
_____ galaxies are those that give off more
energy in radio waves than visible light.
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