2. Galaxies are…
Massive systems of stars, dust and
gas held together by gravity.
Galaxies usually have a clump of stars
at the center called the central bulge.
Most larger galaxies have a black hole
at the center.
3. Spiral Galaxies…
Distinct central
concentration of
stars (bulge) at
center with spiral
arms radiating
outward.
Spiral galaxies
make up
approximately 60%
of the galaxies in
the Universe.
4. Barred Spiral Galaxies…
Similar to a regular spiral galaxy but
with a cross bar cutting through the
center with arms swirling at the ends
6. Irregular Galaxies…
These are the galaxies that are neither
elliptical nor spiral; they are a variety of
shapes.
7. Our Galaxy is…..
The Milky Way Galaxy!
Barred spiral galaxy
120,000 Light years
in Diameter
Every star we see in
the night sky
(between 100-400
billion stars)
Rotates Clockwise
10. What’s in the center?
We know that we have what’s called a
“central bulge”.
It has been recently confirmed that there
is a massive black hole in the center of the
Milky Way.
11. WHAT?!?!? Black Hole?? Nooo!
The Black hole has 4 million times the
mass of the sun, but is billions of times
weaker than black holes in other galaxies.
Sooo… Don’t worry! It’s not going to
“suck” us into it. We’re fine. (but if it did,
you know what would happen…. We
would DIE)
12. Our closest neighbor: Andromeda!
• Andromeda is our
closest neighboring
galaxy
• It is approximately
2.5 million light
years away from
us and is classified
as a spiral galaxy.