This document discusses different types of galaxies. Galaxies are massive systems of stars, dust and gas held together by gravity, and usually have a central bulge containing a supermassive black hole. The main types are spiral galaxies with arms radiating from a central bulge, barred spiral galaxies with a bar through the center, elliptical galaxies in an elliptical shape, and irregular galaxies with no defined shape. The Milky Way is described as a barred spiral galaxy over 120,000 light years in diameter containing between 100-400 billion stars. It has a massive black hole in the center, around 4 million times the sun's mass. The closest galaxy to the Milky Way is the Andromeda galaxy, around 2.5 million light years

1. Galaxies!
Yes, there are more than
just our own.

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

5. Elliptical Galaxies…
 You guessed it!
They are elliptical
in shape!! (I know
you know what
that means…)

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

8. great

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.