1. IN A
WORLD
FAR,
FAR,
AWAY……

2. GALAXIES

3. The Milky Way galaxy is brighter in the summer because you are looking
The area of the sky that this picture was taken from equaled the
size of the President’s eye on a dime held at an arm’s length!
If the galaxy is red, it is and old one. If the galaxy is blue it is a new galaxy
The Milky Way galaxy is brighter in the summer because you are looking
toward the center of the galaxy, where as in the winter you are looking out
through the outer arm, [called the Orion arm}.

6. Older stars are in the nuclear bulge and the outer edge.
Younger stars are
in the spiral arms
of the galaxy.
Distance of our
Solar System from
the Galactic Center
is 25,000 to 27,000
light years.
Galaxies rotate at
the speed of 220 km
per second or 136.7
per second.
Our Sun takes 240
million years to
rotate around the
Galaxy.
Galileo was the first to discover that the Milky Way was made up of millions of stars. He did not realize that our galaxy was one of millions of galaxy in our universe.
contains gas &
dust 32,000 light
years
center of the galaxy
The region from the nuclear bulge
to the edge.
1500 to 2000 light years thick.
The entire Galaxy is contained within this area.
Halo diameter is 130,000 light years.

7. Our Universe contains
billions of galaxies and
each galaxy contains
billions of stars.
Galaxies are large
groups of stars that
move together through
space.
Galaxies can be
based upon their
shape.

8. Galaxies rotate because of gravitational influences and are flattened into their
shape. They begin as elliptical galaxies and flatten out into spiral or barred
spiral galaxies.
Because of this spinning away from the center of the galaxy, the stars appear to
move away from the middle. This is known as the red shift.

9. GALAXY TYPES SPIRAL IRREGULAR ELLIPTICAL Early stage of galaxy
formations.
Lack gas and dust.
More uniform in shape.
15% of galaxies are
this one.
No distinctive shape.
Break up of galaxy.
3% of galaxies
are this one.
NORMAL
BARRED
Middle stage of galaxy.
Flattening out from
elliptical stage.
Most galaxies are this one.

10. ELLIPITICAL GALAXY Shaped like a football. Largest known galaxy type.
M33
R.A. 1h 31m
Dec
Contains mostly older stars
that have bright centers
and little gas.

11. Normal Spiral Arms come from the center of the galaxy.
The arms are due to the rotation of the gravity.
M74
R.A. 1h 34m
Dec
Whirlpool Galaxy
M51
R.A. 12h 37m
Dec
Andromeda Galaxy
M31
RA. 0h 40m
Dec. 41
The Milky Way was
thought to be a
normal spiral galaxy.
It is located in the
Local Group which is
a cluster of galaxies.

12. BARRED SPIRAL Appears to have a bar across the center of the galaxy.
Scientist now think the Milky Way may be this type,
due to recent evidence.
M83
R.A. 13h 34m
Dec
M104
Sombrero Galaxy
R.A. 12h 37m
Dec

13. IRREGULAR GALAXY M82 R.A. 9 h 51m Dec. 69.56 No specific shape
Breaking up of galaxy.
Have close companions of large’
spiral galaxies.
Gravity distorts the shape.
M82
R.A. 9 h 51m
Dec

14. GALAXIES COLLIDING
The universe is expanding and causing two galaxies to
form into one. Our galaxy, the Milky Way, is a combination of
two galaxies. The Milky Way and the Andromeda Galaxy will
eventually collide in a billion years.