1. Groups of Stars

2. In our Milky Way Galaxy stars can arrange themselves in:
Globular clusters
A collection of hundreds of thousands of stars in a small area
These tend to orbit around the centers of galaxies
Believed to be very old stars
Our Milky Way Galaxy has at least 150 globular clusters

3. In our Milky Way Galaxy stars can arrange themselves in:
Open clusters
A close arrangement of a small number of stars
Thought to be created at the same time from the same nebula
Eventually they move away from each other

4. Pleadies Star Cluster (also known as the ‘seven sisters’)

5. In our Milky Way Galaxy stars can arrange themselves in:
Constellations
An arrangement of stars that form a recognizable pattern in the sky
Very useful to find other celestial objects such as planets, nebula, other galaxies, etc.

6. The Big Dipper
Also known as Ursa Major – great bear

7. Casseopeia

8. Cygnus – the northern cross

9. Orion – the hunter

10. Canis Major – greater dog

11. Winter Triangle The three stars of the winter triangle Procyon
Sirius (canus major)
Betelgeuse (orion)

12. Pointer Stars

13. Pointer Stars from the Big Dipper

14. Galaxies
Galaxies are huge formations of millions of stars and clouds of dust (nebula)
They come in many different shapes and sizes

15. Spiral Galaxies
These galaxies have very distinct shapes with spiral arms radiating
from their centers. Our own Milky Way Galaxy is a spiral galaxy.

16. Barred spiral galaxy
Similar to a spiral galaxy, but with only two distinct arms and an
elongated or ‘barred’ central core of stars.

17. Elliptical Galaxies
Elliptical galaxies have an ovoid shape and consist mainly of very old stars with
no new star formation processes.

18. Irregular Galaxies Large Magellanic Cloud Small Magellanic Cloud
Both of these irregular galaxies are small satellite galaxies of the Milky Way.

19. Location of the Andromeda Galaxy

20. A supermassive black hole at the center of a galaxy.

21. Groups of Galaxies
Galaxies tend to form in groups. Our Milky Way galaxy is part of the Local Group of galaxies that includes the Andromeda Galaxy and the Large and Small Magellanic Clouds. There are 30 known galaxies in our group of galaxies. Some galaxy clusters contain hundreds or even thousands of galaxies.

22. Galaxy Collisions
There is lots of evidence that Galaxies have ‘collided’ with each other or are on a collision path
with each other. The collisions can change the shape of the galaxies and can also result in the exchange of materials
between the two galaxies.

23. Hubble Deep Field View
Looking at a piece of the sky no wider than the width of a dime at 75 feet away
Hubble found about 1500 galaxies which takes the estimated number of
galaxies in the universe into the billions!!