1. Galaxies

2. Galaxy
A large assembly of stars and nebulae

3. Group of Galaxies

4. The Milky Way
Our galaxy
Flat disk with spiral arms

5. More about galaxies 58)There are 3 major types of galaxies Spiral
Elliptical
Irregular

6. Spiral galaxies. Disk shaped with a central bulge.
The center is black Hole

7. Elliptical galaxies
Elliptical or round shape
No disk
Stars but no gas

8. Irregular galaxies
Irregular shape, and does not swirl.

9. Inside the Galaxies Nebulas
(space gas clouds found in spiral galaxies)
Globular Clusters
(groups of older stars at the edge of galaxies)
Open Clusters
(smaller groups of clusters younger stars)

10. Milky Way
Spiral
67) Contains single stars, double stars, star systems, dust and gases
Shaped like a disk with a bulge in the center
The bulge is very dense

11. 68) The Milky Way Galaxy contains dust and gas.
60) Our Solar System is located in Orion’s Arm of the Milky Way Galaxy.

13. More Facts about the Milky Way…
Held together by gravity
Can be seen on a very clear night
Got its name from the hazy/milky appearance

14. Our Solar System Is located in the Milky Way Galaxy
Is a single star system (Sun)

15. Quick Facts about the Sun
25) A medium sized star
Located near the edge of the Milky Way—did you see it in the previous slide?

16. Supernova
A _____________ is basically the death of a large star by explosion.

17. 61) An exploding star is known as a supernova.

18. Quasars
Small, powerful source of energy thought to be cores of distant spiral galaxies

19. They emit radio waves and bright light

21. Black Holes
63)A _______ is a giant star or group of stars that has/have collapsed because of their enormous gravity.

23. Where did its name come from?
It is called a black hole because not even light can escape!

25. What is a constellation?.
A pattern or group of stars in the sky is called a constellation.

26. Different Constellations - Star Patterns

27. The Big Dipper

28. Why do constellations change from season to season?
64)Because the Earth orbits the sun!
Most constellations appear in many different positions in the sky as the Earth revolves around the sun.

29. Constellations
Earth rotates on its axis, this makes most constellations appear to rise in the east and set in the west during the night.
There is a group of stars that appear in the sky all night long and all year long. It seems that these stars do not rise and set, but circle the Earth’s north pole each night. These stars are called circumpolar.