1. This pictures covers about the size of your “pinky” finger nail held at arms length.
Each speck is a galaxy – each galaxy contains 100’s of billions of stars!!

2. Galaxies
Galaxies are collections of stars, gas, and dust held together by gravity.
Scientists believe there are about 125 billion of these structures in our universe.

3. 3 Shapes of Galaxies:
Elliptical Galaxy
Spiral Galaxy
Irregular Galaxy

4. 1) Spiral Galaxies From above, looks like a pin-wheel
From the side, looks like a fried egg
They have lots of gas, dust and young stars
The “bulge” is made up of older stars, the disc is made of young stars
The “glow” around galaxy is called the “halo”
TOP VIEW
(pinwheel)
SIDE VIEW
(fried egg)

5. Milky Way Galaxy – Home Sweet Home
We live out in one of the arms of the galaxy

6. 2) Elliptical Galaxies Looks like an ellipse (stretched out circle)
Made of very little gas and dust, mostly stars
Contain some of the oldest stars in the universe
The largest galaxies are elliptical
More than half the galaxies are elliptical

7. 3) Irregular Galaxies These galaxies have no regular shape
Made up of a mixture of old and new stars
Contain lots of gas and dust

8. Comparing Galaxies continued…
Star Clusters (#, size, mass, colour, brightness and speed they spin)

9. Ex. Nebula found in Sagittarius
Nebulae
made of different amount and type of gas & dust
commonly consisting of 70% Hydrogen, 28% Helium, 2% Heavier elements
1) Diffuse Nebula - gases glow from stars within them
Ex. Nebula found in Sagittarius

10. 2) Dark Nebula nebula not near a bright star
Ex. Horse Head Nebula in Orion

11. Nebulas
Cone Nebula
Ring Nebula

12. Nebulas IC

13. Nebulas
Dumbell Nebula
Crab Nebula

14. North American nebula
Cat’s eye nebula
ring nebula
ant nebula