1. Nebulae

2. “Nebula” comes from the Latin word for cloud. “Nebulae” is the plural. It is loosely applied to anything that looks fuzzy or extended in a telescope.

3. To astronomers in the early 1900s, galaxies were classified as nebulae, because they looked like fuzzy “blobs”. Today we know galaxies are collections of billions of stars. We will limit our nebulae to clouds of gas floating in space.

4. The Order of things: You live on Earth

5. The Earth is one of eight identified planets that orbit around the Sun in our Solar System

6. The Sun is just a star, an average star. It just looks so big and bright, because it is so close, compared with other stars.

7. The Sun is just one of hundreds of billions of stars in our galaxy, the Milky Way

8. The known universe contains at least 1,000,000,000 galaxies

9. There are four types of Nebulae: Emission Reflection Dark Planetary

10. Emission Nebulae are made of ionized hydrogen. When free protons recapture electrons, the electrons emit specific wavelengths (colors) of light, often ending up with a distinctive pink color. An emission nebula is caused when a cloud of hydrogen gas is heated by a nearby O or B star (25000 K).

13. Reflection Nebulae are caused when clouds of dust scatter the starlight from behind them. They tend to be bluer in color, as short wavelengths of light scatter easier than longer wavelengths.

17. Dark Nebula are cold, dense clouds of gas and dust that block out the light from behind them.

20. Planetary Nebulae are the remains of a dying star throwing off its outer layers

23. http://www.youtube.com/watch?v=8x41n9t hAU8&feature=topics

24. Quiz! Identify what the following pictures are: Emission Nebula Reflection Nebula Dark Nebula Planetary Nebula Galaxy Number 1 – 8 on a separate sheet

25. 1

26. 2

27. 3

28. 4

29. 5 6

30. 7 8

31. Check yourself 1.Emission nebula 2.Emission nebula 3.Galaxy 4.Planetary nebula 5.Reflection nebula 6.Dark nebula 7.Emission nebula 8.Dark nebula