Nebulae

“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.

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.

The Order of things:

You live on Earth

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

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.

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

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

There are four types of Nebulae:Emission Reflection

DarkPlanetary

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).

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.

Dark Nebula are cold, dense clouds of gas and dust that

block out the light from behind them.

Planetary Nebulae are the remains of a dying star

throwing off its outer layers

http://www.youtube.com/watch?v=8x41n9thAU8&feature=topics

Quiz!Identify what the following pictures are: Emission NebulaReflection NebulaDark NebulaPlanetary NebulaGalaxy

Number 1 – 8 on a separate sheet

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Check yourself

1. Emission nebula2. Emission nebula3. Galaxy4. Planetary nebula5. Reflection nebula6. Dark nebula7. Emission nebula8. Dark nebula