|The Horsehead Nebula. Copyright Association of Universities for Research in Astronomy Inc. (AURA), all rights reserved.|
Nebulae are clouds of interstellar gas and dust. These can be either bright or dark. A bright nebula is one which can be observed a luminous patch of light. A dark nebula is one which can be observed as a dark patch against a bright background. There are several different types of nebulae including planetary, reflection, and emission nebulae.
|An Emission Nebula (M 8). Copyright Association of Universities for Research in Astronomy Inc. (AURA), all rights reserved.|
An emission nebula is a region of hot interstellar gas which shines by its own light. This luminosity comes from the interaction between free electrons and the ions making up the gas.
|A Planetary Nebula (M 57). Copyright Association of Universities for Research in Astronomy Inc. (AURA), all rights reserved.|
A planetary nebula is an expanding and usually symmetrical cloud of gas ejected from a dying star. These are a type of emission nebula and are thought to come from red giant stars.
A reflection nebula is one which shines by reflecting the light from a nearby star or star cluster. These are situated near the stars which provide the light.
If you do not see frames, click here to go to the frames page.
If you do not want to use frames, click here to go to the non-frames home page and sitemap.