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Nebuleas |
The Three Types of Nebulaes |
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Nebuleas
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Nebulae is a cloud made of gas and dust in space. The term was originally applied to any object with fuzzy telescopic appearance. Nowadays the term nebula means gaseous nebula. The term extragalactic nebula, originally used for galaxies, is now absolute. There are three types of gaseous nebula. Emission nebulae shines by their own light, for example, the Crab Nebula. Reflection nebulae reflects light from nearby bright sources such as stars, for example, the Pleiades are surrounded by a Reflection nebulae. Dark nebulae, or absorption nebulae, appear dark against a brighter background, for example, the Horsehead Nebulae. This broad classification scheme has been carried over to other wavelenghts, giving rise to terms such as infrared reflection nebula. Emission nebulae include the diffuse nebulae or H II regions around young stars. Planetary nebula around old stars, M57, and supernova remnants, M1.
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