Galactic Dust and Nebulae

What is a nebula?

A nebula, derived from the Latin, meaning “mist,” is any cloud or collection of interstellar medium in one location in space. Nebulae are produced in many different ways. For example, they can be gathered together by gravity, dispersed by stars, or lit up by a powerful radiation source nearby. As beautiful as nebulae are, however, most of them nonetheless contain only a few thousand atoms or molecules per cubic centimeter. This is many times sparser than even the best laboratory vacuum chambers on Earth can achieve.


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