Nebulae are large clouds of gas in space. They are primarily composed of hydrogen gas, but they usually contain smaller amounts of other common gases and dust. Nebulae that glow only from reflected starlight are called reflection nebulae. Investigate the various varieties of nebulae using Wolfram|Alpha.
Explore emission nebulae, which glow due to the gases being excited by ultraviolet light from nearby stars.
Compute the location and get properties of a nebula: