It’s an enormous cloud of molecular hydrogen gas that may one day condense down into stars. However, because its light is only detectable in a rarely studied part of the spectrum, all this gas ...

Hot gases don’t produce a continuous emission spectrum. Black hydrogen absorption lines are at the same wavelength as the bright hydrogen emission lines. Key fact Line emission spectra are ...

For example, the Orion Nebula, which was previously thought to be the closest star forming cloud to Earth, is so bright that it’s visible ... ultraviolet emission of molecular hydrogen directly ...