Emission nebulae are glowing, spread-out clouds of ionized gas that shine with their own light. In this image of NGC 2313, the bright star V565 at the center lights up a silvery curtain of gas and ...

The Crab Nebula, a supernova remnant nebula ... The red hue is evidence of ionized hydrogen, which gives off visible light at a wavelength of 656.3 nm. Likewise, the green is from a rare ...