an image of a very large cloud in the sky

Hubble Sees a Horsehead of a Different Color Caption Looking like an apparition rising from whitecaps of interstellar foam, the iconic Horsehead Nebula has graced astronomy books ever since its discovery over a century ago. The nebula is a favorite target for amateur and professional astronomers. Credits NASA, ESA, and the Hubble Heritage Team (STScI/AURA)