Labels:text | screenshot OCR: NEBULAS A NEBULA IS A CLOUD, or any other only if they obscure light coming from object, made of interstellar gas and starfields or bright nebulas behind them. dust. Bright nebulas are clouds or wisps Many objects that were once called of gas that glow or scatter starlight. Dark nebulas have been reclassified. These nebulas do not glow and can be seen objects appeared to astronomers in earlier centuries to be fuzzy, cloudlike structures, but later astronomers with improved telescopes were able to identify these "nebulas" as galaxies or star clusters. THE HORSEHEAD NEBULA The dark Horsehead Nebula is silhouetted against the bright nebula behind it. Emission nebula Dark nebula Reflection nebula NEBULAS SEL GALLERY DARK BRIGHT NEXT ALSO NEBULAS NEBULAS