Astronomy: Nebulae

Centuries ago it was already known that our universe is filled with stars, planets and nebulae. Well known nebulae are the Orion nebula, the Crab Nebula, the Andromeda nebula and the Eagle nebula. This blurry spot in the sky, a nebula, is the combined light of millions of stars. The nebula is a large area filled with gas and dust clouds that is lighted from stars. There are different kinds of nebulae: The hydrogen gas in some nebulae is heated by hot bright stars, so the gas emits light itself on specific lightwaves. This is the case for the Orion nebula, the glowing hydrogen gas can be recognized by its red color. Cooler nebulae do not emit light theirselves, but absorb light from near stars. This absorbtion can also be seen on specific lightwaves. It's also possible that you are observing a nebula that is only reflecting light from near stars. And the most dense nebulae are cool areas with densities that completely mask stars behind them. These nebulae can be recognized by dark strokes in the light band of our Milky Way Galaxy. Related subjects >> Formation of planets in the Orion nebula >> The Crab nebula >> The Andromeda nebula >> The Horsehead nebula >> The Eagle nebula >> The Sombrero nebula >> The Tarantula nebula >> The Universe

The Crab Nebula The Andromeda Nebula