• any fuzzy patch of light in the night sky was once called a nebula – no ways, many of these are known to be galaxies.

Clusters of galaxies
Each of these fuzzy blobs is a galaxy, together making up the Perseus Cluster,
one of the closest clusters of galaxies.

Orion Nebula (Messier 42) in the Orion constellation.
Nebulae are gigantic clouds of gas and space dust.

The Orion Nebula is a glowing just visible to the naked eye.

  • glowing nebulae give off a dim, red light as they hydrogen gas in them is heated by radiation from nearby stars.
  • reflection nebula not only have no light on their own, they also soak up all light – they can only be seen as patches of darkness, blocking out light from the stars behind them.
  • the Horsehead Nebula in Orion is the best known dark nebula – as it name suggests, it is shaped like a horse head.

The Horsehead Nebula (B33)

  • planetary nebulae are thin ring of gas cloud that are thrown out by dying stars. Despite their name, they have nothing to do with planets.
  • the Ring Nebula (Messier 57)  in Lyra is the best known of the planetary nebulae.

Messier 57 in the constellation of Lyra.

Back to  Stars and Galaxies  page / next to  Black Holes  page.

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