Many names used by astronomers are misleading or outdated. A good example is the term planetary nebula, which astronomers use to refer to:

Question

Quizplus · Accepted Answer

The term planetary nebula is misleading because it has nothing to do with planets. Instead, it refers to the shell of gas and dust that is ejected by a dying low-mass star in its final stages of life. The name comes from the fact that early astronomers thought these objects looked like giant planets when viewed through early telescopes.

Many Names Used by Astronomers Are Misleading or Outdated