More on planetary nebula from Fact Monster:

• nebula - nebula nebula [Lat.,=mist], in astronomy, observed manifestation of a collection of highly rarefied ...
• Ring nebula - Ring nebula Ring nebula, planetary nebula in the northern constellation Lyra; cataloged as M57 or ...
• Lyra - Lyra Lyra [Lat.,=the lyre], northern constellation lying S of Draco, E of Hercules, and W of ...
• STARS - Great globes of intensely hot gas called stars pour light and heat into space. A star is born in a vast NEBULA of gas and dust and may shine steadily
• Encyclopedia: Astronomy: General - Encyclopeadia articles concerning Astronomy: General.

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