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The Ring Nebula
The Ring Nebula is an example of a “planetary nebula”—though
these objects have nothing to do with planets. Through
early, low-powered telescopes, their circular shapes
resembled planets. Planetary nebulae are formed when a
Sun-like star begins to run out of fuel, inflates to become
an enormous Red Giant star, and then blows its outer layers
into space. The shell of gas, expanding and cooling, will
eventually dissipate, and all that will be left of the
original star is a compact, Earth-sized object known as a
White Dwarf—the dead star’s remains. The Ring Nebula is
believed to be about 2300 light years away and about one
light year in diameter. |
