These great hollow globes of artificial super-metals, and artificial transparent adamant, ranged in size from the earliest and smallest structures, which were no bigger than a very small asteroid, to spheres considerably larger than the Earth. (Olaf Stapledon, STAR MAKER)
Sunday, September 15, 2013
Bipolar Nebula
Today's Astronomy Picture of the Day shows one of the many (many!) amazing shapes a planetary nebula can take. M2-9 has gas clouds not in a sphere or an irregular shell but as a pair of clouds expanding in opposite directions.
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