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)
Tuesday, June 10, 2014
Today's Astronomy Picture of the Day shows us two views of Messier 51, the Whirlpool Galaxy. "Mouse over" to alternate between visible and x-ray wavelengths.