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)
Thursday, January 17, 2013
Today's Astronomy Picture of the Day shows Cassiopeia A, or Cass A, the expanding remains of a supernova in our galaxy. Optical and x-ray wavelengths are combined to show the complexity of the shockwave and expanding gas.