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)
Monday, August 3, 2015
Today's Astronomy Picture of the Day shows a rare proton arc over Lake Superior in the Upper Peninsula region of Michigan (my first view of an aurora was in the Upper Peninsula region, but I never have seen anything like this!).