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, May 29, 2018
The Thin Skin
Today's Astronomy Picture of the Day shows some of the activity that happens in the thin skin of our planetary protection barrier (the atmosphere) and what happens when it is penetrated by a visitor.