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, July 28, 2019
Today's Astronomy Picture of the Day brings us "visible" and infrared views of the North American Nebula in the constellation of Cygnus. "Mouseover" the image in the link to switch between the views.