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, April 30, 2013
Today's Astronomy Picture of the Day shows all the currently operating uncrewed exploration vehicles crawling through our Solar System. Now...how about some crewed exploration?