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)
Saturday, December 5, 2015
Today's Astronomy Picture of the Day is a short video demonstrating how much our knowledge of the structure of our galaxy has changed in my life. From zero known exoplanets to 1,705 and counting.