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, May 20, 2013
Under the Blue Glare
Today's Astronomy Picture of the Day a view of our yellow star in a different light. By looking at the light emitted by ionized calcium, we can get a better view of the current activity on the Sun, including some large regions of sunspots.