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)
Thursday, March 21, 2013
Today's Astronomy Picture of the Day shows NGC 2736, part of the Vela supernova remnant. This composite shows beautifully the ripples of the expanding interstellar shock wave. The nova is popularly known as The Pencil Nebula.