... Neighboring Galaxy: The Large Magellanic Cloud . 4.08.2001 . ... Spiral disks are loose conglomerations of billions of stars and diffuse gas all gravitationally orbiting a galaxy center. Burning Tree Sprite . ... Oceans Under Jupiters Callisto . ... This planetary nebula's simple, graceful appearance is thought to be due to perspective -- our view from planet Earth looking straight into what is actually a barrel-shaped cloud of gas shrugged off by a dying central star. ... Martian Dust Storm . ...