Why is there lightning on Jupiter? Lightning is a sudden rush of electrically charged particles from one location to another. To create lightning, charges must first separate inside a cloud. On Earth, drafts of colliding ice and water droplets usually create this charge separation, but what happens on Jupiter? Many astronomers theorize that Jovian lightning is also created in clouds containing water ice. To help investigate this, the above photograph was taken in October by the Galileo spacecraft now orbiting Jupiter. Clouds are dimly lit by sunlight reflected off Jupiter's moon Io. The bright flashes appear to originate in active regions at the level where water clouds would exist, and illuminate an even lower cloud level containing ammonia. One thing is for sure: lightning on Jupiter is a lot brighter than lighting on Earth.

This beautiful cosmic portrait features NGC 891. The spiral galaxy spans about 100 thousand light-years and is seen almost exactly edge-on from our perspective. In fact, about 30 million light-years distant in the constellation Andromeda, NGC 891 looks a lot like our Milky Way. At first glance, it has a flat, thin, galactic disk and a central bulge cut along the middle by regions of dark obscuring dust. Also apparent in NGC 891's edge-on presentation are filaments of dust that extend hundreds of light-years above and below the center line. The dust has likely been blown out of the disk by supernova explosions or intense star formation activity. Faint neighboring galaxies can also been seen near this galaxy's disk.