01 October 1999
Vol 286, Issue 5437

About The Cover

Cover image expansion

COVER An artistic view from Ganymede, one of the four large moons orbiting Jupiter. Europa, Jupiter, Io, and Callisto are shown from left to right. Observations from planetary science missions have enhanced our understanding of the jovian system and other planets, and astronomers have detected extrasolar planets and imaged planetary disks. These advances are part of the special section on planetary systems beginning on page 65 [Images: JPL/NASA; composite by Alan T. Stonebraker]