For the past thirty years, NASA has sponsored numerous highly ambitious space exploration missions that have dramatically expanded the existing knowledge base about various planetary bodies throughout our universe. The agency's New Horizons project intends to begin a mission to explore Pluto and Charon sometime in the near future, and the hope is that the project would also explore a variety of...

Offered by the National Space Science Data Center of NASA, the Planetary Fact Sheets Web site contains helpful information for students studying astronomy. The site lists links to all of the planets, their satellites, and their rings, as well as to tables comparing all the planets. The planet pages contain a photograph and a simple list of dozens of facts such as mass, volume, distance to the...