File:KSC-04-S-00395 (ksc 121304 comet history).webm

English: Comets. Throughout history they have inspired curiosity and fear -- fascination and dread. While the movement of the moon and stars was predictable, comets appeared in the night sky without warning. Their appearance was generally regarded as a sign from the heavens -- more often than not an ominous one. Mythology surrounding comets transcends societies, cultures and religions. They've been blamed for earthquakes, wars, pestilences, and floods -- and they have coincided with major historical events -- most notably the death of Julius Caesar in 44 BC. The ancient Chinese recorded their observations of comets, providing extensive historical information for later astronomers. Aristotle believed that comets formed in the atmosphere, making them similar to thunder and lightning. It wasn't until the 16th century that astronomers made the discovery that comets were celestial phenomena. In the centuries since, we've continued to broaden our knowledge and understanding of these once-feared apparitions as we've studied them from afar. These cosmic nomads carry revealing clues about the history of the solar system as they continue to play an active role in shaping and transforming the environment around them. But the mysteries that lie within a comet have yet to be explored -- until now. What if we could reach beneath the surface of a comet’s nucleus - to reveal matter from the time when the solar system was forming? In July 2005, NASA will do just that when the two-part Deep Impact spacecraft stages a collision with a comet named Tempel 1. Knowledge gained from the Deep Impact mission will be combined with that from other missions -- answering old questions and raising new ones. Deep Impact will give insight into our solar system’s future -- and bring forth hidden pieces of its past -- through these strange and beautiful visitors - comets.