Today scientists are still very interested in studying comets. This collection is an artist’s conception of progressive views of the Comet Kohoutek based on sketches and a description by Skylab-4 astronaut Edward Gibson. An early discovery of a large comet in an orbit that would reach close to the Sun at the end of 1973 prompted NASA to initiate Operation Kohoutek, a program to coordinate widespread observations of the comet from ground observatories, aircraft, balloons, rockets, unmanned satellites, and Skylab. Click on image for full size (546K JPEG) Courtesy of NASA

Civilizations throughout recorded history have been fascinated with comets, and have held them in awe, fear, and wonder. The author above, Gadbury, was writing about all of the terrible things he thought could happen because of the passing of a comet. Civilizations around the world have seen comets as omens of either good or bad things that would soon happen. For instance, Augustus Caesar became emperor of Rome around the same time a comet appeared in the sky. This was widely held as a sign that his time as emperor would be blessed by the gods.

Even though comets were long thought to have supernatural roles, scientists and philosophers tried to understand what comets were and where they came from. The Greek philosopher Aristotle thought that comets were meteors. Much later, Descartes from France thought they were messengers from other worlds. Still another philosopher, Georges-Louis Buffon, thought that comets were the source of the Sun's energy, and that they had actually set the planets in their orbits around the Sun. Gradually, though, scientists began to see that comets appear and disappear with regular cycles, and that they are actually small balls of ice and dust trailed by a tail of gas and dust. Today, scientists are still trying to find out all they can about comets. Missions such as the Rosetta mission will do just that!