Comets were feared by ancient and medieval people. They thought that comets meant some form of doom. Often it was a bad omen for stuff like famine, drought, war, disease, etc… Halley’s comet came around in 1066 and was thought to be a bad omen for the English side of the battle. In 1456, Pope Callixtus III excommunicated Halley’s comet declaring it to be an “instrument of the devil”! Other astrological phenomena have been feared too, like eclipses, meteor showers, and supernovas among others. Often, people believed that supernatural beings controlled the sky and the Earth and were angry at humans. Comets sometimes were thought to be a good sign (usually by the opposing side!). William the conqueror took Halley’s comet to be a good sign in 1066. Ancient people were much more observant of the sky, as it helped them through the year, and they noticed if something changed.
Why do celestial phenomena, particularly comets, provoke such extreme reactions? “Whenever a major event occurs in the environment that is unusual, it is frightening because it is not natural and because we have no explanation for it and can’t control it,” explains Robert Kohlenberg, an associate professor of psychology, who studies how people learn. “Explanations of phenomena such as comets are ultimately appealing because they offer control and the possibility of protecting ourselves against possible harm. This is very reasonable and accounts for why we have science and also why some people come up with less than conventional ideas to explain phenomena. Everything is always answered in terms of what motivates us. In this case, the motivation is protection. If something is unknown, there is no conceivable way of dealing with it,” he adds. (Humans Have Feared Comets and Other Celestial Phenomena Through The Ages)