A star with a demonic reputation climbs the northeastern sky this evening. Algol represents the head of Medusa, a monster that’s part of the constellation Perseus. The star periodically fades and brightens, which may have helped inspire its reputation. The person who first proposed why the star acts so oddly was born 250 years ago today. John Goodricke came from a well-to-do family. That was important because while he was quite young, Goodricke was afflicted with a disease that left him completely deaf. But his family was able to send him to one of the few schools for the deaf, in Scotland. After completing his education, Goodricke returned to the family home, where he befriended Edward Pigott, a neighbor who’d built an observatory. They decided to study variable stars — those whose brightness changes. Algol was one of their first targets. They found that its brightness varies with a period of 2.8 days. Goodricke suggested that the change was the result of a faint star or a large plane
