The Demon Star marked on an ancient Egyptian calendar may be the earliest known record of a variable star, according to astronomers.
MSNBC reports that researcher Lauir Jetso, an astronomer at the University of Helsinki, stated that:
“It seems that the first observation of a variable star was made 3,000 years earlier than was previously thought.”
A variable star is a star that dims in the night sky by a factor of ten when it is eclipsed in the night sky, and the dimming is visible with the naked eye. Web Pro News reports that in the Egyptian calendar, called the Cairo Calendar, a papyrus document dating between 1163 and 1271 B.C, Sebastian Porceddu, an astronomer and Egyptologist at the University of Helsinki:
“The eclipse seems to be linked with the lucky days, because it represents the pacification of the Eye of Horus. A bright Eye of Horus meant it is raging and a threat to mankind.”
According to MSNBC, the ancient Egyptians wrote their calendars to show lucky and unlucky days, using three hieroglyphics which indicate either good or bad luck. This reference in the Egyptian calendar closely resembles the pattern of Algol, also known as the Demon Star, which is located about 93 light-years away in the constellation Perseus.
The name comes from the Arabic phrase, ra’s al-ghul, which also means “the demon’s head.” It is the brightest known variable star, also known as an eclipsing binary star. According to MSNBC, the large member of the system, Beta Persei A, is regularly eclipsed by the dimmer Beta Persei B. From our point of view on Earth, Algol’s dimming can be seen without a telescope.
With the discovery of the Demon Star’s reference in the Cairo Calendar, scientists will be looking for more references of variable stars in ancient texts.