For millennia humans have looked up to the heavens in wonderment, trying to decipher their secrets. The Zodiac, the Chinese lunar mansions, the Indian nakshatras have been attempts to understand the night sky. What they could not understand, they explained on the basis of gods and heroes. Tales of heroic conquests, estranged lovers, and demonic entities were tied to patterns in the night sky and apparent anomalies. Thus, astronomy became forever intertwined with mythology.
Though the ancient astronomers’ explanations were quite unscientific, their observations were rather astute. One such observation was the varying brightness of the star Algol located in the Perseus constellation. The star derives its name from the Arabic r’as-al-ghul (Yep, like the Batman comics) which translates to ‘the demon head’. This star is associated with “the winking eye” of Medusa – the snake headed gorgon whose one look could scare you solid. The constellation’s illustration depicts Perseus holding Medusa’s severed head. The star must have appeared sinister to the ancients, periodically dimming in a sea of steadily shining stars. However, we now know that Algol is a multiple star system with an eclipsing binary. It was one of the first few variable stars to be discovered. Algol B, the less luminous component eclipses Algol A, the brighter one, every 2.86 days with the eclipse lasting 10 hours.
The conquest of Perseus over Medusa is just one of many stories the Greeks associated with the star patterns. However, the Greeks weren’t the first to connect the dots. Mesopotamian illustrations dating back to 3200 BC depict patterns which we know today as Leo, Taurus and Scorpion. In fact pattern recognition is a defining characteristic of sentient life and early humans must have associated the patterns in the sky to their environment. Consequently, the same patterns has changed meanings over time and over different civilizations.
Consider one of the most prominent constellations – Orion. The constellation has taken many avatars – The true shepherd of Anu in Mesopotamia, the god of death Osiris in ancient Egypt, the incestuous king Prajapati in India and of course the fierce demigod hunter Orion in Greece. These are just some of its depictions. In fact in Japanese folklore, Orion has been variously represented as an hourglass shaped percussion instrument, a kimono sleeve and even an ancient battlefield. Not only that, the three stars on the belt of Orion have meant different things to the Japanese based on their primary occupation. To those in construction, they were Shakugo Boshi – the ruler stars. To bamboo growers, they were the Take No Boshi – the bamboo joint stars. To the weavers, they were the Kase Boshi – the three prongs of the weaving instrument. It is fascinating to see how human creativity and imagination have worked together with their environment to assign importance to a bunch of stars arranged so by pure coincidence.
However this tapestry of stars has not always been the same, nor ever will be. Stars fade out as dwarfs or die in bright supernovae and from these remnants new stars are born, continuously changing the cosmic landscape. One of the most recent supernovae was recorded by Chinese Astronomers in 1054 AD. The explosion was so bright that it was visible in sunlight for 23 days and for two years afterwards at night. The Chinese dubbed as a ‘guest star’, heralding the success of the king. We now know remnants of the supernova as the Crab Nebula (M1).
In addition to star life cycles, the complex interaction of gravity and the continuous expansion continues to alter the position of stars. The proper motion of the stars would mean the ancestors of the human species would have seen a completely different sky. This also means that if we manage to survive a couple millions years more, we would see distorted forms of the patterns that are so familiar to us today. For example the big dipper will be completely distorted in 100,000 years (as seen in the figure). Human imagination though, will form new patterns, new association and new mythologies.
– Meet Upadhyay
Former President , AAC