Constellations

By Sophie Planos

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When you hear the word “constellations” you probably just think about stars, but what are they really and why do they exist? The constellations you see at night depend on your location on Earth and the time of the year. They are traditionally named after what they resemble, such as Ursa Major (The Great Bear), or mythological figures like Orion and Hercules. To this day, astronomers still use constellations to name stars and meteor showers. There are different definitions for constellations, but many people think of them as a group of stars. Typically it's a group of stars that looks like a particular shape in the sky and has been given a name. These stars are not connected at all, they just look very close together which creates a picture of an object, animal, or person if you look very closely. Today, there are 88 official constellations, all of which have different shapes, names, and backstories. But, over time cultures around the world have had different names and numbers of constellations depending on what people thought they saw. The 88 constellations act as a handy map of the skies and a seasonal calendar used from ancient times. Where did the constellations come from? The origins of the patterns are not known for certain, although the ancient Chinese and Egyptians are known to apply symbolic sky maps. The basic pattern followed today is that of the ancient Greeks and those given in Ptolemy’s Algamest (dating from c.150 AD) are still in use. When Ptolemy conceived their patterns the stars were thought to be equidistant from the Earth. This model was created from Aristotle's idea of crystalline spheres, where stars and planets orbit around a central earth. Therefore, a relationship between groups of stars would have been a realistic assumption.