Pegasus

Pegasus is the winged horse of Greek myth, and his origin is told by Hesiod: when Perseus struck off the head of the Gorgon Medusa, Pegasus and the warrior Chrysaor sprang from her blood or her severed neck, born beside the streams of Ocean, a birth from violence and from the monstrous. His name was linked by the ancients to the springs (pegai) at which he was born. Tamed at last by the hero Bellerophon with a golden bridle given by Athena, Pegasus carried him into the air to kill the fire-breathing Chimera from above, out of reach of its flames.

Pegasus was set among the stars as one of the larger northern constellations, and its most recognisable feature, the Great Square of Pegasus, formed by four bright stars, is one of the standard reference asterisms amateur astronomers use to navigate the autumn sky; one corner of the square is technically shared with the neighbouring constellation Andromeda rather than belonging to Pegasus alone, a quirk of the traditional boundaries drawn between the two figures. Pegasus's constellation lent its name to modern astronomy in an unexpected way: the star 51 Pegasi, in the same constellation, was found in 1995 to be orbited by a planet, 51 Pegasi b, the first exoplanet ever confirmed around a Sun-like star, a discovery that won its finders the 2019 Nobel Prize in Physics and that briefly carried the working nickname Bellerophon before being formally named Dimidium.

Where Pegasus struck the ground with his hoof on Mount Helicon, the spring Hippocrene, the horse's fountain, burst forth, sacred to the Muses, so that the winged horse became an emblem of poetic inspiration and of the imagination taking flight. The story ends as a warning against pride: Bellerophon, grown arrogant, tried to ride Pegasus up to Olympus itself, but Zeus sent a gadfly to sting the horse, which threw its rider back to earth to wander crippled and alone while Pegasus went on to the gods and was set among the stars as a constellation. Aspiration, inspiration and the danger of overreaching all gather to the winged horse.

The image has had a long modern afterlife detached from its myth: the British Army's airborne forces adopted a maroon shield bearing Bellerophon astride Pegasus as their formation insignia during the Second World War, a badge still worn by British parachute and glider units today, and the American oil company Mobil has used a red flying horse as its trademark since the 1930s, both cases drawing purely on the image of speed and flight rather than on the underlying story of pride and its fall. The horse-shaped star pattern the Greeks read as Pegasus is not read that way everywhere: traditional Chinese astronomy divides the same stars among several unrelated xingguan, star-officer groupings tied to a wall enclosure and a legendary flying corridor rather than to any horse, a reminder that a constellation's shape is a culturally specific way of connecting points of light, not a feature of the sky itself.