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The Story of Andromeda

The constellation Andromeda contains our Galaxy's companion, the Andromeda Galaxy. Under clear skies on a dark night, it can be seen with the naked eye. At a distance of 2.2 million light years, it is the farthest object we can see without a telescope, and yet it is but the first stop in the vastness of the universe outside our Galaxy.

As a tribute to our search for knowledge about these objects in the universe, we recount an early story to explain what we see in the sky.

In Greek mythology, Andromeda was the daughter of Queen Cassiopeia and King Cepheus of Ethiopia. Andromeda's mother claimed she was more beautiful than the sea nymphs, the Nereids. The Nereids felt insulted by this and complained to the sea god Poseidon.

Poseidon threatened to send a flood and a sea monster, Cetus, to destroy the kingdom of Ethiopia. The king consulted the oracle of Ammon who advised him to sacrifice his daughter. Andromeda, dressed only in jewels, was chained to a sea-cliff. At this time, Perseus, a Greek hero was traveling along the coast of Africa to the north. He noticed the beautiful woman chained to a rock and instantly fell in love with her.

Perseus offered to rescue Andromeda in return for her hand in marriage. Andromeda had already been promised to a man named Agenor. However, hoping to save their daughter from the approaching sea monster, King Cepheus and Queen Cassiopeia consented in bad faith to Perseus' request.

drawing of Andromeda
The Constellation Andromeda

Perseus was a valiant warrior and possessed some powerful weapons, including the head of the Gorgon Medusa, which had the capability to turn everything into stone. With the aid of the Gorgon's head, Perseus slew Cetus and freed Andromeda. On Andromeda's insistence, the wedding was then celebrated. Her parents, who had forgotten their promise to Perseus, informed Agenor of the wedding. He interrupted the ceremony with an armed party.

A violent fight took place with King Cepheus and Queen Cassiopeia siding with Agenor. Perseus prevailed, using the Gorgon's head to petrify his opponents. Finally, Andromeda left her country to live with Perseus, who later became the king of Tiryns and Mycenae. The goddess Athena placed the figure of Andromeda among the stars as a reward for keeping her parents' promise.

Imagine the Universe is a service of the High Energy Astrophysics Science Archive Research Center (HEASARC), Dr. Alan Smale (Director), within the Astrophysics Science Division (ASD) at NASA's Goddard Space Flight Center.

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