As we gaze at the night
sky on a clear night we see thousands of stars scattered in random groups.
Some of these groups have been named and are called
constellations. It is important to remember
that even the patterns of stars we identify by name as constellations do
not have physical association with each other. Some of the stars
in a constellation may be much farther apart than others. The only
thing they have in common is they lie in the same direction as we see them
Half of toady's 88 constellations were named in ancient times. These ancient constellations were thought of as loose groupings of stars. A star could even belong to more than one constellation. In ancient times Alpheratz was thought to belong to Andromeda and Pegasus. In 1928 the International Astronomical Union gave each constellation definite boundaries. This meant each constellation would represent not just a group of stars, but a region of the sky. Thus any star within the region was part of the constellation. This new representation places Alpheratz in the constellation Andromeda.
Two of the oldest constellations are Taurus and Leo. These constellations are thought to have originated in Mesopotamia more than 5000 years ago. Others were added by Babylonian, Egyptian, and Greek astronomers. In some instances these star patterns had religious significance, but some were designed as navigation aids for sailors. Orion and Hercules honored great heroes. When looking at Orion or Hercules you might notice they do not look like either man, but the American Flag does not look like America either. The constellations were meant to symbolize their objects, not represent them.
Many cultures named and created stories about the constellations. The Greco-Roman tradition of naming constellations and creating mythologies did not extend to the Southern Hemisphere. This is because the extreme southern sky is never visible from the latitudes of the Mediterranean. After Magellan's circumnavigation of the world in 1521, many of the constellations were named in the eighteenth century by mariners and scientists who traveled south of the equator. Many civilizations living in the Southern Hemisphere had their own cultural beliefs concerning the heavens which were not adopted by the Europeans. Today we can find constellations mythologies from a variety of cultures, including Greek, Northern European, South American, African, and Native American.
Helpful Constellation and Mythology links:
guide to the heavens
Astronomy for kids