Long before the invention of the telescope, early civilizations invented star patterns and named them after animals, objects, heroes, gods, and beasts from stories and myths. Many of these myths were probably created to explain changes in the sky due to seasons, etc. The ancient Greeks named many constellations. For example, they told the story of Orion, the hunter, who leaped into the sea to escape a scorpion's bite, which explained why the constellation Orion disappears from the sky when the constellation Scorpius rises. Different civilizations imagined different patterns, and some stars were included in more than one pattern. Over time, the situation became confusing.
In 1929 the International Astronomical Union defined 88 constellations that are today recognized as the 'official' constellations. Many of these constellations are derived from the complex creations of Greek mythology, like Andromeda, Perseus, and Orion. Others came from ancient cultures such as the Egyptians and Chaldeans and still others were not defined until the 17th and 18th century. In the past, people used the constellations as markers. Some used the constellations to navigate their boats across the sea, to mark seasons of the year, or to locate special stars. Today, astronomers still use constellations as a handy marker to indicate a general area of the sky where far away celestial objects appear. Many of these extremely distant objects can be seen only with powerful telescopes.
'The strength and weakness of physicists is that we believe in what we can measure. And if we can't measure it, then we say it probably doesn't exist. And that closes us off to an enormous amount of phenomena that we may not be able to measure because they only happened once. For example, the Big Bang. ... That's one reason why they scoffed at higher dimensions for so many years. Now we realize that there's no alternative... '