Humans have been fascinated by the night skies since time began. At some
point,ancient people noticed that certain stars moved in an unusual path across the heavens. Most stars rose in the East and slowly crept across a steady and straight course the sets finally in the West. However,people noticed several other stars in existence that did not conform to this pattern. Because they had tendency to wander back and then forward again along their paths,the ancient Greeks called them asteres planetai,which means “wandering stars.” Theses are known today simply as planets. The ancients believed these planets held a special status distinct from other stars. It was even suggested that the planets were moving in a circular pattern,better known as an orbit.