One of the world's oldest observatories has been uncovered by archaeologists near the city of Linfen in Shanxi province in northern China.
They estimate the remains, in the Taosi relics site, are about 4,100 years old. That would make the Linfen observatory some 3,000 years older than the Mayan observatory uncovered in Central America, which in turn is older than the astronomical observatory built by Ulug'bek in Samarkand in 1428.
What's been found of the observatory is a 130-ft.-diameter semicircular platform made of rammed earth and surrounded by 13 stone pillars within a 200-ft. outer circle. The observatory may have been used to mark the movement of the Sun through Earth's seasons.
Rammed earth was a construction technique in which a mixture of soil and water were molded in forms. The forms then were removed, leaving solid earthen walls up to two feet thick.
The 13 pillars, each at least 13 feet tall, formed 12 gaps between them. Ancient astronomers observed the direction of sunrise through the gaps.
They also were able to distinguish the seasons of the year. The site may have been used to observe stars and the Moon.
From the observatory, ancient Chinese astronomers may have made some of the earliest recorded observations of stars in their night skies. The site also may have been used for sacrificial rites, according to the official Xinhua News Agency.
Chinese archaeologists in 2004-2005 spent 18 months simulating ancient uses of the site to validate their theories about it. They found the seasons they calculated were only one or two days different from the traditional Chinese calendar, which is still widely used today.
Astronomical observation and the making of calendars is regarded as one of the symbols of the origin of civilization. A historical document says that China had special officials in charge of astronomical observation as early as the 24th century BC. The discovery of the ancient observatory in Taosi confirmed the records.
The Taosi relics site, dated back to 4,300 years ago, is located in Xiangfen County, Linfen City of Shanxi Province, and covers an area of 3 million square meters. It is believed to be a settlement of the period of the five legendary rulers (2,600 BC-1,600 BC) in Chinese history.