Newsletter April 2007

The oldest solar observatory in the Americas, dating back 2,300 years, has been found in the archeological site of Chankillo in the Casma-Sechin River Basin on the coast of Peru. Chankillo is a ceremonial center inhabited during the 4th century BC. The observatory consists of 13 towers running 1000 feet north to south along the ridge of a low hill, forming a toothed horizon, and two buildings positioned 750 feet east and west of the towers which serve as observation points:

The Chankillo Ceremonial Center

The Sun rises in the east and sets in the west. Standing on the western observation point, one can see the Sun rising in the east at a certain point along the ridge of towers depending on the time of the year. Standing on the eastern observation point, one can see the Sun setting in the west at a certain point along the ridge of towers depending on the time of the year. The 13 towers span the annual rising and setting arcs of the Sun.

The 13 Towers

Solstices occur twice a year when the Sun is at its greatest distance from the celestial equator. During the summer solstice (December in Peru) the Sun rises just to the right of the right-most tower, and during the winter solstice (June in Peru) the Sun rises just to the left of the left-most tower. As the year goes by, the rising and setting positions of the Sun move along the toothed horizon formed by the towers. By keeping track of the number of days it took for the Sun to move from tower to tower, these ancient astronomers were able to keep a calendar.

The Sun rising just to the left of the left-most tower,
as viewed from the western observation point, during the winter solstice in June in Peru.

Ivan Ghezzi from the Pontificia Universidad Catolica del Peru says: “Many indigenous American sites have been found to contain one or a few putative solar orientations. Chankillo, in contrast, provides a complete set of horizon markers and two unique and indisputable observation points.”

The ceremonial center of Chankillo has an area of 1.5 square miles and contains many buildings, plazas and a great, fortified temple. The temple always got a lot of attention from archeologists, who did not realize the towers were an observatory for many years. Clive Ruggles, professor of archaeoastronomy at Leicester University, UK comments: “These towers have been known to exist for a century or so. It seems extraordinary that nobody really recognized them for what they were for so long.”

Archeologists say that the people who inhabited Chankillo were an ancient Sun cult whose ceremonies and rituals revolved around the Sun. These people worshiped the Sun like the Incas did, but did so almost two millennia earlier.

Source: National Public Radio, BBC News, MSNBC

PAST NEWSLETTERS:

• Newsletter December 2007
• Newsletter November 2007
• Newsletter October 2007
• Newsletter September 2007
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• Newsletter July 2007
• Newsletter June 2007
• Newsletter May 2007
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• Newsletter February 2007
• Newslette January 2007