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Ancient observatories and the summer solstice

Thousands of people gathered to watch the sun rise over Stonehenge for the 2005 summer solstice. (Photo: Andrew Dunn

Since ancient times, people have been marking the summer solstice, the point at which the sun appears to halt its northward trek and begin the journey southward. The days grow shorter, and the long days of summer begin to wane as the Earth tilts on its axis away from the sun in the northern hemisphere.

Midsummer celebrations have been most popular in northern European countries, most notably Norway, Sweden, Denmark, Finland, Latvia, Lithuania, Germany, Ireland, and Britain. One of the most famous celebrations takes place at Stonehenge, where around 15,000 people, many of whom are druids and pagans, will descend on the site to view the sunrise at this ancient observatory on one of only two days during the year that visitors are allowed to touch the stones (the winter solstice is the other).

Believed to be constructed somewhere between 3000 BC and 1600 BC, the mechanics of its creation are still a mystery. Geologists know where the rocks came from, but it's unknown how the people of that time period were able to physically engineer such a monument. What is known is that the stones are aligned to midsummer sunrise and midwinter sunset.

On the summer solstice, the rising sun appears behind what is known as the "Heel Stone," which creates a long shadow aligning with two pillar stones with another laid across the top so that the shadow forms a horseshoe that opens toward the sun.

Stonehenge isn't alone in being oriented to the sun. The Mayan pyramid Kukulkan at Chichen Itza is constructed so that its axes that run from northwest to southwest are oriented toward the rising sun at the summer solstice and the setting sun at the winter solstice.

Because of its alignment, however, it's at the equinoxes that this pyramid shows how uniquely and imaginatively it was constructed. At sunset on the equinox, seven isosceles triangles are formed from the shadows and sunlight in such a way that it looks like a serpent's body running the length of the pyramid and ending at the bottom at a serpent's head, which is carved at the base of the stairs and is also illuminated.  

Believed to be constructed by the Mayans around 1000 AD, each of the four sides has 91 steps, which, when combined with the top, add up to 365, the number of days in the year. There are also nine terraces divided into eighteen segments, representing the eighteen months of the Mayan calendar.

Its Peruvian cousin, Machu Picchu, built by the Incas, is also oriented to the sun. The Torreón, or "tower," also called the Temple of the Sun, receives a direct ray of sunlight through a window during the solstice in June.

Astronomical observations didn't only occur in large temples or with large stones, however. The Gotland Grooves, a network of grooves carved into rock in various places in Europe but concentrated on the island of Gotland just off the coast of Sweden, may be proof of that. Although the formation and purpose of these grooves is a matter of controversy, the grooves appear to be aligned with celestial bodies, and most run across the island in a consistently east-west pattern.

In ancient times, there were no telescopes and no weather reports. The heavens were the key to the patterns of the earth—planting and harvesting in particular. The inhabitants of the world were closer to the earth and to the heavens, reading the signs they could find there, learning to live with and adapt to the patterns of nature.

With all our technology today, while we may be able to forecast our immediate weather and know what events the heavens will bring, we nevertheless ultimately find ourselves in the same situation as the ancients—learning to live with and adapt to the patterns of nature. Patterns we may be able to predict, but not control.

Representative Image Caption
Thousands of people gathered to watch the sun rise over Stonehenge for the 2005 summer solstice. (Photo: Andrew Dunn
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