The stone circle of Nabta Playa marks the summer solstice, a time that coincided with the arrival of monsoon rains in the Sahara Desert thousands of years ago. (Credit: Wikimedia Commons)
Topics: African Studies, Astronomy, Astrophysics, Diversity in Science
For thousands of years, ancient societies all around the world erected massive stone circles, aligning them with the sun and stars to mark the seasons. These early calendars foretold the coming of spring, summer, fall, and winter, helping civilizations track when to plant and harvest crops. They also served as ceremonial sites, both for celebration and sacrifice.
These megaliths — large, prehistoric monuments made of stone — may seem mysterious in our modern era, when many people lack a connection with, or even view of, the stars. Some even hold them up as supernatural or divined by aliens. But many ancient societies kept time by tracking which constellations rose at sunset, like reading a giant, celestial clock. And others pinpointed the sun’s location in the sky on the summer and winter solstice, the longest and shortest days of the year, or the spring and fall equinox.
Europe alone holds some 35,000 megaliths, including many astronomically-aligned stone circles, as well as tombs (or cromlechs) and other standing stones. These structures were mostly built between 6,500 and 4,500 years ago, largely along the Atlantic and Mediterranean coasts.
The most famous of these sites is Stonehenge, a monument in England that’s thought to be around 5,000 years old. Though still old, at that age, Stonehenge may have been one of the youngest such stone structures to be built in Europe.
The chronology and extreme similarities between these widespread European sites lead some researchers to think the regional tradition of constructing megaliths first emerged along the coast of France. It was then passed across the region, eventually reaching Great Britain.
But even these primitive sites are at least centuries younger than the world’s oldest known stone circle: Nabta Playa.
Located in Africa, Nabta Playa stands some 700 miles south of the Great Pyramid of Giza in Egypt. It was built more than 7,000 years ago, making Nabta Playa the oldest stone circle in the world — and possibly Earth’s oldest astronomical observatory. It was constructed by a cattle worshiping cult of nomadic people to mark the summer solstice and the arrival of the monsoons.
“Here is human beings’ first attempt to make some serious connection with the heavens," says J. McKim Malville, a professor emeritus at the University of Colorado and archeoastronomy expert.
Nabta Playa: The World's First Astronomical Site Was Built in Africa and Is Older Than Stonehenge, Eric Betz, Discover Magazine