A researcher at the University of Edinburgh has discovered what he believes is the earliest calendar of its kind at Gobekli Tepe, an archaeological excavation site in what is now southern Turkey that used to be an ancient complex of templelike enclosures.

The researcher, Martin Sweatman, a scientist at the University of Edinburgh in Scotland, said in research published last month that V-shaped markings on the lunisolar calendar, which combines the movements of the moon and sun, recorded a major astronomical event that had a huge impact on Earth — making the ancient pillar part of an ancient version of a memorial.

Sweatman said the intricate carvings at Gobekli Tepe tell the story and document the date when fragments of a comet — which came from a meteor stream — hit Earth roughly 13,000 years ago. The comet strike, which the latest research has placed in the year 10,850 B.C., has long been a source of disagreement among academics and researchers.

This is not the first time that Sweatman has been able to connect the impact of the comet to the site in Turkey, he said. In 2017, he linked the two in an academic paper in which he contended that the carvings at Gobekli Tepe were memorialized in the pillars, and that the site was used as a place to observe space.

At the time, a group of excavators at Gobekli Tepe challenged those findings. Jens Notroff, an archaeologist who wrote the post on the excavators’ website, was not immediately convinced about the new findings and questioned whether the markings had a deeper meaning. He said on the social network X that there was “an obsession with the idea that there *must* be a secret, a hidden code which needs to and can be decoded — while it’s really just about past humans living their lives.”

Sweatman said the recent discovery that one of the pillars also depicts a lunisolar calendar — and thus marks the day of the impact — lined up with his prior research. “We can be very confident indeed that it’s a date,” he said.

The comet strike ushered in a 1,200-year ice age and led to the extinction of many large animals, Sweatman said. For humans, the comet probably also led to differences in lifestyle and agriculture that helped usher in the rise of civilization as we know it.

Although Sweatman has long researched the symbols at the ancient site in Turkey, this recent breakthrough came in the form of a tip when someone emailed him that the V-shaped symbols on the pillar could be interpreted as markings of the lunar cycle. “I had not spotted that myself before,” he said. “I had always wondered what these box- and V-symbols might mean.”

Each V-shaped symbol could represent a single day, according to Sweatman’s research.