Quick Answer
Structure AB at Karahan Tepe contains the oldest known winter solstice alignment on Earth: on the winter solstice sunrise, sunlight enters through a rectangular porthole, travels between pillars, and illuminates a carved stone head on the opposite wall for approximately 45 minutes — a phenomenon dated to around 9000 BCE, approximately 7,000 years older than Stonehenge’s famous solar alignment. Researchers Hugh Newman and J.J. Ainsworth first documented this alignment on December 20–21, 2021, and confirmed it through astronomical calculations adjusted for the year 9000 BCE. The precision of this design demonstrates that Pre-Pottery Neolithic builders understood the solar year well enough to encode astronomical knowledge in stone architecture — a capability previously thought impossible at this date.
On the morning of December 20, 2021, at approximately 7:37 AM, two researchers watching the sunrise at Karahan Tepe witnessed something that no one had seen with understanding for over 11,000 years. A beam of sunlight entered through a rectangular porthole in the southeast wall of Structure AB, traveled between the pillars, and landed directly on a carved stone head protruding from the opposite wall. The light moved slowly across the face — from the side to the mouth and neck — over the course of roughly 45 minutes.
What they had discovered was the oldest known solstice alignment on Earth. Approximately 7,000 years older than Stonehenge’s famous sunrise corridor.
I remember reading about this discovery and feeling the ground shift under my assumptions. I had been visiting Karahan Tepe regularly since early 2020, and I had stood in Structure AB many times. But I had never been there at dawn on the winter solstice. Now, every December visit to the site carries a different weight.
How the Alignment Works
The mechanics are elegant in their simplicity. Structure AB is a trapezoidal enclosure roughly 7 meters long and 6 meters wide, cut into the bedrock. In its southeast wall, a rectangular porthole about 70 centimeters wide opens toward Structure AD. On the opposite western wall, a carved stone head projects from the rock.
On the winter solstice — the shortest day of the year — the sunrise occurs at an azimuth of approximately 122°44’. At this angle, sunlight passes through the porthole, travels between two T-shaped pillars in the outer circle and the central pillars of Structure AD, and strikes the carved head inside Structure AB. The illumination begins when the sun reaches about 2 degrees above the horizon and lasts for approximately 45 minutes.
The researchers who first documented this alignment, Hugh Newman and J.J. Ainsworth, reconstructed the original conditions using astronomical calculations adjusted for the year 9,000 BCE. At that date, sunrise on the winter solstice would have occurred at roughly 7:57 AM, with atmospheric refraction adjusted for temperatures around 15°C. The alignment holds.
The Carved Stone Head
The target of this solar event is an oversized human head carved from the bedrock of Structure AB’s western wall. The face has open, eye-shaped carvings and a mouth shown in an open position. The head is oriented so that it “looks toward” the porthole — directly into the path of the incoming solstice light.
There is something deeply affecting about this arrangement. The builders positioned this face so that once a year, on the darkest morning, the returning sun would touch it. Whatever this meant to them — rebirth, renewal, the beginning of a new cycle — the intentionality is undeniable.
A Neolithic Calendar in Stone?
The winter solstice alignment has led some researchers to propose that Structure AB functioned as a calendar. A hypothesis put forward by Martin Sweatman suggests that the 11 pillars in Structure AB may represent 11 lunar months and 11 epagomenal days. Under this model, the stone head represents either the final lunar month or the first day of a new annual cycle.
The math works out: 11 lunar months of approximately 29.5 days equals roughly 324.5 days, plus 11 epagomenal days, bringing the total to 335.5 — close to the ancient Egyptian model. Alternatively, 354 days (12 lunar months) plus 11 days matches a luni-solar calendar of 365 days. The winter solstice sunrise would have marked the moment when the calendar reset — Day One of the new year.
This is a hypothesis, not a proven fact. But the alignment itself is real, documented, and reproducible. The calendrical interpretation fits the physical evidence with remarkable precision.
Why This Changes Everything
Before this discovery, the oldest widely accepted solar alignment was at Newgrange in Ireland, dating to approximately 3,200 BCE. Stonehenge’s solstice alignment dates to roughly 3,000 BCE. Karahan Tepe pushes this capability back to approximately 9,000 BCE — doubling the known timeline of human astronomical architecture.
This means that more than 11,000 years ago, people in southeastern Turkey understood the solar year well enough to design a building that would capture a specific moment of sunlight on a specific day. They understood the relationship between the sun’s position, the horizon, and the passing of seasons with enough precision to encode that knowledge in stone.
For me, as someone who has spent decades introducing visitors to Turkey’s archaeological heritage, this is the single most powerful fact about Karahan Tepe. It takes the site from “impressive ancient ruins” to “evidence of sophisticated astronomical knowledge at the dawn of civilization.”
Visiting During the Winter Solstice
If you are planning a trip to Karahan Tepe and have flexibility in your schedule, December is worth considering. The winter solstice typically falls on December 21 or 22. Southeastern Turkey in December is cold — temperatures in the Tektek Mountains can drop near freezing — but the landscape has a stark beauty that summer visitors never see.
I should note that access to Structure AB during the actual solstice sunrise may depend on excavation schedules and site management. But even visiting the site in the days around the solstice, knowing what happens with the light, changes your entire perception of the space.
Frequently Asked Questions
What is the winter solstice alignment at Karahan Tepe? On the winter solstice, sunlight enters through a porthole in Structure AB and illuminates a carved stone head on the opposite wall for approximately 45 minutes. It dates to around 9,000 BCE.
Is the Karahan Tepe solstice alignment older than Stonehenge? Yes — approximately 7,000 years older. Stonehenge’s solar alignment dates to roughly 3,000 BCE, while Karahan Tepe’s is dated to approximately 9,000 BCE.
When was the solstice alignment discovered? It was first observed and documented on December 20–21, 2021, by researchers Hugh Newman and J.J. Ainsworth.
Can visitors see the alignment? The solstice event occurs around sunrise on December 21–22 each year. Access may depend on site conditions and excavation schedules.
Does this prove the builders had astronomical knowledge? The alignment is physically documented and astronomically verified. Whether it represents systematic astronomical knowledge or a one-time observation is debated, but the precision of the design strongly suggests intentional planning.