Today, Sirius can be seen almost worldwide as the brightest star in the sky – excluding the sun – and the fourth brightest night-sky object after the moon, Venus and Jupiter. Sirius is so noticeable that its rising and setting was used as the basis for the ancient Egyptian calendar, says Magli. At the latitude of Göbekli Tepe, Sirius would have been below the horizon until around 9300 BC, when it would have suddenly popped into view.
“I propose that the temple was built to follow the ‘birth’ of this star,” says Magli. “You can imagine that the appearance of a new object in the sky could even have triggered a new religion.”
Using existing maps of Göbekli Tepe and satellite images of the region, Magli drew an imaginary line running between and parallel to the two megaliths inside each enclosure. Three of the excavated rings seem to be aligned with the points on the horizon where Sirius would have risen in 9100 BC, 8750 BC and 8300 BC, respectively (arxiv.org/abs/1307.8397).
The results are preliminary, Magli stresses. More accurate calculations will need a full survey using instruments such as a theodolite, a device for measuring horizontal and vertical angles. Also, the sequence in which the structures were built is unclear, so it is hard to say if rings were built to follow Sirius as it rose at different points along the horizon.
Ongoing excavations might rule out any astronomical significance, says Jens Notroff, also at DAI. “We are still discussing whether the monumental enclosures at Göbekli Tepe were open or roofed,” he says. “In the latter case, any activity regarding monitoring the sky would, of course, have been rather difficult.”
This article appeared in print under the headline “Stone Age temple tracked the dog star”