Built more than 4,500 years ago, during Egypt’s 4th Dynasty of pharaohs, the pyramids at Giza are some of the most celebrated manmade monuments in history. Yet no one really knows how these magnificent ancient structures were built, on such a massive scale, in a relatively short period of time. The recently launched Operation Scan the Pyramids project aims to probe this enduring mystery by using high-tech but non-invasive methods to examine the pyramids. Using one of these methods—infrared thermography—an international team of scientists and architects recently detected a mysterious thermal anomaly, or hot spot, on the eastern wall of the Great Pyramid of Giza, which may hint at some kind of passageway or chamber inside.
In recent months, experts have been searching for hidden chambers located within the Egyptian pyramids, as well as for additional insight into how these amazing structures could have been built. Organized by the Faculty of Engineering of Cairo and the Paris-based Heritage Innovation Preservation Institute, the Operation Scan the Pyramids project aims to conduct in-depth examinations of the pyramids using non-invasive methods such as thermal imaging and muon radiography, a Japanese technique that has been used to peek inside active volcanoes as well as the nuclear reactors of Fukushima.
Last week, an initial infrared temperature scan of the famous tomb belonging to the pharaoh Tutankhamen, better known as King Tut, turned up promising results: a temperature difference in the tomb’s northern wall, which may indicate a hidden cavity behind the wall’s surface. Their work follows up on claims made earlier this year by Egyptologist Nicholas Reeve of the University of Arizona, who proposed that ultra high-resolution images of Tut’s tomb showed hidden doorways leading to previously unexplored burial chambers, possibly including the final resting place of the legendary Queen Nefertiti, who was married to Tut’s father.
Now, Egypt’s Antiquities Ministry has announced that a thermal scan of the three ancient pyramids built on the Giza plateau, some 20 km from Cairo, during the 4th dynasty (between 2613-2494 B.C.), has identified some intriguing anomalies. In particular, a scan of the largest of the three pyramids—known locally as Khufu and internationally as Cheops, but often referred to simply as the Great Pyramid—revealed higher temperatures in three of the stones at the bottom of the eastern wall. Though the authorities cannot say definitively what this anomaly means, they speculate that such differences in temperature could indicate empty areas inside the structure, internal air currents or the use of different building materials.
An international team—including scientists and architects from Egypt, Canada, Japan and France—conducted the thermal scanning at different times of the day and night. They focused particularly on sunrise, when the sun heats the limestone of the pyramids from the outside, and on sunset, when the structures were cooling down. In the case of the Khufu pyramid, they found that while much of the wall heats up and cools down uniformly (with a typical difference of only 0.1 to 0.5 degrees Celsius between adjacent stones), a three-stone spot on the eastern wall acted differently. When compared with surrounding stones, this area showed a difference in temperature of 11 degrees Fahrenheit (6 degrees Celsius), appearing as a bloom of red on the thermal scans.
By the time Operation Scan the Pyramids concludes, at the end of 2016, researchers will have scanned the Great Pyramid and the second-largest of the Giza pyramids, built for Khufu’s son Khafre, as well as the Bent Pyramid and the Red Pyramid, both built at Dahshur (about 15 km south of Saqqara) by Snefru, Khufu’s father and the founder of the 4th Dynasty. The goal of the scanning project is to find more anomalies, each of which will provide another clue for Egyptologists to investigate in their attempts to solve the enduring mysteries of the pyramids.