Using various scanning technologies, researchers have found two inexplicable voids.
The Great Pyramid at Giza, Egypt, has long been rumored to contain hidden passageways leading to secret chambers. Now a team of researchers has confirmed the 4,500-year-old pharaonic mausoleum contains two unknown cavities, possibly hiding a corridor-like structure and more mysterious features.
The announcement by the ScanPyramids project comes at the end of a year-long effort to use various scanning technology on Old Kingdom pyramids, including the Great Pyramid, Khafre or Chephren at Giza, the Bent pyramid and the Red pyramid at Dahshur.
Carried out by a team from Cairo University's Faculty of Engineering and the Paris-based non-profit organization Heritage, Innovation and Preservation (HIP Institute) under the authority of the Egyptian Ministry of Antiquities, the ScanPyramids project used three innovative techniques — muography, thermography and 3-D simulation — to deeply investigate the Great Pyramid of Giza.
An unknown cavity was detected at a height of about 345 feet from the ground on the northeastern edge of the monument, while a "void" was found behind the northern side at the upper part of the entrance gate.
"Such void is shaped like a corridor and could go up inside the pyramid," Mehdi Tayoubi, founder of the Paris-based Heritage Innovation Preservation Institute, told Seeker.
He added that no link can be made between the two cavities at the moment.
Built for the pharaoh Cheops, also known as Khufu, the Great Pyramid is the largest of a family of three pyramids on the Giza plateau, on the outskirts of Cairo. It's the last remaining wonder of the ancient world.
A striking thermal anomaly was detected in November 2015 by French infrared specialist Jean-Claude Barré on the northern side of the monument, right where four chevrons — blocks placed according to an inverted V-shaped pattern — overhang the descending corridor.
When the pyramid was finished some 4,500 years ago, the chevrons were not visible in that area, but were hidden under casing stones that were dismantled over the centuries.
"Today we still see the remains of those chevrons and oblique stones which most probably are parts of propped missing chevrons covering a kind of void that might have existed before stones were dismantled," the researchers wrote in a statement.
In the construction of the pyramid, chevrons were not used for decoration, but to protect a void and prevent the roof from collapsing.
"Why many chevrons are put to protect such a small area at the beginning of the descending corridor?" the researchers wondered.
After carrying out a 3-D reconstruction of the area, they decided to install three aluminum plates at the bottom of the descending corridor in an attempt to capture cosmic particles.
The technology, known as muography, relies on the muons that continually shower the Earth's surface. They emanate from the upper layers of Earth's atmosphere, where they are created from collisions between cosmic rays of our galactic environment and the nuclei of atoms in the atmosphere.
"Just like X rays pass through our bodies allowing us to visualize our skeleton, these elementary particles, weighing around 200 times more than electrons, can very easily pass through any structure, even large and thick rocks, such as mountains," Tayoubi said.
Tayoubi and his colleagues placed detectors sensitive to muons, called emulsion plates, inside the pyramid to discern dense areas from less dense areas — essentially the bones and tissue of the pyramid. When the films from the detectors were analyzed at Nagoya University in Japan, they revealed a significant excess of muons in the same direction, strongly pointing to a corridor-like void.
"The precise shape, size and exact position of this void is now under further investigation," the researchers said.
To that end, they added 12 new muon emulsion plates in the descending corridor.
"They will be collected by the end of October," Tayoubi said.
The investigation of the Great Pyramid also involved muon gas detectors, basically telescopes pointed on the northeastern side of monument from the outside.
Overall, they accumulated around 50 million muon cosmic particles, revealing muon excess at a spot close to the edge, at around 345 feet from the ground.
"This excess corresponds to an unknown cavity, measuring about 30 square feet. It's the same volume as another known cavity located on the same edge," Tayoubi said.
"Several studies from The French Alternative Energies and Atomic Energy Commission (CEA) and Nagoya university were conducted to confirm the excess of muons was not statistical fluctuation or noise," he added.
The excess was measured to be largely above 5 sigmas, corresponding to an effect with a probability above 99.9999%. In other words, the findings don't seem to have been some odd fluctuation of muons.
The results have been submitted to a scientific committee led by the former minister of antiquities Zahi Hawass.
In the committee are also Mark Lehner, director of Ancient Egypt Research Associates (AERA), Miroslav Barta, director of the Czech Archaeological Mission in Saqqara, Rainer Stadelmann, former director of the German Archaeological Institute and Mahmoud Afifi, director of the Egyptian Antiquities sector at the Ministry of Antiquities.
Zahi Hawass, who heads the committee, believes more research is needed before it can be confirmed that the results point to hidden cavities or secret rooms.
"These people are scientists and do not have an archaeological background. The core of the pyramid was built using long stones and small stones. If you know that, you'll find anomalies everywhere," Hawass told Seeker in a phone interview.
"I think there are no secret rooms and these anomalies have to do with the way the pyramid was built," Hawass said.
He urged that more research, including a photogrammetric map of the pyramid, is needed.
In this view, the committee approved the ScanPyramids request to extend the time of the project for another year.
"We have so many other data to analyze. Many new scientific teams from prestigious international universities want to join the project. Our knowledge on the pyramid is progressing," Tayoubi said.