Scientists Discovered Suspected Secret Chamber In The Great Pyramid of Giza

Khufu’s Pyramid 3D cut aerial view. The fuzzy white dots represent the location of the newly discovered void. (Image: ScanPyramids Mission)

Although constructed around 5,000 years ago, the Great Pyramids of Egypt are still packed with surprising secrets. Scientists used a technique that leverages the power of cosmic rays to confirm the presence of a big empty space in the Khufu’s pyramid - a void which signals the presence of the potential existence of a hidden chamber.

It’s tempting to believe that there is no other great archaeological discovery from ancient Egypt to be made, but new research published in Nature proves there is still plenty for scientists to uncover.

An investigation in the internal structure of the largest pyramid in Giza, Khufu’s pyramid, has revealed the presence of a large, inaccessible “void” within the structure. The researchers, Mehdi Tayoubi from the HIP Institute, France, and Kunihiro Morishima from Nagoya University, Japan, are not sure that the cavity is a hidden chamber, but they are reasonably convinced that it's a deliberate architectural feature of the pyramid.

Cross section of the Great Pyramid showing the location of the void. This interpretation shows it in a horizontal position, but the researchers say it could also be inclined, tipped downward toward the North Face Corridor. Could an undiscovered tunnel connect the two hidden features? (Image: ScanPyramids Mission)

By making meticulous measurements of muons, researchers managed to characterize the densities in the pyramid, revealing the presence of an empty space which measures at least a hundred feet (30 meters) in length.

That Khufu’s pyramid might still hold a chamber waiting to be found is within the realm of possibility.

This massive structure was built on the Giza Plateau during the Egyptian Fourth Dynasty (c. 2613 to 2494 BC) by the Pharaoh Khufu (sometimes referred to as Cheops), who reigned from 2509 to 2483 BC. The pyramid initially measured 481 feet (146 meters) in height and was the tallest structure in the world for more than 3,800 years.

There are three known rooms inside the monument: the King’s Chamber, the Queen’s Chamber, and an unfinished room cut into the bedrock upon which the pyramid was built. There is also the Grand Gallery, a sloped hallway-like structure measuring 28 feet (8.6 meters) high, 153 feet (46.7 meters) long, and about 6 feet (2 meters) wide. The original entrance leading to these internal structures, known as the “descending corridor,” is located at the North Face, but today, tourists are allowed to enter the pyramid through a tunnel attributed to Caliph al-Ma’mun (around AD 820).

A glimpse inside the Great Gallery. The void is located directly above this spectacular structure, and it’s roughly the same size and shape. (Image: ScanPyramids Mission)

Archaeologists do not have the original blueprints to Khufu’s pyramid. Also, there is no consensus on how the structure was built or what hidden features might still lie inside. The only known documents, that's written on papyri, describe the logistics of the construction, like, for instance, how the stones were transported.

Detecting hidden chambers or corridors isn't easy for archaeologists, who must not damage ancient structures in any way. Egypt’s Supreme Council of Antiquities is strict about what can and can't be done to those historic monuments, requiring scientists to find alternative ways of exploring the pyramids.

Back in the '60s, archaeologist Luis Alvarez thought of using muons - a type of elementary particle which is capable of penetrating dense materials in order to peer inside Khafre’s pyramid. Unfortunately, his team didn't have the technological and scientific knowledge to pull it off, but Alvarez’s idea has now proven its worth. Today, the technique, which is known as muography, is being used by archaeologists to analyze ancient Roman structures as well as Mexican pyramids, and by geologists to explore features such as volcanoes. It has also been used to assess damage at the beleaguered Fukushima nuclear power plant, and by the US military to discover hidden caves and tunnels in Afghanistan.

In terms of the physics involved, muon particles come from the interactions of cosmic rays with the atoms in the upper atmosphere. They pepper the Earth at almost the speed of light (they are harmless to humans and animal life), and researchers can visualize the presence and trajectory of these particles using various muon detection schemes. Muons are only partially absorbed by solid objects, and can thus penetrate stone. However, by mapping the positions and trajectories in these particles, researchers can visualize the internal composition of solid structures and reveal things like stone formations or open-air cavities.

Last year, the ScanPyramids project used muography and infrared thermography (which measures temperature) to reveal a corridor directly above the Great Pyramid’s original entrance. Using the same idea, the researchers have now found the large void located directly above the Grand Gallery. To validate the void's presence, the researchers recruited specialists from three different institutions. Each team employed their unique muon detection technique and stationed their scanners both within and outside the pyramid.

A researcher from Nagoya University at work. This muon detector was positioned within the Queen’s Chamber. (Image: ScanPyramids Mission)

Researchers from Nagoya University used nuclear emulsion films to track the muons in three dimensions, a team from France’s Alternative Energies and Atomic Energy Commission (CEA) used scintillator hodoscopes (scintillating materials emit light when particles pass through it), and researchers from KEK High Energy Accelerator Research Organization did it using gas-based detectors. Because only 1% of muons reach the detectors, data should be meticulously accumulated over the course of several months (the exposures started in December 2015).

All three teams reached the same conclusion: there is a large, open cavity directly above the Great Gallery, and it is approximately the same size and shape. The void is around 70 feet (21 meters) above the ground and is at least 100 feet (30 meters) long, yet the researchers are not sure of its inclination.

The researchers used augmented reality to create a 3D reconstruction of the void. (Image: ScanPyramid Mission)

Finally, the researchers managed to rule out “non-void” possibilities. Because small gaps or crevices can't be detected using the muon technique, as it can only detect wide open spaces, there is virtually no way that space is a “swiss cheese” of stone, as several scientists have speculated. It is also unlikely that it’s merely a sign of interior wear-and-tear, some kind of collapse or construction flaw in the design, or the juxtaposition of small and large stones. Importantly, the area in question produced the same muon data patterns as scans made of the Grand Gallery - a known “void” within the structure.

According to Kathlyn M. Cooney, an Associate Professor of Ancient Egyptian Art & Architecture at the University of California Los Angeles, it is too early to speculate about the true nature of the void, yet a hidden chamber isn't an impossibility. Cooney, who was not involved in the new study, said that Khufu and his father Sneferu, unlike their Third Dynasty predecessors, started to “float” chambers within their pyramids.

Like the ScanPyramids archaeologists, Cooney does not know what’s inside the void, but she said that “it would be extraordinary to find potential materials [such as] funerary items and treasures that are almost 5,000 years old.”

More radically, INRIA researcher Jean-Baptiste Mouret, member of the ScanPyramids team, is currently designing an innovative robot which will be capable of squirming through a tiny hole, and perhaps fly like an aerial drone once it is within the cavity (that's 21st century's archaeology).

During the press conference, the researchers said they would like to perform more long-term muon scans of the structure in the future, and from different positions. That should allow them to create a more accurate picture of the space, and potentially find more hidden features.

An aerial view of the Great Pyramid. (Image: ScanPyramid Mission)

Unfortunately, the void is located in a place that's hard to access, and some drilling might be required. This prospect could be minimized should the researchers find any hidden adjoining corridors. Take the recently discovered corridor above the original entrance; this passageway could contain a tunnel all the way to the void in a mirror image of the structures below it.

Sources: Nature, Gizmodo