The team of researchers will employ drones, advanced scanners, and something called “cosmic ray muons” to probe the ancient tombs.
Khufu’s Pyramid, the last of the “seven wonders of the ancient world” still standing. Image by Nina Aldin Thune via Wikimedia Commons
In a snazzy video released in October, a group of Canadian, Egyptian, French, and Japanese researchers announced an initiative to probe the secrets of the Egyptian pyramids using a vast array of impressive, space-age-sounding technologies. Endorsed by the Egyptian Ministry of Antiquities and officially helmed by Cairo University and the Heritage Innovation Preservation Institute, the initiative, dubbed the ScanPyramids Project, will cover the Bent and Red pyramids at the Dashur necropolis and the famous Khafre and Khufu pyramids at Giza (with brief detours to investigate the tomb of King Tutankhamen). The arsenal the researchers will bring with them is dizzying, including things like drones kitted out with radiography and thermal imaging scanners. But what’s really getting everyone’s attention is a plan to explore the pyramids by measuring something called cosmic ray muons—a seemingly crazy technology that makes this sound like an unprecedentedly inventive endeavor, allowing us to model the deepest interior contours of the pyramids without ever needing to touch them.
Although cosmic ray muons might sound exotic, they’re actually a common, elementary form of particle, constantly raining from the skies onto Earth. Hundreds of times heavier than electrons, but similarly tiny, they have a neat ability to penetrate even the densest materials, although they tend to slow down a bit as they do. Measuring the characteristics of muons passing through an object gives us a sense of the density within, revealing possible cavities within a structure.
Archaeologists have long used all sorts of crazy scanners to peer beneath the earth and within tombs without ever breaking ground. In fact, archaeology’s been so proactive about using advanced scanning technologies that the field has actually made contributions to the realm of physics (rather than just acting as a late adopter of physics’ toolkit). As far back as 1986, we were using noninvasive microgravimetry technologies on these same pyramids to measure the density of the materials inside and create models of the structures’ interiors; as recently as 2000, researchers returned with ground-penetrating radar analyses. Cosmic ray muons have actually been used for quite a long time (since the 1950s) in archaeology—even at Egypt’s pyramids.
In the 1960s, the archaeologist Luis Alvarez (a Nobel Prize winner famous for postulating that dinosaurs went extinct because of an asteroid impact) took a muon detector to the pyramid of Khafre at Giza. He believed he could use it to detect density fluctuations that might help him locate hidden chambers. Like most using scanning technologies on the pyramids, Alvarez was able to identify some voids and oddities but unable to get a comprehensive sense of the interiors and how they were constructed, leaving many mysteries for later generations.
Alvarez’s early muon scans were very basic, and the technology lay dormant for some time. But around the turn of the millennium, researchers at the National Autonomous University of Mexico decided to dust it off, spending the better part of a decade developing new sensors to investigate pre-Columbian ruins in Mexico and Belize with markedly more success in passage detection.
Tutankhamen's burial mask. Image by Bjørn Christian Tørrissen via Wikimedia Commons
So while the use of cosmic ray muons has recently caught the attention of the press and the public, employing the method at the pyramids is not a particularly massive innovation. But in any case, the importance of the ScanPyramids Project doesn’t lie with any individual technology, scanner, or drone. Instead, the significance of the endeavor is the fact that so many of them are being used in concert, dovetailing the most advanced versions of the technologies involved. The cosmic ray muon detectors that will be used for scanning the pyramids, for instance, are derived from those perfected earlier this decade by Japanese researchers to investigate the interiors of nuclear reactors and volcanoes in disaster zones. (As of December 17, the start of the second phase of the project, detectors have been installed by academics from Nagoya University in the Bent Pyramid and are being calibrated at the Great Pyramid Khufu—the former should yield data for analysis within the first weeks of 2016.) The detectors are infinitely more robust than what Alvarez would have used half a century ago.
Using individual scanner technologies is a bit like peering through an isolated peephole at the history of a structure. Ground-penetrating radar can tell you where there’s stone, giving you external contours. Cosmic ray muons can give you a few dimensions of internal density, and a sense of where there might be an unknown chamber or opening. Using just one or two technologies, we can only glean shadows of realities—limits that mean a lot of tantalizing clues about the pyramids’ puzzles, but enough mystery left over that we mainly trade in theories and speculation. Case in point: Within the first two weeks of the first phase of thermal scanning on the Khufu pyramid in early November, scientists found an anomaly in the rate of warming in three stones on the ground-floor façade, fueling speculation that there might be a hidden chamber there, but providing little resolution or proof. But combining all the tools at their disposal, the researchers behind the ScanPyramids Project should be able to put together the most comprehensive model of the pyramids and their interiors that has ever existed, bringing us closer to understanding intricate unknowns concerning their construction, function, and hidden secrets.
A 1909 representation of the known interior of Giza’s Khufu Pyramid (Great Pyramid)
Unfortunately, being realistic rather than giddy about the potential of this project, even ScanPyramids’ preponderance of new information won’t give us the final word on the pyramids. Muon detection can only go so far. And if we do discover a secret chamber, there’s only so much we can find out about it noninvasively. Ultimately, archaeology is a destructive science—to understand the full contours of a hidden room or the intricate details of a pyramid’s construction, you usually have to go in, even if just to give other, more advanced machines the direct access they need to do their own noninvasive scans.
But while scans like the ones to be used on the pyramids don’t mean an end to picks and shovels, they do mean more precision and care in the destructive science we do execute. If we can get a sense of where a secret tomb is, then we don’t have to go swinging hammers in search of them. We can be more surgical and selective in where we choose to scrape and peel, and be sure that we invade only the known and most promising sanctums of a structurally intact ancient wonder. For instance, many are excited about the ScanPyramids Project’s attempts to confirm that indentations on the northern wall of the tomb of King Tutankhamen indicate the presence of a secret chamber, believed by some to be the long-lost tomb of Queen Nefertiti. If the scans can prove definitively that there’s something there—and as of late November, researchers say the evidence provided by thermal scans has them 90 percent certain that there is—we have a reason to probe further. And unlike in ages past, these days that could involve just drilling a hole and dropping in a scanning robot, rather than busting down the door.
That’s the true promise of this project—not space-age rays and waves and crazy applications of drones, but the use of robust and multifaceted models to grant us greater precision. The fuller a picture we get, the more we can adapt and target future technologies and expeditions to teach us about the past without destroying it. It becomes easier for us to stick the pick only exactly where it needs to be. And as we test and improve these technologies in the great showrooms and subjects of fascination that are the pyramids, hopefully we’ll attract interest in funding further study, using ever-superior models of the same concepts to explore the secrets of history elsewhere in the world.