Reading the Heat of the Giza Pyramids with Infrared Thermography

In the first episode of “Spectroscopy Around the Globe,” the role of spectroscopy in learning more about the Giza Pyramids was explored. The below is an except from the most recent episode of “Spectroscopy Around the Globe.”

Let's begin with a technique that's perhaps the most visually intuitive: IR thermography.

In October 2015, an international team from Egypt, France, Canada, and Japan launched a project called ScanPyramids. Its mission was to non-invasively scan four of Egypt's great pyramids, including Khufu’s and Khafre’s at Giza, using a suite of modern imaging technologies. The very first tool they deployed was the infrared (IR) camera.^1,2

Here's the basic principle. All materials absorb and release heat differently. Solid limestone heats up at a certain rate and cools down at a certain rate. Empty air does not. So if there's a void (such as a hidden corridor, a sealed chamber, or a cavity) behind a pyramid wall, it will appear as a temperature anomaly when scanned by an IR camera.

The ScanPyramids team conducted their thermal surveys at two key moments: sunrise, as the morning sun began heating the limestone from the outside, and sunset, as the stones were cooling down.^1,2 By tracking the rate of that heating and cooling across the surface, researchers could identify where the stone was behaving differently from what you'd expect.

The results were striking. Across all the pyramids studied, multiple thermal anomalies were detected.^1,2 But one stood out in particular: on the eastern side of the Great Pyramid of Khufu, at ground level, three adjacent stones were running roughly six degrees Celsius warmer than the surrounding limestone. Most block-to-block temperature differences were only 0.1 to 0.5 degrees, so six degrees was, in the words of Egypt's then-Minister of Antiquities Mamdouh El-Damaty, "particularly impressive."^1,2

What could cause such an anomaly? Possible explanations included empty spaces behind the surface, internal air currents channeling heat differently, or the use of different construction materials.^1,2 No single conclusion was drawn at the time — but the anomaly helped guide the next phase of investigation, pointing researchers toward areas of interest to examine with more penetrating techniques.

Infrared thermography has a key limitation: it only tells you that something is different. It doesn't tell you what that something is. For that, you need tools that can go deeper.

References

1. Bouazza, N. High-tech Scans Look to Unravel Mysteries of Egypt Pyramids. Phys.org. Available at: https://phys.org/news/2015-11-high-tech-scans-unravel-mysteries-egypt.html (accessed June 19^th, 2026).
2. Heilpern, W. Pyramids of Giza: What Do ‘Thermal Anomalies’ Reveal? CNN.com. Available at: https://www.cnn.com/2015/11/10/africa/egypt-giza-pyramids-thermal-anomalies (accessed June 19^th, 2026).