A project to scan Egypt's pyramids for 4,500-year-old secrets is turning up "anomalies" that may lead to hidden passages and more, Discovery reports. Two weeks of thermal scanning have revealed signs of internal cavities and structures in several pyramids and a standout anomaly at the so-called Great Pyramid, also known as Cheops. "This anomaly is really quite impressive and it's just in front of us, at the ground level," says researcher Mehdi Tayoubi. He called the anomaly "impressive and obvious" but inconclusive. Antiquities Minister Mamdouh el-Damaty was more specific: "There is something like a small passage in the ground that you can see, leading up to the pyramids ground, reaching an area with a different temperature," he said, per the AP. "What will be behind it?"
In this first phase of the Scan Pyramids project, a team from Cairo University and the Heritage, Innovation and Preservation organization explored the pyramids with technologies including a thermal camera. The idea was to see how pyramid stones heated up in the morning and cooled down in the evening, and big temperature differences between adjacent stones could indicate structural differences inside the pyramid. Led by Tayoubi, researchers spotted a 6-degree difference in a block of stones on the ground level at Cheops. "We need now to build models and thermal simulations to test different hypotheses in order to understand what we have found," says Tayoubi. The project is slated to continue next year with an infrared scan of the pyramids. (Also giving up potential secrets? King Tut's tomb.)