Magdeburg, June 5, 2025 – The ancient and enigmatic Nebra Sky Disc has revealed new secrets thanks to a groundbreaking study conducted by materials researchers at Otto von Guericke University Magdeburg in collaboration with the State Office for Heritage Management and Archaeology of Saxony-Anhalt. Two decades after the disc’s discovery, researchers have succeeded in reconstructing its manufacturing process using cutting-edge analytical techniques.
By combining modern forensic materials science with experimental archaeology, the team discovered that the disc’s blank was originally cast at temperatures exceeding 1200°C in central Europe nearly 4,000 years ago. It was then repeatedly reheated to around 700°C and forged into its final form. According to Professor Dr. Thorsten Halle, this process bears remarkable similarities to today’s industrial metalworking techniques.
Using just a tiny 5 mm³ sample of the original artifact, Professor Halle’s team—together with experts from Delta Sigma, a Magdeburg University spin-off—employed electron backscatter diffraction and scanning electron microscopy to analyze the metal’s crystalline structure. This approach allowed them to trace the precise steps taken by Bronze Age metalworkers.
“These electron backscatter measurements let us scan the surface and create a kind of fingerprint of the material’s microstructure,” explained Prof. Halle. “The orientation, size, and deformation of the metal grains help us understand how many times and in what way the disc was heated and reshaped.”
This process, known as recrystallization, allows metals to “heal” after being deformed—restoring their softness and malleability. It’s a technique still used today in manufacturing aluminum foil and car parts. The findings clearly indicate that the disc was cast and then deliberately heated and forged at least ten times.
“It’s like forensic detective work for metals,” said Halle. “By examining the microscopic structure, we read the disc’s metallurgical diary. Just as a fire investigator can deduce the cause of a short circuit from a melted cable, we can reconstruct the history of this artifact through its microstructure.”
What makes this discovery even more astonishing is that the disc was crafted without modern tools, written knowledge, or measuring instruments. “It was pure trial and error,” noted Halle. “They must have failed hundreds of times—cracking or breaking the disc—yet they persisted until it worked.”
A vital contributor to the project was master coppersmith Herbert Bauer from Halle, who recreated the disc using only Bronze Age techniques—including stone hammers and charcoal furnaces. These replicas were also examined microscopically, providing conclusive evidence that validated the reconstruction.
The study, published in Nature Scientific Reports in November 2024, attracted significant international attention. “Over 20,000 downloads in just a month, and coverage in major news outlets and science publications around the world—interest in the Nebra Sky Disc remains as strong as ever,” said Halle.
For Otto von Guericke University’s materials science program, the project not only supports cross-disciplinary collaboration but also showcases its global leadership in the field. From aerospace alloys to biocompatible implants and now ancient artifacts, Magdeburg’s materials research continues to set standards. “With our high-resolution electron microscopes and analysis tools, we can uncover the hidden past—and help shape the future,” Halle added.
Currently, the team is developing an innovative eddy current app that will allow archaeologists to quickly and non-destructively assess material properties in the field using just a smartphone. “Soon, experts at excavation sites might be able to tell instantly whether a newly unearthed axe was cold- or hot-forged—without even touching it.”
Cover Image Credit: The Nebra Sky Disc with the marked sample extraction point ((c) Reproduced with permission by State Office for Heritage management and Archaeology, Saxony-Anhalt—State Museum of Prehistory, photo: J. Lipták, Munich).
