Cosmic Ray Scan Of El Castillo At Chichén Itzá May Reveal Hidden Chambers

Jan Bartek - AncientPages.com - El Castillo, also known as the Temple of Kukulcán, is a prominent stepped pyramid located at the center of Chichen Itza in Yucatán, Mexico.

Credit: Kukulcan - Public Domain, El Castillo and the NAUM Project INAH. Image compilation by AncientPages.com

Constructed by the pre-Columbian Maya civilization between the 8th and 12th centuries CE, it served as a temple dedicated to Kukulcán, the Feathered Serpent deity of the Yucatec Maya. This deity is closely associated with Quetzalcoatl, revered by the Aztecs and other ancient Central Mexican cultures. El Castillo measures nearly 55.5 meters on each side and stands about 30 meters tall, making it the largest structure by volume at Chichen Itza.

The National Institute of Anthropology and History (INAH) has announced a new mapping project to detect interior structures within El Castillo. As part of this initiative, Mexican and American scientists will install two muon detectors in tunnels inside the pyramid. The primary goal is to identify rooms known as Offering and Sacrifice chambers—and potentially to discover another hidden chamber—using muon tomography. This non-invasive method allows researchers to explore internal features without damaging or disturbing the monument.

Edmundo García Solís, principal investigator for this project, explained that this study represents years of preparation and experimentation; fieldwork is scheduled to begin in late 2025. The effort will test the effectiveness of muon imaging on one of Mesoamerica’s most significant monuments, using detectors designed specifically for these conditions.

Guadalupe Espinosa Rodríguez, director of the Chichén Itzá Archaeological Zone, notes that El Castillo dates to around the 10th century CE and was constructed in several phases, as were many other Maya temples. In earlier excavations during the 1930s, led by Eduardo Martínez Cantón and José Erosa Peniche, archaeologists excavated a tunnel from the north side that led to chambers containing offerings such as a Chac Mool sculpture and a red-painted jaguar throne—features now targeted for further study using muon technology through existing tunnels.

Previous research conducted by the National Autonomous University of Mexico’s (UNAM) Institute of Geophysics in 2016 used electrical resistivity tomography; the results suggested the presence of additional internal spaces within El Castillo. Muon imaging offers an advantage because it can scan at virtually unlimited depths inside stone structures.

This approach builds upon successful experiments conducted beneath Teotihuacan’s Pyramid of the Sun, using similar techniques developed by physicist Arturo Menchaca Rocha, who now contributes expertise to this new project at Chichén Itzá.

Credit: INAH

For their work on El Castillo, scientists have built two identical muon detectors designed for use in confined spaces with high humidity (nearly 100%) and temperatures of approximately 32°C (90°F). Each detector consists of three folding electronic planes mounted onto frames suitable for these challenging conditions.

According to García Solís: “These detectors measure differences in density—the most pronounced being empty voids.” If another chamber exists but is partially filled rather than empty, it would require more data because the contrast levels detected by the instruments are lower.

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The initial six-month phase primarily aims to map known chambers clearly; if anomalies suggesting additional rooms are identified during scanning, the team will reposition equipment accordingly before concluding their contribution once all available data have been gathered.

Researchers hope that applying this advanced technique could help confirm or refute longstanding archaeological theories—including one proposed by historian Virginia E. Miller, suggesting an earlier substructure within El Castillo may have functioned as a royal burial site.

Source: INAH

Written by Jan Bartek - AncientPages.com Staff Writer