Solar Reflection Geometry of the Great Pyramid of Giza: A Proposed Optical Alignment with the Richat Structure, Mauritania

The original casing stones of the Great Pyramid of Giza (Khufu, c. 2560 BCE) were composed of polished white Tura limestone, now largely stripped. The pyramid's faces are inclined at 51.8 degrees from horizontal — a well-documented architectural parameter. Basic optics shows that a reflective surface at this angle produces a horizontal reflected beam when the sun reaches an elevation of 13.6 degrees, occurring twice daily at Giza's latitude (29.98°N). We calculate the great-circle bearing from the Great Pyramid to the Richat Structure ("Eye of the Sahara," Mauritania) using published GPS coordinates, obtaining 267.16 degrees — 2.84 degrees off due West. This bearing falls within the angular range illuminated by the pyramid's western face at the calculated sun elevation. Two documented ancient sites — Siwa Oasis, Egypt (550 km, 4.80° deviation) and Tassili n'Ajjer, Algeria (2,326 km, 3.89° deviation) — lie along the same bearing between Giza and Richat. All calculations are reproducible from publicly available coordinates using standard spherical geometry and solar optics formulas. We propose this geometric consistency warrants physical investigation of the Richat Structure and the intermediate sites.