The Egyptians started building the Great Pyramid of Giza on August 23, 2470 B.C., according to controversial new research that attempts to place an exact date on the start of the ancient construction project. A team of Egyptian researchers arrived at the date based on calculations of historical appearances of the star Sothis—today called Sirius. Every year around the time of the Nile River floods, Sothis would rise in the early morning sky after a long absence. "The appearance of this star indicates the beginning of an inundation period" for the Nile, said team leader Abdel-Halim Nur El-Din, former head...
