Thuban is a former Pole Star

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Thuban is a former Pole Star
Bruce McClure and Deborah Byrd in ASTRONOMY ESSENTIALS | BRIGHTEST STARS | May 21, 2019

Thuban was the Pole Star some 5,000 years ago, when the Egyptians were building the pyramids.

The Great Pyramid of Giza, an enduring monument of ancient Egypt. Egyptologists believe that it was built as a tomb for fourth dynasty Egyptian Pharaoh Khufu around 2560 B.C. Image via Nina Aldin Thune/Wikimedia Commons.

Thuban is not a particularly bright star, but it holds a special place in the hearts of stargazers. That’s because Thuban – a relatively inconspicuous star in the constellation Draco the Dragon – was the Pole Star some 5,000 years ago, when the Egyptians were building the pyramids.

Among the many mysteries surrounding Egypt’s pyramids are the so-called “air shafts” in the Great Pyramid of Giza. These narrow passageways were once thought to serve for ventilation as the pyramids were being built. In the 1960s, though, the air shafts were recognized as being aligned with stars or areas of sky as the sky appeared for the pyramids’ builders 5,000 years ago.

One of the “air shafts” follows a crooked course through the Great Pyramid, so you couldn’t have sighted stars through it. To this day, the purpose of these passageways inside the Great Pyramid isn’t clear, although they might have been connected to rituals associated with the king’s ascension to the heavens. Whatever their purpose, the Great Pyramid of Giza reveals that its builders knew the starry skies intimately. They surely knew Thuban was their Pole Star, the point around which the heavens appeared to turn.

Past and future pole stars. Indeed, Thuban at times made a better pole star than our modern Polaris. Various sources claim that Thuban almost exactly pinpointed the position of the north celestial pole in the year 2787 B.C.