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Precession

The “wobble” of the Earth’s rotational axis, which sweeps out an imaginary cone, much like a spinning top, once every 26,000 years. Precession changes the pole star as seen from Earth. Thuban, the brightest star in the constellation Draco, was the pole star while the Egyptians built the Pyramids in Egypt. Since that time, the motion of precession has rotated the Earth’s axis away from Thuban and towards Polaris, the current pole star. In 13,000 years, Earth’s rotational axis will point towards Vega, the new pole star.

Featured Images

Dog Days August 7, 2022
Great Pyramid of Khufu at Giza

Lining Up September 30, 2021
diagram showing future north stars

Royal Pole Star September 19, 2017

Radio Programs

Moon and Spica The star of a down-to-Earth discovery August 3, 2022

Thuban A once-and-future North Star September 30, 2021

Moon and Antares Shifting stars across the night sky September 12, 2021

Moon and Aldebaran Keeping an eye on the eye of the bull April 15, 2021

Moon and Spica Eyeballing some changes in the sky January 5, 2021

Future North Poles Lining up the North Stars July 18, 2020

Moon and Spica Lining up a bright star June 28, 2020

Summer Solstice Springing into summer June 20, 2019

Alderamin Lining up a future North Star September 19, 2017

The Dog Days Sweating through the Dog Days of summer August 6, 2017

Pole Stars Lining up the north stars March 5, 2017