Your Zodiac Sign Is 2,000 Years Out of Date

"The Earth wobbles like a top. A spinning top starts to wobble soon after it is set into motion. The Earth does the same thing, only more slowly. It takes 26,000 years for the North pole to trace out a complete circle in the sky, pointing at different stars along the way. Scientists call this wobbling motion axial precession. This wobble means that our view of the stars shifts by one degree every 72 years."

"Since you can't see stars during the day, he waited for a lunar eclipse when the moon is directly opposite the sun and used the moon's position to work out where the sun was. By comparing his measurement with earlier ones, he found that our view of the stars shifts by about one degree per century not too far from modern measurements."

"Whether you care about horoscopes or not, you probably know your zodiac sign. You've probably known it for most of your life. Zodiac signs were originally based on the stars. But over thousands of years, our view of the stars has shifted. That means, if you account for this shift, your sign might not be what you think. Below, we'll tell you what it would be instead."

Earth's axial precession shifts the apparent positions of constellations over millennia. The North Pole traces a complete circle in roughly 26,000 years, altering which stars the pole points at. This wobble shifts the sky by about one degree every 72 years, producing noticeable differences over centuries. Hipparchus detected the shift over 2,000 years ago by using a lunar eclipse to infer the sun's position and comparing measurements, finding about one degree per century. Western astrology uses the tropical zodiac tied to the seasons rather than current stellar positions, so traditional zodiac signs no longer align with the actual constellations.

Read at www.nytimes.com