"What's your sign?" But before you ask or answer that question, consider this: Your zodiac sign corresponds to the position of the sun relative to constellations as they appeared more than 2,200 years ago. Your zodiac sign is not what you think it is.
The Earth continually wobbles around its axis in a 25,800-year cycle. This wobble—called precession—is caused by the gravitational attraction of the Moon on Earth's equatorial bulge.
Thanks to Earth's wobble, astrological signs are not what you think they are!
Astrological signs are determined by the position of the sun relative to certain constellations on a person's day of birth. The problem is, the positions were determined more than 2,000 years ago. Nowadays, the stars have shifted in the night sky so much that horoscope signs are nearly a month off.
"Astrology tells us that the sun is in one position, whereas astronomy tells us it's in another position," said Joe Rao, SPACE.com's skywatching columnist and a lecturer at New York's Hayden Planetarium.
The shift is caused by precession, the wobble in the Earth's axis caused by the gravitational attraction of the moon to the Earth's equator.
"The earliest known astronomer to recognize and assess the movement of precession was Aristarchus of Samos, who lived around 280 B.C.," Rao told LiveScience.
Here are the "real" dates of astrological signs, according to astronomers:
Capricorn: Jan. 20-Feb. 16.
Aquarius: Feb. 16-March 11.
Pisces: March 11-April 18.
Aries: April 18-May 13.
Taurus: May 13-June 21.
Gemini: June 21-July 20.
Cancer: July 20-Aug. 10.
Leo: Aug. 10-Sept. 16.
Virgo: Sept. 16-Oct. 30.
Libra: Oct. 30-Nov. 23.
Scorpio: Nov. 23-29.
Ophiuchus: Nov. 29-Dec. 17.
Sagittarius: Dec. 17-Jan. 20.
The list includes Ophiuchus, a formation the ancient Babylonians discarded because they wanted 12 star signs, not 13.
Another neat fact to ponder over coffee:
The North Star, Polaris, for example; It's the star most closely aligned with Earth's North Pole. But back when the pyramids were constructed, the star that aligned with the North Pole wasn't Polaris at all: It was a star in the constellation Draco called Thuban. In 12,000 years, Earth's North Star will be Vega, the brightest star in the constellation Lyra.
- Astrology: Why Your Zodiac Sign and Horoscope Are Wrong https://shar.es/1xWobv via @LiveScience
- http://www.nbcnews.com/id/41062376/ns/technology_and_science-science/t/wobbly-earth-means-your-horoscope-wrong/#.V92n1MBIvkl.twitter via @msnbc