January 14, 2011

Has Earth’s ‘Wobble’ Forced Changes In Astrological Signs?

What's your sign?

No, that's not a bad pick-up line. Rather, it's a question that a lot of people think they know the answer to--but, according to scientists, they would be wrong.

The zodiac star signs were created some 2,000 years ago, according to what Minnesota Planetarium Society board member Parke Kunkle told the Chicago Sun Times on Friday.

However, the star signs that most people associate themselves with based on their birthdays may be inaccurate, thanks to the moon's gravitational pull, which Kunkle says is forcing the Earth to twist on its axis. The phenomenon is known as the Earth's "wobble" and according to various reports that have surfaced recently, it has forced an approximately one-month shift in the star signs.

Unbeknownst to the ancient astrologers, the Earth continually wobbles around its axis in a 25,800-year cycle," Pedro Braganca said in an October 2007 article written for LiveScience. "This wobble--called precession--is caused by the gravitational attraction of the Moon on Earth's equatorial bulge."

"Over the past two-and-a-half millennia, this wobble has caused the intersection point between the celestial equator and the ecliptic to move west along the ecliptic by 36 degrees, or almost exactly one-tenth of the way around, he added. "This means that the signs have slipped one-tenth--or almost one whole month--of the way around the sky to the west, relative to the stars beyond."

A recent Pew survey discovered that approximately one-fourth of those living in the US believe in astrological signs--figures that rise to as much as 31% of the American population, according to a recent Harris Poll. For those folks, we present the "correct" astrological signs, as cited by Kunkle and other astronomers familiar with the matter.

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-Dec. 17

Sagittarius: Dec. 17-Jan. 20

This list appears to be the source of some debate, however, as some experts list Scorpio as lasting from Nov. 23 to Nov. 29 and insert a thirteenth sign, Ophiuchus, from Nov. 30 to Dec. 17. LiveScience Senior Writer Stephanie Pappas writes that Ophiuchus was a formation that had been discarded by the ancient Babylonians because they wanted there to be just 12 signs, not 13.


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