No, your zodiac sign hasn't changed

Tattoo parlor owners must be salivating. An assertion in a Minneapolis Star Tribune article that our understanding of the zodiac is off by about a month - and that therefore people have been identifying themselves with the wrong sign - caught fire on the internet Thursday, and many folks are in an absolute panic on social media.

"If my zodiac symbol has been changed to a Libra, what am I supposed to do with my Scorpio tattoo?!?!," read one tweet Thursday.

Some vowed to get their tats removed. Others groaned about losing the sign with which they’ve identified themselves for years. The zodiac and related terms - including Ophiuchus, said to be a 13th and neglected sign - were trending Twitter topics much of Thursday.

But before astrology fans scrape the ink from their arms because they think they're now a Virgo instead of a Libra, they should consider this: If they adhered to the tropical zodiac - which, if they're a Westerner, they probably did – absolutely nothing has changed for them.

That's worth rephrasing: If you considered yourself a Cancer under the tropical zodiac last week, you're still a Cancer under the same zodiac this week.

That's because the tropical zodiac – which is fixed to seasons, and which Western astrology adheres to – differs from the sidereal zodiac – which is fixed to constellations and is followed more in the East, and is the type of zodiac to which the Star Tribune article ultimately refers.

Two zodiacs. That's nothing new.

"This story is born periodically as if someone has discovered some truth. It's not news," said Jeff Jawer, astrologer with Tarot.com.

The hubbub started with Sunday's Star Tribune article, which said the following: "The ancient Babylonians based zodiac signs on the constellation the sun was 'in' on the day a person was born. During the ensuing millenniums, the moon’s gravitational pull has made the Earth 'wobble' around its axis, creating about a one-month bump in the stars' alignment."

"When [astrologers] say that the sun is in Pisces, it’s really not in Pisces," Parke Kunkle, a board member of the Minnesota Planetarium Society, told the Star Tribune.

"Indeed," the article continued, "most horoscope readers who consider themselves Pisces are actually Aquarians." The article also asserts Scorpio's window lasts only seven days, and that a 13th constellation, Ophiuchus, used to be counted between Scorpio and Sagittarius but was discarded by the Babylonians because they wanted 12 signs per year.

True enough, Jawer says, the sun doesn't align with constellations at the same time of year that it did millennia ago. But that’s irrelevant for the tropical zodiac, codified for Western astrology by Ptolemy in the second century, he says.

In the tropical zodiac, the start of Aries is fixed to one equinox, and Libra the other.

"When we look at the astrology used in the Western world, the seasonally based astrology has not changed, was never oriented to the constellations, and stands as … has been stated for two millenniums," Jawer said.

People who put stock in astrology can ask whether they should adhere to the tropical zodiac or the sidereal zodiac. Jawer argues for the tropical.

"Astrology is geocentric. It relates life on Earth to the Earth’s environment, and seasons are the most dramatic effect, which is why we use the tropical zodiac," he said.