PHILADELPHIA (CBS) – When a Minneapolis astronomer pointed out to the public something that has been known to both astronomers and astrologers for a very long time, it nevertheless caused an Internet sensation.

The talk is about a 13th sign of the zodiac — and the possibility that your own sign of the zodiac may be the wrong one for your birthdate.

The Minneapolis astronomer suggested that the signs of the zodiac are wrong and the wobble in the earth’s orbit is throwing off astrology charts from when they first were started by the ancient Babylonians.

Now, it’s a hot topic on Facebook, blogs, and astrology websites.

(Astronomer Derrick Pitts. File photo)

But Derrick Pitts, chief astronomer of the Franklin Institute in Philadelphia (right), says the information has been known to astronomers for thousands of years and for some reason went “viral.”

“People are now recognizing that there is an additional constellation through which the sun passes, and this is the constellation Ophiuchus (oh-FEE-ew-cuss).  True, it’s a mouthful to say, but it’s a small part of the path along which the sun travels,” Pitts explained to KYW Newsradio.

According to this alternative view of the zodiac, you are of the Ophiuchus sign if you were born between November 29th and December 17th.  And it suggests that your sign, no matter when you were born, may be off a  month.

Many astrologers say the new chart doesn’t work and it’s nothing to worry about.

Reported by John McDevitt, KYW Newsradio 1060.