Way back when, the ancient Babylonians based zodiac signs on the constellation the sun was in on the day a person was born.

But this was thousands of years ago when the Earth was positioned, in relation to the sun and the stars behind it, in a different place on the rotational axis.

The result: The sign you think you are, and the sign you really are in terms of the constellation the sun is in on your birthday are different.

"Because of this change in the tilt the Earth is over here and the sun is in a different constellation than it was 3000 years ago when this study of the stars began," explains astronomer Parke Kunkle.

This is not a "new" thing, according to Kunkle. This alignment shifted a long, long time ago. It's just, the Horoscope world didn't shift with it. "This is not something that happened today, this has gone on for thousands of years," Kunkle said.

If you are curious about what your sign may be now, here is the list:

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- Nov. 29
Ophiuchus:* Nov. 29- Dec. 17
Sagittarius: Dec. 17- Jan. 20


* Discarded by the Babylonians because they wanted 12 signs per year.