According to the Astronomer Parkle Kunkle, as the earth and the sun gradually move, the signs slowly change as well.

Parke Kunkle is a board member of the Minnesota Planetarium Society. He says the dates of numerous zodiac signs have changed due to the earth's alignment changes.

The discrepancy occured because the moon’s gravitational pull is twisting Earth on its axis.

According to Kunkle, there really should be a 13th sign, Ophiuchus. It seems the Babylonians who made the zodiac skipped Ophiuchus because they only wanted 12 signs.

Below are the correct signs according to Kunkle.

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

However, there are ongoing debate among scientists and science communities regarding this issue. Many scientists says that this factor has always been taken into account.