Science Space How to Understand Zodiac Signs Through the Stars By Kristen Bobst Writer University of Southern California Trinity College Dublin University of Florida Kristen Bobst has written educational apps for kids and reports on space exploration for a variety of websites. our editorial process Kristen Bobst Updated May 31, 2020 Constellations change over time, and often the constellation you were born under won't even be visible in the night sky. Zakharchuk Nataliia/Shutterstock Share Twitter Pinterest Email Science Space Natural Science Technology Agriculture Energy Many people believe that the astrological sign they were born under can influence their mindsets, even their destinies, and while not everyone buys that concept, there's still plenty to learn from the skies above. Zodiac charts are based on geographic location and culture. While the Chinese zodiac is based on birth year and applies an animal to each sign, the Western zodiac borrows heavily from Hellenistic and Babylonian teachings about the constellations. More simply, the Western zodiac consists of 13 constellations that exist along the sun's annual path across the sky. There are 88 total constellations, as determined in 1930 by the International Astronomical Union. PHOTO BREAK: How much do you know about the moon? What Are Constellations? Constellations are patterns in the night sky as observed from Earth. We know that the stars within constellations share no definite relationship with one another, other than they can be seen at certain times in the same area of the sky. The stars in one constellation are not necessarily even near one another in space; constellations are merely the product of perspective. But constellations also change. Everything in space is in motion, so things shift over time. According to Discovery.com, "Stargazers of the future will look into a different night sky. That's because the stars are constantly moving relative to each other." Whether or not you believe in astrology, you can use star charts to see the constellation each sign is based on in the night sky at the appropriate time of year. The constellation related to your astrological sign, however, won't necessarily be visible in the sky on your birthday. SPACE.com explains: "Ironically, if you are born under a particular sign, that constellation it is named for is not visible at night. Instead, the sun is passing through it around that time of year, making it a daytime constellation that can't be seen." How Do Constellations Relate to the Zodiac? Understanding the constellations of the zodiac. NASA NASA breaks down how you can understand the concept of the zodiac in relation to constellations, with the illustration at right. "Imagine a straight line drawn from Earth through the sun and out into space way beyond our solar system where the stars are. Then, picture Earth following its orbit around the sun. This imaginary line would rotate, pointing to different stars throughout one complete trip around the sun — or, one year. All the stars that lie close to the imaginary flat disk swept out by this imaginary line are said to be in the zodiac." The constellations are Sagittarius, Capricornus, Aquarius, Pisces, Aries, Taurus, Gemini, Cancer, Leo, Virgo, Libra, Scorpio and Ophiuchus the serpent, which is sometimes referred to as the 13th sign. So, if you want to look at the sky and study the zodiac, you can that with star charts. In short, a star chart is a map of the night sky. There are plenty of apps you can download and many other online resources that will help guide you in viewing the night sky and recognizing the constellations in the zodiac. (We wrote about 8 free apps for astronomy lovers, which also includes a good star chart app and much more.) Even if you don’t believe in astrology, understanding the nature of constellations and their historical relationship with the zodiac can prove to be fascinating. So take a look upward and see what the stars hold for you.