How do horoscopes work?

Abigail (Oli) Grenke, Journalist

   It is difficult to scroll through social media without seeing seemingly endless pages, accounts, and posts regarding zodiac signs. Despite their growing popularity online, a deeper knowledge of zodiac signs and their origins seems to be lacking.

   In astrology, the “celestial sphere,” in the simplest of terms, is an imaginary sphere, with the Earth inside at the center. All of space is projected onto the sphere from the inside, therefore, the observer can see how things in space move relative to the Earth. In the western world, the zodiac is based on the sun’s path through the earth’s celestial sphere over the span of one year. This circular path is also known as the ecliptic.

   The twelve zodiac signs were created when the ecliptic was divided into twelve parts by people thousands of years ago. All twelve parts are equal portions, or arcs, of the ecliptic, measuring 60 degrees. As the sun travels along the ecliptic, it crosses through each part, or arc, in approximately 30 days. These parts were then given names, now called zodiac signs.

    This division occurred near the end of the fifth century BC and can be traced back to Babylonian astronomy. However, the Hebrews were the first to link constellations with each zodiac sign.

   By the fourth century BC, Babylonia was at the front of astronomy. To the Greek and Roman people, ‘Babylonian wisdom,’ or the zodiac, was a supernatural skill used to see the future and make predictions based on the stars.

   Ptolemy, a Greek astronomer, wrote the book Tetrabiblos, a work that laid the foundation of modern astrological tradition. In fact, the function of the planets and signs of the zodiac in the western world today remain essentially unchanged from how they were perceived by Ptolemy.

   Often, zodiac signs are the first thing to come to mind when thinking about astrology. The zodiac is a form of sun-sign astrology, which is often used to create horoscopes.

   One’s zodiac sign is determined by the sun’s position on the ecliptic when they are born. For example, if someone was born when the sun was at about 60 degrees, which occurs between Apr. 21 and May 21, then their sign is Taurus. Therefore, all one needs to create a sun-sign horoscope for someone is their birth date. They often predict an individual’s future, or detail character traits they possess based on of their sign.

   There is no evidence supporting the accuracy and legitimacy of such horoscopes, as they are not justifiable by the scientific method. Even by experts, they are considered to be a very simplistic and limited form of astrology.

   So, do not worry about that Facebook post claiming that all Tauruses have bad luck. It will probably be fine – the future, after all, is not written in the stars.