You may not believe in horoscopes and think that they do not exist and do not affect you. But they do. Being very popular on social media and pop culture, chances are some of your friends believe them, and how they treat and perceive you is just a tad bit affected by when your birthday is.

And they aren't just a contemporary pop-culture craze. The study of astronomy and astrology is historically rich and has played a significant role in developing civilisations and cultural practices around the globe.

But what exactly are they? Let's dive deeper into the origins of astrology and what determines our horoscopes to gain a more concrete understanding of how the sun and the stars determine our collective fate.

History

Since the earliest times, people looked for indications in the natural world for what may happen in their lives. Some examples of this practice, which came to be known as divination, are tea-leaf reading and looking at spots in the liver and entrails of animals.

It is believed that ancient Babylonians began stargazing in the second millennium BC. They realised that by tracking the movement of celestial bodies, they could predict changes in seasons and eclipses. The earliest piece of evidence of the practice of astrology can be traced back to Babylon in the first millennium BC in The Venus tablet of Ammisaduqa, which traces the motion of the planet Venus. To this, the ancient Egyptians contributed the idea that patterns of stars made up constellations and that the sun appears to "move" at specific times of the year.

It is believed that all these ideas came together when Alexander the Great, the king of the Ancient Greek Kingdom of Macedon, conquered Egypt around 330 BC.

The Greeks were very interested in maths and logic, and thus they came up with the complicated mechanism which determines how your birthday determines your zodiac sign.

How is your Zodiac sign determined?

The most popular and culturally relevant zodiac signs are of the tropical zodiac which is based on the seasons. It is calculated by the path of the Sun against the sky, called the ecliptic, as it travels through an imaginary 360-degree circle known as the zodiac.

The logic that led to the creation of the familiar zodiac signs known today is best described by NASA:

"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 in the zodiac are simply the constellations that this imaginary straight line points to in its year-long journey."

Each zodiac sign is named after the shape of the constellation that the straight line points to. This idea that there are 12 signs along the zodiac that are 30° wide and that the sun moves through these signs regularly during the year was codified by the astronomer Ptolemy, author of the Tetrabiblos, which became a core book in the history of Western astrology.

Is the sun sign all we need to know?

The prevalent sun signs are far from the only sign in your astrological profile or "birth chart". The position of the moon at the time of your birth determines your moon sign, and your rising sign is the zodiac sign that was rising on the eastern horizon at the exact moment of your birth. It is believed that the sun sign determines your personality and character, making it the most defining zodiac sign in your chart. Each of these zodiac signs is thought to fall under each of the ruling elements of Earth, Air, Water, and Fire. The ruling element is one of the many things that affect the personality traits of each zodiac sign.

Is there any truth to horoscopes?

Most likely not. From a scientific standpoint, no evidence supports the validity of astrology or horoscopes. Studies and experiments have generally failed to prove any correlation between astrological predictions and actual events or personality traits.

However, astrological practices remain extremely popular and many continually swear on their accuracy both in terms of predictions of the future and individual personality traits. Psychologists propose the theories of the "Barnum Effect" and "Confirmation Bias" to explain this phenomenon.

The former explains that general statements that could apply to many people are perceived as highly accurate for individuals. Horoscopes are often written in a way that they can be broadly applicable, leading individuals to see them as personally relevant. The latter explains that people tend to remember the predictions that come true and forget the ones that don't. This selective memory reinforces the belief in horoscopes.

A long history and cultural heritage also give astrology a sense of legitimacy and tradition that can make it seem real to many people.

Despite the scientific illegitimacy of astrology being widely known, the continual relevance of horoscopes is understandable. In today's volatile and alienating world, horoscopes are a powerful tool that dually promotes a sense of community and individual identity. Both real and unreal, they are a forgivable indulgence.

Amrin Tasnim Rafa is a sub-editor at Campus, Rising Stars, and Star Youth