The sun is the center of our solar system, and therefore represents the main, most present part of your personality. In fact, several people see the sun sign as an indicator of your attitude towards life, your reaction to what happens to you, and your core being (via Today). 

As astrologers Lisa Stardust, Renée Watt, and Ashley Otero explained to Bustle, the sun sign is likely the "main" sign people know, with many horoscopes based on it alone, and it makes sense. Otero said, "Being the only star amongst the other nine spheres that our Earth mingles with in space, the sun is the symbol of centeredness, illumination, and life — because without it, we'd cease to exist!"

You probably already know your sun sign, which is calculated using your month and date of birth and is sometimes called a star sign. This is the sign you'll look up when you're checking your horoscope, whether you're a Capricorn, Gemini, Aquarius, or another sign. While Otero says the sun sign "symbolizes one's vital life force, spirit, intellect, and identity," Stardust says this sign represents our "ego and will," and determines what you're most passionate about in life. Even more, you might actually begin to identify more with your sun sign as you get older. According to Refinery29, your sun sign is actually more of an indicator of who you will be in the future.