The Sun, a 4.5 billion-year-old yellow dwarf star, is a massive, glowing sphere of hydrogen and helium at the heart of our solar system. Positioned about 93 million miles (150 million kilometers) from Earth, it is the only star in our planetary system. Its energy is fundamental to sustaining life on our planet.
Although the Sun appears as a constant, unwavering source of light and heat from Earth, it is actually a dynamic and ever-changing star. It continuously emits energy into space, influencing the entire solar system. The study of the Sun and its effects is known as heliophysics.
As the largest object in our solar system, the Sun has a vast diameter of approximately 865,000 miles (1.4 million kilometers). Its immense gravity holds everything in orbit, from the largest planets to the smallest debris. This gravitational force ensures the solar system remains intact.
Despite its crucial role in our existence, the Sun is merely an average-sized star compared to others in the universe. Some stars are up to 100 times larger, and many solar systems contain multiple stars. By studying our Sun, scientists gain valuable insights into the behavior and characteristics of distant stars, helping to expand our understanding of the cosmos.
