A Sun is the star at the center of our solar system. It is a massive ball of hot plasma, primarily composed of hydrogen and helium. The Sun generates energy through nuclear fusion, converting hydrogen into helium and releasing light and heat. This energy is essential for life on Earth, influencing climate and weather patterns. The Sun has a diameter of about 1.4 million kilometers and is approximately 4.6 billion years old. It is classified as a G-type main-sequence star (G dwarf) and is expected to continue shining for several billion more years before evolving into a red giant and eventually a white dwarf.