The star at the center of our solar system is the Sun. It is a nearly perfect sphere of hot plasma, primarily composed of hydrogen and helium, and is the most important source of energy for life on Earth. The Sun generates energy through nuclear fusion reactions occurring in its core, where hydrogen atoms combine to form helium, releasing enormous amounts of heat and light. Positioned approximately 93 million miles from Earth, the Sun's gravitational pull keeps the planets, moons, and other celestial bodies in orbit around it, influencing climate and weather patterns.