In the Sun, approximately 620 million tons (562 million metric tons) of hydrogen fuse into helium every second. This process, known as nuclear fusion, is the driving force behind the Sun's energy production. During fusion, four hydrogen atoms combine to form one helium atom, releasing enormous amounts of energy in the form of photons and neutrinos. This continuous fusion process provides the Sun with its immense power and heat, allowing it to shine and sustain life on Earth.