Where Does the Sun Get Its Energy?
The sun is a kind of atomic furnace. Its energy comes from the energy of atoms which are being changed into different forms. The sun’s core is believed to be a super-hot, dense mass of atomic matter. Under these conditions, the crowded jumble of atomic particles smashes into each other violently.
They sometimes ram into each other so hard that they unite in a process called “fusion.” As they fuse, the atomic particles release energy and cause the sun to shine. The sun has enough atomic fuel left to keep on shining for five billion more years!
How is the sun actually fueling itself?
It is converting its own mass into energy. By combining protons (the nucleus of hydrogen) into helium, it squeezes some mass into energy – 4.3 billion kg per second. It is Einstein’s famous E=mc^2 which gives us the quantitative relationship between mass and energy, where c is the speed of light.