Question

 How does nuclear fusion power the sun?

Answer 1

The Sun's energy comes from nuclear fusion reactions that occur in its core. These are the same reactions that power hydrogen bombs and other nuclear weapons. The energy produced by these reactions is emitted from the Sun as light and heat.

Answer 2

Nuclear fusion powers the sun by combining hydrogen atoms to form helium in a process called thermonuclear fusion. At the high temperatures and pressures found at the sun's core, hydrogen atoms collide with enough energy to overcome their electrostatic repulsion and fuse together to form helium. This process releases a tremendous amount of energy in the form of light and heat, which is what makes the sun shine. The energy released from nuclear fusion also provides the pressure that counteracts the force of gravity and keeps the sun from collapsing in on itself.