Question: Where does the energy to keep a star alive come from?

Nick Wright answered on 13 Mar 2014:

Good question! The energy comes from a nuclear reaction that converts hydrogen into helium in the core of the star. This energy is created because when you combine 4 hydrogen atoms into a helium atom, the helium atom weights slightly less than the 4 hydrogen atoms, and this mass is converted into energy according to the famous equation E = m c (squared). The ‘E’ stands for energy, the ‘m’ stands for mass, and the ‘c’ is the speed of light, which has a constant, set value in this equation.