What is the process when two atoms combine to form a lager atom real easing energy?

The process when two atoms combine to form a larger atom while releasing energy is called nuclear fusion. In fusion, lighter atomic nuclei, typically isotopes of hydrogen, collide under extreme temperature and pressure conditions, such as those found in stars. When they fuse, they form a heavier nucleus and release energy due to the conversion of mass into energy, as described by Einstein's equation E=mc². This energy is what powers stars and contributes to the heat and light they emit.