What occurs during nuclear fusion?

During nuclear fusion, low atomic number nuclei come together to form a heavier nucleus. This process typically occurs in the cores of stars, where immense pressure and temperature allow hydrogen nuclei to overcome their electrostatic repulsion and combine to form helium or other heavier elements.

The energy released during fusion is a result of the mass difference between the reactants and the products, according to Einstein's equation, E=mc². This release of energy is what powers stars and is why fusion is often considered a potential source for clean energy on Earth. It is essential to understand that fusion involves the combining of nuclei, unlike fission, where larger nuclei are split into smaller ones.