What happens during the fusion of hydrogen in stars?

During the fusion of hydrogen in stars, hydrogen nuclei combine to form helium, releasing energy in the process.

The fusion of hydrogen in stars is a fundamental process that powers the stars, including our Sun. This process is also known as nuclear fusion. It occurs in the core of the star where the temperature and pressure are extremely high. The high temperature provides the necessary energy for hydrogen nuclei to overcome their natural repulsion due to the same positive charge. Once they get close enough, the strong nuclear force takes over and binds them together, forming a helium nucleus.

The fusion process starts with two hydrogen nuclei (protons) combining to form a heavy hydrogen nucleus (deuterium), a positron (a particle with the same mass as an electron but with a positive charge) and a neutrino. The deuterium nucleus then combines with another proton to form a light helium nucleus (helium-3). Two helium-3 nuclei can then combine to form a helium-4 nucleus and two protons.

This process releases a tremendous amount of energy. The energy is released because the mass of the helium nucleus is slightly less than the total mass of the four protons that entered the fusion process. This difference in mass is converted into energy according to Einstein's famous equation, E=mc^2, where E is energy, m is mass, and c is the speed of light. This energy is what makes stars shine and provides the heat and light that we receive from the Sun.

The fusion of hydrogen in stars is not only crucial for the existence of stars, but it also plays a significant role in the universe. The energy released during this process is responsible for the star's ability to counteract the force of gravity, preventing the star from collapsing. Furthermore, the fusion process leads to the creation of heavier elements, contributing to the chemical diversity of the universe.