When two hydrogen atoms fuse together, a process known as nuclear fusion, they can form a helium atom. This fusion process occurs under extremely high temperatures and pressures, typically found in the core of stars like our Sun.
In the specific case of hydrogen fusion, the primary reaction that takes place is called the proton-proton chain. There are several steps involved in this process, but I'll provide a simplified overview:
- Two hydrogen nuclei, each consisting of a single proton, approach each other due to the high temperatures and pressures.
- One of the protons undergoes a process called beta-plus decay (or positron emission), where it is transformed into a neutron, a positron (a positively charged electron), and a neutrino.
- The two protons, one now a neutron, combine to form a deuterium nucleus (one proton and one neutron).
- The deuterium nucleus quickly captures another proton to form a helium-3 nucleus (two protons and one neutron).
- Two helium-3 nuclei collide and fuse, resulting in the formation of a helium-4 nucleus (two protons and two neutrons) and two free protons.
- Energy in the form of gamma rays is released during the fusion process.
Overall, hydrogen fusion in stars is a crucial process that releases an immense amount of energy, powering the star and generating heat and light. It is an essential step in stellar nucleosynthesis, leading to the production of heavier elements as stars evolve.