“Hydrogen clumped together into stars, and the extreme gravitational pressure inside stars began fusing hydrogen into helium, a process that fires every star in the sky”
Take a look around yourself, everything you observe, touch, and taste is an indirect result of a process called fusion. There is another process that is the opposite of fusion called fission. Both of these processes turn mass into energy on an atomic level. As implied by their names, in nuclear fusion two atoms are fused to form a larger atom. In nuclear fission, a heavy atom is split into smaller atoms. During both of these processes, a certain amount of the mass of the elements are converted into energy. If you want to see nuclear fusion at work in real time, just look up at the Sun because the one and only purpose of the Sun is to fuse lighter elements into heavier ones. And also don’t actually look directly at the Sun because you will damage your eyes.
But why does the Sun and as a matter of fact, all the stars in the universe carry out this process of nuclear fusion and not fission? The answer comes down to a single reason; the composition of the stars. In the early stages of each star’s life cycle, a majority of its mass comes from hydrogen. Hydrogen is the lightest element on the periodic table, meaning that it can only undergo fusion.
Because the pressure caused by the Sun’s gravitational pull is very high, it acts as an activation energy for fusion. Once this reaction starts, the protons of hydrogen atoms are squeezed together to form deuterium, an isotope of hydrogen with a neutron. The formation of deuterium releases anti-electrons and neutrinos. Anti-electrons, or positively charged electrons, quickly collide with regular electrons and annihilate. This annihilation results in a 100 percent conversion of mass into energy, meaning that the anti-electrons and electrons vanish into nothingness when they collide.
Deuterium then fuses into Helium-3 which then collide with more He-3’s to form He-4. This process proceeds until the fusion of elements forms iron. As soon as iron is created, fusion becomes endothermic; more energy is required to fuse atoms than the energy released. At this point a star like our Sun has reached the end of its life. Much more massive stars, however, first implode forming elements that are heavier than iron. Then this implosion leads to an explosion called a supernova that releases tremendous amounts of energy and the star’s contents. Next time you see a piece of gold, just know that it was created during a supernova (cool ehh!).
Nuclear fission is not as common as fusion mainly because it requires heavier elements like uranium. Also fission can be spontaneous (natural) or induced. A spontaneous reaction results when a heavy unstable nucleus splits into two or more stable elements. In this case, the fission reaction is considered a mode of radioactive decay. Induced fission reaction is the process that runs nuclear power plants. Heavy elements are hit with neutrons causing them to split. This results in a conversion of mass into energy and creation of lighter elements. This energy is then used to create electricity that end up powering our homes and workplaces.
Induced nuclear fission is a very efficient form of energy production compared to the traditional method using fossil-fuels. Fusion, on the other hand, has the greatest energy yield out of the three. So why not switch to fusion power plants? The greatest challenge that is preventing scientists from switching to fusion power plants is that containing the reaction is very difficult. Scientists around the world are working on ways to overcome this challenge. Until then, we are stuck with fission powered nuclear plants.
