4.6 billion years ago, the star at the heart of our solar system was born and shed its first light onto the surrounding debris. The sun is one of the most important celestial objects involved in our survival, second only to the Earth itself. Yet, even after 4.6 billion years, how does the sun still keep shining with so much intensity? Well, it all starts with just two atoms of hydrogen and a process they undergo called nuclear fusion. In this article, we will explore what the process of nuclear fusion entails, why it is so rich in energy, and the efforts of how we have tried to harness it for our own purposes.

How Does Nuclear Fusion Work?

As the name states, it involves the fusing of two atoms together to create one new atom. In the case of the sun, the elements fusing are hydrogen atoms, which are positively charged protons. In order for two atoms to fuse, there must be immense amounts of pressure such that the elements can collide together rapidly. The reason for this is that similar to any magnet, where two hydrogen atoms sharing the same positive charge will repel each other, making it extraordinarily difficult to fuse them together. Yet under the gravity of the sun, hydrogen atoms continuously fuse in a nuclear fusion reaction to form helium.

When two hydrogen atoms form one helium atom, the mass of the helium atom is less than the combined mass of the two hydrogen atoms. Using Einstein’s mass-energy equivalence theory which explains how mass can be turned into energy, the remaining mass that did not become helium after the reaction is released as an abundance of energy. Even though only 0.7% of the sun is used in nuclear fusion, over 3.8 x 1026 joules of energy are released. With this much energy, the sun is able to emit light across vast distances between it and the planets in the solar system.

Can We Replicate Nuclear Fusion?

There have been efforts to try and harness the power of nuclear fusion for energy production. Mainly, the Tokamak is currently the leading concept for a nuclear fusion power plant. The main challenge that comes with replicating nuclear fusion is creating enough pressure and thrusting enough energy to fuse two atoms together, as it requires energy comparable to the pressure within the sun’s core. First introduced by a Russian scientist in the 1960s, the Tokamak tackles this problem with a doughnut-like structure supported by magnetic fields. 

The machine first places gaseous elements within the system under extreme heat and pressure to create plasma, which is an extremely hot and light-emitting state of gas. Then, the tokamak will use magnetic fields to control that plasma and help induce the fusion of elements. The heat that is produced from the fusion reaction is then captured in the walls of the machine, which will then be used to power a mechanical generator to produce electricity. If this machine works, it can easily sustain a large human population with zero carbon emissions or radioactive waste. However, the cost to fund a machine capable of creating pressure to fuse two atoms is still too high and not comparable to other energy sources. 

Despite the challenges, the world is still pushing to create the largest tokamak energy power plant in hopes that the fusion reactor can become cost-efficient and energy-efficient. ITER is an ongoing energy project in southern France supported by 35 countries hoping to foster a future with nuclear fusion. To learn more about this promising endeavor, visit the ITER website.