How does the sun produce energy through nuclear fusion?

The Sun produces energy through nuclear fusion by fusing hydrogen nuclei into helium, releasing vast amounts of energy.

In the core of the Sun, where temperatures reach around 15 million degrees Celsius, nuclear fusion occurs. This process involves hydrogen nuclei (protons) colliding with such force that they overcome their natural repulsion and fuse together. The primary fusion process in the Sun is called the proton-proton chain reaction.

In the first step of this reaction, two protons fuse to form a deuterium nucleus (one proton and one neutron), releasing a positron and a neutrino. Next, the deuterium nucleus fuses with another proton to create a helium-3 nucleus (two protons and one neutron), emitting a gamma-ray photon. Finally, two helium-3 nuclei collide to form a helium-4 nucleus (two protons and two neutrons), releasing two protons in the process.

The energy released during these fusion reactions comes from the conversion of mass into energy, as described by Einstein's famous equation, E=mc². This equation shows that even a small amount of mass can be converted into a large amount of energy. In the Sun, the mass difference between the reactants and the products in the fusion process is converted into energy, which radiates out from the core and eventually reaches Earth as sunlight.

This energy is crucial for life on Earth, providing the heat and light necessary for plants to photosynthesise and for maintaining the planet's climate. Understanding nuclear fusion in the Sun helps scientists develop potential future energy sources, such as fusion reactors, which could provide a nearly limitless and clean energy supply.