Nuclear Fusion

Fig. 1.

The sun in all its glory

Nuclear fusion is the process by which the sun releases insane amounts of energy to fuel life on earth. This energy is released when atoms combine together due to the intense heat and pressure on the sun, which reaches earth in the form of light and heat. The sun releases almost 4 x 10²⁶ watts PER SECOND, and of all of the mass that undergoes the fusion process, only about 0.7% of it is turned into energy!

In the sun, there is an abundance of hydrogen atoms (with one proton and one electron). In a series of steps, protons from various hydrogen atoms fuse together to eventually form a helium atom, which consists of 2 protons, 2 neutrons, and 2 electrons. Firstly, two hydrogen atoms fuse, after which they vibrate around within the sun until another hydrogen atom collides with it. In this instance, a gamma-ray is emitted while at the same time an atom with three protons forms (as each hydrogen atom has one proton). This gamma-ray travels out into the solar system and reaches earth in the form of sunlight. 

But where does the heat come from? Basically, two 3 proton atoms (Their real names are helium-3 nuclei but who cares) collide and form a larger atom with 6 protons, which decomposes down to a helium atom with 4 protons and 2 extra neutrons. The final atom of helium has less mass than the four individual atoms of hydrogen, and so has less energy. The energy that is missing has been emitted into the solar system as heat.

This is a small topic but quite interesting: it is what powers our world!