Daily Mail: This is the view inside the doughnut-shaped JET reactor, the largest fusion device on Earth. During a reaction, nuclear fuels are held away from the walls by electromagnets, and reach temperatures more than ten times hotter than the core of the sun The highly compacted core of the sun is a very hot place indeed. In the star’s burning heart, hydrogen atoms collide at immense speeds. This welds them together and turns them into helium atoms, which each release a burst of energy …