The sun is a small star composed of hot gas, mainly hydrogen and helium.
Its nuclear fusion processes are what makes it emit tremendous amounts of energy.
The fascinating thing about the sun is that it's core converts an estimated 3.4*((10)to power of 38) hydrogen nuclei (protons) into helium nuclei. It releases 4.26 metric tonnes of energy per second. The Thermonuclear fusion in it's core is vast, abd beyond imagining.