Transition: The part of the Sun we see is its surface layer at only fifty-seven hundred degrees Kelvin. Gas that hot has the electrons stripped off from the protons, but it’s far too cool for fusion to occur. However the temperature, pressure, and density all increase as you move towards the center of the Sun. At a region where the temperature exceeds ten million degrees fusion can occur of hydrogen with protons fusing to form helium nuclei in three stages in the proton-proton chain. At the very center of the Sun the temperature is fifteen million Kelvin. The conditions in the Sun are predicted by the same gas laws that apply to calculations of the atmospheres of planets. At the center of the Sun the pressure is two hundred and fifty billion times the pressure at the sea level of Earth. The density is a hundred and sixty times that of water, twenty times that or iron. One cubic inch of the Sun’s interior would weigh five pounds brought to Earth, yet it’s a gas, a plasma. Despite the violent reactions occurring in the center of the Sun, the Sun is stable. It’s more like a reactor, and it’s certainly not a bomb.