Taking the Sun’s Temperature The Core of the Sun is at an amazing 15 million degrees Celsius (27 million degrees Fahrenheit). This temperature allows nuclear fusion to take place - the ultimate power plant for our Solar System. Inside the Sun, the temperature decreases from the Core all the way to the Sun's visible surface called the Photosphere, which is at 6,000 °C. Moving upward through the Chromosphere, temperatures increase dramatically. The Corona (the Sun’s extended outer atmosphere) has temperatures of 1-2 million degrees and produces a type of high-energy light called X-rays. Scientists still do not know what heats the Corona. Two Types of Radiation: Electromagnetic (EM) Waves Particles (usually charged and moving very fast) The light that we see from the Sun comes to us as electromagnetic waves. Particle radiation comes from the Sun in explosions like Solar Flares and high energy Cosmic Rays. It is also made from the decay of radioactive nuclei such as uranium. Particle radiation usually moves near the speed of light.