Through these new windows that open for telescopes above the Earth's atmosphere, we can see radiation emitted from many different parts of the Sun. Each solar region has its own temperature, density, and other characteristic physical conditions and emits its own kind of light. We have measured temperatures on the Sun ranging all the way from a mere 4200 C in the coolest regions to over 50 million C in the hottest solar flares. Rays from the Sun. Solar features at different temperatures emit characteristic radiation of different forms, ranging from radio and infrared waves to visible light, ultraviolet, X-rays, and gamma rays.
Drawing shows typical temperatures, while legend at the left indicates corresponding radiations.
Infrared and visible light are suitable for study of coolest layers, while much information on the hot corona can only be gleaned from X-rays. Energetic atomic particles from solar flare explosions produce gamma rays. The solar gas in this region shines mostly in visible and infrared light. Above the minimum temperature region, the gas gets hotter. On Earth we use a very similar process on a vastly smaller scale to generate X-rays for medical examinations.