What are x-rays?
X-rays are a highly energetic form of light, not visible to human eyes. Light can take on many forms -- including radio waves, microwaves, infrared, visible, ultraviolet, X-ray and gamma radiation. Very low temperatures (hundreds of degrees below zero Celsius) produce mostly low energy radio and microwave photons, whereas cool bodies like ours (about 30 degrees Celsius) produce largely infrared radiation. Objects at very high temperatures (millions of degrees Celsius) emit most of their energy as x-rays.