Astronomy Fundamentals

Time, Waves, and Particles

What are X-rays?

X-rays are electromagnetic waves whose wavelengths range between about 10–11 and 10–8 (one hundred-billionth and one hundred-millionth) of a meter. This kind of radiation can penetrate the tissues of the human body, so it may be used to take pictures of people’s internal systems and skeletons, for example, at a doctor’s office.


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