The nature of X-rays

It took over a decade after their discovery to identify the nature of X-rays.

Figure 3: Spectrum of electromagnetic radiation. X-rays are on the short wavelength end of the electromagnetic spectrum and cannot be detected by the human eye.

Like radio waves, microwaves, visible light and gamma rays, X-rays are part of the electromagnetic spectrum (Ref: Figure 3). Depending on the wavelength different parts of the electromagnetic spectrum have different properties and applications. One particularly useful property of X-rays is their ability to penetrate solid materials of considerable thickness. Their short wavelength allows for high resolution imaging if appropriate optical components are available.

Sources of electromagnetic radiation can be both natural and man-made. The most familiar source to us is the sun, which emits radiation over the full range of wavelengths. Our eyesight has evolved to be sensitive to the most prominent part of the spectrum left after transmission through the earth's atmosphere, namely visible light.