Did you know that x rays were discovered by accident? German scientist, Wilhelm Conrad Roentgen first found them in 1895 when experimenting with vacuum tubes. He named them "X" in order to show that it was an unknown type of radiation and the name stuck. X rays have frequencies ranging from 3*10^16Hz to 3*10^19Hz and wavelengths from 10^-11m to 10^-8m which is smaller than a single atom. The picture to the right is the first x ray ever taken (from NASA.) It is of Mrs. Roentgen's hand, the bulge on her ring finger is that of her wedding ring. Due to the thickness of Earth's atmosphere, we are not able to x ray astronomy from the ground. Because of this we have to place x ray telescopes and detectors on our satellites!
X rays can also affect matter. They possess intrinsic energy that is sometimes transferred to the matter they interact with. This transfer is made either through absorption or scattering.
How do medical x rays work? X rays penetrate more easily through some materials than others. For example, they penetrate easily through skin but not through bone. Therefore, when x rays are taken of us, the skin appears to be transparent leaving the bones behind. These x rays are produced by colliding high-energy electrons into a metal target. Two other sources that can produce x rays are active galactic nuclei (AGN) and x ray binaries. Medical x rays do expose people to radiation although the benefits far outweigh the risks. So next time you get an x ray remember that it was one of the biggest technological advances in the medical community. (The picture on the left is an x ray of the sun taken by NASA.)
