Gamma rays are constantly pummeling Earth with extremely high energies. Luckily, our atmosphere stops almost all of this damaging radiation. Gamma rays were discovered by French Physicist Paul Villard in 1900 while doing research on radiation emitted from the element Radium. They weren’t formally named until the year 1903 by his colleague, Ernest Rutherford, and it wasn’t until 1914 that they were known to be a part of the electromagnetic spectrum.
Gamma rays are a form of light that have the shortest wavelength and most energy of all of the electromagnetic spectrum, and are therefore not visible to the human eye. Gamma rays are very closely related to X-Rays, the current distinction between the two is that the former is emitted by the nucleus of an atom and the latter is emitted by the electrons outside the atom. Gamma rays have wavelengths of less than 10 picometers, and frequencies above 10^19 Hertz. This gives them an energy above 100 keV. Gamma rays are emitted by black holes, neutron stars, supernovae, pulsars, and radioactive decay in space. In the laboratory, they can be seen when we smash atoms together in particle accelerators, during nuclear fission, and the collision of an electron and positron (anti-electron).
Gamma rays are detected in a field of astronomy known as gamma-ray astronomy. Interestingly enough, they cannot be detected by our standard mirror telescopes because such a high energy wave passes right through our equipment. The only way to detect a Gamma ray is through a method called Compton scattering, where a gamma ray photon strikes an electron, losing energy. This can only be done in spacecraft or balloons near the top or above the atmosphere. These detectors are how we have found the phenomena of gamma ray bursts, which happen daily, release more energy than our Sun will in it’s entire lifetime, and are still a mystery to science.
There are several ways that we use gamma rays today. They are used to sterilize medical equipment, prevent fruits and vegetables from sprouting, as well as their use in CT scans and radiation therapy. Additionally, gamma rays kill living cells and are used in gamma-knife surgery to eradicate cancer in the body. Gamma rays can also cause cancer when directed at humans, as they can alter the structure of our very DNA. Gamma ray detectors are also used by the Bureau of Customs and Border Protection in the Container Security Initiative to scan ship containers before entering US ports.