Hertz are most commonly used as a measurement of frequency in electromagnetic waves. As part of the metric system, hertz occupy a logarithmic scale that allow for easier conversion between variant magnitudes of measurement (i.e. Hertz and MHz). The boson, or force carrier, for the electromagnetic force is the photon. One photon is defined as a particle, or rather, one wavelength of light. The electromagnetic spectrum is separated into several distinct categories, which are organized in terms of radiant energy. For example, at the lower end of the spectrum are radio and infrared waves. These are examples of non-ionizing radiation and are generally considered harmless to organisms. A radio wave, for instance, has a relatively high wavelength and low frequency. On the other hand, gamma rays have incredibly short wavelengths and very high frequencies. This is why they are so dangerous from a biological perspective. The relationship between frequency and wavelength is inversely proportional. A coherent stream of photons with high wavelengths has a low measure of frequency. This relationship is quantified by establishing that the wavelength of a photon multiplied by its frequency is equal to the speed of light. The realization that the speed of light is a natural constant in the universe is what led to the advent of modern physics and quantum mechanics as advancements over classical mechanics and Maxwell's Laws of Electromagnetism. Hertz are named after Heinrich Hertz, who was born in 1857 and later expanded upon electromagnetic field theory and previous revelations put forth by James Clerk Maxwell. In addition to his research into the physical sciences, Heinrich Hertz also took a keen interest in meteorology and continuum mechanics. Many people use this unit of measurement on a day-to-day basis without even realizing it. For example, radio receivers capture signals based upon their frequency.