Kelvins (K) are a unit of measurement for temperature in the International System of Units (SI). Named after the Scottish physicist William Thomson, 1st Baron Kelvin, the Kelvin scale starts at absolute zero, the point where all molecular motion ceases, which is 0 K. Unlike the Celsius and Fahrenheit scales, the Kelvin scale does not use degrees; instead, it directly measures thermal energy. The Kelvin scale is widely used in scientific contexts, particularly in fields like physics and engineering. For example, the temperature of stars and other celestial bodies is often expressed in Kelvins, making it essential for understanding astrophysics and related disciplines.