The kelvin is a unit of measure for temperature based upon an absolute scale. It is one of the seven base units in the International System of Units (SI) and is assigned the unit symbol K.
The speed of light (SoL) in vacuum, commonly denoted c, is a universal physical constant important in many areas of physics. Its precise value is 299.792.458 metres per second.
A light-year (LY), is a unit of length used informally to express astronomical distances. It is approximately 9 trillion kilometres (9.460.730.472.580 kilometres or 63.241 Astronomical Units). A light-year is the distance that light travels in vacuum in one Julian year (365.25 days).
The astronomical unit (AU) is a unit of length, roughly the distance from Earth to the Sun. It is now defined as exactly 149.597.870.700 metres (about 150 million kilometres). It is used primarily as a convenient yardstick for measuring distances within the Solar System or around other stars.