Energy and momentum are interpreted as components of the four-momentum vector, and mass is the magnitude of this vector, so in geometric units these must all have the dimension of length. We can convert a mass expressed in kilograms to the equivalent mass expressed in metres by multiplying by the conversion factor "G"/"c"2. For example, the Sun's mass of in SI units is equivalent to . This is half the Schwarzschild radius of a one solar mass black hole. All other conversion factors can be worked out by combining these two.