## Planck Temperature

• The Planck temperature is the unit of temperature in the system of Planck units. It has the value:

Tp = 1.41 × 1032K

In SI units, measurements of temperature are made in degrees Kelvin (usually given the symbol K). While the Kelvin is convenient for everyday usage, such as measuring the daytime temperature (around 300 K on a nice warm summer's day) or a human's normal body temperature (310 K = 37 degrees Celsius), a consequence of using SI units is that the fundamental constants take on values that are not always convenient for use in equations:

Speed of lightc = 299792458 m s-1
Gravitational constantG = 6.673(10) x 10-11 m3 kg-1s-2
Plank's constant (reduced) = h/2π = 1.054571596(82) x 10-34 kg m2 s-1
Boltzmann constantk = 1.3806502(24) x 10-23kg m2 s-2K-1

The Planck temperature is found using the relationship between energy and temperature:

Tp = Ep/k

where k is the Boltzmann constant, and Ep = mpc2 ( mp is the Planck mass and c is the speed of light).

By redefining the base units for length, mass and time in terms of the Planck units, the fundamental constants have the values: c = G = = k = 1.