Geometrized units
In physics, especially in the general theory of relativity,
geometrized units or sometimes geometric units,
is a physical unit system in which all
physical quantities are expressed in the unit of length: meter.
In this system, the speed of light c and the
gravitational constant G are set to one, c = 1 and G = 1 (and sometimes also
Boltzmann constant k = 1).
In this system, formulas appear simpler because all constants drop out.
A time interval is in geometrical units expressed in meters, the distance travelled by light in that interval.
In exactly the same way as we can use light-seconds as a distance in meters, we can express a mass (kilogram) as "mass-meters".
The Sun has a mass (in conventional units 2×1030 kg) which is expressed in mass-meters as 1.5 km.
The conversion from conventional units (kg) is
mass [meters] = G/c2 mass [kg] =
0.742 × 10-27 (m/kg) mass [kg]
Other conversions are given in the table by expressing the number 1.0
in different ways.
| Converting geometrized units to conventional units
|
| 1.0 | = | c | = | 2.997930 ×108 | m/s
|
| 1.0 | = | G/c2 | = | 0.7425×10-27 | m/kg
|
| 1.0 | = | G/c4 | = | 0.826×10-44 | m/N
|
| 1.0 | = | Gk/c4 | = | 1.140×10-67 |
m/K
|
See also
