Planck frequency ÔPlanckis 1040 times higher than middle D on the piano, equivalently the D string on a violin or guitar. A more common notation would be OMEGAPlanck, but I prefer not to rely on the Greek capital omega coming through in HTML and substitute a circumflex O.
Planck frequency has the value
ÔPlanck = 1.8551 × 1043 per second,
with estimated uncertainty 7.5 × 10-4 . The CODATA recommended value of its reciprocal, the Planck time tPlanck is listed at the NIST website as
tPlanck = 5.3906 × 10-44 second
CODATA's estimated relative uncertainty of 7.5 × 10-4
amounts to about 1/13 of a percent. Planck units are customarily based on
h-bar, the compatible format for frequency being angular rather than
cyclic—radians per second rather than cycles per second.
http://physics.nist.gov/cgi-bin/cuu/Value?plkt|search_for=universal_in!
The natural unit of force c4/G is basic to the prevailing model of gravity—as the central coefficent in the 1916 Einstein equation relating energy-momentum density to curvature. In Planck units, having c4/G as the unit force and c the unit speed makes c5/G the unit of power. Dividing any power by h-bar gives a square frequency. In this case, dividing Planck unit power by h-bar gives c5/h-barG as the square of the unit frequency.
The physical picture is of a beam of light whose power is determined by two frequencies—the rate photons arrive and the average frequency of an individual photon. These two multiplied together give a square frequency which, multiplied by h-bar, gives the power of the beam(wattage in effect.) Any power can be divided by h-bar to give the square of a frequency. In the case of Planck units, dividing the Planck unit power by h-bar gives the square of Planck unit frequency:
c4/G is the Planck unit force
c5/G is the Planck unit power
h-bar×(square of Planck unit frequency) is the unit power.
h-barÔPlanck2 =
c5/G
This is equivalent to saying that Planck frequency is SQRT (c5/h-bar G) and means that the Planck time unit, the reciprocal of unit frequency, is SQRT (h-bar G/c5).
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