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Topic: Planck units

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In the News (Fri 26 Apr 19)

  Planck units - Wikipedia, the free encyclopedia
In physics, Planck units are physical units of measurement originally proposed by Max Planck.
The Planck units are often semi-humorously referred to by physicists as "God's units".
It is a definition of unit charge that is a natural extension of how the other Planck units were defined and is referred to by physicists in some publications.
en.wikipedia.org /wiki/Planck_units   (1877 words)

 Kids.net.au - Encyclopedia Planck units -   (Site not responding. Last check: 2007-10-20)
Planck units are a system of units of measurement based on the fundamental constants:
These units have the advantage of simplifying many equations, because expressed in Planck units, all the constants on which they are based have the numerical value 1.
The relevant parts of Planck's 1899 paper leave some confusion as to how he managed to come up with the units of time, length, mass, temperature etc. which today we define using h-bar and motivate by references to quantum physics before things like h-bar and quantum physics were known.
www.kidsseek.com /encyclopedia-wiki/pl/Planck_units   (440 words)

 Planck's Hypothesis
Planck, who was a colleague of Wien's when he was carrying out this work, later, in 1900, based quantum theory on the fact that Wien's law, while valid at high frequencies, broke down completely at low frequencies.
Planck himself in [7] explains how despite having invented quantum theory he did not understand it himself at first:- I tried immediately to weld the elementary quantum of action somehow in the framework of classical theory.
Planck was also the first to succeed in getting, by means of the said relation, a highly accurate value for the number in question, the so-called Avogadro constant.
hypertextbook.com /physics/modern/planck/index.shtml   (1034 words)

 Planck time - Wikipedia, the free encyclopedia
Named after Max Planck, in physics Planck time is the natural unit of time, denoted by t
The Planck time is the time it would take a photon travelling at the speed of light to cross a distance equal to the Planck length.
However, this may not be taken as a "quantum of time." Within the framework of the laws of physics as we understand them today, we can neither measure nor discern any difference between the universe at the time it first came into existence and the universe anything less than 1 Planck time later.
en.wikipedia.org /wiki/Planck_time   (187 words)

In [Planck 1899] fundamental units of mass, length and time, and therefore all mechanical quantities, are expressed in terms of the physical constants
This essential Planck level quantization is a fundamental idea in Loop Quantum Gravity as pursued by Lee Smolin, which owes its genesis to a formulation of QCD due to Kenneth Wilson, in terms of loops.
The Schwarzschild diameter for the Planck mass is the Planck length.
graham.main.nc.us /~bhammel/PHYS/planckunits.html   (2410 words)

 Planck units - Psychology Central   (Site not responding. Last check: 2007-10-20)
Because the electromagnetic force between two particles is proportional to the product of the charges of each particle (each which would, in Planck units, be proportional to \sqrt{\alpha} \ ), the strength of the electromagnetic force relative to other fundamental forces is proportional to {\alpha} \ .
The Planck impedance comes out to be the Characteristic impedance of free space Z_0 \ scaled down by 4 \pi \ meaning that, in terms of Planck units, Z_0 = 4 \pi Z_P \ .
These units have the advantage of removing a factor of 8 \pi \ from the Einstein equation, Einstein-Hilbert action, Friedmann equations, and the Poisson equation for gravitation, at the expense of introducing one into Newton's law of universal gravitation.
psychcentral.com /psypsych/Planck_units   (2220 words)

 [No title]
Max Planck started quantum theory by showing that radiant energy is proportional to hn where h is a quantum whose value was determined experimentally by Planck and n is the numerical value of the frequency.
If the units for Planck's constant had been understood correctly, so that red shift could be properly explained, then the wave theory for light would have been vindicated to some extent at least.
According to my encyclopedia, Planck introduced his constant in 1905 to explain the distribution in frequency of radiant energy in a cavity of a body as a function of the temperature of that body.
www.softcom.net /users/greebo/plck.htm   (2281 words)

 QG and Planck units   (Site not responding. Last check: 2007-10-20)
The preferred unit of energy in physics is the the electron volt (or eV for short) is the amount of work necessary to move one electron across a potential of one volt.
Theoretical physicists are now confident that the role of the Planck values in quantum gravity, cosmology, and elementary particle theory will emerge from a unified theory of all fundamental interactions and that the Planck scales characterize the region in which the intensities of all fundamental interactions become comparable.
planck units are a system of units in which the unit speed is the speed of light-----that is, one unit length per unit time works out to be c.
www.physicsforums.com /showthread.php?t=41132   (3137 words)

 [No title]   (Site not responding. Last check: 2007-10-20)
Planck Time and "Tocks" As discussed earlier, the metric-60 unit "tock" is derived from physicists' best estimation of the Planck Time, and is defined as precisely 5.39121 x 10-44 seconds.
Planck Length and "Tocks" +As noted earlier, distances are also measured in tocks, where one tock is the distance light travels in a vacuum in one tock (1.61624 x 10-35 m).
Planck Charge and "Sparks" The Plank charge, qp, is defined in terms of the speed of light (c), Planck's constant (h), and the permittivity of free space (?0): qp = (2ch?0)1/2 It is about 11.7 times the charge on an electron (ignoring the sign).
jean.nu /Projects/novels/autonomy/draft-04/change-2005.07.24.txt   (3224 words)

 Planck mass - Psychology Central   (Site not responding. Last check: 2007-10-20)
Unlike most of the other Planck units, the Planck mass is on a scale more or less conceivable to humans, as it is roughly the mass of some fleas.
The Planck mass is the mass of a fl hole whose Schwarzschild radius multiplied by π equals its Compton wavelength.
The radius of such a fl hole is roughly the Planck length, which is believed to be the length scale at which both general relativity and quantum mechanics simultaneously become important.
psychcentral.com /psypsych/Planck_mass   (266 words)

 Fundamental Quantum Cosmological Units
As an example, the unit of length, one meter, was introduced during the French revolution, and in 1791 it was defined as one ten millionth of the distance between the North Pole and Equator, measured along the longitude circle through Paris.
After the introduction of his quantum constant, Max Planck showed, by a pure consideration of dimensions, that it was possible to construct a length, a time and a mass, by means of Newton's gravitation constant, the velocity of light and the new Planck constant.
The cosmological mass unit, 1 masson, is on the other hand a variable unit, as it must be assumed that the product of elementary mass and the cosmic evolution quantum number is constant, equal to the total matter/energy mass of the Universe.
www.rostra.dk /louis/quant_05.html   (3454 words)

 Planck's Units
The naturality of c as unit binds units into families among which ratios are powers of c; thus time and length are members of one family, along with area/time and the inverse of accellerations; while mass, momentum and energy are members of another family.
Quite a good unit of charge is the charge on the electron, or a third of it, give or take sign: this is clearly a genuine irreducible quantity of charge, making it ideal as a unit, hence widely used.
However, the form of Planck's units thus far is based on the constants in the field equations themselves, rather than on the bodies controlled by these: though better (by virtue of its real irreducibility), it is defined in the same spirit as the atomic mass unit, rather than in terms of the field equations.
www.chaos.org.uk /~eddy/physics/planck.html   (2120 words)

 Gregory Hodowanec: An Alternative Determiantion for the Velocity of Light
Planck suggested that experimentally determined universal constants could be used to “establish units of length, mass, time, and temperature, which are independent of special bodies or substances, which necessarily retain their significance for all times and for all environments, terrestrial and human or otherwise, and which may, therefore, be described as ‘natural units’”.
Planck chose the constants h, his Planck constant, C, the velocity of light in vacuum, and G, the gravitational constant.
However, it occurred to me at that time that these natural units could perhaps be the dimensions of the aether, but pressures of earning a living and raising a family delayed my looking into this further at this time.
www.rexresearch.com /hodorhys/veloclit.htm   (1460 words)

 Online Encyclopedia and Dictionary - Planck units
They form a system of natural units because they are defined exclusively in terms of the following fundamental physical constants — the units are natural because the numerical values of these five universal constants become 1 when expressed in units of this system.
ML The Planck units are often semi-humorously referred to by physicists as "God's units".
Accordingly these five dimensionful fundamental physical constants can be expressed in terms of the five base Planck units as:
fact-archive.com /encyclopedia/Natural_units   (1312 words)

 Unified Theory: Freespace constants derived
Although the Kelvin unit in ST has the same dimensions as energy, the conversion constant for Kelvin is not the same.
The ampere is the next redundant unit introduced in the SI due to lack of knowledge of the EM nature of matter.
This unit is defined as that constant current which, if maintained in two straight parallel conductors of infinite length, of negligible circular cross section, and placed 1 meter apart in vacuum, would produce between these conductors a force equal to 2 x 10-7 newton per meter of length.
www.blazelabs.com /f-u-const.asp   (3290 words)

 Human-scale Planck Units
The Planck quantities are normally defined in terms of c, h-bar, and G—the speed of light in empty space, Planck's constant, and the gravitation constant.
Partly for educational reasons it would be useful to have a unit of mass which is LARGE enough that its attraction for another unit could be detected and yet SMALL enough that one could see the acceleration effects of forces applied to it.
In the natural Planck units, temperature and brightness (that is radiant flux or power per unit area) are related by a simple fourth-power (quartic) formula.
www.planck.com /humanscale.htm   (4849 words)

 Theory: Units
It is a fundamental constant of nature, but its numerical value depends on the units we use for energy and temperature.
The units we use should be of a size that makes sense for the particular subject at hand.
It is easiest to define units in each area of science, and then relate them to one another rather than to go around measuring particle masses in grams or cheese in proton mass units.
www2.slac.stanford.edu /vvc/theory/units.html   (529 words)

 Planck units
Since these are specialized units that are only intended to be used under extremely narrow situations (this is clear when you look at the definition of the candela), we can make the sweeping generalization that all applications using these units can in fact use the derived units for energy and power (combined with other units).
For instance, the Planck equivalent of the candela would just be the power unit; the lumen equivalent would be the power unit times the steradian, and the lux equivalent would be the power unit times the steradian divided by the square of the Planck length.
Note that the Planck units are traditionally expressed in terms of hbar, where hbar == h/(2 pi).
www.alcyone.com /max/writing/essays/planck-units.html   (686 words)

 Center for Natural Units
In some areas of basic research the Planck units are used instead of conventional (metric) ones.
These units were proposed in 1899 by Planck as a general-purpose universal set of natural units for science.
Practical-sized versions of the Planck units — power-of-ten multiples of the small ones and power-of-ten fractions of the large — presented as a postmetric system of adapted traditional units.
www.planck.com   (1586 words)

 The Cosmological Quantum Units and the Planck Units
The socalled Planck units are not based on a physical theory, and neither are they themselves base for a physical theory.
The intention of Max Planck was – in 1899 –; to find a unit of length, a unit of time and a unit of temperature, independent of specific local systems and the existence of man.
The cosmological quantum units, discovered by me, elementary length, elementary time and elementary mass, which are basical for my holistic quantum cosmology (see this), are as such much more fundamental than the Planck units.
www.rostra.dk /louis/quant_12.html   (1045 words)

 CSP Part 1, Summary   (Site not responding. Last check: 2007-10-20)
Planck's Constant is energy divided by frequency, or energy times time.
Planck's constant can always be reduced to these factors, with the form of the base force chosen to suit the context.
and α are both dimensionless, the net dimensions of the Planck units (length, time, mass and force) are much more obvious in the simplified form.
www.csphysics.com   (531 words)

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