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  2. Planck units - Wikipedia

    en.wikipedia.org/wiki/Planck_units

    The Planck Units are derived from the left-most vertice of the triangle, where the schwarzchild radius meets the compton wavelength. In particle physics and physical cosmology, Planck units are a system of units of measurement defined exclusively in terms of four universal physical constants: c, G, ħ, and k B (described further

  3. Orders of magnitude (time) - Wikipedia

    en.wikipedia.org/wiki/Orders_of_magnitude_(time)

    10 −14 qs: The length of one Planck time (t P = / ≈ 5.39 × 10 −44 s) [3] is the briefest physically meaningful span of time. It is the unit of time in the natural units system known as Planck units. 10 −30: quectosecond: qs Quectosecond, (quecto-+ second), is one nonillionth of a second 10 −27: rontosecond: rs

  4. Orders of magnitude (length) - Wikipedia

    en.wikipedia.org/wiki/Orders_of_magnitude_(length)

    1 Planck length: 0.0000162 qm Planck length; typical scale of hypothetical loop quantum gravity or size of a hypothetical string and of branes; according to string theory, lengths smaller than this do not make any physical sense. [1] Quantum foam is thought to exist at this scale. 10 −24: 1 yoctometer 142 ym

  5. List of physical constants - Wikipedia

    en.wikipedia.org/wiki/List_of_physical_constants

    While the values of the physical constants are independent of the system of units in use, each uncertainty as stated reflects our lack of knowledge of the corresponding value as expressed in SI units, and is strongly dependent on how those units are defined. For example, the atomic mass constant is exactly known when expressed using the dalton ...

  6. Planck constant - Wikipedia

    en.wikipedia.org/wiki/Planck_constant

    The Planck constant, or Planck's constant, denoted by , [1] is a fundamental physical constant [1] of foundational importance in quantum mechanics: a photon's energy is equal to its frequency multiplied by the Planck constant, and the wavelength of a matter wave equals the Planck constant divided by the associated particle momentum.

  7. Geometrized unit system - Wikipedia

    en.wikipedia.org/wiki/Geometrized_unit_system

    The geometrized unit system is not a completely defined system. Some systems are geometrized unit systems in the sense that they set these, in addition to other constants, to unity, for example Stoney units and Planck units. This system is useful in physics, especially in the special and general theories of relativity.

  8. Time-variation of fundamental constants - Wikipedia

    en.wikipedia.org/wiki/Time-variation_of...

    In such systems, it is meaningful to measure any specific quantity which is not used in the definition of units. For example, in Stoney units, the elementary charge is set to e = 1 while the reduced Planck constant is subject to measurement, ħ ≈ 137.03, and in Planck units, the reduced Planck constant is set to ħ = 1, while the elementary ...

  9. Natural units - Wikipedia

    en.wikipedia.org/wiki/Natural_units

    In physics, natural unit systems are measurement systems for which selected physical constants have been set to 1 through nondimensionalization of physical units.For example, the speed of light c may be set to 1, and it may then be omitted, equating mass and energy directly E = m rather than using c as a conversion factor in the typical mass–energy equivalence equation E = mc 2.