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  2. Planck units - Wikipedia

    en.wikipedia.org/wiki/Planck_units

    The Planck time, denoted t P, is defined as: = = This is the time required for light to travel a distance of 1 Planck length in vacuum, which is a time interval of approximately 5.39 × 10 −44 s. No current physical theory can describe timescales shorter than the Planck time, such as the earliest events after the Big Bang. [ 30 ]

  3. Orders of magnitude (length) - Wikipedia

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

    120 μm – the geometric mean of the Planck length and the diameter of the observable universe: √ 8.8 × 10 26 m × 1.6 × 10 −35 m; 120 μm – diameter of a human ovum; 170 μm – length of the largest mammalian sperm cell (rat) [103] 170 μm – length of the largest sperm cell in nature, belonging to the Drosophila bifurca fruit fly ...

  4. Orders of magnitude (time) - Wikipedia

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

    The smallest meaningful increment of time is the Planck time―the time light takes to traverse the Planck distance, many decimal orders of magnitude smaller than a second. [ 1 ] The largest realized amount of time, based on known scientific data, is the age of the universe , about 13.8 billion years—the time since the Big Bang as measured in ...

  5. Unit of time - Wikipedia

    en.wikipedia.org/wiki/Unit_of_time

    The amount of time light takes to travel one Planck length. quectosecond: 10 −30 s: One nonillionth of a second. rontosecond: 10 −27 s: One octillionth of a second. yoctosecond: 10 −24 s: One septillionth of a second. jiffy (physics) 3 × 10 −24 s: The amount of time light takes to travel one fermi (about the size of a nucleon) in a ...

  6. Natural units - Wikipedia

    en.wikipedia.org/wiki/Natural_units

    Planck considered only the units based on the universal constants G, h, c, and k B to arrive at natural units for length, time, mass, and temperature, but no electromagnetic units. [7] The Planck system of units is now understood to use the reduced Planck constant, ħ, in place of the Planck constant, h. [8]

  7. List of physical constants - Wikipedia

    en.wikipedia.org/wiki/List_of_physical_constants

    The constants listed here are known values of physical constants expressed in SI units; that is, physical quantities that are generally believed to be universal in nature and thus are independent of the unit system in which they are measured.

  8. Orders of magnitude (mass) - Wikipedia

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

    DNA sequence of length 4.6 Mbp, the weight of the E. coli genome [27] 10 −17 ~1 × 10 −17 kg Vaccinia virus, a large virus [28] 1.1 × 10 −17 kg Mass equivalent of 1 joule [29] 10 −16: 3 × 10 −16 kg Prochlorococcus cyanobacteria, the smallest (and possibly most plentiful) [30] photosynthetic organism on Earth [31] [32] 10 −15 ...

  9. The Scale of the Universe - Wikipedia

    en.wikipedia.org/wiki/The_Scale_of_the_Universe

    Average size of an atom's nucleus 10-14 meters — Uranium nucleus — 1.5 × 10-14 meters Picometer: 10-12 meters 10-12 meters Gamma ray wavelength 10-12 meters 10-12 meters Electron compton wavelength: 2 × 10-12 meters — Helium atom 3.1 × 10-11 meters 2.5 × 10-11 meters Hydrogen atom 2.5 × 10-11 meters 3.1 × 10-11 meters