What is Planck: Definition and 388 Discussions

Max Karl Ernst Ludwig Planck, (German: [maks ˈplaŋk] (listen); English: ; 23 April 1858 – 4 October 1947) was a German theoretical physicist whose discovery of energy quanta won him the Nobel Prize in Physics in 1918.Planck made many substantial contributions to theoretical physics, but his fame as a physicist rests primarily on his role as the originator of quantum theory, which revolutionized human understanding of atomic and subatomic processes. In 1948, the German scientific institution Kaiser Wilhelm Society (of which Planck was twice president) was renamed Max Planck Society (MPS). The MPS now includes 83 institutions representing a wide range of scientific directions.

View More On Wikipedia.org
Recent contents Top users
  1. M

    B Surface volume of 3-sphere with radius of 2 Planck length?

    What is the surface area ("surface volume") of a 3-sphere having a radius of 2 Planck lengths? Is the product of the Planck's constant, Einstein's proportionality constant and Planck time also equal to this volume? Does this equivalence signify anything? What does it signify?
  2. J

    B Direct detection of Planck mass WIMPs?

    Are the current dark matter detection experiments sensitive to Planck mass WIMPs? I've just looked at the Wikipedia WIMP article. It shows the excluded parameter space for the CDMS experiment with WIMP-nucleon cross section vs WIMP mass curves but they only go up to a WIMP mass of 1000 GeV.
  3. M

    B Why did Max Planck assume discrete energy values?

    I've read several articles discussing how Max Planck decided to assume that the energy radiated by oscillators in a black-body came only in discrete increments of En = nhf, where n is an integer. Using this concept, he determined that the average energy of an oscillator was given by...
  4. M

    Is there any proof to show that gravity works at the Planck length?

    Is there any experimental proof which shows that the force of gravity works at Planck length? Has it been verified already? Is it verifiable?
  5. J

    I Is the Planck length a proper length?

    The reciprocal of the Planck length, ##\Lambda=1/l_P##, is used as a high-frequency cutoff in the particle-physics estimation of the vacuum energy. For example in "the cosmological constant problem" Steven Weinberg says that summing the zero-point energies of all normal modes of some field of...
  6. Auto-Didact

    A Erebons: Planck mass Dark Matter particles

    Erebon theory is a novel explanation of dark matter recently invented by Roger Penrose. Erebons are scalar particles of the order of a Planck mass which can only interact gravitationally. When erebons decay, they release their energy as oscillating classical gravitational waves on the order of...
  7. J

    I Planck length and space expansion/contraction

    Imagine a cubic volume of space, defined today, with edges of the order of the Planck length. As cosmological time goes forward this volume expands so that the edges of the cube expand with the scale factor. This seems ok. However, as physics is time-reversible, it should be valid to imagine...
  8. Arman777

    I Size of an electron and Planck Volume.

    Theres something that bothers me, We claim that electron is a point particle.From that, Can we assume the volume the electron is ##(l_{h})^3## ( where ##l_h## is Planck length ) ? We know that every information can be described in bits like volume is ##(l_{h})^3## so, In every bit of...
  9. Lunct

    B What is the significance of the Planck length in physics?

    The definition of the Planck length I have found is that it is the shortest length that has meaning. What is meant by that? Can someone give be a better definition of what it is?
  10. J

    I Does the Planck length expand in a FRW universe?

    By using particle physics natural units with ##\hbar=c=1## so that Planck's length ##l_P=(8\pi G)^{1/2}## we can express Einstein's field equations as $$G_{\mu\nu}=l_P^2\ T_{\mu\nu},$$ where ##G_{\mu\nu}## has dimension ##[\hbox{proper length}]^{-2}##, ##l_P## has dimension ##[\hbox{proper...
  11. K

    I Higgs field couples to Planck quantum black holes?

    current proton decay experiments disfavor popular GUT like SU(5) Does the hiearchy problem for the higgs field require that the higgs couple to a GUT scale, if it exists, or to a Planck scale? does this require the higgs couples to Planck mass quantum mechanical black holes? since the Higgs...
  12. K

    I Does Planck time violate Lorentz-invariance

    I am well aware that spatial discreteness is in conflict with Lorentz-invariance. If there were a theory of QG that proposed Planck time as the smallest interval of physical time, would that be in conflict with Lorentz-invariance?
  13. O

    B Exploring the Mysterious Planck Scale: The Secrets of the Smallest Unit of Space

    It will take a particle accelerator that size of the solar system or more to peek inside the Planck scale.. does this mean the Planck scale is a no man's land.. or empty? but for a passing electromagnetic field or strong field.. doesn't it pass thru or touch the Planck scale at all? If it...
  14. W

    I Plateau models of inflation after Planck

    Reading some of the critics and defenders of inflation in various papers, one thing I note they have in common is that both seem to agree the plateau models of inflation are favoured by Planck. According to one of the critics of inflation "The plateau-like potentials selected by Planck2013 are...
  15. Zahidur

    B Why did Max Planck quantize light?

    I've read up on the history of quantization and I can't seem to find a definitive answer on why Planck actually quantized light. Some sources say that he came up with the idea of energy being quantized in order to solve the blackbody problem, whilst others say that he was trying to create a more...
  16. M

    B Thermal and Non thermal light emission

    I am now working on Thermal and Non-thermal light emission of materials, particular concerning the Planck law and Generalize Planck Law. I really want to understand the fundamental concept of this. So could you please suggest me some material, book on this subject? Thank you so much in advance,
  17. M

    I Has Planck length been derived rigorously?

    ħello. Here is my question: Has the so-called "planck length" (~1.61622837 * 10^(-35) meters) been derived with mathematical rigor within standard quantum field theory? If so, I need help finding this proof. Any literature would be appreciated. Also: If it has, then doesn't this imply a...
  18. A

    I Vacuum cutoff, normal ordering, Planck scale and 10^120....

    Hi all, This is a followup to a question from a couple of months ago regarding vacuum energy and cutoffs, basically to clarify some ideas. Given the usual picture of the vacuum as containing quantized harmonic oscillators at every point, it is not possible to apply a 'fixed' energy cutoff (at...
  19. nomadreid

    I Is the Planck Length the Ultimate Limit of Measurement?

    If I understand correctly, the Planck length, or maybe a tenth of it, is considered the point at which quantum effects mess up any attempt to apply our present physical laws, and so one could not even in theory make a dependable measurement of something smaller. However, I was wondering what...
  20. Buzz Bloom

    I Qs re average and peak wavelength of Planck distribution

    This thread is prompted by a closed thread which left it’s OP’s original question unanswered. ->https://www.physicsforums.com/threads/average-wavelength-for-blackbody-radiation.423536/ The original question asked: is the ratio, of (a) the wavelength corresponding to the average energy in the...
  21. F

    I Length Contraction & Time Dilation Beyond Planck Scale: Correct?

    If an object was traveling fast enough relative to an observer such that it's length is contracted down to the Planck scale (as with time), I would imagine that any further increase in speed would result in no more observable relativistic effects? Please correct me if I'm wrong.
  22. Battlemage!

    I Does Planck Time Imply an Acceleration Limit?

    Mods, I wasn't sure whether to put this in quantum physics or relativity, but since the speed of light is the limiting factor I chose here. Move wherever you think is best. Okay so the speed of light is the asymptote for the speed that objects can accelerate to, and the Planck time is the...
  23. L

    I Converting Planck data for spherical projection

    Does anyone know how I could convert data from Planck, which appear as an oval shape, into a form that I can easily map onto a sphere (ie. a rectangular shape in 2:1 aspect ratio)? Here is an example Planck image: http://sci.esa.int/science-e-media/img/61/Planck_CMB_Mollweide_4k.jpg I see that...
  24. D

    I Found a Planck value that relates to classical gravity

    Hello, I was researching the Planck Constant values and decided to build a math software to scan for potential values that relate to permittivity of free space and permeability of free space and found one of the 2010 CODATA values (specifically the Magnetic Resonance Imaging value). Can I get...
  25. AndyWeb

    B The Universe: A Planck Clock Exploration

    Hello, I was watching watch videos lol. I bought a new automatic watch and I was interested to see how they work, here is a nice YouTube video; There are various types of watches / clocks. Sun dial, mechanical, kinetic, quartz and of course atomic. They all, however, measure time kinda...
  26. Metals

    I Blue lights (LEDs) consume more power than red (and green)?

    Referring to LEDs as I'm not aware of any other "colour-producing" light, does blue light use more energy than red light? Planck's formula (E=hf) leads me to believe that blue light would drain a battery quicker than red, due to its higher frequency. Surely a device emitting blue light would...
  27. F

    I Comparing Reduced Planck Masses

    What is the difference between these reduced Planck masses? ##M_p = \sqrt \frac{ħc}{8πG}~## and ##~M_p = \sqrt \frac{1}{8πG}## I see people use either, but what is the difference? It can't be that ħ and c are set to 1 because G is also a Planck unit and it would be nonsense to set a Planck...
  28. C

    B Understanding Planck Mass and Gravity Formula for the Hierarchy Problem

    from the formula M_p=\sqrt{\frac{\hbar c}{G} If gravity is weak.. Planck mass is huge. Does the formula assumes whether general relativity is classical limit of some quantum theory or whether general relativity needs quantization? Because the problem with the Hierarchy problem in the...
  29. C

    B How Does Changing Gravity and Speed of Light Affect the Planck Scale?

    If gravity becomes stronger. would the Planck length becomes longer or bigger? Would speed of light c also have the same effect of changing the Planck length size? Would anyone know any java website that can make you adjust the strength of gravity and c and see how big or small the Planck scale...
  30. Zahidur

    I Subbing Planck length into length contraction equation?

    I was wondering if it is possible to work out the maximum amount of energy an object with mass can have using the length contraction equation (i.e. "actual" length divided by Lorentz factor). The way I thought of doing this was by rearranging e = mc^2 to get c^2 = e/m. Then, substitute e/m into...
  31. A

    I Can the Planck equation be derived by considering phonons?

    As far as I understand, phonons are just thermal vibrations of atoms in a lattice and blackbody radiation is just the radiation emittied due to thermal oscillations accelerating the atoms back and forth. Is there any example of a derivation of the Planck equation from considering black body...
  32. E

    I Planck formula and density of photons

    Hello! Let's consider again a system of atoms with only two permitted energy levels E_1 and E_2 > E_1. When electrons decay from E_2 level to E_1, they generate a photon of energy E_{21} = E_2 - E_1 = h \nu. The number of photons (per unit frequency, per unit volume) emitted by such a system in...
  33. facenian

    I Is There a Mistake in My Understanding of Planck Units and Dimensional Analysis?

    Since ##c=1## we have ##[l]=[t]##, ##\hbar=1## and from Einstein law ##E=\hbar\omega\rightarrow [E]=[t^{-1}]##, ##G=1\rightarrow [E]=[m]^2[t^{-1}]## then we must have ##[m]=1## but since ##E=mc^2\rightarrow [E]=[t]^2## Can someone please point out my mistake
  34. Adgorn

    Planck time at the speed of light

    I know that if an object moves at the speed of light, from its persepctive time will stop to a halt. However the smallest unit of time should be the plank time. So my question is, will the object (say a photon) experience throughout its life a single still "frame", or will it experience...
  35. G

    B Below and above the Planck Scale

    Below Planck scale means inside the Planck scale, and above Planck scale means outside of Planck scale? If the term is correct.. why doesn't quantum gravity theory like Loop Quantum Gravity affect low energy experiments above the Planck scale (outside of Planck scale)? Quantum field theory is...
  36. Ken Gallock

    B Is it possible to do experiment on the Planck scale?

    Hi. I was wondering if experiments on the Planck length (about 10-35 m) are possible or not. If it is possible, what kind of experiment would that be? If it's not, then what is the problem? Or what is need to be done? Thanks.
  37. P

    I Could Planck have used different energy-frequency relation?

    Hello, as a non-physicist enthusiast, but with decent math background, I tried to learn a bit about origins of quantum theory and very soon raised some questions, which I hope this community will answer. So, Planck tried to model the blackbody radiation on where Raighley and Jeans have failed...
  38. edguy99

    B What is the relationship between the Planck length and black holes?

    This article is posted on twitter with the byline: "You, me, and even aliens from Alpha Centauri could arrive at the same Planck units." but does not explain why. http://www.symmetrymagazine.org/article/the-planck-scale I believe I have read (but cannot find the reference now) the following...
  39. kini.Amith

    I What is Planck curvature and its significance in the expansion of the universe?

    I was reading a paper by Starobinsky on spectrum of relict gravitational radiation. He uses the term Planck curvature as follows "We construct a model in which the universe was perpetually in the quantum state with the radius of curvature of the order of Planck curvature, and later left this...
  40. B

    B 2 events in a planck time not violate conservation of energy

    This thread is about a topic that unexpectedly came up in my thread titled "Contradiction between Cosmos and what someone here told me?". I will subsequently call that thread "Contradiction" for brevity. I am not sure if this thread belongs on the Quantum Physics forum or the chemistry forum...
  41. Y

    B About the Lorentz invariance of Planck constant

    Is it proved experimentally that the Planck constant is invariant in the moving system? If that experiment exists, would you show me that in detail?
  42. J

    I Why is Planck radiation the most radiation a body can emit?

    Why is Planck radiation the greatest amount of radiation that anybody at thermal equilibrium can emit from its surface, whatever its chemical composition or surface structure?
  43. skepticwulf

    B Object projected vertically upwards and Planck time

    When we throw an object vertically , its speed decreases due to gravity and comes to a halt at the very top, V=0 and starts falling down. What can we say about that "halt" moment? Is it defined in terms of seconds? Does it last as long as Planck time? being the smallest measurement of time that...
  44. bbbl67

    I Can interactions happen at less than the Planck Time?

    I was watching this PBS Spacetime video, and something they said bugged me. They said that some subatomic interactions are occurring at time scales less than the Planck Time. And thus, this would also mean that these things are happening at scales less than the Planck Length as well. My...
  45. G

    I Physical implications from Vitali sets or Banach-Tarski?

    Hi. Can we infer something about physics from stuff like Vitali sets or the Banach-Tarski paradox? Maybe if we assume the energy in a given space volume to be well defined and finite, that there must be fundamental particles that can't be split, or that there must be a Planck length and energy...
  46. T

    Gravitational waves, distance and space-time

    So the discovery of gravitational waves observed a contraction and stretching of space-time, and I've been trying to understand how the expansion of the universe means that space itself is growing. I want to understand how this actually works in relation to 'things' like a photon and an atom...
  47. B

    What was the role of Hawking Radiation in the early universe?

    Amount of Planck energy is 1.956 * 10^9 J. Was this total energy of universe at plank time at big bang cosmology model? It's clear this amount of energy is not enough for making our solar system, even it's not enough for making mass of me ( 60 kg ). Should we postulate energy increase in the...
  48. Alettix

    What is the explanation for the differential form of Planck's law?

    Hello! I have a little trouble with understanding Planck's law of radiation, and wondered if you could help me with it. :) The equation is: ## \frac{dI}{d\lambda} = \frac{2\pi hc^2}{\lambda^5(e^{hc/\lambda kT}-1)} ## (1) where T is the temperature, k Boltzmann's constant, h Planck's constant...
  49. T

    News Planck, Schrodinger, and what to do during political catastr

    When I was young I read Schrodinger's memoirs. I can't find a book, but I remember he described an interesting conversation with Max Planck about what to do during the political catastrophe. The conversation was in 1940, and Schrodinger was asking Planck's opinion on what to do - to immigrate...
  50. naima

    Is Fokker Planck equation equivalent to Schrodinger equation

    I found this question here but i do not understand the answer. One equation is from classical physics and the other from quantum physics. Is there another way to go from classical to quantics than the analytical extension?
Back
Top