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.

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  1. T

    Rotating/overextreme Planck BH?

    I see there are new BH theories: "Planck stars" and "no Hawking radiation but a bounce in slow motion" What's about old BH puzzles from that point of view: rotating BH, overextreme BH, naked singularities? Do these theories favor Einstein-Cartan over classic GR?
  2. I

    Is the Planck Length a 3d area?

    If so, is 'its half' also not a real size of space? What I am asking is pretty much; what is the meaning of the notion of a 'smallest possible' 3d area? What is the meaning of that cusp between 2d and 3d? Almost like asking what is in between 1.999999999999(repeating) and 2. Must...
  3. A

    Can someone tell me planck constant?

    Every time i see it it's different. I want the full Planck constant(every number) and is there any proof for the constant?
  4. L

    Planck length and quantized position

    After reading an article on Planck length, I began to wonder whether or not the theoretical limit implied that position could be quantized in whole integer multiples of Planck length? To demonstrate what my question is asking mathematically I hope you will scrutinize the equations below: If...
  5. FysixFox

    A quick question concerning constants and planck units

    Recently I have taken an interest in physical constants (and, through it, an interest in SI units and the upcoming redefinition of the kilogram). I actually have a list of almost all of them now, standard uncertainties included. After a bit, I decided to have a bit of fun messing around with the...
  6. S

    Analysis: Why BICEP2 & PLAnck Are in Tension

    An interesting blog post arguing the reason that BICEp 2 and PLAnck are in tension is becuase BICEP 2 underestimated galactic foreground emission. http://resonaances.blogspot.co.uk/2014/05/is-bicep-wrong.html
  7. MTd2

    BICEP & Planck: Estimating Polarized Galactic Dust Emission

    To estimate polarized emission from the galactic dust, BICEP digitized an unpublished 353 GHz map shown by the Planck collaboration at a conference. However, it seems they misinterpreted the Planck results: that map shows the polarization fraction for all foregrounds, not for the galactic dust...
  8. Chronos

    Eternal inflation disfavored by Planck and BICEP2?

    This paper; http://arxiv.org/abs/1404.4614, Negative running prevents eternal inflation, claims Planck and BICEP2 data favors negative running of the spectral index of curvature perturbations from inflation at the 2 sigma level. It further asserts this is sufficient to preclude eternal inflation.
  9. R

    If gravity is curvature of spacetime, why unified force @ Planck epoch

    Hi Bear with my possible ignorant. I am puzzled over this dilemma. If General Relativity states that gravity is the curvature of spacetime, that is, no spacetime no gravity, and the cause of curvature is matter (mass), it means that if no matter, there is no gravity. I understand that...
  10. Entanglement

    Planck and Maxwell-boltzman distribution

    Is there a relation between these two distributions ?
  11. S

    Exploring the Smallest Measurable Units: Planck Length & Pi

    Hi all. This is my first time posting so forgive me If I am doing something wrong. I am a year 7 student interested in all types of physics and my question is, if nothing can be smaller than Planck length then wouldn't past a certain point the digits of pi become obsolete? Simply because the...
  12. S

    Absolute time, local time, planck time

    While Planck time is usually regarded as the shortest unit of time, isn't the shortest unit of time that can exist is the time it took to go from absolute time, the big bang, to everything after that i.e. local time? Did local time exist at the instant of the Big Bang?
  13. sweetdreams12

    Finding the Most Probable Frequency/Wavelength of Planck Functions

    I came across this question and though I've looked it up but I haven't found anything concrete and in truth confuses me more. It was posed by my lecturer and it is: For the Planck function Bv(t), what is the most probable frequency vp at a given temperature? Similarly for the Planck function...
  14. apeiron

    Why is Planck time scaled by c^5?

    Just curious. The Planck length is lpl = (hG/c3)1/2 = 10-33cm And it seems intuitive that it's c cube because space has three dimensions for the action. But the Planck time is tpl = (hG/c5)1/2 = 10-43s So is there some obvious physical reason why c is to the power of five here?
  15. T

    Proving the Total Energy Density of Planck-Body Law: λ to f Domain Conversion

    Homework Statement Starting from the Planck-Body Law I_{λ}dλ = \frac{2\pi c^{2}h}{λ^{5}} \frac{1}{e^{hc/(λkT)} - 1}dλ where λ is the wavelength, c is the speed of light in a vaccuum, T is the temperature, k is Boltzmann’s constant, and h is Planck’s constant, prove that the total energy...
  16. marcus

    What's really down in a BH? (a Planck star)

    Planck star is a proposed new idea which, if it gains support, will change how we think about "black holes". One can think of a Planck star as a slow-motion bounce that because of extreme time-dilation can take hundreds of billions of years to mature. When it finally does, the star breaks...
  17. marcus

    Planck Stars: Carlo Rovelli & Francesca Vidotto

    I just logged this on the biblio thread. This is in case there are questions, or things people want to discuss. http://arxiv.org/abs/1401.6562 Planck stars Carlo Rovelli, Francesca Vidotto (Submitted on 25 Jan 2014) A star that collapses gravitationally can reach a further stage of its...
  18. Tclack

    Are Planck Units the Ultimate Limit for Measurements?

    So, the three very small quantities: Planck length Planck mass Planck time Does the physical interpretation actually mean for example that when something moves, the smallest distance it can move is one Planck length, that there's no such thing as moving half a Planck length? And further...
  19. W

    Is Max Planck law true for all electromagnetic waves?

    Is it true that the energy in electromagnetic waves can only be released in "packets" of energy? Or is this only the case for a system where a standing wave change from one mode to another which results in sending out an electromagnetic wave (photon). In other words if I ride on my bike...
  20. B

    Fokker Planck Solution Biased Random Walk

    This is part b) of an assignment question. In part a) we were asked to derive the Fokker Planck relation for the biased random walk. The answer is: dP/dt = -vdP/dx + D d2P/dx2 Where the first term is the drift term due to the biased motion and the second term is the diffusion term. Then...
  21. M

    Bose-Einstein Stats and Planck Formula

    I worked out the Planck Black-Body Radiation Formula using Bose-Einstein Statistics, but I feel there is something conceptual I am missing here. When Planck derived the formula, he started out with the Boltzmann distribution function, and assumed that there were discrete energy levels...
  22. C

    Planck Arriving at a Relation Between Energy and Frequency with h

    Hello, I have recently been reading some texts focusing on modern physics. Both include sections on Planck and how he arrived at the conclusion that energy is not continuous. However I am confused as to what conditions inspired him to make this leap. I am aware of the Ultraviolet Catastrophe...
  23. arivero

    How big/small is Planck constant?

    I was thinking, given than h, c and G have different units, I can not compare a unit to other. But when we say that the quantum path integral recovers classical mechanics for very small h, there it seems we have a sense of how small h is. So, h is small... respect to what? Is it respect to E...
  24. jbunch

    Gravitational Forces on Mass < Planck Mass: Evidence?

    Is there any experimental or observational evidence that conclusively shows gravitational forces acting on mass that is less than the Planck mass? thx
  25. lonewolf219

    Planck and Boltzmann Distribution

    Does anyone know if Max Planck knew about the Boltzmann distribution before he published his results in 1900? Also, when Planck introduced h, did he also give the value?
  26. T

    Metric expansion in terms of planck pixels

    what if the evolution of the universe over time and the expansion of space a series of binary events such that the same quantity of energy is divided geometrically from one into two, four, eight, sixteen pieces, such that each Planck time is equivalent to one such split and each Planck length is...
  27. A

    Interacting Photons at Planck Energy: What are the Properties and Possibilities?

    What are the properties of a photon with Planck energy? Is it even possible to interact with it, or does it just travel trough all matter?
  28. marcus

    Meissner sees Penrose-type circles in Planck CMB map

    Meissner et al just posted a paper where they see those circles in the high res. microwave sky of Planck. Who knows if this is real, or what it would mean if it were confirmed? Meissner has a followup paper in preparation with Penrose and others. Either way I think it's pretty interesting...
  29. M

    Is Planck Time and Length the Smallest Possible Units of Measurement?

    Hope someone can clear this up for me, is Planck time the shortest possible time in which a particle or quark or anything can perform some kind of action? Also is Planck length the shortest distance in which an object can actually move? Anything shorter than that and the object doesn't mean...
  30. F

    The end all be all of the planck scale

    I have always understood Planck time as being the the smallest amount of time that has any physical significance and the Planck scale as being the region where space and time collapse on each other and all of our mathematics fail. Why are these seemingly magic numbers the end all be all of...
  31. R

    Blackbody radiation and Planck constant questions

    Ive been reading lately about the Planck constant and have been trying to learn more about it if possible. The way I understand it, the constant came about from experiments with black body radiation. Planck noticed that the experimental data fit the equation e=hf. My first question: how...
  32. I

    Have the planck scales been proven to be true?

    has it been proven that space and time are quantized in the Planck length and Planck time?
  33. M

    Planck Constant Significance

    Is there an intuitive explanation of why E/w = 2*L, where E/w is the ratio of the energy of any photon to its angular frequency and L is the magnitude of the spin of any electron? Evidentially there is a mathematical derivation of L=hbar/2 from some base assumptions, and evidentially E=hbar*w...
  34. M

    Question about the Planck spaces and observable universe, .

    From Wikipedia: http://en.wikipedia.org/wiki/Googolplex A Planck space has a volume of a Planck length cubed, which is the smallest measurable volume, at approximately 4.222×10^-105 cubic meters = 4.222×10^-99 cubic cm. Thus 2.5 cubic cm contain about a googol Planck spaces. There are only...
  35. marcus

    Criteria for causal independence (new paper, Planck data)

    I don't know whether this has much general interest. I am interested by communication horizons in cosmology, or causal horizons if you prefer. This paper claims to study several cases including how far apart two quasars would have to be to have been out of contact ever since the end of the...
  36. H

    Expand and derive the planck occupanncy

    Homework Statement The average energy of a harmonic oscillator is written using Boltzman statistics as: <ε> = (<n> +.5) = \frac{\sum_{n} ε_{n} exp \frac{-ε_{n}}{kt}}{\sum_{n} exp \frac{-ε_{n}}{kt}} Expand the expontentials and hence derive the Planck Occupancy <n> = n(ω,T)...
  37. S

    Planck Time? Why does it exist?

    I've recently heard of Planck Time.. I read that it is the minimum time interval that can EXIST. What exactly changes in time intervals that are less than Planck time? And if I am not mistaken by the meaning of Planck Time; What is the reason that there is such a limit? For Example, the...
  38. adjacent

    Finding the weight of the planck

    Homework Statement The information is on the attachment the plank is uniform meaning the mass of the plank is uniformly spread so the center of gravity is in the mid point of the plank.The plank is in equilibrium.Find the weight of the plank,Let the weight be w. Homework Equations...
  39. marcus

    Video talk on Planck results by Kendrick Smith

    http://pirsa.org/13040123/ Results and highlights from Planck Speaker(s): Kendrick Smith Abstract: Cosmological results from Planck, a third-generation satellite mission to measure the cosmic microwave background, have just been announced. These results improve constraints on essentially all...
  40. C

    Prove that Planck function increases with temperature

    Homework Statement Prove that the Planck function increases monotonically with temperature. Homework Equations Bv(T) = 2hv3c-2(ehv/kT - 1)-1 The Attempt at a Solution I first went through this piece-by-piece, but I am not a mathematician so I don't know if this constitutes...
  41. marcus

    Which Planck numbers to use? (Ned Wright's choice?)

    Planck team published several sets of of basic cosmic parameters in their report http://arxiv.org/pdf/1303.5076v1.pdf see for example Table 5 on page 22. The rightmost column of Table 5 is labeled "Planck+WP+highL+BAO". That seems to be the set of numbers that Ned Wright chooses to report, for...
  42. M

    Exploring Higgs Inflation After Moriond & Planck

    I figure that we need a thread specifically for this topic, while we try to sort out just how minimal physics could be, in the wake of the Moriond conference on the Higgs and the data release from the Planck collaboration. Fedor Bezrukov has written many papers on Higgs inflation, and curiously...
  43. marcus

    A history of the universe using the new Planck numbers

    Here's a sample history from fairly far back in the past, going up to the present (S = 1) in 20 expansion ratio steps, and then in another 20 expansion steps, going out a good stretch into the future, when distances will be 25 times what they are today. I could have asked for a wider expanse of...
  44. N

    Article on New Planck Satellite data

    Universe as an Infant: Fatter Than Expected and Kind of Lumpy http://www.nytimes.com/2013/03/22/science/space/planck-satellite-shows-image-of-infant-universe.html?nl=todaysheadlines&emc=edit_th_20130322the universe may be 13.8 B years old [a bit older than thought] and expanding more slowly...
  45. Chronos

    Planck Mission Reveals Universe Features: String Theory Hits

    The Planck mission has revealed some interesting features of the universe. I will attempt to recap some of the highlights from preprint papers at http://www.sciops.esa.int/index.php?project=PLANCK&page=Planck_Published_Papers . XV: there is a 5-10% deficit in low mode [l<40] power...
  46. S

    Large Scale anomaly in Planck data

    Just watching tweets come out of the conference, apparently there is a large scale anomaly that has come out of PLanck . One tweet says challenge to inflation, another says could be pre big bang physics. Obvioulsy I am just reading tweets, so not sure what's real yet. But this could be exciting...
  47. S

    What Exciting Discoveries Will the Live Planck Results Reveal?

    http://spaceinvideos.esa.int/esalive You can watch a live webcast of the Planck results, 10 am CET 21st MArch . Lets hope they discover something exciting and its not just WMAP to a few more decimal places. But of course there's strill the polrisation data 1 year away , nice article here...
  48. F

    Koch snowflake and planck length

    surely if you keep adding smaller and smaller sides to the snowflake they will become even smaller than the Planck length and so how can the perimeter be infinite- or is the infinite perimeter only theorteically possible with maths, but not actaully acheivable?
  49. S

    When Will We Know If Planck Discovered B Mode Polarisation?

    In case you didn't know already the first all sky Cmb map will be released at a press conference at ESA HQ March 21st http://smsc.cnes.fr/PLANCK/Fr/GP_actualites.htm This will be followed by a conference to discuss the cosmological data in Holland April 2nd-April 5th...
  50. D

    What Happens When the Universe is Reduced to the Planck Length?

    What would happen if the entire universe would be reduced in size by several orders of magnitude. I mean not just the distances between the galaxies but also the size of every planet, every atom, every nucleus and so on. That also means the strength of all forces would have to become smaller...
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