Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

What would be the world be like if Plank's Constant is modified?

  1. Jun 10, 2010 #1
    How would the universe will be if Planck's constant is found to be a number different from 6.626 x 10-34 m2 kg/s. For Example what if it were to be 1 somewhere? Hypothetical Question.
  2. jcsd
  3. Jun 10, 2010 #2
    Planck constant is 1 in Planks units.
    The same is true for G and c (speed of light)

    These constants are not the parameters at all, they are just mere consequence of a bad choice of the units we used - meter, second etc.

    What can be varied (and it is very interesting) if you vary parameters of the Standard Model.
  4. Jun 10, 2010 #3


    User Avatar
    Gold Member

    I believe he means what if plank's constant was not a constant.
  5. Jun 10, 2010 #4
    I went through some calculations with having planck's constant as 1, it gave me answer like as we will go lock the door knob, we would like scatter in parts. I greatly suspect my effort. Can this be true? super unusual phenomenons with changed value?
  6. Jun 10, 2010 #5
    i meant that what would a world like parrallel world which has different planck's constant than ours.
  7. Jun 10, 2010 #6
    1 in what units?
    The value for h or c MEANS NOTHING. It just emans that we use some weird ad-hod definitions of METER, SECOND, GRAM etc. In feets per second c is different. So the next logical step is to use units, which are natural for the Nature:


    There is an irresistable beauty how the formulas become very simple, getting rid of different powers of G, c and h.
  8. Jun 10, 2010 #7
    i used joules per second
  9. Jun 10, 2010 #8
    no, you should use planks units everywhere: for example, planks time instead of second. The result you get will be the same, but the formulas will be simpler. You will see that (as there is no longer 'h' in formulas) there is nothing to be 'varied'
  10. Jun 10, 2010 #9
    oh no. the question is hypothetical. As they say there might exist parallel universes, so if they do, i think they might not have the exact constants as we have. So in that case Planck's unit would result in phenomenons of our universe. Which is not what i want.
    Didn't meant it for real, but a 'think experiment'.
  11. Jun 10, 2010 #10
    There are 2 cases:

    You vary the parameters of the standard model and look (theoretically) what happens. Even question is theorectical, it is very important in understanding of the cosmology and life in our Universe.

    But you can't change h in the same way you can change anything else. Of course, you can ask 'what happens if laws of our Universe were absolutely different. But it is a major change, not a minor change. (Max Tegmark call it level IV multiverse).

    Again, h is not a constant or a parameter. Example:
    We measure distance in meters, and surface- in square feets. Then the formula would be (h, w are height and width in meters):

    S = 10.82 *h*w

    The number 10.82 is a result of a bad choice of units. The same as h, G or c! In natural units the formula is

    S = h*w

    And the parameter simply dissapears. The same as h,G and c. So by asking 'what if h would be different' you are asking 'what if instead of 10.82 it would be 5.41' But it means that in natural units it would be

    S = h*w/2

    It is not just a different parameter, but different geometry and mathematics.
  12. Jun 10, 2010 #11
    Read George Gamow's book(s) on Mr. Tompkins, in which both the speed of light and Planck's constant are adjusted to affect daily activities. See


    Bob S
  13. Jun 10, 2010 #12
    Thanks Bob, that's exactly what i wanted. Science Fiction.
    I apologize if the question was framed the wrong way.
  14. Jun 10, 2010 #13
    I think you shifted towards mathematical constants. I assume that the simplest definition of 'our' universe is to list the universal constants, for example charge on electron, c, G, h, magnetic constant etc. Constants like that.
    Any change in these numbers should not be applicable for our universe but if parallel universe exist, some universe other than ours.
    Physicist say energy equal to Ten to the 19 billion electron volts "The Planck Energy", will be able to get us to parallel universe. Who knows, we are still on a trail.
  15. Jun 10, 2010 #14
  16. Jun 10, 2010 #15
    To show you why it is wrong a hint:

    Do you know that c = 299,792,458 m/s?
    Do you know that this value is exact?
    So it is 299,792,458.000000000000000000000000000000000000000000000000000000000000000000000000000000000000... m/s ?
  17. Jun 10, 2010 #16
    This is so unusual. I am taught h, c and G are constants. In a nutshell. you're trying to say that these 19 numbers are responsible for giving universe it's peculiar properties and not planck's constant etc.
    I think i got what you are saying as in E=hv ; h is only a number we use to convert v the frequency of radiation to Energy of a quantum. Or "result of bad choice of units". ok, these are the values that are there as we had to make formulas pass dimensional analysis.
  18. Jun 11, 2010 #17
    Yes. Intuitively I understand what you are trying to achive. Like, "make h bigger or smaller". Or c "slower". But making c smaller means that at 1 second light should traverse the different number of atoms. To achive that, you can change the parameters of the SM, for example, by making the electromagnetism 'weaker' you can make atoms 'larger', hence, light will traverse macroscopic objects 'slower'. Of course, you can make many other unexpected effects. In fact, this is the most interesting problem I know - to define the borders of that 19-dimensional 'cloud', and to understand, what is broken when you change the parameters. To understand, if we are in the middle of that cloud or not.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook