Notices
Results 1 to 14 of 14

Thread: Is there a limit on the frequency of light?

  1. #1 Is there a limit on the frequency of light? 
    Time Lord
    Join Date
    Mar 2007
    Posts
    8,035
    Is there a minimum wavelength?


    Some clocks are only right twice a day, but they are still right when they are right.
    Reply With Quote  
     

  2.  
     

  3. #2  
    Veracity Vigilante inow's Avatar
    Join Date
    Oct 2009
    Location
    Austin, TX
    Posts
    3,499
    Zero.


    Reply With Quote  
     

  4. #3  
    Quagma SpeedFreek's Avatar
    Join Date
    Jan 2011
    Location
    London, UK
    Posts
    2,787
    Or a Planck length.

    Take your pick!
    Reply With Quote  
     

  5. #4  
    Time Lord
    Join Date
    Mar 2007
    Posts
    8,035
    Quote Originally Posted by inow
    Zero.
    Does that mean that a single photon could potentially have infinite energy? (Or approaching infinity.)
    Some clocks are only right twice a day, but they are still right when they are right.
    Reply With Quote  
     

  6. #5  
    Veracity Vigilante inow's Avatar
    Join Date
    Oct 2009
    Location
    Austin, TX
    Posts
    3,499
    I don't understand the question.
    Reply With Quote  
     

  7. #6  
    Forum Bachelors Degree x(x-y)'s Avatar
    Join Date
    Jul 2010
    Location
    UK
    Posts
    462
    Well, from what I know:

    Planck Length = 16.1625281x10^-36 m.

    Thus, as



    the maximum frequency is



    giving a value of ~1.856x10^43 Hz.

    And thus, the maximum Energy is



    Which is ~1.2298x10^10 J.

    But, that's probably wrong- I'm only currently doing AS level physics!

    EDIT: I know that the speed of light in a vacuum is not exactly , I was just doing rough calculations...
    "Nature doesn't care what we call it, she just does it anyway" - R. Feynman
    Reply With Quote  
     

  8. #7  
    Forum Bachelors Degree x(x-y)'s Avatar
    Join Date
    Jul 2010
    Location
    UK
    Posts
    462
    So, from the lack of replies, what I put is either right, or so stupid that people don't know what to reply with!
    "Nature doesn't care what we call it, she just does it anyway" - R. Feynman
    Reply With Quote  
     

  9. #8  
    Forum Ph.D.
    Join Date
    Jan 2009
    Posts
    951
    what's your definition of -light- vis or entire EM spectrum?
    Reply With Quote  
     

  10. #9  
    Time Lord
    Join Date
    Mar 2007
    Posts
    8,035
    Quote Originally Posted by x(x-y)
    So, from the lack of replies, what I put is either right, or so stupid that people don't know what to reply with!
    It all depends on whether the Plank length is an actual limit or not. Does something prevent wavelengths shorter than that?

    Clearly we don't observe photons with that much energy striking the Earth very often (or at least they're not making it through the upper atmosphere), so maybe something does limit them from getting that energetic.


    Quote Originally Posted by fizzlooney
    what's your definition of -light- vis or entire EM spectrum?
    Definitely inclusive of the entire spectrum. I should have said EM radiation, to be more clear.
    Some clocks are only right twice a day, but they are still right when they are right.
    Reply With Quote  
     

  11. #10  
    Forum Bachelors Degree x(x-y)'s Avatar
    Join Date
    Jul 2010
    Location
    UK
    Posts
    462
    Quote Originally Posted by kojax
    Clearly we don't observe photons with that much energy striking the Earth very often (or at least they're not making it through the upper atmosphere), so maybe something does limit them from getting that energetic.
    Well, I suppose that's one of the many things that the AMS-02 recently installed on the ISS will probe and study...
    "Nature doesn't care what we call it, she just does it anyway" - R. Feynman
    Reply With Quote  
     

  12. #11  
    Forum Freshman
    Join Date
    Oct 2010
    Posts
    81
    Well, if the frequency was higher than the amplitude, then the light would be going up and down faster than the speed of light... so there is a limit to amplitude but not frequency, and that's relative to frequency. Or am I wrong? Thought experiment...
    Reply With Quote  
     

  13. #12  
    Time Lord
    Join Date
    Mar 2007
    Posts
    8,035
    Quote Originally Posted by Pomegranate Cameron
    Well, if the frequency was higher than the amplitude, then the light would be going up and down faster than the speed of light... so there is a limit to amplitude but not frequency, and that's relative to frequency. Or am I wrong? Thought experiment...
    Yeah.

    I see you are yet a padawan in the understanding of light. It doesn't physically move up and down. It's magnetic and electric fields reverse direction (pointing always at right angles to the direction the light is traveling) , but the beam of light itself physically stays traveling in a straight line toward its destination.
    Some clocks are only right twice a day, but they are still right when they are right.
    Reply With Quote  
     

  14. #13  
    Forum Sophomore
    Join Date
    Feb 2011
    Posts
    162
    In regard to the OP, there is a maximum gamma ray energy that has actually been observed:

    The highest energy measurements of gamma-rays are accomplished using ground-based instrumentation which also measure cosmic rays. Reliable detections of very high energy gamma-ray radiation from individual astrophysical sources, specifically from a couple of active galaxies and from the Crab Nebula, have extended up to about 10^27 Hz (5 x 10^12 eV).
    (ref. http://imagine.gsfc.nasa.gov/docs/as...s/970412e.html )

    According to Wikipedia:

    In physics, the electron volt (symbol eV; also written electronvolt) is a unit of energy equal to approximately 1.60210−19 J.
    (ref. http://en.wikipedia.org/wiki/Electronvolt )

    This would make these highest observed gamma ray photons have an energy of about 3.1 x 10^-7 J. This is about twice the kinetic energy of a flying mosquito according to the cited article on electron volt.

    These observed gamma ray photons were produced at great distances from us. Presumably, the energy they had at the point of origin could have been much higher but their energy might have been diminished by scattering and other effects by the time they got here.

    Chris
    It is difficult to say what is impossible, for the dream of yesterday is the hope of today and the reality of tomorrow.
    Robert H. Goddard - 1904
    Reply With Quote  
     

  15. #14  
    Forum Freshman
    Join Date
    Oct 2010
    Posts
    81
    @kojax, I am aware . But both the analogy and reality hold true to the same idea, do they not?
    Reply With Quote  
     

Bookmarks
Bookmarks
Posting Permissions
  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •