Is there a limit to how much energy can be stored in a photon?

  • #26
and is there a lower limit? Theoreticly there is none but is there a point where the frequency of a radio wave is too low for an electron to emit?
 
  • #27
SteamKing
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That's 16 Joules as I read the wiki... an almost mind-boggling number, enough energy to be macroscopically observable.
According to the wiki article:

10 TeV = 16 Micro Joules, so 16 TeV = 25.6 Micro Joules.

10Eev = 16 Joules
 
  • #28
LURCH
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There is no upper limit. The energy E is simply E=hf, and the frequency f can be arbitrary high. The only question is whether the are processes via which high-energy photons a produced.
But frequency is inversely related to wavelength, right? Can wavelength be arbitrarily short? What if a photon contains so much energy that the wavelength is shorter than Planck length; can that photon exist? I have also heard the statement (here in the Forums, actually) that there is a lower limit, if you envision a wavelength too long to fit within the universe. Those are some pretty exterme scenarios, but do they make sense on theoretically?
 
  • #30
if a photon with wavelenth big as universe were to be produced couldnt it affect an object at the end of the universe?
 
  • #31
and is there a minimum frequency that an electron can emit?
 
  • #32
otherwise an electron at zero kelvin could emit a photon tap into zero point energy by emmiting a radio wave with a very long wavelenth?
 
  • #34
Well, about high energy gammas, the most energetic ones are produced in violent phenomena in the cosmos.
(e.g in AGN's , GRBs etc).
There are also photons produced in the p+γ(CMB)->π0 +p, π0->γγ
The maximum energy gained by photons this way is of order ~10^19 eV.

The gammas however interact with CMB photons via the γ+γ=>e+e process and rapidly lose energy this way
Electrons on the other hand either interact via inverse compton or by bremsstrahlung and create more photons which interact/radiate again, leading to measured photons in the GeV-TeV range on earth.

These are the gammas we measure in our air shower arrays:)
 
  • #35
there a has to be a limit tn mthe lowest frequency,otherwise an electron at zero kelvin could emit a photon tap into zero point energy by emmiting a radio wave with a very long wavelenth. Where is my logic faulty?
 
  • #36
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"zero kelvin electron" sounds a bit faulty

If there is no limit to the universal rate of expansion then I see no limit to the amount of cosmological red-shift endured by a photon, and so no limit on the wavelength of a photon. If the cosmic expansion continues, which looks fairly likely, surely an unattenuated photon will eventually have an arbitrarily long wavelength after enough time elapses.
 
  • #37
About the GZK cutoff, yes it exists (or so we believe) which prohibits us from observing protons more energetic than 6*10^19 eV (taken that the interaction length of the proton in the CMB is lower than the proton source- earth distance). Of course, there might be a way for a (e.g)10^25eV proton to be created and its interactions to create high energy gammas before it is attenuated by the CMB.. Just speculating.
Or there might be some more exotic production channels for gammas that do not respect the GZK cutoff.. But these are all speculations (to be answered by Pierre Augere and IceCube hopefully).

About why gamma gamma interactions occure, check the so called "Delbruck scattering".
Now, about the low energy photons I have no better explanation than the one proposed by MikeyW
 
  • #38
OmCheeto
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There is not a limit.

Proof: Consider the following: suppose there were a maximum energy, E_max. You create a source of photons of energy E_max. Now you start walking towards it, blueshifting them. Now their energy is greater than E_max.
I like Lurch's argument about the "Planck length".


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pppppppppppppps. Why is this in the "General Physics" section?
and yes, I did self sensor my "I'm smarter than Einstein and Feynman combined, to the 12th power!", 47 comments
 
  • #39
it was moved from general physics.
 
  • #40
it was moved from quantum physics.
 
  • #41
concerning blue and redshifting: if you travel at c parellel to light the magnetic component disapears. What happens concerning the magnetic part of em radiation if a tachyon is travelling parellel to it?0_0
 
  • #42
OmCheeto
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I like Lurch's argument about the "Planck length".


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pppppppppppppps. Why is this in the "General Physics" section?
and yes, I did self sensor my "I'm smarter than Einstein and Feynman combined, to the 12th power!", 47 comments
hmmm.... Regarding V50's comment, the extractable energy of the universe, and the "Oh My God Particle" I studied this morning;

The particle was traveling very close to the speed of light — assuming the particle was a proton, its speed was only about 1.5 femtometers (quadrillionths of a meter) per second less than the speed of light, translating to a speed of approximately 0.9999999999999999999999951c.
Given that I have a mass of roughly 68 kilograms, and given the limited total extractable energy of the universe to accelerate "me", relative to the "OMG Particle", there is of course, a practical limit.

unsubscribe. :blushing:
 
  • #43
concerning blue and redshifting: if you travel at c parellel to light the magnetic component disapears. What happens concerning the magnetic part of em radiation if a tachyon is travelling parellel to it?0_0
and what would happen?
 

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