Gamma photon wavelength: Is there a limit?

[jerromyjon]

Is there any known limit to the energy of a photon? I've seen a reference to pair production in the highest bracket over 1.02 MeV and I've seen references to energies from cosmic sources in the TeV range which aren't very well understood but is there any theoretical limit?

 

[mfb]

At least with current physics, such a limit is impossible. Imagine a photon would have a "maximal energy" in our lab frame. Then another observer, moving in the opposite direction, would observe a higher than maximal energy.

 

[jerromyjon]

Thank you for your reply! I don't see how that makes a difference though, observation doesn't affect its maximal velocity. I am trying to grasp wavelength relevance which is exactly proportional to energy if I am not mistaken. I've read that the wavelength ranges overlap to some degree but generally gamma rays originate in the nucleus of atoms and x-rays originate from electrons in the shell. The wavelengths are roughly the scale of an atom and shorter for gamma, longer for hard x-rays. I'm just trying to get it into a reasonable perspective...;)

 

[mfb]

The velocity is always the speed of light.
The frequency and therefore the energy (yes, they are exactly proportional) depends on the observer.

I've read that the wavelength ranges overlap to some degree but generally gamma rays originate in the nucleus of atoms and x-rays originate from electrons in the shell.

Well that is just a naming convention.

 

[jerromyjon]

Is that exclusively due to frequency shift from gravitational, doppler and cosmological differences or are there other factors?

 

[mfb]

In the setup I described (as an example), just doppler effect.

 

[jerromyjon]

Thank you very much, I get your point. Velocity is a constant because it is the same for all observers, but energy varies with respect to the observer.