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

1. Is there a minimum wavelength?

2.

3. Zero.

4. Or a Planck length.

5. Originally Posted by inow
Zero.
Does that mean that a single photon could potentially have infinite energy? (Or approaching infinity.)

6. I don't understand the question.

7. 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...

8. So, from the lack of replies, what I put is either right, or so stupid that people don't know what to reply with!

9. what's your definition of -light- vis or entire EM spectrum?

10. 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.

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.

11. 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...

12. 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...

13. 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.

14. 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 1.602×10−19 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

15. @kojax, I am aware . But both the analogy and reality hold true to the same idea, do they not?

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