Is there an upper limit to the energy of a photon?

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csmyth3025

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I was thinking about the Oh My God! particle (described here:http://www.fourmilab.ch/documents/OhMyGodParticle/) and what sort of effects such a particle might encounter in it's travels. This particle (assumed to be a proton) is estimated to have been traveling at 0.9999999999999999999999951 c (relative to the Earth).

If this proton ran head-on into a high-energy gamma ray photon going in the opposite direction, the energy of the photon would be blue-shifted to a higher level. Is there any limit to the amount of energy such a photon can have?

What effect would a collision like this have on the proton?

Chris
 
K

kg

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I posted a similar question a while ago. I believe I worded it as "is there a limit to how short the wavelength of a photon could be" the shorter the wavelength the higher the energy. I recall the consensus at the time was that there was no theoretical limit to how short a photons wavelength could be.
 
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SJQ

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I, too, asked a similar question (haven't figured out how to cleanly copy between threads), but I phrased it in terms of maximum frequency/minimum wavelength of a photon, with a view to the effect of the Planck length and 1/4 lambda (1/4 wavelength).

Rampart's response was that the Planck energy probably represented a finite, albeit large, limit to an individual photon's energy. I was thinking more in terms of physical dimensions (antenna theory), but if the Planck distance is representative of some minimum physical distance possible (i.e., the granularity of the universe), my question probably becomes somewhat nonsensical for a sufficiently short wavelength/high frequency/energy photon. Rampart's response didn't seem unreasonable - if I knew, I wouldn't have asked.


Topic review: Maximum possible frequency

Quote SJQMaximum possible frequency
by SJQ » Fri May 07, 2010 4:24 pm

In the electromagnetic spectrum, is there some MAXIMUM possible frequency? What happens as 1/4 wavelength approaches the Planck length? No application (well, not yet, anyway), just idle curiousity....


Quote rampartsRe: Maximum possible frequency
by ramparts » Sat May 08, 2010 2:15 am

Yeah, I believe that sets a maximum energy for a photon (that is, the Planck energy).
 
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csmyth3025

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Thanks for the replies kg & SJQ, and thanks Ramparts for pointing us in the right direction.

A read of the Wikipedia article on Planck energy (here: http://en.wikipedia.org/wiki/Planck_energy) indicates that:
"E[sub]p[/sub]=(h*c[super]5[/super]/G)[super]1/2[/super] = ~1.956 × 10[super]9[/super]J = ~1.22 × 10[super]19[/super]GeV = ~0.5433 MWh", where E[sub]p[/sub] is the Plank energy.

The same article goes on to say:

"...The ultra-high-energy cosmic rays observed in 1991 had a measured energy of about 50 joules, equivalent to about 2.5×10[super]−8[/super] Ep...", and that:

"... The Planck energy is not only the energy needed (in principle) to probe the Planck length, but is probably also the maximum possible energy that can fit into a region of that scale. A sphere 1 Planck length in diameter, containing 1 unit of Planck energy, will result in a tiny (and very hot) black hole..."

Could such an energetic photon (in its particle aspect) be expected to fit inside a sphere of 1 Planck length diameter (1.616252(81)×10[super]−35[/super]meters)?

The related Wikipedia article on Planck temperature (here:http://en.wikipedia.org/wiki/Planck_temperature) stipulates that the plank temperature (T[sub]p[/sub])=1.416785(71) × 10[super]32[/super]K.


Is this the black body temperature at which the emission of such photons (equivalent to the Planck energy) would be observed?

Chris
 
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SJQ

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The Plank temperature (Tp) is 1.416785(71) × 10[super]32[/super] °K. To quote Paris Hilton (who I doubt even knows this site exists, never mind would contribute to it...):

"That's hot!"

(so shoot me.....) :lol:

SJQ
 
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