Highest energy electromagnetic waves?

[Beetle99]

Let’s see, gamma rays have a wavelegnth of 10^-5?

Cosmic rays are even smaller and thus higher energy, 10^-6 or so?

What are the highest energy electromagnetic waves that are possible? Is there a limit?

And if there is a limit, at 10^whatever, why is this a limit? Why wouldn’t you be able to go on and on ad infinitum squeezing more and more energy into a smaller and smaller space?

[scr4]

Cosmic rays are paticles, not electromagnetic waves.

Any photon above a couple hundred keV energy is called a gamma ray. There is no upper limit in energy that I’m aware of, besides the practical concerns of how to generate such a high-energy photon.

[Mangetout]

*Originally posted by scr4 *
Cosmic rays are paticles, not electromagnetic waves.

Is that right, or do they have the same sort of wave/particle duality that photons famously have? (depending on how you examine them)

[Popup]

*Originally posted by Mangetout *
**

Cosmic rays are paticles, not electromagnetic waves.

Is that right, or do they have the same sort of wave/particle duality that photons famously have? (depending on how you examine them) **

While it’s not exactly wrong to call the cosmic radiation waves, it’s misleading. At those tremendusly high energies (several GeV/TeV) the wave-nature is negligible, and they behave mostly as particles.
Extremely energetic cosmic rays strike the earth every day at an energy several orders of magnitudes higher than what we can produce (or even contemplate to produce) in our multi-billion dollar/euro laboratories, such as CERN or Fermilab.

[scr4]

*Originally posted by Mangetout *
**Is that right, or do they have the same sort of wave/particle duality that photons famously have? (depending on how you examine them) **

Sorry, I should have said that cosmic rays are massive particles - protons, neutrons and atomic nuclei. As opposed to gamma rays, which are photons. Yes, both can be considered either waves or particles.

I think the CERN particle accelerators go up to 10^12 eV. The highest energy cosmic ray particle recorded is of the order 10^20 eV, a hundred trillion times more energy. Cosmic gamma rays up to 10^12 eV range are observed, but I don’t know about anything higher. It should be easier to accelerate massive particles than photons though. Once a photon is created, you can’t add energy to it. Massive particles can be accelerated gradually.

[flex727]

*Originally posted by scr4 *
**Once a photon is created, you can’t add energy to it. Massive particles can be accelerated gradually. **

Sure you can - just drop it into a gravity well.

[rsa]

The Oh-My-God Particle

This is a proton, not a photon but is quite interesting.

On the night of October 15, 1991, the Fly’s Eye detected a proton with an energy of 3.2±0.9×10^20 electron volts.[1,2] By comparison, the recently-canceled Superconducting Super Collider (SSC) would have accelerated protons to an energy of 20 TeV, or 2×10^13 electron volts–ten million times less. The energy of the Oh My God particle seen by the Fly’s Eye is equivalent to 51 joules–enough to light a 40 watt light bulb for more than a second–equivalent, in the words of Utah physicist Pierre Sokolsky, to “a brick falling on your toe.” The particle’s energy is equivalent to an American baseball travelling fifty-five miles an hour.

How fast was it travelling?

v = 0.9999999999999999999999951 c

So taking 3×10^8 metres per second as the speed of light, we find that the particle was traveling 2.9999999999999999999999853×10^8 metres per second, thus 1.467×10^-15 metres per second slower than light–one and a half femtometres per second slower than light. If God’s radar gun is slightly out of calibration, this puppy’s gonna be doin’ hard time for speeding. After traveling one light year, the particle would be only 0.15 femtoseconds–46 nanometres–behind a photon that left at the same time.