> Sokolsky has calculated that at 3×1020 eV, even a single proton could travel no farther than 10 megaparsecs
I wonder how fast proton looses energy (due to interactions with photons of background radiation).
How much energy it would need to travel to us from edge of observable universe?
Particle have (very short) wavelegths associated with them. It might be interesting to observe larger amount of such high energy photons coming from same point in the sky especially if there is a black hole near their path that could bend it slightly. Maybe we could get some diffraction patterns. ... yeah I'm probably insane.
The usual energy loss mechanism for cosmic-rays (fast protons) is reverse-compton scattering off the cosmic-microwave background photons, which is quite amazing really. Some of the most energetic particles scattering off the ubiquitous but very low energy background.
Anyway, if you propose that this is the mechanism for energy loss and you know how dense the CMB photons are (which we do very well) then you can predict interesting things like the maximum distance a cosmic ray can travel before it runs out of steam entirely, see
I was looking at that too... the trick that I see is that that's a statistical limit, not a "travel X miles, lose X% energy, no matter what" limit. It's still entirely possible for a particle to be over the limit, it's just highly unlikely.
We detect super-energetic particles frequently, but only a couple "over the limit". Seems to fit the statistical model to me.
I wonder how fast proton looses energy (due to interactions with photons of background radiation).
How much energy it would need to travel to us from edge of observable universe?
Particle have (very short) wavelegths associated with them. It might be interesting to observe larger amount of such high energy photons coming from same point in the sky especially if there is a black hole near their path that could bend it slightly. Maybe we could get some diffraction patterns. ... yeah I'm probably insane.