High-Energy Photon: What Happens?

Click For Summary
SUMMARY

The discussion centers on the implications of high-energy photons, particularly those with wavelengths smaller than the Planck length (approximately 1.6 x 10^-35 meters). Participants clarify that, according to local Lorentz invariance, photons can theoretically possess any wavelength, regardless of its size relative to the Planck length. The conversation highlights the misconception that the Planck length represents a fundamental limit in physics, emphasizing that new physics may emerge at this scale, although current understanding does not preclude the existence of such photons.

PREREQUISITES
  • Understanding of Einstein's mass-energy equivalence (E=mc²)
  • Familiarity with the concept of wavelength and its relation to energy in photons
  • Knowledge of local Lorentz invariance in physics
  • Basic comprehension of the Planck length and its significance in theoretical physics
NEXT STEPS
  • Research the implications of local Lorentz invariance in modern physics
  • Explore the significance of the Planck length in quantum gravity theories
  • Investigate the properties and behaviors of high-energy photons in particle physics
  • Study current theories that propose new physics at scales smaller than the Planck length
USEFUL FOR

Physics students, theoretical physicists, and anyone interested in the fundamental properties of light and energy at quantum scales.

Tumorsito
Messages
9
Reaction score
0
Ok guys, so let's suppose we have a mass of 1kg.
We can calculate the energy that matter could deliver. E=mc², roughly 10^8c. Supposing this energy was delivered from a photon (supposing it exists such a processus that could delivery such energy in a single photon), we can calculate the wavelength corresponding. More or less 2x10^-42. Which is less than the Planck length . My question is, (i just started a physics degree so I don't have that much knowledge), when this photon will be produced, what will happen? Space between wavelength is smaller than PL.
 
Science news on Phys.org
Hi T, :welcome:

Don't get carried away -- there are a few rules that need to be satisfied. But ##c^2## in Si units is an awful lot of energy, that's for sure. If it's real, your high-energy photon simply propagates until it encounters something ...
 
BvU said:
Hi T, :welcome:

Don't get carried away -- there are a few rules that need to be satisfied. But ##c^2## in Si units is an awful lot of energy, that's for sure. If it's real, your high-energy photon simply propagates until it encounters something ...
Yes, we are ok for saying it's a lot lot of energy, but just in the case we have a photon this energetic, how could it exists if it has a wavelength less big than pl.
 
By (at least local) Lorentz invariance, the wavelength of a photon can be anything, either much larger or smaller than the Planck length. After all, if you emit a photon in my direction, I can boost to a very fast (close to the speed of light) velocity where the photon wavelength becomes arbitrarily small. Anything preventing me from doing so would violate local Lorentz invariance.

It is not clear to me what your problem is with photons with such a small wavelength unless you believe that local Lorentz invariance fails, in which case you should specify what theory you propose to replace what is currently accepted.
 
Tumorsito said:
how could it exists if it has a wavelength less big than pl.
You may have been victimized by the common misconception that the Planck length is the smallest possible length, sort of the "pixel size" of the universe. This misconception is so common that we even have an Insights article about it: https://www.physicsforums.com/insights/hand-wavy-discussion-planck-length/

Nonetheless it is possible likely that some interesting new physics will appear at that length scale. The Planck length is many orders of magnitude smaller than any of our experiments can reach so anything anyone says about what that interesting new physics might be is complete guesswork. All we can say now is that based on what we know now there's nothing wrong with photons whose wavelength is smaller than the Planck length... but it wouldn't be amazing to find that when we know more we'll have a different answer.
 
  • Like
Likes   Reactions: Dale
Ok ty everybody for your awnsers. I think it's what Nugatory said. Didnt knew that, thanks for sharing!
 

Similar threads

Graduate Shift in wavelength of photons from the Sun using energy argument
  • · Replies 3 ·
Replies
3
Views
2K
High School What happens to a photon's energy when it is refracted?
  • · Replies 13 ·
Replies
13
Views
2K
Graduate What Happens to Photons and Particles in Our Universe?
  • · Replies 1 ·
Replies
1
Views
2K
High School Planck's equation and upper and lower bounds on the energy of a photon
  • · Replies 8 ·
Replies
8
Views
2K
Undergrad Ultra-high energy photon interactions with matter
  • · Replies 8 ·
Replies
8
Views
2K
High School Photon absorption -- What happens to the excess energy?
  • · Replies 12 ·
Replies
12
Views
2K
Undergrad Do atoms recoil when emitting a photon?
  • · Replies 38 ·
2
Replies
38
Views
6K
Graduate Is the Photon Mass Really Zero or Does It Have a Finite Value?
  • · Replies 6 ·
Replies
6
Views
3K
High School What happens to excess energy when an electron gets excited by light?
  • · Replies 7 ·
Replies
7
Views
2K
Graduate Wavelength, energy and photons.
  • · Replies 28 ·
Replies
28
Views
9K