Do Photons Have Different Rest Mass?

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Discussion Overview

The discussion centers around the concept of whether photons have different rest masses, particularly in relation to their frequencies and energy. Participants explore the implications of mass definitions in the context of photons moving at the speed of light.

Discussion Character

  • Debate/contested

Main Points Raised

  • One participant asserts that while photons do not have mass when moving at their constant speed, they believe photons should have a rest mass that varies with frequency.
  • Another participant states that photons are massless and have zero rest mass, challenging the idea of varying rest mass.
  • A third participant reiterates that photons have zero rest mass due to their speed being equal to c, but suggests that the concept of inertial mass may differ from rest mass.
  • A later reply references a previous inquiry on the same topic, indicating ongoing interest or confusion regarding the mass of photons.

Areas of Agreement / Disagreement

Participants express disagreement regarding the existence and variability of photons' rest mass, with some asserting that photons are massless while others propose that rest mass could differ based on frequency.

Contextual Notes

The discussion involves different definitions of mass, including rest mass and inertial mass, which are not fully resolved. The implications of these definitions on the understanding of photons remain unclear.

physicsatiztech
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"the mass of photon"

I definitely know that photons don't have any mass if it is moving with it's well-known speed. However, it has its rest mass. So my question is

The energy of photons depend on their frequencies, however the freq. may differ from photon to photon. So I think their rest mass should also differ from photon to photon...

Am I right, or ...?
thanks a lot
 
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Photons are massless--they have zero rest mass.
 
physicsatiztech said:
I definitely know that photons don't have any mass if it is moving with it's well-known speed.
And that speed is always a constant (i.e. has the same value irrespective of the frame of reference) having the value c. The rest mass of any particle which moves with speed = c will have zero rest mass.
The energy of photons depend on their frequencies, however the freq. may differ from photon to photon. So I think their rest mass should also differ from photon to photon...

Am I right, or ...?
thanks a lot
You're not quite right in the sense that you're speaking about two different definitions of mass as if they were one. The value E = pc for a photon means that its rest mass is zero but that its inertial mass is not zero.


Pete
 
I asked this same question many moons ago
MINT!
 

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