[Yahya A.Sharif (OP)]

What is a photon ?
A photon whether it is mass or energy  it shouldn’t move at c.

[Bored chemist]

A photon whether it is mass or energy  it shouldn’t move at c.

Yet it does.

If you say that your view does not agree with reality, it is not because reality has made a mistake,

[alancalverd]

A photon is a mathematical construct that helps us predict the behaviour of electromagnetic radiation.

[Yahya A.Sharif (OP)]

A photon is a mathematical construct that helps us predict the behaviour of electromagnetic radiation.

It contains energy.
Einstein says no mass nor energy should move at the speed c.

[Bored chemist]

A photon is a mathematical construct that helps us predict the behaviour of electromagnetic radiation.

It contains energy.
Einstein says no mass nor energy should move at the speed c.

That's silly.
Einstein knew perfectly well that light
(1) has energy and
(2) travels at the speed of light

So he can't have said

Einstein says no mass nor energy should move at the speed c.

You need to read more carefully or something

[Kryptid]

Let me get some clarification on this: are you simply looking to understand how light can move at the speed of light? If so, then the current location of this topic is acceptable. If you are, instead, trying to assert that light doesn't move at the speed of light and you are trying to convince us that it doesn't, this is belongs in the New Theory section.

[Yahya A.Sharif (OP)]

If you are, instead, trying to assert that light doesn't move at the speed of light and you are trying to convince us that it doesn't, this is belongs in the New Theory section.

I'm speaking about a contradiction in special relativity.

[Yahya A.Sharif (OP)]

Einstein knew perfectly well that light
(1) has energy and
(2) travels at the speed of light

He knew light is energy and it travels with c but he says mass or energy "light" shouldn't move at c.
Can you see any contradiction here ?

[Kryptid]

I'm speaking about a contradiction in special relativity.

Time to move this to New Theories then...

he says mass or energy "light" shouldn't move at c.

Please provide a reputable source that supports this statement. I am not aware of anywhere in special relativity that states that energy cannot move at c.

[Bored chemist]

He knew light is energy and it travels with c but he says mass or energy "light" shouldn't move at c.
Can you see any contradiction here ?

Yes, my understanding of relativity contradicts what you say.

[Yahya A.Sharif (OP)]

he says mass or energy "light" shouldn't move at c.

I am not aware of anywhere in special relativity that states that energy cannot move at c.

Einstein considers a moving object with its rest mass and other energy as a whole mass  in his equations , then mass is just energy and energy is just mass if a photon is energy then it is just a mass , it is a mass moves at c which it shouldn't. He does't distinguish between mass and energy in his theory and equations or mass/energy equivalence

[Bored chemist]

he says mass or energy "light" shouldn't move at c.

I am not aware of anywhere in special relativity that states that energy cannot move at c.

Einstein considers a moving object with its rest mass and other energy as a whole mass  in his equations , then mass is just energy and energy is just mass if a photon is energy then it is just a mass , it is a mass moves at c which it shouldn't. Or mass/energy equivalence

There are , in effect, two sorts of mass.
There is the mass you understand, and the mass you do not understand.

https://en.wikipedia.org/wiki/Mass_in_special_relativity#Relativistic_vs._rest_mass

[Kryptid]

it is a mass moves at c which it shouldn't.

Again, show us from a reputable source that no form of mass can move at c.

[alancalverd]

The speed of propagation of electromagnetic energy is calculated from first principles by Maxwell's equations. The only solution in vacuo is a constant, c.

The quantisation of electromagnetic energy is demonstrated in various experiments and consistent with Planck's calculation of the black body spectrum.

Relativity begins with the assumption that information cannot travel faster than c, and derives a number of experimentally testable results from gravitational red shift to the hydrogen bomb and satellite navigation, that have been shown correct to exceptional accuracy.

Plenty of people don't understand Maxwell, Planck or Einstein, but that's no reason to think they were wrong, as experimental data shows they were correct.

[PmbPhy]

What is a photon ?
A photon whether it is mass or energy  it shouldn’t move at c.

A photon is a quantum of EM radiation. It has mass via its momentum since mass is defined as m = p/v. Since fore a photon v = c we have m = p/c or p = mc. For a photon E = pc we now have E = mc^2

Einstein did in fact show that radiation in another (1907) relativity paper. that light has mass. What Einstein meant was that no body can accelerate from v < c to v >  c in is 1905 paper on relativity.

Whenever people don't clarify what they mean by the term "mass" confusion arises and people make mistakes.
There are two kinds of inertial mass in relativity: proper mass (aka rest mass) and relativistic mass. I wrote a paper on this subject. It's online at

On the concept of relativistic mass
https://arxiv.org/abs/0709.0687

There is a great deal of scientific literature out there who use mass to mean relativistic mass.

[PmbPhy]

Einstein knew perfectly well that light
(1) has energy and
(2) travels at the speed of light

He knew light is energy and it travels with c but he says mass or energy "light" shouldn't move at c.
Can you see any contradiction here ?

The problem is that you're wrong. Einstein never said that.

[talanum1]

A photon is a Riemann Sphere with four charges encoded into it on a circle in the Riemann Sphere. The charges are encoded as "left out events of spacetime". I can picture it.

[Bored chemist]

I can picture it.

I can find a picture of a unicorn. That does not make it real.

A photon is a Riemann Sphere with four charges encoded into it on a circle in the Riemann Sphere. The charges are encoded as "left out events of spacetime".

None of that actually makes sense.

[talanum1]

That does not make it real.

It can explain why and how a photon is emitted at the speed of light.

[Bored chemist]

That does not make it real.

It can explain why and how a photon is emitted at the speed of light.

Since nobody understands it, it doesn't explain anything.

On the other hand we already knew how photons were formed.
https://en.wikipedia.org/wiki/Perturbation_theory_(quantum_mechanics)#Time-dependent_perturbation_theory