How can photons be massless
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How can photons be massless

[From: ] [author: ] [Date: 12-12-23] [Hit: ]
Is this sense of mass applicable to a photon? How much material makes up a photon? What force do we apply to change its acceleration?You might say electromagnetic forces and youd be right. But electromagnetic forces are the result of photons. So does the concept of mass have any meaning for a photon interacting with other photons or with matter?......

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I have no idea why anything you said means light can't have mass.
You said E=(0). You are wrong.
E=mc² is not the whole equation. It is just a famous abbreviation of it.
The whole equation is:
E² -(pc)² =(mc² )²
p here is the momentum of the "thing" in question.
There is an equation for the momentum of light in the 2nd link I provided. yes light can have momentum even if it is massless
Since light can have momentum we use the whole equation to make this shortened version:
E² -(pc)² =(mc² )²
E² -(pc)² =(0*c²)²
E² -(pc)² =0
E²=(pc)²
E=pc
Thus the speed of light times the momentum of the particular photon equals its energy

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What do you mean by 'mass'?

Strange question to begin an answer with, I know, but let's consider it for a moment. If you were talking about a car, then mass is some property of the car related to the 'amount of material' and describes the relationship between the force you apply and the acceleration that results. Is this sense of 'mass' applicable to a photon? How much 'material' makes up a photon? What 'force' do we apply to change its acceleration?

You might say 'electromagnetic forces' and you'd be right. But electromagnetic forces are the result of photons. So does the concept of mass have any meaning for a photon interacting with other photons or with matter? Can we explain what happens without invoking a 'mass' for photons? Well, yes we can!

Of course, you could define mass as the property of objects that produces gravitational forces. But gravity is the curving of spacetime by mass/energy distributed within it. A star has mass, but a photon moves through spacetime, so it doesn't need mass to be deflected by the star - it simply follows the curved spacetime path and is deflected. But again, we don't need mass to describe what happens to the photon.

So, the short answer is, photons are massless because the concept of 'mass' isn't necessary to explain any of our observations involving photons!

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The energy of a photon, is a constant times its frequency. The formula you remember, is for the energy of a particle or body at rest, with mass m.

"Moreover, photons have been shown to oscillate between various different kinds/wavelengths"

No. They do not do this.

To have mass, would violate conservation of charge.

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What Justin said.

BTW where did you learn that photons oscillate between various different kinds/wavelengths? I've never heard of that.

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You have misused the formulas for photon. ( Virus do not get rid the pupils)
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