How Can Light Have Energy But Not Mass?

E=mc^2 which means energy and mass are related, so how can light have energy when it doesn't have mass? The notion of mass changed after works from Lorentz, Einstein, Born and Eddington.

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[Lamnom]

You forgot to square the total energy in your formula. E^2= m^2 * C^4 + P^2 * C^2

[thattwodimensionalant]

Thanks for the great video man, great explanation. I got your point about the momentum of a photon not being dependant on mass because it’s a wave, but light has a particle-wave duality, so how does this apply to light as a particle?

[juancarlosf]

Great video! But I still don't understand what the frequency of a photon means in the real world? I just don't get it, how is it possible that there are radio waves the size of city? Does that mean that photon is that size? So what does the frequency of a photon really represent?

[otakuphoenix]

But don’t light actually stop moving at absolute zero, so then wouldn’t light have rest mass at absolute zero

[nugget]

Light has no mass however mass isn't the only way to store energy. Light stores energy as a wave made of electromagnetic force actually it can be said that light is basically a wave made of force and any force is potential energy.

[VikramKumar-ioso]

I am from India 🇮🇳 great explanation bro.

[ArkenGAMES]

Yeah but mass cannot be at rest either.
The only way where this would be possible is at the "real" center of the universe.

[mathieud]

So hf/c is the momentum of light? Then back to the original equation, is E = (hf/c)²*c² --> (hf)²? Is that correct? Thanks for your video.

[naziyakausar]

Can you please share me the literature source for which you extracted this information. It's really important to me since am working on an article realated to this concept

[esnevip]

So if light gets its intrinsic energy from its momentum, and in a vacuum all light moves at the same rate (c) how does the wavelength increase or decrease the energy of the light without also changing its momentum?

It's hurting my brain meat.

[Ashishkumar-gsmb]

If laser can cut a thing then why cant a light can move object. Light shoud have mass. There is way

[NicorenaudGaming]

I literally watched 2 of your videos and decided to subscribe I love this type of content. Keep up the good work future neil degrass tyson

[NaomiEsayas]

If we substitute the variables respectively according to the video, then E = rest mass which is zero multiplied by the energy due to the momentum. We know that any number multiplied by zero is zero. The equation eventually comes to E =0 so how does this work?!

[DeathRayGraphics]

Hmm. Should I trust someone who just spelled "relativistic" as "relativisitc"? I think I am going to assume that light has mass until you fix this.

[onemanarmy]

Love from india brooo I also have a passion of researching and want to become scientist Bro u have solved my greatest doubt ever thank u 'namaskar'

[nugget]

A simple explanation is that... Mass can be replaced by force. The forces of the universe: Strong, Weak, EM and gravity can store energy. Actually even mass is actually made of forces, it's a byproduct of the strong force. Therefore we should stop thinking in terms of mass and think in terms of force.

[aremijfaye]

What 's wrong with this: E=gamma*m*c^2
With a bit of manipulation we can get E^2 -v^2*E^2 /c^2=m^2 c^4
When v increases, the left hand side term decreases, which means the right hand side (m^2c^4) is decreasing. Which simply means the rest mass decreases. Does it mean an increase in velocity implies a decrease in rest mass? This explains why light has no mass

[toantran-gmcz]

So We must have mass to have a bigger mass . But where mass come from ?

[CuddleStories]

Badzilla is the opposite of Godzilla? But you didn't put is as devilzilla. You chose a characteristic to denote the opposite. So you believe God is good?

[vansf]

Only the nonexistent can be actually zero or nothing or an empty space as the way how such human-invented concepts are used by human limited knowledge to interpret the observed