An object travelling at the speed of light would have infinite mass. So...

An object travelling at the speed of light would have infinite mass. So, why don't we say that photons have infinite mass? Is it because it functions as a wave instead of a particle? Or is it just because infinite mass would imply infinite volume?

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It's duality phenomena

photons aren't objects like you're thinking of

>Infinite mass

Infinite momentum? How does it even work with the mechanics we know? Or is it guarded by something like: achieving c would also demand infinite amount of energy delivered.

>infinite mass implies infinite volume

Since you clearly don't know what the concept of density is, I'm going to assume you are in high school and disregard your question because eventually, as your education level grows, the answers will come as a consequence of higher understanding.

So I would advise you to research your premises and make sure you understand what you think you understand about your premises.

>An object travelling at the speed of light would have infinite mass.
This is not true. An object's mass is defined by its total energy in its rest frame. It doesn't matter how fast it's moving relative to another object; it is always stationary in its own reference frame, by definition. Mass is independent of velocity. It is Lorentz invariant; it does not transform.

>An object travelling at the speed of light would have infinite mass.
at c, mass= rest mass * infinity

>why don't we say that photons have infinite mass?
They have zero rest mass, so...
mass = zero * infinity

...obviously this is wrong, but I'm moderatly drunk, my marriage is falling apart, and I'm a little hungry, but I can't decide what to eat.

I'd like to go out and get something a little special, but I had Japanese steak house for lunch (which is a fuckhuge meal), and I'm kinda trying to lose weight, but why? my wife is such a horrible bitch, why shouldn't i get a little fat?
fuck her...


thoughts?

fuck it, I'm going to the store and getting a frozen pizza

>fuck it, I'm going to the store and getting a frozen pizza
update: I went out and decided to get Quizno's instead.
But they were closed, so I kept driving.
Saw chick-fil-a, but they're closed on Sundays.
Wound up at McDonalds.

I forgot mass is actually a measure of inertia rather than a measure of "stuff". My bad

Op here
So does a photon have essentially infinite inertia then, since c is constant?

What did you order?

The (rest) mass of an object does not change when it accelerates. The notion of "apparent mass" is horribly confusing, and no one uses it any more.

You might know the equation
E = m c^2
The full equation is actually:
E^2 = m^2 c^4 + p^2 c^2
where "p" is momentum. Photons have zero (rest) mass, aka m = 0. Photons do have non-zero momentum, aka p > 0.

>The notion of "apparent mass" is horribly confusing, and no one uses it any more.
To be clear, I meant to use the term "relativistic mass". No one uses the concept of "relativist mass" anymore.

Rest mass would be noted as M with a subscript zero (not sure how to do that on my phone), right? And the M in E=mc^2 is not rest mass?

E = m c^2 is incomplete. It only describes objects without momentum. Photons have zero mass, but they have energy, ergo E = m c^2 cannot describe photons. E^2 = m^2 c^4 + p^2 c^2 is the full equation.

K, I think I more or less understand, thanks

Also, it is true that if find the equation for the amount of energy to accelerate a piece of matter from 0 to X, and if you take the limit of "as X to c", then the resulting limit is "infinity".

>What did you order?
Big Mac combo, medium sized,
Had a Dr. Pepper with it.

If light has no mass then wouldn't E = MC^2 mean that E = 0? Also how tf did we even find out the speed of light in the first place? Did some guy just say ayyo 3 hunny mill yo and then we accepted it, what happened

>An object travelling at the speed of light would have infinite mass. So, why don't we say that photons have infinite mass?

Because photons have no INERTIAL mass. They have a mass-energy equivalence but that's a very different thing.

i love this thread

No an object travelling at the speed of light either must have no mass or infinite energy.

E=mc2 is only true for objects at rest.

Too many calories in the soda. Shame on you for all that sugar!

Photons have no mass
>0 × infinity = 0

∞ is not a thing in physics.

memes

i like you

Not a physicist here, but my guess is, infinity isnt a thing because its an idea, not real?

lol what

how the fuck did you come to this conclusion

Dude, sorry about your marriage. I truly hope you manage to fix that, even if it means leaving your bitch wife

Is everyone in this thread in highschool or what. Read this
math.ucr.edu/home/baez/physics/ParticleAndNuclear/photon_mass.html
For a very basic answer

>mass changes with increasing relativistic speeds

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