The Concept Of Mass

[Moronium]

And it follows from that, energy = mass;  photons have energy therefore photons have mass.

 

 

But you appear to be ignoring the authorities cited in posts 64 & 65, here Popeye.  For example:

 

Light is composed of photons, so we could ask if the photon has mass.  The answer is then definitely "no": the photon is a massless particle.  According to theory it has energy and momentum but no mass, and this is confirmed by experiment to within strict limits.

 

 

You yourself go on on to say:

 

So, following the math this time, photons have no mass, no rest mass, no relativistic mass, no invariant mass, nothing, nada zip. They are massless particles, period.

 

 

You then note that:

 

In my humble opinion, this is all mathematical semantic...there is so much confusion out there.

 

 

As I said earlier, this is at least part of (but not all of) what causes me to be confused about the concept of "mass."  Is there any clear, unambiguous conception of it?

[Dubbelosix]

A few things in this previous posts has some crucial problems.

[Dubbelosix]

@ocean

[Moronium]

Well, energy is frame dependent.

 

Mass is invariant, not frame dependent.

 

The confusion comes from energy = mass in relativity

 

The resolution is that there is only one mass and we need to get away from using the term relativistic mass if you want to be a physicist.

 

I am an engineer, not a physicist so you shouldn't ask me any more questions and I shouldn't be answering them but even if you ask two physicists, you may get two different answers depending upon how old they are!

 

Good post, Popeye.  It seems that it is not "mass" which changes, but rather it's mathematical relationship to energy.  It's more appropriate to talk about "rest energy" than it is "rest mass."

 

Actually E=Mc2 is more precisely stated as Eo=Mc2 where Eo refers to the "rest energy."  When at rest, there is no "momentum." 

Edited April 13, 2019 by Moronium

[Vmedvil2]

Good post, Popeye.  It seems that it is not "mass" which changes, but rather it's mathematical relationship to energy.  It's more appropriate to talk about "rest energy" than it is "rest mass."

 

Actually E=Mc2 is more precisely stated as Eo=Mc2 where Eo refers to the "rest energy."

 

There proper equation for "Relativistic mass" is 

 

 

It is another one of those equations that Moronium won't agree with so there is no point in discussing it since he thinks relativity is flawed but none the less it follows the same form as the other relativity equations.

 

Expressed as Energy it becomes

 

 

 

Link further explaining this equation = http://spiff.rit.edu/classes/phys150/lectures/ke_rel/ke_rel.html

Edited April 13, 2019 by VictorMedvil

[Moronium]

There proper equation for "Relativistic mass" is...

 

It is another one of those equations that Moronium won't agree with so there is no point in discussing it since he thinks relativity is flawed but none the less it follows the same form as the other relativity equations.

 

 

Yeah, Vic. Your relativistic mass equation only refers to OBSERVED time, length, and mass.   Personally I'm not that interested in how some guy, some where, might "observe" something which is somewhere else.

 

I'm interested in what's physically happening objectively, not subjective "observation"

 

In truth the so-called "observer" observes none of those things.  He merely deduces them from dubious premises.

Edited April 13, 2019 by Moronium

[OceanBreeze]

Speaking of relativistic mass, even the father of relativity didn’t like the concept:

 

In a 1948 letter to Lincoln Barnett, Einstein wrote

 

"It is not good to introduce the concept of the mass of a body [math]M\quad =\quad \frac { m }{ \sqrt { 1-\frac { { v }^{ 2 } }{ { c }^{ 2 } }  }  }[/math] for which no clear definition can be given. It is better to introduce no other mass than `the rest mass' m. Instead of introducing M, it is better to mention the expression for the momentum and energy of a body in motion."

 

 

 

When physicists use the term "mass" these days they are (almost) always talking about the invariant rest mass.

 

Personally, I am not here to argue, if someone has their own personal preference for relativistic mass, there is no law against using that concept.

[Vmedvil2]

Speaking of relativistic mass, even the father of relativity didn’t like the concept:

 

In a 1948 letter to Lincoln Barnett, Einstein wrote

 

"It is not good to introduce the concept of the mass of a body [math]M\quad =\quad \frac { m }{ \sqrt { 1-\frac { { v }^{ 2 } }{ { c }^{ 2 } }  }  }[/math] for which no clear definition can be given. It is better to introduce no other mass than `the rest mass' m. Instead of introducing M, it is better to mention the expression for the momentum and energy of a body in motion."

 

 

 

When physicists use the term "mass" these days they are (almost) always talking about the invariant rest mass.

 

Personally, I am not here to argue, if someone has their own personal preference for relativistic mass, there is no law against using that concept.

 

In reality it doesn't matter which equation you use they both come to the same solution the PC one or the gamma equation both come to the same result that kinetic energy/momentum effects the total energy. Personally, I like the idea of "Relativistic Mass" it gives more information about the object in question such as the information dealing with the Strong Nuclear Force/Particles field changes as velocity increases that indeed the very nature of these fields are effected by movement, it gives a bridge between the Relativistic world and the Quantum World.

Edited April 13, 2019 by VictorMedvil

[Moronium]

Personally, I am not here to argue, if someone has their own personal preference for relativistic mass, there is no law against using that concept.

 

The objection seems to be that it is a dubious concept which creates confusion, Popeye.  But, as you say, there's no law against creating confusion.  If there was, we wouldn't have politicians. Or special relativity, for that matter.

Edited April 13, 2019 by Moronium

[ralfcis]

Here Moronium, this involves cartoon math for ya.

 

[Vmedvil2]

Any other questions? 

[Moronium]

Any other questions? 

 

OK, Vic, I'll bite.  Math aside, what does deduction (erroneously called "observation) have to with objective physical "reality?"

[Vmedvil2]

OK, Vic, I'll bite.  Math aside, what does deduction (erroneously called "observation) have to with objective physical "reality?"

Nothing, besides that proven ideas and theories with evidence can lend to the argument that you are right by their merit and evidence.

Edited April 13, 2019 by VictorMedvil

[Moronium]

Let me phrase that

 

Nothing, besides that proven ideas and theories with evidence can lend to the argument you are right.

 

Back to assuming that you are in possession of the TRUTH, eh, Vic?  The  assumption that the postulates of SR have been "proven" displays utter naivete, I'm afraid.

 

Let me put my question in a little more concrete terms.  Let's first drop YOUR assumptions, and assume this: 

 

1. Time does NOT change with motion (clocks do, sure, but not time).  You don't have to agree with this, just assume it.

 

How would that assumption affect all your math formulas?

Edited April 13, 2019 by Moronium

[Vmedvil2]

Let me phrase that

 

 

Back to assuming that you are in possession of the TRUTH, eh, Vic?  The  assumption that the postulates of SR have been "proven" displays utter naivete, I'm afraid.

 

Let me put my question in a little more concrete terms.  Let's first drop YOUR assumptions, and assume this: 

 

1. Time does NOT change with motion (clocks do, sure, but not time).  You don't have to agree with this, just assume it.

 

How would that assumption affect all your math formulas?

 

Basically, it would just remove something called Relativistic and (1-(V²/C²))^1/2 from many equations.

Edited April 13, 2019 by VictorMedvil

[Moronium]

1. Time does NOT change with motion (clocks do, sure, but not time).  You don't have to agree with this, just assume it.

 

 

It may help you to point out that this is the precise assumption made by QM, i.e. that time is absolute, not relative.

[Moronium]

Basically, it would just remove something called Relativistic and (1-V²/C²)^1/2 from many equations.

 

What would the physical effect be?

 

By the way, no it wouldn't do that.

Edited April 13, 2019 by Moronium