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Author Topic: Are mass and energy really interchangeable?  (Read 19887 times)

Offline PmbPhy

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Re: Are mass and energy really interchangeable?
« Reply #50 on: 14/06/2014 03:33:24 »
Quote from: lightarrow
We had a lot of threads about mass in this forum.
And you’ve been ignoring the other definition of mass which is widely used and what is confusing mxplxxx who wrote It is like saying energy is mass*speed of light squared to which you responded I wish you could! To define energy in general is not so simple, my friend!, the accuracy of which depends on which definition of mass one is referring to. Did you ever tell him that there actually is a definition for which his statement is true?

All one has to do is look at the definitions of two main sources on the internet for physics information, i.e. the Usenet Physics FAQ
http://math.ucr.edu/home/baez/physics/Relativity/SR/mass.html
and Wikipedia
http://en.wikipedia.org/wiki/Mass_in_special_relativity
http://en.wikipedia.org/wiki/Mass%E2%80%93energy_equivalence


Quote from: lightarrow
But, as I and others have already written to you, ..
But not all of us. You left the opposing side out, i.e. me. In which case your assertion
Quote from: lightarrow
if the system it's not still, its energy is not its mass multiplied c2.
Quote
is wrong.
 

Offline lightarrow

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Re: Are mass and energy really interchangeable?
« Reply #51 on: 14/06/2014 19:52:54 »
Quote from: lightarrow
Because (and Einstein exploited this fact in GR) gravitational mass and inertial mass are the same thing.
Let’s be precise about this. Inertial mass, which I’ll label mi is not the same thing as gravitational mass. They are not identical, they are proportional.
What follows is how this is all explained in the physics literature, not merely something I came up with. Although it is something I highly agree with.
Einstein used the emperical fact that the inertial mass of an object is proportional to the bodies passive gravitational mass which I’ll label as mp. This is the mass on which gravity acts. If we let active gravitational mass as ma, which is the source of gravity. The gravitational force on the body due to the source, Fg, is then
Fg = Kmamp/r^2
where K is a constant of proportionality. Then since Fg = mai
a = (mp/mi)Kma/r^2
What Einstein exploited was the fact that there exists some constant c such that
mp = c*mi
a = (cmi/mi)Kma/r^2
a = cKma/r^2
Define the constant G = cK and call it the gravitational constant. Then
a = Gma/r^2
Good. And which is the value of that constant c = mp/mi? Which kind of experiment allow/will allow us to measure it?

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Offline lightarrow

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Re: Are mass and energy really interchangeable?
« Reply #52 on: 14/06/2014 19:53:59 »
Quote from: lightarrow
We had a lot of threads about mass in this forum.
And you’ve been ignoring the other definition of mass which is widely used and what is confusing mxplxxx who wrote It is like saying energy is mass*speed of light squared to which you responded I wish you could! To define energy in general is not so simple, my friend!, the accuracy of which depends on which definition of mass one is referring to. Did you ever tell him that there actually is a definition for which his statement is true?
mxplxxx wrote:
<<Returning to my original question, E (kg⋅m2/s2) = m (kg) c (m/s)2 looks remarkably like a units conversion to me! Is mass just concentrated energy? >>
and I replied that we had a lot of threads about mass, so he could look for them and understand that E = mc2 is not simply a units conversion. You don't agree with me? I thought you did.
And about the fact "mass is just concentrated energy" you agree with him?
About what you wrote I intentionally didn't want to argue with you, infact in my replies to him I have used the (generally accepted in modern physics) same equation that you mentioned in one of your first posts of this thread:

E2 = (cp)2 + (mc2)2.

You want to say that it's possible to write E = Mc2 if M is the "relativistic mass"? Say it, if you like.

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« Last Edit: 14/06/2014 19:55:38 by lightarrow »
 

Offline PmbPhy

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Re: Are mass and energy really interchangeable?
« Reply #53 on: 15/06/2014 08:53:12 »
Quote from: lightarrow
..and I replied that we had a lot of threads about mass, so he could look for them and understand that E = mc2 is not simply a units conversion.
And not only do people never do that but if they tried it'd probably be too hard to find, especially the points that needed to be made.

Quote from: lightarrow
You don't agree with me? I thought you did.
Of course I agree with that.

Quote from: lightarrow
And about the fact "mass is just concentrated energy" you agree with him?
Of course not. There is nothing in anything that I've ever posted in this forum that indicates otherwise on these last two points.

I suggest that you try not to be so adverse to when others think that the entire story needs to be explicitly stated rather than assume the reader can dig out the point they wish to make by a vauge suggestion to "search the forum for mass."
 

Offline lightarrow

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Re: Are mass and energy really interchangeable?
« Reply #54 on: 15/06/2014 14:14:15 »
I suggest that you try not to be so adverse to when others think that the entire story needs to be explicitly stated rather than assume the reader can dig out the point they wish to make by a vauge suggestion to "search the forum for mass."
But on the fact "the entire story needs to be explicitly stated" I certainly agree. I suggested him to look for other threads just because I didn't want to write again what I (and you and others) have already written many times about what he needed to know.

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Offline PmbPhy

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Re: Are mass and energy really interchangeable?
« Reply #55 on: 15/06/2014 15:03:08 »
Quote from: lightarrow
But on the fact "the entire story needs to be explicitly stated" I certainly agree. I suggested him to look for other threads just because I didn't want to write again what I (and you and others) have already written many times about what he needed to know.

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I know and fully agree. Unfortunately people like him never do that.
 

Offline yor_on

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Re: Are mass and energy really interchangeable?
« Reply #56 on: 22/06/2014 06:30:14 »
This was a weird read :)

Interesting but weird. A constant is a constant, and it's there, until proven wrong. Physics doesn't once and for all define anything to be 'true for ever', and that goes for everything. Well, as far as I get it at least. When it comes to Planck's constant it's exactly as Pete write. It's a mathematical concept from the beginning to make a possible explanation (black body radiation in this case) for a otherwise very strange behavior. And it has been tested innumerable times and found valid. To call it some kind of 'action'? I don't know? I prefer to think of it as a constant defining a behavior myself. Then again, I'm very partial to constants, you might call me a believer :)

And it's nice to see you writing again Lightarrrow, long time no see.
 

Offline lightarrow

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Re: Are mass and energy really interchangeable?
« Reply #57 on: 25/06/2014 20:14:38 »
And it's nice to see you writing again Lightarrrow, long time no see.
Thank you, yor_on, the same for me about you.
Unfortunately I have just little time to write in this forum.
Bye!

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Offline Mortenson

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Re: Are mass and energy really interchangeable?
« Reply #58 on: 06/07/2014 20:32:01 »
 Hi All - thought I would throw my two cents worth in.  Planck ORIGINALLY worked on electromagnetic theory with energy, an energy constant (energy/EM oscillation), measurement time (of the EM irradiation) and frequency (osc/sec).  His original relationship was thus E = energy constant X measurement time X frequency.

When he wrote his famous paper deriving the formula for black-body radiation, he had to resort to the use of Boltzmann's methods (Planck was not very fond of Boltzman) and this in turn caused him to multiply his original energy constant and measurement time into the single value "h".

The product of energy and time is called "action"  so Planck's constant "h" was and is referred to as an action constant.  Planck didn't really like it at first as he had an energy constant in mind, not an action constant.  It produced the odd result that the fundamental particle of light came in an infinite variety of energies, rather than having a constant defining energy ... a defining constant characteristic such as the charge on an electron.  The units didn't balance either because the "oscillations" in frequency (osc/sec) were unbalanced.

But the number worked and people started using his equation so he went with it.

If we restore his original formula we have E = E/osc X measurement time (sec) X frequency (osc/sec).  Units balance and total energy can be determined.  If you irradiate for 2 seconds instead of one you measure twice as much energy.  The energy constant from Planck's original formulation turns out to be the energy of a single EM oscillation.  The energy is conserved over time and space, and appears to be therefore the true quantum of energy for EM waves.

Because the units did not balance in Planck's condensed E = hf, the engineers and scientists got together back in the thirties and officially changed the nomenclature for frequency from osc/sec to sec-1.  That got rid of the pesky oscillations hanging out of the equation and everything balanced. 

So far so good, but it was incomplete mathematical notation and that never helps anything.  Kind of like describing your miles per hour speed as just hour-1.  You would have to start putting in a lot of fudge factors to account for the fact that it was miles and not kilometers or yards you were measuring.  Same thing happened in quantum mechanics.  More and more fudge factors had to be brought because the foundational quantum equation was abbreviated and incomplete in a mathematical sense.

A lot of the problems in quantum mechanics go away if one uses Planck's original and complete quantum formula.
 

Offline PmbPhy

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Re: Are mass and energy really interchangeable?
« Reply #59 on: 06/07/2014 22:22:23 »
Quote from: Mortenson
The product of energy and time is called "action"…
That is incorrect. You’re confused. There are only two quantities which carry the name action and they are I = Integral L dt where L = Kinetic Energy – Potential Energy = T – V. The other is Integral pdq = nh where n is an integer and h is Planck’s constant. It’s this later integral from the Old Quantum Mechanics that it got one of its alternative names quantum of action. Just because something has the units of action you can’t say that it “is” action. So to be correct product of energy and time is “has units of action.”

Quote from: Mortenson
…  so Planck's constant "h" was and is referred to as an action constant.
That’s incorrect. It was referred to as the “quantum of action.

Quote from: Mortenson
Planck didn't really like it at first as he had an energy constant in mind, not an action constant.  It produced the odd result that the fundamental particle of light came in an infinite variety of energies, rather than having a constant defining energy ... a defining constant characteristic such as the charge on an electron. 
Planck postulated that the walls of a black body could be modeled as being composed of harmonic oscillators. However it was Einstein who postulated that light was quantized.
 

Offline Mortenson

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Re: Are mass and energy really interchangeable?
« Reply #60 on: 08/07/2014 21:58:43 »
Thanks for your thoughtful response PmbPhy.  I am just using the language that Planck and Einstein and the other fathers of quantum language used.  Maybe the translations from German to English are off a little, but I would encourage you to go back and read some of the original papers.  Fascinating reading!

I stumbled across Planck's original relationship a bit by accident.  After digging back through all his old papers and his quantum derivation, I wrote it all up in a nice paper.  Hans Peter Duerr and I (Hans Peter ... Director Emeritus Max Planck Institute for Physics, and Heisenberg protege) sat down together and went through the mathematics step by step.  Afterwards he smiled and said in his wonderful German accent, "Well your mathematics are correct ... the question now is the interpretation!" 

Interestingly, Hans Peter had not read Planck's original papers, and I suspect many other physicists have not read them either.  When I presented the work at the annual APS meeting, there was only one physicist in the audience who had read any of them!

The point is that if we use Planck's ORIGINAL relationship, we gain many more degrees of freedom.  Measurement time is no longer a standardized value of 1 second.  And the clear chemical and materials effects of EM radiation below the molecular bond threshhold (IR, MW and RF) no longer violate quantum relationships.  We suddenly have a real constant for light that is conserved over time and space, yielding a wonderful candidate for the fundamental quantum of light.  When you think it through, many of the paradoxes - those that Heisenberg, Bohr and others struggled with - just dissappear!

So Planck's complete equation has many interesting applications.

PS - The cites to the original papers by Planck, Einstein and others can be found in my papers at newbielink:http://www.EinsteinsHiddenVariables.com [nonactive].  The mathematics I reviewed with Hans Peter are laid out in good detail in papers #1 and #2.
 

Offline mxplxxx

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Re: Are mass and energy really interchangeable?
« Reply #61 on: 01/09/2014 02:21:32 »
I guess we should ask the question "what attribute(s) of mass distinguish it from energy?". Is it in fact a type of particle?
 

Offline PmbPhy

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Re: Are mass and energy really interchangeable?
« Reply #62 on: 01/09/2014 06:16:17 »
Quote from: Mortenson
Maybe the translations from German to English are off a little, but I would encourage you to go back and read some of the original papers.  Fascinating reading!
Thanks, by I've already read them.  :)

 

Offline lightarrow

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Re: Are mass and energy really interchangeable?
« Reply #63 on: 02/09/2014 16:41:44 »
PS - The cites to the original papers by Planck, Einstein and others can be found in my papers at www.EinsteinsHiddenVariables.com.  The mathematics I reviewed with Hans Peter are laid out in good detail in papers #1 and #2.
Juliana, I'm not a scientist but I would like to read the slides you cite in your homepage but those links don't work. I have downloaded the pdf documents in the page "links" to read them. Are they the same of the slides?

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Re: Are mass and energy really interchangeable?
« Reply #63 on: 02/09/2014 16:41:44 »

 

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