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Mass and Energy

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  Mass and Energy ram@zedat.fu-berlin.de (Stefan Ram) - 2026-01-01 16:19 +0000
    Re: Mass and Energy nospam@de-ster.demon.nl (J. J. Lodder) - 2026-01-01 22:38 +0100
    Re: Mass and Energy x <x@x.net> - 2026-01-02 10:03 -0800
    Re: Mass and Energy x <x@x.net> - 2026-01-02 10:06 -0800
      Re: Mass and Energy Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2026-01-02 21:07 +0100
    Re: Mass and Energy "Paul.B.Andersen" <relativity@paulba.no> - 2026-01-04 20:51 +0100
      Re: Mass and Energy Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2026-01-06 03:04 +0100
      Re: Mass and Energy Thomas Heger <ttt_heg@web.de> - 2026-01-06 09:15 +0100
        Re: Mass and Energy "Paul.B.Andersen" <relativity@paulba.no> - 2026-01-06 22:57 +0100
          Re: Mass and Energy Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2026-01-06 23:51 +0100
          Re: Mass and Energy "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2026-01-07 13:20 -0800
            Re: Mass and Energy "Chris M. Thomasson" <chris.m.thomasson.1@gmail.com> - 2026-01-07 13:29 -0800
            Re: Mass and Energy Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2026-01-07 22:53 +0100

#894860 — Mass and Energy

"Paul.B.Andersen" <relativity@paulba.no> wrote or quoted:
:that mass could be converted to energy as
:predicted by Einstein's E = mc².

  I can spot three mistakes here right off the bat.

       First, the phrase "mass could be converted to energy" is based on
  a misconception, since mass already /is/ a form of energy - there's no
  "conversion" happening. It's like saying, "water can be turned into a
  liquid" - no, water /is/ a liquid.

       Second, "E=mc^2" only applies to systems at rest. In general,
  it's "E^2=(mc^2)^2+(pc)^2", where "p" is the system's momentum. 
  (That basically says mass is the magnitude of the four-momentum.)

       Third, mass is conserved in nuclear fission. This point is often
  explained incorrectly, even in otherwise solid textbooks like Grif-
  fiths.

       I've laid out the full argument elsewhere, but here's the (suffi-
  cient) short version:

       Take a nucleus that's at rest, so its total momentum p=0.

       After fission, because momentum is conserved, the total momentum
  of all the fragments is still zero. That means the relation "E^2=(mc^2
  )^2+(pc)^2" simplifies to "E=mc^2" both before and after the split.

       Since energy is also conserved, the total energy E of the nucleus
  and its fragments - including their kinetic energy - stays the same,
  call it E. From "E=mc^2", it immediately follows: if E stays constant,
  m does too.

E_"before" = E_"after" - due to conservation of energy        (0)

E_"before" = m_"before" c^2 - as you said yourself            (1)

E_"after" = m_"after" c^2 - the same as (1), just later       (2)

m_"after" = m_"before" - substituting (1) and (2) into (0)    (3)
                         and dividing by c^2

  Only when you change what you call the "system", and treat the split 
  products separately, do you get systems with nonzero momentum and 
  find a mass defect and non-zero kinetic energies.

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#894861

Stefan Ram <ram@zedat.fu-berlin.de> wrote:

Please do not quote mine,
and please do not break threads,

Jan

> "Paul.B.Andersen" <relativity@paulba.no> wrote or quoted:
> :that mass could be converted to energy as
> :predicted by Einstein's E = mc?.
> 
>   I can spot three mistakes here right off the bat.

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#894868

On 1/1/26 08:19, Stefan Ram wrote:
 > "Paul.B.Andersen" <relativity@paulba.no> wrote or quoted:
 > :that mass could be converted to energy as
 > :predicted by Einstein's E = mc².
 >
 >    I can spot three mistakes here right off the bat.
 >
 >         First, the phrase "mass could be converted to energy" is based on
 >    a misconception, since mass already /is/ a form of energy - there's no
 >    "conversion" happening. It's like saying, "water can be turned into a
 >    liquid" - no, water /is/ a liquid.

The basic problem is that you think that 'science' is
'automatically true' and all you have to do is say
words that sound like 'science' and they are automatically
'true' because they 'sound like science'.

For your words to have value, you must care what is true.

I am skeptical that you care what is true.  I think that
your words can be dismissed as relatively valueless on
that basis.

I do not care if you play with the words 'water' and
'liquid'.  It is reasonable to consider your words
to be relatively meaningless because you do not care
what is true to begin with.

 > ...

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#894869

On 1/1/26 08:19, Stefan Ram wrote:
 > "Paul.B.Andersen" <relativity@paulba.no> wrote or quoted:
 > :that mass could be converted to energy as
 > :predicted by Einstein's E = mc².
 >
 >    I can spot three mistakes here right off the bat.
 >
 >         First, the phrase "mass could be converted to energy" is based on
 >    a misconception, since mass already /is/ a form of energy - there's no
 >    "conversion" happening. It's like saying, "water can be turned into a
 >    liquid" - no, water /is/ a liquid.

The basic problem is that you think that 'science' is
'automatically true' and all you have to do is say
words that sound like 'science' and they are automatically
'true' because they 'sound like science'.

For your words to have value, you must care what is true.

I am skeptical that you care what is true.  I think that
your words can be dismissed as relatively valueless on
that basis.

I do not care if you play with the words 'water' and
'liquid'.  It is reasonable to consider your words
to be relatively meaningless because you do not care
what is true to begin with.

 > ...

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#894870

x wrote:
> On 1/1/26 08:19, Stefan Ram wrote:
>  > "Paul.B.Andersen" <relativity@paulba.no> wrote or quoted:
>  > :that mass could be converted to energy as
>  > :predicted by Einstein's E = mc².
>  >
>  >    I can spot three mistakes here right off the bat.
>  >
>  >         First, the phrase "mass could be converted to energy" is based on
>  >    a misconception, since mass already /is/ a form of energy - there's no
>  >    "conversion" happening. It's like saying, "water can be turned into a
>  >    liquid" - no, water /is/ a liquid.

Correct.

> The basic problem is that you think that 'science' is
> 'automatically true' [...]

No, the problem is that you have no clue what you are talking about, but you
are too incompetent to realize that:

<https://en.wikipedia.org/wiki/Dunning–Kruger_effect>

Also, you have posted this twice.

-- 
PointedEars

Twitter: @PointedEars2
Please do not cc me. / Bitte keine Kopien per E-Mail.

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#894890

Den 01.01.2026 17:19, skrev Stefan Ram:
> "Paul.B.Andersen" <relativity@paulba.no> wrote or quoted:
> :that mass could be converted to energy as
> :predicted by Einstein's E = mc².

I resent very much that you:
1. Break threads so it is impossible to see to what you are responding.
2. Paraphrase and not quote.

I can guess that you were responding to my statement:
  "The atom bomb proved in a very convincing way
   that mass could be converted to energy as
   predicted by Einstein's E = mc²."

This statement isn't very precise, but not wrong.
So let's look at a more precise statement about
what is happening in an atomic fission bomb:

One possible fission process is:

1n + U-235 → Ba-141 + Kr-92 + 3n

The atomic weight (mass) of these are:

Left side:
1n      1.008664  u
U-235 235.0439299 u
-------------------
       236.0525939 u = 3.919748214E-25 kg

Right side:
Ba-141   140.914412 u
Kr-92     91.926156 u
3n         3.025992 u
---------------------
          235.866560 u = 3.916659047E-25 kg

Lost mass: m = 0.1860339 u = 3.089167695E-28 kg

E = mc² ≈ 2.776404839E-11 J

> 
>    I can spot three mistakes here right off the bat.
> 
>         First, the phrase "mass could be converted to energy" is based on
>    a misconception, since mass already /is/ a form of energy - there's no
>    "conversion" happening. It's like saying, "water can be turned into a
>    liquid" - no, water /is/ a liquid.

Note that m = 3.089167695E-28 kg is the _lost_ mass,
it doesn't exist any more.
So where has it gone?
It is converted to E = mc² ≈ 2.776404839E-11 J of _kinetic energy_.
Kinetic energy is not mass. Thus "convert".

> 
>         Second, "E=mc^2" only applies to systems at rest. In general,
>    it's "E^2=(mc^2)^2+(pc)^2", where "p" is the system's momentum.
>    (That basically says mass is the magnitude of the four-momentum.)

E = mc² is the energy content, or the energy equivalent of
the mass m. Mass is invariant, so this equation is valid for
all speeds of the mass.

However, the _total_ energy of a moving mass is:
E = mγc² = mc² + (γ-1)mc²
The first term mc² is the invariant energy content of the mass m,
the second term is the kinetic energy of the mass m.
Kinetic energy is not mass!

> 
>         Third, mass is conserved in nuclear fission. This point is often
>    explained incorrectly, even in otherwise solid textbooks like Grif-
>    fiths.

Could it be that you are wrong and the textbook is right? :-D

Before the fission the mass of the U-235 nucleus + 1 neutron
is: m₁ = 3.919748214E-25 kg

After the fission the mass of the Ba-141 and Kr-92 nuclei + 3 neutrons
is: m₂ = 3.916659047E-25 kg.

So the mass isn't conserved, m = m₁-m₂= 3.089167695E-28 kg has
disappeared because it is converted to kinetic energy which is not mass.

The energy is conserved, though.

Energy before fission:
Energy content of mass m₁ = m₁c² = 3.522894007E-8 J
Total energy before fission E₁ = 3.522894007E-8 J

Energy after fission:
Energy content of mass m₂     E  = m₂c²      = 3.520117602E-8 J
Kinetic energy from lost mass K  = (m₁-m₂)c² = 2.776404839E-11 J
Total energy after fission    E₂ = E + K     = 3.522894007E-8

E₁ = E₂ energy conserved


-- 
Paul

https://paulba.no/

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#894897

Paul.B.Andersen wrote:
> Note that m = 3.089167695E-28 kg is the _lost_ mass,
> it doesn't exist any more.
> So where has it gone?
> It is converted to E = mc² ≈ 2.776404839E-11 J of _kinetic energy_.
> Kinetic energy is not mass. Thus "convert".

/Non sequitur./

>>         Second, "E=mc^2" only applies to systems at rest. In general,
>>    it's "E^2=(mc^2)^2+(pc)^2", where "p" is the system's momentum.
>>    (That basically says mass is the magnitude of the four-momentum.)
> 
> E = mc² is the energy content, or the energy equivalent of
> the mass m.

The first wording is simply wrong.  E (better: E₀) is the *rest* energy of
_an object_ whose mass is m.  One can also call that the energy content _of
that object_ at relative rest (as Einstein did, but this wording is
obsolete), but NOT "of the mass".  Mass is a quantity, not a object; a
quantity has no content.

> Mass is invariant, so this equation is valid for all speeds of the mass.

Again, mass is a quantity, NOT an object.  It does not make sense to say
"speeds of the mass".  That makes as much sense as e.g. "mass of the charge".

> However, the _total_ energy of a moving mass is:
> E = mγc² = mc² + (γ-1)mc²
> The first term mc² is the invariant energy content of the mass m,

No, the first term is the rest energy equivalent to the mass m.

Mass does not have an energy content, _objects_ have.

> the second term is the kinetic energy of the mass m.

No, it is the kinetic energy of an _object_ with mass m and relative speed
v, hidden in γ = γ(v).

> Kinetic energy is not mass!

And mass is NOT energy or "has energy".  You would be well to realize that.

>>         Third, mass is conserved in nuclear fission. This point is often
>>    explained incorrectly, even in otherwise solid textbooks like Grif-
>>    fiths.
> 
> Could it be that you are wrong and the textbook is right? :-D

He is wrong, obviously.  But you are also wrong in multiple respects:

> Before the fission the mass of the U-235 nucleus + 1 neutron
> is: m₁ = 3.919748214E-25 kg
> 
> After the fission the mass of the Ba-141 and Kr-92 nuclei + 3 neutrons
> is: m₂ = 3.916659047E-25 kg.
> 
> So the mass isn't conserved,

Correct.

> m = m₁-m₂= 3.089167695E-28 kg has disappeared because it is converted to
> kinetic energy which is not mass.

Again: NOT the mass is partially converted to kinetic energy, but the rest
energy E_0 = m c^2 *equivalent to* the mass m.

-- 
PointedEars

Twitter: @PointedEars2
Please do not cc me. / Bitte keine Kopien per E-Mail.

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#894898

Am Sonntag000004, 04.01.2026 um 20:51 schrieb Paul.B.Andersen:
> Den 01.01.2026 17:19, skrev Stefan Ram:
>> "Paul.B.Andersen" <relativity@paulba.no> wrote or quoted:
>> :that mass could be converted to energy as
>> :predicted by Einstein's E = mc².
> 
> I resent very much that you:
> 1. Break threads so it is impossible to see to what you are responding.
> 2. Paraphrase and not quote.
> 
> I can guess that you were responding to my statement:
>   "The atom bomb proved in a very convincing way
>    that mass could be converted to energy as
>    predicted by Einstein's E = mc²."
> 
> This statement isn't very precise, but not wrong.
> So let's look at a more precise statement about
> what is happening in an atomic fission bomb:
> 
> One possible fission process is:
> 
> 1n + U-235 → Ba-141 + Kr-92 + 3n
> 
> The atomic weight (mass) of these are:
> 
> Left side:
> 1n      1.008664  u
> U-235 235.0439299 u
> -------------------
>        236.0525939 u = 3.919748214E-25 kg
> 
> Right side:
> Ba-141   140.914412 u
> Kr-92     91.926156 u
> 3n         3.025992 u
> ---------------------
>           235.866560 u = 3.916659047E-25 kg
> 
> Lost mass: m = 0.1860339 u = 3.089167695E-28 kg
> 
> E = mc² ≈ 2.776404839E-11 J
> 
>>
>>    I can spot three mistakes here right off the bat.
>>
>>         First, the phrase "mass could be converted to energy" is based on
>>    a misconception, since mass already /is/ a form of energy - there's no
>>    "conversion" happening. It's like saying, "water can be turned into a
>>    liquid" - no, water /is/ a liquid.
> 
> Note that m = 3.089167695E-28 kg is the _lost_ mass,
> it doesn't exist any more.
> So where has it gone?
> It is converted to E = mc² ≈ 2.776404839E-11 J of _kinetic energy_.
> Kinetic energy is not mass. Thus "convert".
> 
>>
>>         Second, "E=mc^2" only applies to systems at rest. In general,
>>    it's "E^2=(mc^2)^2+(pc)^2", where "p" is the system's momentum.
>>    (That basically says mass is the magnitude of the four-momentum.)
> 
> E = mc² is the energy content, or the energy equivalent of
> the mass m. Mass is invariant, so this equation is valid for
> all speeds of the mass.

You contradicted yourself!!

Here your claim is, that mass is invariant, while a little below you 
claim, that energy is conserved, while mass has vanished from a 
radioactive sample.

But you can't keep both claims, because they contradict each other.

So let's keep energy and regard matter as some strange form of energy.

I actually had this idea long ago and wrote kind of book about it:

https://docs.google.com/presentation/d/1Ur3_giuk2l439fxUa8QHX4wTDxBEaM6lOlgVUa0cFU4/edit?usp=sharing

(As proof of concept I had 'Growing Earth' in mind.)


TH

...

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#894899

Den 06.01.2026 09:15, skrev Thomas Heger:
> Am Sonntag000004, 04.01.2026 um 20:51 schrieb Paul.B.Andersen:
>>
>> E = mc² is the energy content, or the energy equivalent of
>> the mass m. Mass is invariant, so this equation is valid for
>> all speeds of the mass.
> 
> You contradicted yourself!!
> 
> Here your claim is, that mass is invariant, while a little below you 
> claim, that energy is conserved, while mass has vanished from a 
> radioactive sample.
> 
> But you can't keep both claims, because they contradict each other.


Invariant means "the same in all frames of reference"
or "independent of speed".

It does _not_ mean "constant".

Mass is invariant.
The mass of an object is the same in all frames of reference.
The mass of an object does not depend on the speed of the object.

But mass can change. Heat the object, and its mass will increase,

I have told you before, but I know you will not learn.
You never do.


-- 
Paul

https://paulba.no/

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#894900

Paul.B.Andersen wrote:
> Den 06.01.2026 09:15, skrev Thomas Heger:
>> Am Sonntag000004, 04.01.2026 um 20:51 schrieb Paul.B.Andersen:
>>> E = mc² is the energy content, or the energy equivalent of
>>> the mass m. Mass is invariant, so this equation is valid for
>>> all speeds of the mass.
>>
>> You contradicted yourself!!
>>
>> Here your claim is, that mass is invariant, while a little below you 
>> claim, that energy is conserved, while mass has vanished from a 
>> radioactive sample.
>>
>> But you can't keep both claims, because they contradict each other.
> 
> Invariant means "the same in all frames of reference"
> or "independent of speed".

That is what *you* mean by it *here*, NOT what it *generally* means.

What *you* mean *here* is more precisely called "_Lorentz_-invariant".


F'up2 sci.physics.relativity
-- 
PointedEars

Twitter: @PointedEars2
Please do not cc me. / Bitte keine Kopien per E-Mail.

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#894903

On 1/6/2026 1:57 PM, Paul.B.Andersen wrote:
> Den 06.01.2026 09:15, skrev Thomas Heger:
>> Am Sonntag000004, 04.01.2026 um 20:51 schrieb Paul.B.Andersen:
>>>
>>> E = mc² is the energy content, or the energy equivalent of
>>> the mass m. Mass is invariant, so this equation is valid for
>>> all speeds of the mass.
>>
>> You contradicted yourself!!
>>
>> Here your claim is, that mass is invariant, while a little below you 
>> claim, that energy is conserved, while mass has vanished from a 
>> radioactive sample.
>>
>> But you can't keep both claims, because they contradict each other.
> 
> 
> Invariant means "the same in all frames of reference"
> or "independent of speed".
> 
> It does _not_ mean "constant".
> 
> Mass is invariant.
> The mass of an object is the same in all frames of reference.
> The mass of an object does not depend on the speed of the object.
> 
> But mass can change. Heat the object, and its mass will increase,
> 
> I have told you before, but I know you will not learn.
> You never do.
> 
> 

Its odd to think of a cup of water as the water evaporates. The cup is 
an object with its own mass. But, now its holding water. So, the cup 
"weighs" more in a sense... But, as the water evaporates, that weight 
will go back to the weight of the original cup...

Think of two equal mass cups on a scale. They balance. Add water to one, 
its not balanced. However, the water will evaporate and the scale shall 
go back to balanced over time?

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#894904

On 1/7/2026 1:20 PM, Chris M. Thomasson wrote:
> On 1/6/2026 1:57 PM, Paul.B.Andersen wrote:
>> Den 06.01.2026 09:15, skrev Thomas Heger:
>>> Am Sonntag000004, 04.01.2026 um 20:51 schrieb Paul.B.Andersen:
>>>>
>>>> E = mc² is the energy content, or the energy equivalent of
>>>> the mass m. Mass is invariant, so this equation is valid for
>>>> all speeds of the mass.
>>>
>>> You contradicted yourself!!
>>>
>>> Here your claim is, that mass is invariant, while a little below you 
>>> claim, that energy is conserved, while mass has vanished from a 
>>> radioactive sample.
>>>
>>> But you can't keep both claims, because they contradict each other.
>>
>>
>> Invariant means "the same in all frames of reference"
>> or "independent of speed".
>>
>> It does _not_ mean "constant".
>>
>> Mass is invariant.
>> The mass of an object is the same in all frames of reference.
>> The mass of an object does not depend on the speed of the object.
>>
>> But mass can change. Heat the object, and its mass will increase,
>>
>> I have told you before, but I know you will not learn.
>> You never do.
>>
>>
> 
> Its odd to think of a cup of water as the water evaporates. The cup is 
> an object with its own mass. But, now its holding water. So, the cup 
> "weighs" more in a sense... But, as the water evaporates, that weight 
> will go back to the weight of the original cup...
> 
> Think of two equal mass cups on a scale. They balance. Add water to one, 
> its not balanced. However, the water will evaporate and the scale shall 
> go back to balanced over time?

LOL! Think if the cups were made of paper. The water itself might break 
down the cup and parts of the cup would wash away...

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#894905

Chris M. Thomasson wrote to sci.physics.relativity and sci.physics:
> Its odd to think of a cup of water as the water evaporates. The cup is 
> an object with its own mass. But, now its holding water. So, the cup 
> "weighs" more in a sense...

The mass of the cup only has increased because when we say "cup" now we mean
the substance of the cup *and* the water.

> But, as the water evaporates, that weight will go back to the weight of
> the original cup...

That is only true if the water actually leaves the cup.  Put a lid on the
cup so that the water cannot escape, and the mass of the water-filled cup
will not decrease.

But, more relevant to this discussion, by increasing the rest energy of the
water(-filled cup) by increasing the kinetic energy of the water molecules
(and to some extent the substance of the cup, too) by heating the
water(-filled cup), the mass of the water(-filled cup) increases slightly
(probably unmeasurably, given m = E_0/c^2).

See also the videos that I referred to in
<mid:10j721n$1i2q$1@gwaiyur.mb-net.net>.

> Think of two equal mass cups on a scale. They balance. Add water to one, 
> its not balanced. However, the water will evaporate and the scale shall 
> go back to balanced over time?

If the water *leaves* the cup, yes.

Notice also that what you are measuring there is weight, not mass.  That is,
this is only an indirect determination of mass that depends on gravitation,
therefore the assumption of a uniform gravitational field (which we know is
not so, but just a relatively good approximation near the surface).

F'up2 sci.physics.relativity

-- 
PointedEars

Twitter: @PointedEars2
Please do not cc me. / Bitte keine Kopien per E-Mail.

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