• Mass and Energy

    From ram@ram@zedat.fu-berlin.de (Stefan Ram) to sci.physics.relativity,sci.physics on Thu Jan 1 16:19:52 2026
    From Newsgroup: sci.physics

    "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.

    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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  • From nospam@nospam@de-ster.demon.nl (J. J. Lodder) to sci.physics.relativity,sci.physics on Thu Jan 1 22:38:13 2026
    From Newsgroup: sci.physics

    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    Please do not quote mine,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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  • From x@x@x.net to sci.physics.relativity,sci.physics on Fri Jan 2 10:03:39 2026
    From Newsgroup: sci.physics

    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 = mc-#.

    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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  • From x@x@x.net to sci.physics.relativity,sci.physics on Fri Jan 2 10:06:35 2026
    From Newsgroup: sci.physics

    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 = mc-#.

    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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  • From Thomas 'PointedEars' Lahn@PointedEars@web.de to sci.physics.relativity,sci.physics on Fri Jan 2 21:07:29 2026
    From Newsgroup: sci.physics

    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 = mc-#.

    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/DunningrCoKruger_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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  • From Paul.B.Andersen@relativity@paulba.no to sci.physics.relativity,sci.physics on Sun Jan 4 20:51:49 2026
    From Newsgroup: sci.physics

    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 = mc-#.

    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 = mc-#."

    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 raA 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 = mc-# ree 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 = mc-# ree 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 = mc-# 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 = m+|c-# = mc-# + (+|-1)mc-#
    The first term mc-# 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: mreU = 3.919748214E-25 kg

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

    So the mass isn't conserved, m = mreU-mree= 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 mreU = mreUc-# = 3.522894007E-8 J
    Total energy before fission EreU = 3.522894007E-8 J

    Energy after fission:
    Energy content of mass mree E = mreec-# = 3.520117602E-8 J
    Kinetic energy from lost mass K = (mreU-mree)c-# = 2.776404839E-11 J
    Total energy after fission Eree = E + K = 3.522894007E-8

    EreU = Eree energy conserved
    --
    Paul

    https://paulba.no/
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  • From Thomas 'PointedEars' Lahn@PointedEars@web.de to sci.physics.relativity,sci.physics on Tue Jan 6 03:04:28 2026
    From Newsgroup: sci.physics

    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 = mc-# ree 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 = mc-# is the energy content, or the energy equivalent of
    the mass m.

    The first wording is simply wrong. E (better: EreC) 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 = m+|c-# = mc-# + (+|-1)mc-#
    The first term mc-# 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 +| = +|(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: mreU = 3.919748214E-25 kg

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

    So the mass isn't conserved,

    Correct.

    m = mreU-mree= 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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  • From Thomas Heger@ttt_heg@web.de to sci.physics.relativity,sci.physics on Tue Jan 6 09:15:55 2026
    From Newsgroup: sci.physics

    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 = mc-#.

    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:
    -a"The atom bomb proved in a very convincing way
    -a that mass could be converted to energy as
    -a predicted by Einstein's E = mc-#."

    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 raA Ba-141 + Kr-92 + 3n

    The atomic weight (mass) of these are:

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

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

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

    E = mc-# ree 2.776404839E-11 J


    -a-a I can spot three mistakes here right off the bat.

    -a-a-a-a-a-a-a First, the phrase "mass could be converted to energy" is based on
    -a-a a misconception, since mass already /is/ a form of energy - there's no >> -a-a "conversion" happening. It's like saying, "water can be turned into a >> -a-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 = mc-# ree 2.776404839E-11 J of _kinetic energy_. Kinetic energy is not mass. Thus "convert".


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

    E = mc-# 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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  • From Paul.B.Andersen@relativity@paulba.no to sci.physics.relativity,sci.physics on Tue Jan 6 22:57:53 2026
    From Newsgroup: sci.physics

    Den 06.01.2026 09:15, skrev Thomas Heger:
    Am Sonntag000004, 04.01.2026 um 20:51 schrieb Paul.B.Andersen:

    E = mc-# 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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  • From Thomas 'PointedEars' Lahn@PointedEars@web.de to sci.physics.relativity,sci.physics on Tue Jan 6 23:51:57 2026
    From Newsgroup: sci.physics

    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 = mc-# 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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  • From Chris M. Thomasson@chris.m.thomasson.1@gmail.com to sci.physics.relativity,sci.physics on Wed Jan 7 13:20:50 2026
    From Newsgroup: sci.physics

    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 = mc-# 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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  • From Chris M. Thomasson@chris.m.thomasson.1@gmail.com to sci.physics.relativity,sci.physics on Wed Jan 7 13:29:32 2026
    From Newsgroup: sci.physics

    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 = mc-# 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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  • From Thomas 'PointedEars' Lahn@PointedEars@web.de to sci.physics.relativity,sci.physics on Wed Jan 7 22:53:44 2026
    From Newsgroup: sci.physics

    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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