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Newsgroups: sci.physics.relativity
Subject: Re: Energy?
From: nospam@de-ster.demon.nl (J. J. Lodder)
Reply-To: jjlxa31@xs4all.nl (J. J. Lodder)
Date: Sat, 3 Aug 2024 12:43:25 +0200
References: <Energy-20240728103722@ram.dialup.fu-berlin.de> <66A8307B.8B6@ix.netcom.com> <9U6dneBCi4_A_DX7nZ2dnZfqn_qdnZ2d@giganews.com> <66A9CBC9.2213@ix.netcom.com> <T8CdnXBAIsR5Djf7nZ2dnZfqn_adnZ2d@giganews.com> <66AD00A3.3BC9@ix.netcom.com>
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The Starmaker <starmaker@ix.netcom.com> wrote:

> Ross Finlayson wrote:
> > 
> > On 07/30/2024 10:29 PM, The Starmaker wrote:
> > > Ross Finlayson wrote:
> > >>
> > >> On 07/29/2024 05:14 PM, The Starmaker wrote:
> > >>> There is no one person on earth that can even define correctly the
> > >>> word...Energy.
> > >>>
> > >>>
> > >>>
> > >>> Stefan Ram wrote:
> > >>>>
> > >>>>     In a chapter of a book, the author gives this relation for a
> > >>>>     system with mass m = 0:
> > >>>>
> > >>>> E^2/c^2 = p^"3-vector" * p^"3-vector"
> > >>>>
> > >>>>     . Then he writes, "This implies that either there is no particle
> > >>>>     at all, E = 0, or we have a particle, E <> 0, and therefore
> > >>>>     p^'3-vector' <> 0.".
> > >>>>
> > >>>>     So, his intention is to kind of prove that a particle without mass
> > >>>>     must have momentum.
> > >>>>
> > >>>>     But I wonder: Does "E = 0" really mean, "there is no particle."?
> > >>>>
> > >>>>     300 years ago, folks would have said, "m = 0" means that there is
> > >>>>     no particle! Today, we know that there are particles with no mass.
> > >>>>
> > >>>>     Can we be confident that "E = 0" means "no particle", or could
> > >>>>     there be a particle with "E = 0"?
> > >>>>
> > >>>>     Here's the Unicode:
> > >>>>
> > >>>> EÂ"/cÂ" = pâ∞˜ · pâ∞˜
> > >>>>
> > >>>>     and
> > >>>>
> > >>>> |This implies that either there is no particle at all, E = 0, or we
> > >>>> |have a particle, E â≈  0, and therefore pâ∞˜ â≈  0.
> > >>>
> > >>
> > >> Entropy has two definitions, sort of opposite each other,
> > >> "Aristotle's and Leibniz'".
> > >>
> > >> The energy or energeia then relates to the entelechiae,
> > >> content and connectedness, what results to dynamis/dunamis,
> > >> which are the same word, one for power the other potential.
> > >>
> > >> So, energy is defined by other definitions, the least.
> > >
> > > What is Einstein's definition of...Energy?
> > >
> > >
> > >
> > 
> > It's capacity to do work.
> > 
> > It's usual that "everything's energy, after mass-energy equivalence
> > and the energy of the wavepackets of what are photons", yet, it is
> > that quantities are _conserved_ as with regards to changes of state
> > and the _conservation of quantities_ for matter, charge, photon
> > velocity, and neutron lifetime.
> > 
> > I.e., there are conservation laws, about Emmy Noether's theorem
> > and symmetries and invariance, yet they're really continuity laws,
> > and quasi-invariance and super-symmetry, and about running constants,
> > and the regimes of extremes, in a usual theory with least action.
> > 
> > These days sometimes it's "information" instead of "energy" which
> > is "the quantity", with regards to free information and the imaging
> > of optical visible light and these kinds of things, sort of a
> > super-classical and quite modern and thoroughly inclusive sort of
> > theory.
> > 
> > Just like anything else, it's capacity to do work, with regards
> > to "least action: sum-of-histories sum-of-potentials" as it's
> > the potential fields what are real and then intelligence is simply
> > action on information, with, "levers" everywhere.
> > 
> > Moment and Motion, ....
> > 
> > If you want to know Einstein's opinion, his last word on the matter
> > is "Out of My Later Years", "Relativity", one theory, with GR first.
> 
> 
> Okay, let me put it this way...it seems you are trying to make an 'attempt' to
> define the word "energy".
> 
> You got 5 or 6 paragraphs that seems you are scrounging the Internet in
> seach for meanings.
> 
> It sounds like 6 different people wrote it!

Indeed, you may call things 'energy' in any way you want.
But back to basics: something that you call 'energy'
isn't really an energy in a physical sense
unless you can show how it can be converted
(partly, and at least in principle) to 1/2 mv^2.

With conservation of energy of course,

Jan