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| From | Phil Carmody <pc+usenet@asdf.org> |
| Newsgroups | rec.puzzles |
| Subject | Re: Puzzling Questions |
| Date | Wed, 30 Sep 2026 23:33:12 +0300 |
| Organization | A noiseless patient Spider |
| Lines | 24 |
| Message-ID | <877bk232ev.fsf@asdf.ee> (permalink) |
| References | <questions-20260910093009@ram.dialup.fu-berlin.de> <answers-20260917102236@ram.dialup.fu-berlin.de> |
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ram@zedat.fu-berlin.de (Stefan Ram) writes:
> ram@zedat.fu-berlin.de (Stefan Ram) wrote or quoted:
>>"E = mc^2" does /not/ mean that energy (E) can be converted
>>into mass (m), but rather that mass is always conserved.
>>Can you see why? ("c" is a constant, the speed of light.)
>
> Spoiler warning: This post now contains what I deem to be
> the correct answers.
>
> We know from high-school that energy is conserved, i.e.,
> constant. The speed of light also is constant. But when E
> is constant, c is constant, and E=mc^2, m also is constant!
Energy isn't conserved. That was a naive pre-GR view.
The equations of motion are not invariant over time, therefore Noether's
theorem has no symmetry to work with, and provides no invariance law.
Phil
--
We are no longer hunters and nomads. No longer awed and frightened, as we have
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Puzzling Questions ram@zedat.fu-berlin.de (Stefan Ram) - 2026-09-10 08:49 +0000
Re: Puzzling Questions richard@cogsci.ed.ac.uk (Richard Tobin) - 2026-09-10 10:26 +0000
Re: Puzzling Questions ram@zedat.fu-berlin.de (Stefan Ram) - 2026-09-17 09:26 +0000
Re: Puzzling Questions Phil Carmody <pc+usenet@asdf.org> - 2026-09-30 23:33 +0300
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