Symbol mu
mu is part of the quantity the equation computes from the expression on the right.
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Why this formula appears here
Nothing above touches curved spacetime, and this section exists to keep it that way explicitly rather than by omission, because a construction with the words “ledger” and “missing energy” in its own title is exactly the kind of object this subject’s cranks reach for first. State the settled physics plainly before anything else: the local conservation law of general relativity, = 0 , is a differential identity following from the Einstein field equations via the contracted Bianchi identity, and it holds in every spacetime — flat, curved, static, or violently dynamical — without exception. Nothing that follows questions it, qualifies it, or needs it to be anything other…
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Symbol T^munu
unu is part of the quantity the equation computes from the expression on the right.
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Published contexts (2)
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Equation 141 · Evolutionary Physics
The Entry a Relabeling Cannot Write
This equation states an equality: the expressions on both sides have the same value under the article’s assumptions.
Nothing above touches curved spacetime, and this section exists to keep it that way explicitly rather than by omission, because a construction with the words “ledger” and “missing energy” in its own title is exactly the kind of object this subject’s cranks reach for first. State the settled physics plainly before anything else: the local conservation law of general relativity, = 0 , is a differential identity following from the Einstein field equations via the contracted Bianchi identity, and it holds in every spacetime — flat, curved, static, or violently dynamical — without exception. Nothing that follows questions it, qualifies it, or needs it to be anything other…
Equation guide → · Article →Equation 143 · Evolutionary Physics
The Entry a Relabeling Cannot Write
This equation states an equality: the expressions on both sides have the same value under the article’s assumptions.
Cosmology removes the Killing vector altogether rather than merely complicating it. The Friedmann-Lemaître-Robertson-Walker spacetime describing the large-scale universe has no timelike Killing vector in comoving coordinates: its metric depends explicitly on time through the scale factor, and no coordinate change removes that dependence globally. There is consequently no analog of the ADM or Bondi construction supplying a global conserved energy for, say, the universe’s total photon population. A single photon’s cosmological redshift is the precise observational face of that absence: its frequency, and with it its energy, decreases as the universe expands, and this is exactly what an absent…
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