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seen Mar 14 at 14:18

Jan
26
revised Coordinates for FLRW metric
added 27 characters in body
Jan
26
answered Coordinates for FLRW metric
Jan
26
answered What was Einstein's 1923 Nature paper “The Theory of the Affine Field” about?
Jan
25
comment Coordinates for FLRW metric
Am I the only one who finds this question perfectly clear? The answer I was going (actually started) to write would have shown how cosmological time and proper distance along associated spatial slicings are special and why FLRW spacetime is not Minkowski space, even though conformal time and comoving coordinates make it look that way
Jan
24
revised Significance of $\pi$ in physics
mention Newton's law
Jan
24
answered Significance of $\pi$ in physics
Jan
23
comment Locally flat coordinate and Locally inertial frame
Followup question: What happens if the observer is female instead? ;)
Jan
23
comment What is the significance of Planck's constant in De Broglie–Bohm theory or Pilot-wave theory?
it probably doesn't need to be said, but I'll do it anyway so no one else has to do it: as far as we know, there is no such thing as a smallest quantum of energy
Jan
23
comment Probability of spontaneous Boltzmann brain formation
everyone you observe is also one if you were a Boltzmann brain, there wouldn't be anyone else...
Jan
18
comment What kind of object is the Landau--Lifshitz pseudotensor?
the Landau-Lifshitz and Einstein pseudotensors are different objects, so you might want to edit your question to plural (or clarify in which one you're interested in)
Jan
18
comment Independence of thermodynamic variables
see also physics.stackexchange.com/a/160101/6389
Jan
18
revised Symplectic geometry in thermodynamics
added 190 characters in body
Jan
18
revised Symplectic geometry in thermodynamics
added 190 characters in body
Jan
18
answered Symplectic geometry in thermodynamics
Jan
18
comment Using Lagrangian mechanics instead of Newtonian mechanics
Newton only works in inertial frames while Lagrangian formulations work in arbitrary frames of reference Newtonian mechanics works fine in non-inertial frames if you include fictious forces; if properly generalized, it is actually more general than Lagrangian mechanics as it does not require forces to be derived from a potential
Jan
15
answered What is potential energy truly?
Jan
15
comment Where is the potential energy saved?
@Sofia: you'd have to ask Worldsheep about why he felt the need to qualify these statements; possibly, it has to do the GR (no energy density for gravity) and the non-uniqueness of the Poynting vector, but he may have been thinking about something completely different...
Jan
15
comment Where is the potential energy saved?
@Sofia: yes, we're in agreement; I just did not get your objection until your final comment
Jan
15
comment Where is the potential energy saved?
@Sofia: from your answer one understands that the electric field and the potential are due only to the bigger charge no, one has to consider the field generated by both charges; the potential energy comes from the mixed term when evaluating $|E_1+E_2|^2$
Jan
15
comment What is potential energy truly?
yes, I was getting at the $00$ component of stress-energy; also note that Noether's 2nd theorem does apply to GR...