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seen Mar 28 at 6:24

Mar
18
awarded  Promoter
Mar
16
asked EPR paradox: instantaneous vs very fast?
Mar
16
asked General formula to compute the redshift (first order perturbations)
Jul
11
accepted Why is that the space-time associated with the Earth is not shrinking?
Jul
11
accepted Einstein tensor in Friedmann equations : where is the missing $c^2$?
Jun
18
accepted General expression of the redshift: explanation?
Jun
17
comment General expression of the redshift: explanation?
So this is a fraction of sums and not a sum a fractions ?
Jun
17
revised General expression of the redshift: explanation?
added 4 characters in body
Jun
17
asked General expression of the redshift: explanation?
May
26
awarded  Yearling
May
6
accepted Stress energy tensor of a perfect fluid and four-velocity
May
5
comment Stress energy tensor of a perfect fluid and four-velocity
Oh, ok, I do not see this as pedantic but completely justified. But I still do not understand from where comes the minus between $\frac{dx^0}{d\tau}$ and $-\frac{dt}{d\tau}$ because for me $x^0=t$ (so when I write $g_{00}dx^{0}dx^{0}$ I get $-c^2dt^2$).
May
5
awarded  Commentator
May
5
comment Stress energy tensor of a perfect fluid and four-velocity
Thanks. And what is the notation $(x^0, x^i)^T$ ?
May
5
comment Stress energy tensor of a perfect fluid and four-velocity
In your notations can you define what is $\tau$ in my notations (as a function of $s$ or/and $t$)
May
5
comment Stress energy tensor of a perfect fluid and four-velocity
So for you at which specific step my calculations are false ?
May
5
comment Stress energy tensor of a perfect fluid and four-velocity
In the second part, as my fluid is at rest, I think that the terms $\frac{dx}{dt}$, $\frac{dy}{dt}$, $\frac{dz}{dt}$ are negligible compared to $c^2$, isn't it ?
May
5
revised Stress energy tensor of a perfect fluid and four-velocity
added 84 characters in body
May
5
comment Stress energy tensor of a perfect fluid and four-velocity
If I consider a fluid at rest in comoving coordinates, then I think that $T^{00}=\rho$
May
5
asked Stress energy tensor of a perfect fluid and four-velocity