- #1
GRstudent
- 143
- 1
Hi all,
I have been trying to solve the Einstein Field Equations for its (0,0) component. So I have got that (c=1)
Einstein Tensor (upper,0,0)=8*pi*G*T(upper,0,0)
Now, let's see what T (0,0) really is. It is energy density, right? So According to famous E=mc^2 the energy density is the same as mass density, assuming the speed of light to be equal to one. Therefore, the (0,0) components of the Stress-Energy Tensor is just the mass density. So we have that
Einstein Tensor (upper,0,0)=8*pi*G*ρ
Now, let's see what Einstein Tensor G(0,0) really is
Ricci(0,0) - 1/2*g(upper 0,0)*Ricci scalar
Ricci scalar is obtained by contracting it with metric tensor so we have that
Ricci (upper,0,0) - 1/2*g(upper 0,0)*Ricci (upper0,0)*g(lower, 0,0)=8*pi*G*ρ
So g(upper 0,0)*g(lower, 0,0) is 1 so we have that
Ricci (upper 0,0) - 1/2*Ricci(upper 0,0)=8*pi*G*ρ
1/2 Ricci (upper 0,0)=8*pi*G*ρRicci(0,0)=4*pi*G*ρNow look carefully to the Right Hand Side of the Equation. It is the same from the Poisson's Equation where
Set of second partial derivatives of the Gravitational potential=4*pi*G*ρ
Therefore, is it true that the zero-zero component of the Einstein Tensor, and subsequently the Ricci tensor, is just the [Set of second partial derivatives of the Gravitational potential] or 4*pi*G*ρ
Thanks!P.S I apologize for not using MathCodes--never used them before and would appreciate if someone will show me how to use them.
I have been trying to solve the Einstein Field Equations for its (0,0) component. So I have got that (c=1)
Einstein Tensor (upper,0,0)=8*pi*G*T(upper,0,0)
Now, let's see what T (0,0) really is. It is energy density, right? So According to famous E=mc^2 the energy density is the same as mass density, assuming the speed of light to be equal to one. Therefore, the (0,0) components of the Stress-Energy Tensor is just the mass density. So we have that
Einstein Tensor (upper,0,0)=8*pi*G*ρ
Now, let's see what Einstein Tensor G(0,0) really is
Ricci(0,0) - 1/2*g(upper 0,0)*Ricci scalar
Ricci scalar is obtained by contracting it with metric tensor so we have that
Ricci (upper,0,0) - 1/2*g(upper 0,0)*Ricci (upper0,0)*g(lower, 0,0)=8*pi*G*ρ
So g(upper 0,0)*g(lower, 0,0) is 1 so we have that
Ricci (upper 0,0) - 1/2*Ricci(upper 0,0)=8*pi*G*ρ
1/2 Ricci (upper 0,0)=8*pi*G*ρRicci(0,0)=4*pi*G*ρNow look carefully to the Right Hand Side of the Equation. It is the same from the Poisson's Equation where
Set of second partial derivatives of the Gravitational potential=4*pi*G*ρ
Therefore, is it true that the zero-zero component of the Einstein Tensor, and subsequently the Ricci tensor, is just the [Set of second partial derivatives of the Gravitational potential] or 4*pi*G*ρ
Thanks!P.S I apologize for not using MathCodes--never used them before and would appreciate if someone will show me how to use them.
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