Einstein’s General Relativity

Derivations, Applications and Reflections – by Albert Prins

Appendices

Appendix 1

Formulas of General Relativity.

Summary of important metric, curvature, and field equations.

\( ds^2 = g_{\mu\nu} dx^\mu dx^\nu \)

\( G_{\mu\nu} = \frac{8\pi G}{c^4} T_{\mu\nu} \)

Appendix 2

Derivation of the Derivative of the Christoffel Symbols.

Schematic derivation of \( \nabla_\lambda \Gamma^\rho_{\mu\nu} \) and related identities.

Appendix 3

Mathematical Derivation of Schwarzschild.

Step-by-step: from metric to Riemann and Ricci tensors for the Schwarzschild solution.

Appendix 4

The Schwarzschild Formula Extended for Electric Charges.

Connection between surface integral and volume source: divergence theorem in curved space.

Appendix 5

Schwarzschild Solution Inside a Mass.

\( \nabla^2 \Phi = 4\pi G \rho \) as the Newtonian limit of the field equations.

Appendix 6

Derivation of Gauss’s Theorem.

Relation between flux through a surface and volume.

\(\oint_{\partial V} \vec{F}\cdot d\vec{A}=\iiint_V (\vec{\nabla}\cdot\vec{F})\, dV\)

Appendix 7

Derivation of the Laplace and Poisson Equations.

\( \nabla^2 \Phi = 4\pi G \rho \) as the Newtonian limit of the field equations.

Appendix 8

Tidal Forces.

Spaghettification.

Appendix 9

Special Relativity.

Lorentz transformations, time dilation, length contraction, and \( E = mc^2 \).

Appendix 10

Specific Angular Momentum.

Conservation of \(L/m\) in a central potential and in Schwarzschild geometry.

Appendix 11

Considerations on Rotation.

Rotations.

Appendix 12

Derivation of the Euler–Lagrange Equation.

Variational principle: \( \frac{d}{d\tau} \left( \frac{\partial L}{\partial \dot{x}^\mu} \right) = \frac{\partial L}{\partial x^\mu} \).

Use of the Appendices

  • Appendix 1: Quick formula reference.
  • Appendix 8: Intuitive understanding of tidal forces and curvature.
  • Appendix 9: Refresher on special relativity.

All appendices are in principle self-contained.