General Relativity

Firstly, I'll start off by saying that I don't know anything about this theory. I do know that it states that mass curves spacetime, and acceleration is due to the apparent motion of particles along that line.

Einstein Field Equations

\(G_{\mu \nu} + \Lambda g_{\mu \nu} = \kappa T_{\mu \nu}\)

I will have to question:

• What is the abstract of this theory?
• What is \(G\)?
• What is \(\mu\)?
• What is \(\nu\)?
• What is \(\Lambda\)?
• What is \(g\)?
• What is \(\kappa\)?
• What is \(T\)?

Answers

• \(G_{\mu \nu}\) is the Einstein tensor
• \(g_{\mu \nu}\) is the metric tensor
• \(T_{\mu \nu}\) is the stress-energy tensor
• \(\Lambda\) is the cosmological constant
• \(\kappa\) is the Einstein gravitational constant

Now I have to ask:

• What is a tensor? A: A tensor is a multidimensional array of numbers, in the order o
• What is the Einstein tensor?
• What is the metric tensor?
• What is the stress-energy tensor?
• What is the cosmological constant?
• What is the Einstein gravitational constant?

Answers

• The Einstein tensor is a tensor defined as \(G_{\mu \nu}=R_{\mu \nu}-\frac{1}{2}g_{\mu \nu}R\)
• It is also known as the trace-reversed Ricci tensor (or Ricci curvature tensor)
• It is used to express the curvature of a pseudo-Reimannian manifold

Now I have to ask

• \(R_{\mu \nu}\) is the Ricci curvature tensor
• \(R\) is the scalar curvature