relativity

Basic idea

Special relativity: physics is the same in all inertial frames; the speed of light is invariant. General relativity: gravity is the curvature of spacetime by mass-energy.

Key formulas

• $E = mc^2$
• Lorentz factor: $\gamma = 1/\sqrt{1-v^2/c^2}$
• Spacetime interval: $ds^2 = -c^2 dt^2 + dx^2 + dy^2 + dz^2$
• Einstein field equations: $G_{\mu\nu}+\Lambda g_{\mu\nu}=\dfrac{8\pi G}{c^4}T_{\mu\nu}$

Pages

• Relativity
• Speed of light

Siblings

• loop quantum gravity
• quantum loop gravity
• quantum physics
• string theory