physics

Basic idea

The study of matter, energy, space, and time. Modern physics rests on two incompatible pillars: general relativity (gravity at large scales) and quantum mechanics (matter at small scales).

Key formulas

• Newton's second law: $F=ma$

• Mass-energy equivalence: $E=mc^2$

• Schrödinger equation: $i\hbar\partial_t\psi = \hat H\psi$

• Einstein field equations: $G_{\mu\nu}+\Lambda g_{\mu\nu}=\dfrac{8\pi G}{c^4}T_{\mu\nu}$