← All parts of this equation

Equation 124 · Part 1 · The Bend an Elevator Cannot Fake

Symbol Phi

Φ(r)=−GM/r\Phi(r) = -GM/r
Φ\Phi

What this part means

Phi is part of the quantity the equation computes from the expression on the right.

Its job in the formula

Phi is part of the quantity the equation computes from the expression on the right.

The passage around this formula

For Earth modelled as a point mass, Φ(r)\Phi(r) = -GM/r gives a radial second derivative of magnitude 2GM/R3R^3 and, since Φ\Phi is harmonic in vacuum, transverse second derivatives of magnitude GM/R3R^3 with the opposite sign — a trace-free tensor in the exact ratio 2:{-1}:{-1} . With the standard gravitational parameter GM⊕M_\oplus =…

Read this part in the article →

Learn the underlying idea

A function assigns an output to each allowed input. The expression f(x) means “apply f to x”.

Open the illustrated functions: inputs become outputs guide →

See this notation across published equations →

Sources cited in the surrounding passage

These citations provide research context; check each source for the exact claim it supports.