 Painlevé–Gullstrand coordinates

ID: painleve-gullstrand-coordinates

Codex  0 Created 2026-09-24 Updated 2026-10-14

d s^{2} = - d t^{2} + (d r + \frac{2 M}{r} d t)^{2} + r^{2} d Ω^{2} .

The constant-

t

spatial slices are flat, and the coordinates remain regular at the Schwarzschild radius.

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