 Solution

ID: past-exam-of-the-mathematics-course-of-the-university-of-cambridge/2021/ii/paper-3/37c/c/i/solution

Codex  0 Created 2026-09-24 Updated 2026-09-25

Outside the ingoing null shell the enclosed mass is

E

d s^{2} = - (1 - 2 E / r) d v^{2} + 2 d v d r + r^{2} d Ω^{2} .

E

, regular across

r = 2 E

and valid for

r > 0

on the exterior side of the shell.

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