- #1
maxverywell
- 197
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Birkhoff's theorem says that a spherically symmetric vacuum solution to Einstein's field equations in exterior region is necessarily static.
Now, in wikipedia article it says:
How is that a consequence of Birkhoff's theorem which speaks only about the exterior region?
Now, in wikipedia article it says:
http://en.wikipedia.org/wiki/Birkhoff's_theorem_(relativity)Another interesting consequence of Birkhoff's theorem is that for a spherically symmetric thin shell, the interior solution must be given by the Minkowski metric; in other words, the gravitational field must vanish inside a spherically symmetric shell.
How is that a consequence of Birkhoff's theorem which speaks only about the exterior region?