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<blockquote data-quote="freyar" data-source="post: 6638551" data-attributes="member: 40227"><p>It's a matter of the math, I'd expect, not having worked it out myself.&nbsp; It's often easier to write down and work with a toy model that's less realistic.&nbsp; For example, the full spacetime of a real black hole like the ones we have evidence for should include (at early times) a star or some other matter that collapses to create the black hole.&nbsp; But that's a very messy situation.&nbsp; It's much easier to write down a solution describing a black hole that just sits there unchanging forever with nothing else around.&nbsp; Incidentally, black holes like that also have two distinct &quot;universes&quot; that can only access each other IIRC by FTL travel through the black hole.&nbsp; But that toy mathematical description (the Schwarzschild metric) is also very useful as a close approximation for the metric around any roughly spherical object --- it works very well for the sun, for example.&nbsp; I'm sure you dealt with the same kind of thing in the physics classes you mention you've taken.</p></blockquote><p></p>

[QUOTE="freyar, post: 6638551, member: 40227"] It's a matter of the math, I'd expect, not having worked it out myself. It's often easier to write down and work with a toy model that's less realistic. For example, the full spacetime of a real black hole like the ones we have evidence for should include (at early times) a star or some other matter that collapses to create the black hole. But that's a very messy situation. It's much easier to write down a solution describing a black hole that just sits there unchanging forever with nothing else around. Incidentally, black holes like that also have two distinct "universes" that can only access each other IIRC by FTL travel through the black hole. But that toy mathematical description (the Schwarzschild metric) is also very useful as a close approximation for the metric around any roughly spherical object --- it works very well for the sun, for example. I'm sure you dealt with the same kind of thing in the physics classes you mention you've taken. [/QUOTE]

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