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Not necessarily. If you replaced the sun with an equivalent mass black hole, none of the orbits of the planets would change.


Sure, because none of the planets are anywhere near close enough to the sun to experience tidal forces. But if you were to approach the sun VS a sun-mass black hole, at some distance the difference would become noticeable through tidal forces (ignoring the massive difference in emitted radiation, of course).


I'd like to see a simulation of what that would look like. I mean, if by magic the sun was replaced with an equivalent mass black hole in an instant would anything be visible from earth before the inevitable freeze?


From Earth's perspective, you wouldn't see anything interesting except for the sun vanishing. Gravitationally, all that matters is the absolute mass, so all the dynamics of the solar system stay the same.

A black hole of 1 solar mass has a radius of something like 3km. Totally invisible from Earth. You probably wouldn't even see any gravitational lensing. All we would see is the sun there one moment, and then nothing the next.

Life on Earth would continue for a while, but the planet would eventually freeze over.

So, nothing interesting. The sun vanishes and then some time later you freeze and/or starve to death.


Ah, thanks for the explanation. They key thing I didn't realize is that it'd only be 3km!




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