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loki130 t1_je6ndgd wrote

Reply to comment by someon332 in Ask Anything Wednesday - Physics, Astronomy, Earth and Planetary Science by AutoModerator

The distortion of spacetime in the black hole is such that it’s geometrically possible to move outwards (or even remain still). It would be like trying to go north from the north pole.

Also the thing about not having to reach escape velocity is only sort of true. If you start near a planet and start moving at less than your current escape velocity, you could indeed escape the planet, but escape velocity drops as you get further from the planet, so you would have to cross that escape velocity at some point.

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someon332 t1_je7polu wrote

Could you expand a bit more on it being “geometrically impossible”? As in, what makes it so? Is it just how the math works out, that standing still or escaping such bent spacetime would require infinite amounts of energy?

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mfb- t1_je7szo5 wrote

It's like trying to reach last Monday. In which direction would you walk? Similarly, avoiding the singularity is as impossible as trying to avoid reaching the next Sunday.

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