The rubber-sheet analogy (img) for gravity is good for event horizon vs. spaghettification / tidal forces. The rubber sheet both has a slope (first derivative of height of the sheet as you go towards the center) and also has a curvature (second derivative). The event horizon is a point of a certain slope, and your atoms getting ripped apart by gravity is a point of a certain curvature. A really big black hole is “gentler”: at the event horizon, there’s less curvature, so space is locally flat and you feel like you’re on a normal free-fall trajectory—albeit one that will have a messy end. A small black hole has higher curvature at the event horizon—a black hole the size of an atom would be ripping other atoms apart before they crossed the event horizon (ignoring Hawking radiation).
Oh, huh, I just looked at wikipedia and it actually uses a 10 solar mass black hole as an example. In their example you basically have a steel cable that can hold 1 metric ton, and you put a 500 gram weight at each end. This weighted cable snaps due to the tidal forces well outside (300 km from the surface) of a 10-solar-mass black hole, but only snaps deep inside a supermassive black hole.
In terms of time, you can cheat a little, but basically yeah, you fall in really fast once you cross the event horizon—your maximum time is about 3⁄2 of the time it would take light to cross the distance of the Schwarzchild radius.
The largest known black hole has an event horizon of at least 3,900 AU, which is 22 light days. So you could maybe spend a month inside it before hitting the singularity.
Holy christ that is big. So, is that large enough that (according to the other claims about larger black holes having smoother event horizonal tidal forces), a fairly normal human ship could actually plunge in and experience some noticeable “normal” experiences for awhile before getting spaghettified? (or at least, “basic physics” says they have normal enough experience that it becomes an interesting question whether black holes have weird properties that might bring into question whether their experiences are morally relevant?)
I’m not a physicist but I believe the answer is yes, you could easily cross the event horizon of a supermassive BH without being spaghettified.
However, if the firewall solution to the black hole information paradox is true, then you’d be ripped apart at the moment you cross the event horizon. The firewall is super controversial in physics, because it violates Einstein’s equivalence principle. According to Einstein, there is nothing special about the moment you cross the event horizon; in principle, you could cross without even noticing. (Of course in reality you’d see such crazy shit that it’d be hard to be caught unawares.)
The rubber-sheet analogy (img) for gravity is good for event horizon vs. spaghettification / tidal forces. The rubber sheet both has a slope (first derivative of height of the sheet as you go towards the center) and also has a curvature (second derivative). The event horizon is a point of a certain slope, and your atoms getting ripped apart by gravity is a point of a certain curvature. A really big black hole is “gentler”: at the event horizon, there’s less curvature, so space is locally flat and you feel like you’re on a normal free-fall trajectory—albeit one that will have a messy end. A small black hole has higher curvature at the event horizon—a black hole the size of an atom would be ripping other atoms apart before they crossed the event horizon (ignoring Hawking radiation).
Oh, huh, I just looked at wikipedia and it actually uses a 10 solar mass black hole as an example. In their example you basically have a steel cable that can hold 1 metric ton, and you put a 500 gram weight at each end. This weighted cable snaps due to the tidal forces well outside (300 km from the surface) of a 10-solar-mass black hole, but only snaps deep inside a supermassive black hole.
In terms of time, you can cheat a little, but basically yeah, you fall in really fast once you cross the event horizon—your maximum time is about 3⁄2 of the time it would take light to cross the distance of the Schwarzchild radius.
The largest known black hole has an event horizon of at least 3,900 AU, which is 22 light days. So you could maybe spend a month inside it before hitting the singularity.
Holy christ that is big. So, is that large enough that (according to the other claims about larger black holes having smoother event horizonal tidal forces), a fairly normal human ship could actually plunge in and experience some noticeable “normal” experiences for awhile before getting spaghettified? (or at least, “basic physics” says they have normal enough experience that it becomes an interesting question whether black holes have weird properties that might bring into question whether their experiences are morally relevant?)
I’m not a physicist but I believe the answer is yes, you could easily cross the event horizon of a supermassive BH without being spaghettified.
However, if the firewall solution to the black hole information paradox is true, then you’d be ripped apart at the moment you cross the event horizon. The firewall is super controversial in physics, because it violates Einstein’s equivalence principle. According to Einstein, there is nothing special about the moment you cross the event horizon; in principle, you could cross without even noticing. (Of course in reality you’d see such crazy shit that it’d be hard to be caught unawares.)