I would have like to have place for 'frames of reference' in the Caption too, but it was impossible, and the Q above is what leads to my Q below. The idea behind the first Q is that as you come near a Black Holes EV (Event Horizon) you will find all 'frames' getting 'compressed' meaning that trying to touch the EV with a steel rod will break the tip into smithereens, as it gets more and more compressed when closing to that mythical EV.

Also, the different 'frames of reference' created for a far observer, versus a near observer free-falling towards a BH, will make it impossible for them to agree on what they see, and where that Event-horizon will be. Read

The Event Horizon for a fuller description of how the different frames will express itself.

The main thing here is that for the far observer observing it will take the near observer an infinite time to reach that EV as he falls, which (hopefully) makes the caption above to become sensible

as if it take him a infinite time according to the far observer, then you as easily can exchange that time to 'infinite distance' at the speed of ?? whatever number you like..

After all Distance is made by 'velocity x time = Distance' right? Not speed x time as you can have a light corn bounce between mirrors, well, there it will come out the same, but if it was a ping-pong ball it would lose some time at every bounce and so diffuse the answer, I think?

Any which way, you now have it in a nutshell, a black one too, very difficult to locate..

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As i understands it's all about 'frames of reference'. For the far observer the infalling observer never will touch the event horizon, for the infalling observer it will seem as if he too never will touch the event-horizon, although he possibly can arrive at the center of the singularity. That one is slightly weird to me

"Observers who fall into the hole are moving with respect to the distant observer and so perceive the horizon as being in a different location, seeming to recede in front of them so that they never contact it. Increasing

tidal forces (and eventual impact with the hole's

gravitational singularity) are the only locally noticeable effects"

This might help us to see some light in the tunnel.

"It has been ninety years since Schwarzschild presented the first exact solution to the field equations of general relativity (Schwarzschild 1916). Representing the spacetime curvature outside of a spherical mass distribution, the existence of singularities in the solution led to several confusing problems. Importantly, the coordinate time is seen to diverge as an object falling in this spacetime approaches the Schwarzschild radius (r = 2m, in units where G = c = 1 and where m is the mass of the black hole), with the conclusion that the entire history of the Universe can pass before anything actually falls to this radius.

Paradoxically, the proper time as experienced by the falling object is finite through r = 2m and the faller reaches r = 0 in finite time. A reformulation of the Schwarzschild solution in free-falling coordinates revealed the Schwarzschild radius to be an event horizon, a boundary which can only be crossed from r > 2m, but not from r < 2m, leading to notion of complete gravitational collapse and the formation of black holes (Painlev´e 1921). However, even with these advances, the singular state of the Schwarzschild solution at r = 2m led even the most famous relativist to suggest that black holes cannot form (Einstein 1939).

The resolution was ultimately provided by Finkelstein (1958) who derived a coordinate transformation of the Schwarzschild solution which made it finite at r = 2m; this was, however, a rediscovery of the earlier work by Eddington (1924) who apparently did not realize its significance 2. With this transformation the true nature of the Schwarzschild radius was revealed, acting as a one-way membrane between the Universe and inner region of the black hole.

As discussed in many texts, the transformation to Eddington-Finkelstein coordinates clearly reveals the ultimate fate of an infalling observer. Now crossing the event horizon in a finite coordinate time, the future light cones for all massive explorers are tilted over such that there is no way back and the future ultimately lies at the central singularity. But after crossing the horizon, how long does the intrepid explorer have until this happens, and what can they do to maximize their survival time? For a free-falling path, the calculation of the proper time experienced by the explorer is a question found in graduate texts (e.g. see problem 12-14 in Hartle 2003) and it is straightforward to show that the maximum time that can be experienced below the event horizon is = m (1)

For a stellar mass black hole, this will be a fraction of a second, but for a supermassive black hole, this may be hours. As will be shown later, this maximum time applies to a faller who drops from rest at the event horizon and any one who starts falling from above the event horizon and free falls into the hole will experience less proper time on the journey from the event horizon to the singularity.

From

No Way Back: Maximizing survival time below the Schwarzschild event horizon. And there we will find the proper math too.

As for the gravity, as i understands it, what will kill are 'tidal forces', like the frame dragging of a spinning BH, all depending on what type of BH one falls into. A free fall is just following the geodesics of SpaceTime and as such 'weightless', no matter where you fall. The same as a uniform motion inside a 'black box' will seem equivalent to all other uniform motions, no matter their velocity as compared to a common frame of reference or 'origin', as I understands it that is

But the closer one comes to the EV the more accentuated the different 'frames of reference' will be, and the more compressed they should become. But before passing any EV the tidal forces will tear apart all particles in your body, the directions depending on the tidal forces vectors. Ouch, it seems as if i was wrong there saying that you will be killed by tidal forces before the EV. It depends on the size apparently.

" For a supermassive black hole, such as those found at a galaxy's center, this point lies within the event horizon, so an astronaut may cross the event horizon without noticing any squashing and pulling (although it's only a matter of time, because once inside an event horizon, falling towards the center is inevitable). For small black holes whose Schwarzschild radius is much closer to the singularity, the tidal forces would kill even before the astronaut reaches the event horizon For example, for a black hole of 10 Sun masses and the above-mentioned rope at 1000 km distance, the tensile force halfway the rope is 325 N. It will break at a distance of 320 km, well outside the Schwarzschild radius of 30 km. For a black hole of 10,000 Sun masses it will break at a distance of 3200 km, well inside the Schwarzschild radius of 30,000 km. "

Spaghettification Anyway: Here's my question.

This is quite a headache for me, wondering how to differ one of those frames from another, I mean, a cubic mm of 'normal matter' on Earth, how many different 'frames' does it contain? it have quarks, electrons, atoms etc, all having their own mass, spins and gravity, shouldn't they too represent different 'frames of reference'? As well as a cubic mm of the event horizon (ahem:) or a black hole would do?

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