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Random thought for y'all for Christmas!
Blackholes might very well be empty inside! 😮
I am not sure what happen to the original matter that formed the black hole, but anything else that fall in the black hole later will never cross the event horizon before the end of times... 😮
The reason is, while they all accelerate to incredible speed while falling (like 99.99999% of light speed) their time is also slowing to a freeze (gravity slow time)...
Which mean, good news, next time you fall into a black hole, you will only cross the event horizon by the end of times. So you might die, but very well after everything else in the universe has gone cold and dark.... 😮
And it will only take you 5 minute - of your own relative time, so you don't even have to wait! 😆
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Many years ago, when Scientific American was published by Freeman & Co and was still a respectable publication, Freeman had special book offers to SA subscribers, such as a paperback version of Misner, Thorne and Wheeler: Gravitation. The ad claimed that it required a 'fundamental knowledge of elementary calculus', which I thought I possessed ... Well. Two thirds of its 1300 pages are still Greek to me.
But, this book has a chapter "§32.6 The fate of a man who falls into the singularity at r=0" (make sure that you thoroughly understand the 859 preceding pages  ), discussing this situation in great detail and grave seriousness, rather than the tongue-in-cheek that the chapter title might lead you to think. The discussion appears far less optimistic about the experience than what Super Lloyd seems to suggest.
Please don't ask me for explanations. I do not claim to thoroughly understand the 859 preceding pages.
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Well.. I think you might be confused by a totally different phenomenon. Gravity gradient, which will split apart your body (aka spaghettification).
It only happen with small black hole though 
Because on large black hole, with a larger event horizon, the gradient is weaker at the event horizon so, funnily enough, they are more "gentle"... (1/x is very gentle slope far enough away)
modified 24-Dec-21 20:43pm.
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Hmmm,
TLDR:
The 'stuff' falls in, but observers outside can't see it.
Not looking to get into a physics debate, but I think you may be misunderstanding whatever you are reading. The local frame of reference for particles falling into a black hole will have time at a normal speed.
The "frozen" in whatever you are reading is referring to observations made outside the event horizon. It even applies to observations made a few atoms away. Atoms right next to each other will experience time at different rates as objects approach the event horizon due to the extreme curvature.
Anyone watching objects fall into a black hole would see them slow down and 'stick' to the outside. But the particles themselves (local reference frame) time flows normally as they fall through.
This is a more accurate description. I'm surfing the net on my TV, this took forever to type.
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I think you misread what I said.
Look, like I said, it only takes you 5 minutes of your (own relative) time.
Thing is, those 5 local minutes will be enough for the whole outside universe to die a cold slow death....
look some detailed information here if you insist
Does time pass faster or slower close to the black hole?
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Super Lloyd wrote: those 5 local minutes will be enough for the whole outside universe to die a cold slow death.
Yep, maybe... assuming the universe will keep expanding and die a cold death. That's not settled yet. There is some new data making some arguments for steady-state.
We can use a simple mental experiment and make a good guess what it would look like if you were falling through. All of the star light that illuminated the object for billions of years falling would be experienced by the object over those 5 minutes. So we can make an educated guess that you would see extremely bright light right before passing through. Pure speculation of course, but a good guess.
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So we should have called them 'Oreo holes'! 
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Well,
I've always thought calling them "Black Holes" gives the wrong impression. I've read that they were called "Frozen Stars" prior to John Wheeler giving the more popular name. I think "Frozen Star" is much more accurate and puts the emphasis on time dilation rather than light.
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If we start discussing various kind of our-world holes as analogies of black holes, we might end up running into some sort of censorship.
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Hmmm,
This is a good example of why I try not to discuss physics on internet forums. Most people don't understand what they are reading.
That's something completely different. That article is about Hawking radiation. I'm not commenting on it because I don't know if it's correct. Susskind argued about it for the last decade. I have no idea if he's right.
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Yeah, it's completely different.. but it's all I find after 10 minute googling.
anyway what you said is also a know idea discussed in black hole circle, I just couldn't find a link... anyway it's close enough.
although, I can feel a pedant.. so probably not worth continuing what's going to be.. a very fruitless discussion... I agree.. bye!
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Ok,
Just want to clarify that most of what we are discussing is classical mechanics regarding the second law of motion[^], we didn't really touch anything theoretical.
I didn't want to comment on your link because it was a multi-tiered theory.
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I never got the grasp of my "Misner, Thorne and Wheeler: Gravitation", but I seriously hope that the astronomers find enough black matter to ensure that universe will eventually collapse into a huge Gnab Gib, the ending time.
I never was comfortable with eternity, never could accept it as a physical reality. I am happy with Big Bang, the start. I would like to know that it is ending as well. Not only "us", but time itself.
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trønderen wrote: I seriously hope that the astronomers find enough black matter to ensure that universe will eventually collapse
Without going into any details, it looks to me that the matter that falls into the singularity at the center of our galaxy shares space with the matter outside. I could be wrong, but that's the conclusion I arrive at when I explore with geometry. I'm probably wrong.
trønderen wrote: I never was comfortable with eternity, never could accept it as a physical reality. I am happy with Big Bang, the start. I would like to know that it is ending as well. Not only "us", but time itself.
I don't have any answer for this, no idea.
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Well, the Hubble telescope caught a small planet being drawn into a black hole last year. In fact, the detail of the image was so good that you could see the lawyers rushing to the scene.
anonymous.
>64
If you can keep your head while those about you are losing theirs, perhaps you don't understand the situation.
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What they just saw the planet get very close.... You never seen one cross the event horizon. Not just because light can come back from the event horizon, but also because as you get increasingly close to the surface, time freeze....
look some detailed information here if you insist
Does time pass faster or slower close to the black hole?
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The sun revolves around Sagittarius A*(the name of the Milky Way's black hole) just like we revolve around the sun. But don't worry about the black hole. The sun will expand and swallow us all well before we have to worry about a black hole. Not to mention in a few million years we will get to meet our neighbors in the Andromeda Galaxy, when our galaxies collide and combine! 
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Super Lloyd wrote: Which mean, good news, next time you fall into a black hole, you will only cross the event horizon by the end of times....And it will only take you 5 minute - of your own relative time, so you don't even have to wait!
Wasn't mentioned but those thought experiments involve particles. Not people.
You would be dead long before you could see any relativistic effects. If not radiation then differential gravity would tear you into pieces (particles.)
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jschell wrote: If not radiation then differential gravity would tear you into pieces (particles.)
Haha.. this effect that you mention, also known as spaghettification, only happen for "small" black hole. But doesn't happen with the really big one at the center of galaxies. Their event horizon being way too large, the gravity gradient is not significant at the event horizon.
Granted I didn't specify I was talking about those, but thing is, it just doesn't happen all for all blackholes! 
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I've mentioned here before that whenever I catch myself forgetting that I don't know it all, I try my hand at a brain teaser I've been trying to solve for years now.
The problem is simple: Convert a finite automata to a regular expression.
The solution had eluded me. I've attacked it many different ways.
Finally I settled on the state removal method as it generates the cleanest regular expressions, and seemed easier for me to understand than methods like Arden's theorem: R=QP* whatever the heck that means.
Anyway, I solved it I think. I still need to create a battery of tests, but it seems to be working so far.
(abcd|12(3|55|77|99)4)(ef)*g
q0:
(12(34|554|774|994)(ef)*g|abcd(ef)*g) -> q1
*q1:
(12(34|554|774|994)(ef)*g|abcd(ef)*g)
It's not the exact same regex, because that's not necessary. It just has to match the same text as the original one matched.
If anyone is curious, here's my mess. The main meat is in Program.cs under the ToRegex() method in the main project. The rest is support.
GitHub - codewitch-honey-crisis/FAToRegex: A testbed for FA to Regex via state removal in C# (work in progress)[^]
Anyway, point is, now I need another problem I can't solve, that students can, that I can attack for years to keep me humble.
Real programmers use butterflies
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honey the codewitch wrote: I need another problem I can't solve
Looks like you are using the state elimination method, so I would argue that you haven't fully solved the problem until you can do it with Arden’s method.
Or maybe you can do the reverse and convert a regular expression to a DFA next.
Best Wishes,
-David Delaune
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I already do convert regex to DFA.
I could use Arden's theorem, but I wouldn't feel humbled by it. Learning it requires a pretty solid grasp of mathematical formalisms and symbols that I still struggle with. Learning that stuff will take awhile, and not knowing it doesn't really bother me. I've never strictly needed it, although at times it would be helpful, admittedly.
But my point is because I don't know those things, not being able to solve it using Arden's theorem isn't something I feel like I *should* be able to do. Sure, I have instructions, but they are quite literally Greek to me. 
And Arden's theorem produces an inferior result to the state removal method, so there's no practical reason for me to solve it that way.
I may do it one day, once I have those formalisms under my belt much better than I do now, but for now it wouldn't scratch the same itch for me. I have a feeling when I do master those formalisms, Arden's theorem will be easy to implement. It's obviously recursive. I can "see" some of it, but through a glass darkly. I've even got an inkling of an idea of how it works. So I can see that it's easy to do if you understand those formalisms - likely *easier* than the state removal method.
Edit: I'll get some additional challenge out of refining it, but nothing that will replace what not being able to solve the problem did for me. Oh well. On to new challenges. I'll find something. Maybe it's time to dive into the back end of compilers instead of the front end. I've written an assembler and disassembler for a pike virtual machine in C#, so maybe I should write a compiler in C# just so that it can be tinkered with. Maybe therein I'll find a problem among the weeds that will satisfy me the way this one did.
Real programmers use butterflies
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So my audio playback on the laptop was breaking up constantly. So I tried my other laptop, and same thing!
Both are running W10, so I figured a Microsoft broke something in an update. So down the rabbit hole I go:
1. Rebooting didn't fix anything.
2. Drivers were all up to date.
3. Different audio playback proggies all exhibited the same problem!
4. Even Audicity!
As Holmes would say, "Quote: Once you eliminate the impossible, whatever remains, no matter how improbable, must be the truth.
I decided to look at the main speaker interface -- it's one of those cheap Logitech speaker systems that has a bass-y speaker in the main box and little speakers for the stereo stuff and the bass is so gawdawful that I snipped the wire, I still have to add it the audio pot that I bought to control the volume, but I digress...
And what do I find?
The power plug input to the box is not fully seated in the receptacle!
Push it in properly, and no more breaking up of the audio! I guess certain frequencies of the audio (not very high, mind you) was somehow reverberating into the box just enough to momentarily break the power connection.
Sorry to blame you, Microsoft and W10! 
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Marc Clifton wrote: Sorry to blame you, Microsoft and W10!
You shouldn't be, Marc. As any good engineer, you first traced the most likely path of failure. 
/ravi
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