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17 Nov 2017 08:48

https://m.youtube.com/watch?v=8kZ8_EGCrSQ
First, there was darkness. Then came the Strangers. They were a race as old as time itself. They had mastered the ultimate technology-- the ability to alter physical reality by will alone. They called this ability "Tuning." But they were dying. Their civilization was in decline, and so they abandoned their world, seeking a cure for their own mortality. Their endless journey brought them to a small, blue world... in the farthest corner of the galaxy. Our world. Here, they thought they had finally found... what they had been searching for.
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17 Nov 2017 11:09

"I'm sorry, but when you ask "will allow us to overcome constraints that are rooted in laws of universe" you mean they will be violated, it seems to me that he clearly answered, and the answer is that's impossible by definition.

If you don't mean that, then there's no agreement in basic terminology and the discussion is DOA."


Glad you agree that the dispute is semantic in nature.

"We don't know if some "laws of the universe" actually exist, but we assume that they do, and it's been a very successful assumption regardless of whether it holds or not."

The turkey agrees with you.

"Mouthwash, in this case I not only completely agree with  Watsisname in what he said but I would like to point out that answering you question may imply that laws of nature are something that nature has in it and not a consequence of the act of observing it and describing its behaviour with mathematical rules."

We don't even know for sure that mathematics is not self-contradictory. How can we make such an assertion about the universe?

(Here's a neat short story about that concept, if you want to explore it more.)

"Some mechanism could be involved in the fine-tunning of those universal parameters but that doesn't mean that the only mechanism possible is an intelligent superior being doing it because he want life in his universe. Why should he wanted to do in that way anyway? maybe also a superior being could want to do a universe without life and having much more complex phenomena. Why the intelligent being that simulated reality wanted it like this? It looks like he is the fine-tunned one because is, as an intelligence, particularly fine for us to exist. You just displaced the problem. Why no other mechanism is possible? Top-down cosmology for example, etc..."

I know of no way for meaningful structures like life to form other than through natural selection or intelligent design (or some combination thereof). The fact that the universe would be desolate and lifeless without such precise calibration shows that it, in some way, owes its nature to either of the two.

"This is very very important. Besides jokes, the universal constants are suited for life but only in the most exquisite parts of it. Life can't arise in stars, not in cold places (because of complex chemical reactions been impossible in those environments), not in objects with huge gravity, nor in objects with high doses of radiation. And that without mentioning that life can't arise or thrive in empty space (the vast majority of what there is in the universe). So yeah the universe is suited for life, but only in this tiny little patches and only during a very short time period (could life develop when the universe becomes black hole zoo without stars? could live develop when thermal equilibrium is reached? could have developed when this was a elementary particles plasma soup?)."

All of this just seems to be aimed at refuting intelligent design. But I would point out that it is a waste of time guessing at the motives of such a designer. Just because it wanted sentience doesn't mean it is a sentience-maximizer.

"Maybe if the universal laws and constants were different then life could arise on much more places, maybe some rules allow space-time to behave in a self conscious complex dynamical way and entire light years of space are living and thinking instead of just a small dust particle suspended in a sunbeam in the void."

That is not true. Our current observations would be extremely improbable if such universes existed (or were more common than [an unthinkably large number] to one). The fact that we find ourselves here shows that humanity's 'measure' is quite large.

"Why you even need a mechanism to explain we are here? This has to do with the anthropic principle, I mean you wouldn't be able to ask that question if you weren't here in the first place so what sense does thinking the universe is fine-tunned for you make?

You don't need other universes to explain this. Even if this is the only universe you still exist and therefore the probability is still 100% sure life is compatible with this context even if this context was nearly impossible. If we have a winning loto that doesn't mean that we have tried many, maybe just one was saled. But the difference here is that you would exist and ask this question only if the wining loto was the one that was saled."


You're confusing objective fact with subjective probability. Even if that shockingly improbable lottery ticket was won, it is still rational for me to believe that it wasn't.

"Another thing is the fact that you seem to be very confident with the idea of the impossibility of other life forms and physical structures as complex as ours arising from another set of natural laws. If the universe had other rules that would allow for other life forms then they would think exactly the same as you. You are interpreting that only one kind of life could have the right to be and as a consequence that only one kind of parameters are suited for life ignoring all the possible values where the universe would be suited for it (even better than our current parameters)."

I never denied the possibility of observers in other universes. But keep in mind that just because something is possible doesn't mean it is probable. There may be countless configurations of natural laws that result in life, but certain ones are going to be more common than others. One should always assume that your circumstances aren't unusual.
 
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17 Nov 2017 15:21

Mouthwash wrote:
Source of the post Anyway, I think the real discussion is about the effects of laws. Law of gravity implies that matter inside an event horizon is stuck forever, while quantum mechanics shows that isn't true.

Matter inside an event horizon will never escape.  No particle inside a horizon ever leaves the horizon.  Quantum mechanics does not say that this is not true.  If you fall into a black hole, you will not come back out again.  Nor will an electron.  Or a photon.  The uncertainty principle does not save them.  Quantum tunneling does not save them.  All particles inside a horizon will end up at the singularity, because inward is the only direction they can move as dictated by the space-time geometry itself.

What quantum mechanics does say is that black holes radiate.  Not because particles inside the horizon are escaping, but because the vacuum outside of the horizon can be shown to have an effective temperature, and an entropy, and thus it radiates as a blackbody.  That radiation is not the matter that fell into the hole, it is the information of that matter in a maximally scrambled form -- mostly photons with wavelengths comparable to the diameter of the hole.

Another possible point of confusion is that according to observers outside the hole, the inside of the hole does not exist.  Matter never crosses an event horizon according to outside observers.  So as outside observers, we don't even need to worry about matter escaping from the interior, because it is never in the interior.  

If we instead hop into the frame of reference of the material falling in, then we do cross the horizon, and we never escape.

This may feel self-contradictory, and if so, welcome to general relativity. :)  It's not really a contradiction, it's just confusing.
 
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17 Nov 2017 16:16

Mouthwash wrote:
Source of the post What I asked about was the possibility that some future discovery will allow us to overcome constraints that are rooted in laws of our universe. You responded by saying "well if we discover anything like that then we were wrong about the laws to begin with, they aren't being violated." Which doesn't provide any useful answer to the question, only clarifies terms. That's what semantic quibbling is.

Very well, but I still believe that I have answered the question directly.  My assertion is that this cannot happen; that any observed violation of nature is indistinguishable from nature.  The question itself is poorly posed.  You might ask instead if we may discover that our understanding of nature might be wrong in such a way as to allow something to occur which we had thought was impossible.  In which case the answer is yes, and this has already happened several times.

The distinction involves what I feel is not merely semantics, but an important grasp of what physics is and what physics can determine, which I've spent some time reviewing.  If you still have qualms with any of this, then I'd like for you to think about a few examples, and then answer the following: 

1)  The gravitational force is F = GMm/r2.  For a long time, this was considered a fundamental law.  Then it was discovered that it does not apply near very massive objects.  Rather, it is an approximation to how gravity works in the limit that r is much greater than 2GM/c2.  To be more general or more precise, we need general relativity.

2)  Take a glance at charge-parity symmetry.  For a long time, this was considered to be a fundamental law.  Then we discovered that it does not hold in some interactions.

3)  Momentum conservation is considered a fundamental law.  Suppose tomorrow an experiment discovers an interaction in which it is not conserved.

For each of these three cases, state whether the deeply rooted laws of the universe were violated.  Specifically, did nature contradict itself, or did we merely update our understanding of how nature works?  Explain how you arrive at your answers.  If they have different answers, justify why.
 
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Mr. Missed Her
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20 Nov 2017 11:02

On entropy:

Watsisname wrote:
Laws of Thermodynamics in a nutshell:
1) You cannot win.
2) You cannot break even.
3) You cannot escape from the game.


I can't refute this. In the end, entropy will win the war. It's inevitable. But I've just won a hypothetical battle by letting the Earth cool off, while keeping the heat energy I caught neatly in line in batteries.
Before I continue questioning a law of physics, I should figure out precisely what it says.

Boundless Chemistry:
The second law of thermodynamics states that the entropy of any isolated system always increases.

Wikipedia:
The second law of thermodynamics states that the total entropy can never decrease over time for an isolated system, that is, a system in which neither energy nor matter can enter nor leave.

Both say I can't win a battle.

So, my solar panel plan does violate the second law, which clearly says that entropy can't ever decrease in an isolated system. It doesn't say that entropy must eventually increase, which would be the case as my batteries degrade and leak power over the eons.
The laws of thermodynamics aren't actually laws. They're correlations. It's technically possible for entropy to decrease with just the right arrangement of matter and energy, but it's so freakishly improbable that it's not worth considering. And I didn't just happen to decrease entropy, I used a method that is guaranteed to kill entropy, or your money back.
Now, it's quite possible I'm wrong. This law has been accepted as true for decades. Perhaps this situation technically doesn't decrease entropy. Maybe the flying spaghetti monster will intervene. If I am wrong, please point out how.

On the current laws of the universe discussion:

So, precisely what are we arguing about? I'm seeing a lot of "the laws of the universe don't change, we just get them wrong sometimes." Yes, that's true. But what point is being proved?
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21 Nov 2017 00:22

"Matter inside an event horizon will never escape.  No particle inside a horizon ever leaves the horizon.  Quantum mechanics does not say that this is not true.  If you fall into a black hole, you will not come back out again.  Nor will an electron.  Or a photon.  The uncertainty principle does not save them.  Quantum tunneling does not save them.  All particles inside a horizon will end up at the singularity, because inward is the only direction they can move as dictated by the space-time geometry itself.

What quantum mechanics does say is that black holes radiate.  Not because particles inside the horizon are escaping, but because the vacuum outside of the horizon can be shown to have an effective temperature, and an entropy, and thus it radiates as a blackbody.  That radiation is not the matter that fell into the hole, it is the information of that matter in a maximally scrambled form -- mostly photons with wavelengths comparable to the diameter of the hole."


Huh, okay. Seems like I misunderstood the whole concept to begin with. But if that is the case, why would a black hole evaporate? Doesn't it have to lose mass and energy?

"Another possible point of confusion is that according to observers outside the hole, the inside of the hole does not exist.  Matter never crosses an event horizon according to outside observers.  So as outside observers, we don't even need to worry about matter escaping from the interior, because it is never in the interior.  

If we instead hop into the frame of reference of the material falling in, then we do cross the horizon, and we never
escape."


My understanding is that it takes infinitely longer for any length of time to pass inside, so it 'freezes' according to an outside perspective. But black holes themselves have a finite duration. So from the perspective of matter falling into an event horizon, the black hole just evaporates the moment it enters and it's a googol years later.

"Very well, but I still believe that I have answered the question directly.  My assertion is that this cannot happen; that any observed violation of nature is indistinguishable from nature.  The question itself is poorly posed.  You might ask instead if we may discover that our understanding of nature might be wrong in such a way as to allow something to occur which we had thought was impossible."

You are arguing that even if we were to find a property of the universe that allows us to generate infinite energy or exceed the speed of light, all it really means is that we misunderstood what the laws were to begin with. But the laws that we currently accept seem self-consistent and inviolable in principle. So asking if they can be 'violated' or 'cheated' is just a shorthand for asking if their consistency was an illusion. There's no good reason to belabor the point any more than that.

"For each of these three cases, state whether the deeply rooted laws of the universe were violated.  Specifically, did nature contradict itself, or did we merely update our understanding of how nature works?"

I think our real disagreement is whether nature is consistent, so that it can't be violated by any means within the system (leaving aside violations from outside the system - we have no basis for claiming the physical world is the deepest level of reality, after all). Such a concept has already been posited in the form of cosmic strings. Even if you don't accept their existence, why should we assume the universe's laws are perfect rather than just 'good enough?' If they're reliable enough to allow the universe to survive and have structure, why should they do much more than that?
 
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21 Nov 2017 15:37

Mouthwash wrote:
Source of the post Huh, okay. Seems like I misunderstood the whole concept to begin with. But if that is the case, why would a black hole evaporate? Doesn't it have to lose mass and energy?


Virtual particle pairs in the vacuum are generated and self annihilate never violating mass/energy conservation.  On the edge of a black hole's event horizon one of the virtual particles falls in and the other does not, this means the black hole loses a minuscule amount of mass in this interaction, as it must for conservation of energy.  If you stretch this out over the lifetime of a black hole, we're talking many quadrillions of years, the black hole will eventually completely evaporate.  Nothing ever escapes the black hole however in this interaction, all things beyond the horizon must head towards the singularity.

Mouthwash wrote:
Source of the post My understanding is that it takes infinitely longer for any length of time to pass inside, so it 'freezes' according to an outside perspective. But black holes themselves have a finite duration. So from the perspective of matter falling into an event horizon, the black hole just evaporates the moment it enters and it's a googol years later.


If I watched you fall into a black hole then we each have different experiences. I see you reach the horizon, well just to it, freeze, and then infinitely red shift where I can no longer see you. From your perspective you see the black shadow ahead of you forever, and behind you a wonderfully blinding light, and then you die shortly after because the very fabric of space rips you apart.

If you are confused here, there are two series of events, this is where space-like and time-like come into play.
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21 Nov 2017 20:41

If we went to the surface of Venus today and landed near one of the old Russian Venera probes, how would it have changed over the past 50 years on Venus? Would it even be recognizable?
Image
or would it just be a melted lump of scrap metal? And if it was still the same sort of shape, would it be rusty, burnt, or maybe clean? Perhaps it would be stained yellow.
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21 Nov 2017 22:36

"Virtual particle pairs in the vacuum are generated and self annihilate never violating mass/energy conservation.  On the edge of a black hole's event horizon one of the virtual particles falls in and the other does not, this means the black hole loses a minuscule amount of mass in this interaction, as it must for conservation of energy.  If you stretch this out over the lifetime of a black hole, we're talking many quadrillions of years, the black hole will eventually completely evaporate.  Nothing ever escapes the black hole however in this interaction, all things beyond the horizon must head towards the singularity."

But the black hole is still losing energy that must, at one point, have been inside the event horizon.

"If I watched you fall into a black hole then we each have different experiences.  I see you reach the horizon, well just to it, freeze, and then infinitely red shift where I can no longer see you.  From your perspective you see the black shadow ahead of you forever, and behind you a wonderfully blinding light, and then you die shortly after because the very fabric of space rips you apart."

I'm not talking about a human being. I just mean matter. No atom ever falls into the event horizon at all, even from its own perspective, because the black hole would evaporate before it could do so.
 
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Watsisname
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22 Nov 2017 21:21

Mouthwash wrote:
Source of the post Huh, okay. Seems like I misunderstood the whole concept to begin with. But if that is the case, why would a black hole evaporate? Doesn't it have to lose mass and energy?
...
But the black hole is still losing energy that must, at one point, have been inside the event horizon.

Half correct!

It is true that the Hawking radiation is carrying away the mass of the hole, so over time the black hole does shrink.  But we must not think of this as mass or matter escaping the interior.  Remember that from our perspective outside the hole, there is no interior.  And from the perspective of things falling in, they never escape (more about that in a moment).

So where does that radiation come from?  It's coming from the vacuum outside of the horizon.  Doc's explanation using virtual particles is a popular one, but I'll take the approach used by those who first developed the idea -- particularly Bekenstein and Hawking -- which laid the foundation for Black Hole Thermodynamics.

From our perspective outside the hole, we see things vanishing into it.  But an important principle of physics is that information cannot be destroyed.  So what is happening to the information that goes into a black hole?  Is it truly lost forever, or is it preserved somewhere somehow?

Bekenstein thought a lot about this and developed a very beautiful thought experiment to analyze it.  He asked "how many possible ways are there of building a black hole?"  His procedure was to imagine building a black hole by dropping in one photon at a time (photons are massless, but they do have energy, and thus add to the mass of the hole).  Furthermore, to minimize the information required, suppose that each photon carries no information about the angle it intersects the horizon.  To do this, make the wavelength of the photon equal to the size of the horizon at the time it falls in.

Grind through the physics and algebra, and you'll end up with a very curious result.  The hidden information, or entropy, of the black hole is not proportional to its volume as one might have guessed.  More volume = more stuff = more entropy, surely?  But no!  Instead, it's proportional to the surface area of the horizon.  The horizon itself carries the entropy.

Bekenstein's calculation was fairly non-rigorous, but Hawking went on to develop it further and ultimately arrived at the conclusion that not only do black hole horizons have entropy, they must also have an effective temperature.  By thermodynamics, anything with temperature and entropy will radiate.  Essentially, the black hole horizon acts like a blackbody and so it radiates at that effective temperature with a blackbody spectrum. 
 
So yes, you can actually calculate the temperature of a black hole, and find that larger black holes have lower temperatures (very close to absolute zero) and radiate photons of correspondingly long wavelengths.  This is the Hawking radiation.  It's not stuff escaping from inside, it's the horizon itself radiating as if it has heat.  But since mass-energy is conserved, that radiation carries away the mass of the black hole.  Your radiating heat from your body carries away some of your mass, too! (A very tiny fraction). :)

This may still seem deeply unsettling.  How is a black hole built from matter then losing mass if the matter that built it isn't escaping?  I think a satisfying answer is provided by Kip Thorne:  A black hole is not made of matter.  Anything that falls into it is destroyed and converted into mass in the form of gravitational field.  Let's look at this more carefully from two perspectives and in doing so answer another point of confusion about what happens to things inside:

Mouthwash wrote:
Source of the post My understanding is that it takes infinitely longer for any length of time to pass inside, so it 'freezes' according to an outside perspective. But black holes themselves have a finite duration. So from the perspective of matter falling into an event horizon, the black hole just evaporates the moment it enters and it's a googol years later.
...
No atom ever falls into the event horizon at all, even from its own perspective, because the black hole would evaporate before it could do so.

Again half correct. :)

The infinite time dilation is relative to an observer far away.  If we drop a wristwatch into a black hole from far away, we first see it first accelerate as it falls deeper into the gravitational well.  But then something curious happens.  Near the horizon it will start slowing down, and gently come to rest on the horizon an infinite time later.  Weird!  But even weirder is that if we read the time on the watch, we see that it does not read an infinite time later!  As it slowed down near the horizon, it also began ticking more slowly, the rate decreasing exponentially closer to zero.  We can wait a million years, yet the watch would still read (if we could read it -- the light coming from it is also redshifted to blackness) only a very short time elapsed since we dropped it.

All of this so far is true.  And it is very tempting to think "time slows down and stops at the horizon, therefore if you fall in, your trip takes an infinite time and the hole evaporates in front of you."  But that part is wrong!  

That the wristwatch does not report an infinite time elapsed to the horizon is the clue.  The wristwatch is reporting what we call "proper time", the elapsed time that an object measures in its own frame of reference.  That the watch reads a finite and short time elapsed on its trip to the horizon suggests there is a part of its journey that we are missing.  Afterall, no observer directly experiences the effects of time dilation!  If you're on a rocket ship flying past Earth at nearly the speed of light, everyone on Earth says your clocks tick very slowly.  But do you see your clocks ticking slowly?  Do you move in slow motion and speak in slow sentences?  No!  

Similarly, if we fall in along with the wristwatch, we will not see the wristwatch ticking slowly.  We do not come gently to rest on the horizon.  We do not see universe time leap ahead to infinity. 

We fall straight through the horizon and end up at the singularity.  Long before the black hole evaporates.

Let's summarize these two wildly different experiences again briefly:

From outside the hole, we say objects slow down and vanish from view near the event horizon(This is gravitational time dilation and gravitational redshift -- they are the same effect.)

Falling in ourselves, we say everything falls through the horizon and ends up at singularity in a very short proper time.  We do not see time go to infinity, and the black hole's evaporation does not save us from our destruction at the singularity.  (And this is true for any particle, not just a human being).

Hopefully that helps clear a few things up!


DoctorOfSpace wrote:
Source of the post If you are confused here, there are two series of events, this is where space-like and time-like come into play.


I prefer to say there is one continuous sequence of events for something falling into a black hole.  It's just that the event corresponding with the object crossing the horizon occurs at t=infinity according to outside observers, and events below the horizon never occur according to outside observers.  If the object is a flash grenade and it goes off the instant it crossed the horizon in its frame of reference, then we observe an infinitely redshifted flash an infinite time later.  If the flash grenade instead goes off below the horizon, then we never know.  Another way of saying the interior doesn't exist except for those who make the journey into it.
 
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22 Nov 2017 22:08

Watsisname wrote:
Source of the post That the watch reads a finite and short time elapsed on its trip to the horizon suggests there is a part of its journey that we are missing.

I think the issue is that then why don't we also miss the part when the black hole vaporises?  If vaporising black holes are observable, how can we observe that before something falling into it (and if vaporising black holes aren't observable, hawking radiation loses predictive power).
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22 Nov 2017 22:21

The answer is similar as to why gravitational waves from a black hole merger are not infinitely redshifted / time dilated.  Black hole evaporation is visible (for outside observers) because it is not a discrete event happening at the horizon.  Rather, it is a process that affects the gravitational field globally.  The escape of a photon of Hawking radiation to very far away removes mass-energy from the hole, so the mass of the black hole is decreased, and several consequences must follow.  The horizon minutely shrinks inward, and the gravitational potential at an arbitrary point outside the horizon is decreased.  Thus the information that the hole is radiating away is known to distant observers in finite time.
 
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22 Nov 2017 22:29

So, everybody will observe an object falling into a black hole being rescued by hawking radiation except the object itself?

Edit: Can this apparent paradox be resolved somehow similar to showing how events apparently can happen in different sequences for different observers in spacetime?
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22 Nov 2017 23:37

midtskogen wrote:
Source of the post So, everybody will observe an object falling into a black hole being rescued by hawking radiation except the object itself?

Depends on what you mean by being rescued.  In the object's frame it is destroyed in the singularity.  Everybody outside the hole sees the information of that object emitted from the horizon over the lifetime of the black hole, as utterly scrambled, maximum entropy Hawking radiation.  Which is a pretty bad way to be rescued. :)
 
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23 Nov 2017 00:10

midtskogen wrote:
Source of the post Can this apparent paradox be resolved somehow similar to showing how events apparently can happen in different sequences for different observers in spacetime?

It's similar, but not quite analogous.

In flat space-time, two events which are in one another's "elsewhere" have ambiguous order.  Elsewhere is the region of space-time which is outside of the light cone, more distant in space than in time, so that the two events can't transfer information between them and they are not causally related.  "Which event happens first" depends on the motion of the observer, but since these events are not causally related this isn't a paradox.

Events in a black hole work a bit differently.  There is still a causal disconnect, but now it is only one way, because of the presence of a horizon. Light from the outside observers can reach events in the interior, but not the other way around.  If I fall into a black hole while you send signals to me from far away, I still get (at least some of) those signals after crossing the horizon.

So what is the apparent paradox for the black hole and how is it resolved?  The paradox is that it seems like an event is happening in two locations.  How can that be true?  It isn't true. They're different events!  

Let's say we drop a digital timer, starting at 00m:00s, into a black hole, and have fixed to it a light bulb which flashes every second as measured on that timer. Perhaps we also fix a radio beacon to it which transmits along with the flash a timestamp for what the timer reads.

Suppose the (proper, timer-measured) freefall time between the timer getting dropped and it crossing the horizon is 2 minutes.  In the timer's frame, it reads 02:00 exactly at the horizon.  This is an event.  It's a unique thing that occurs in a point in space at a moment in time.  Then let's say the timer hits the singularity 4 seconds of proper time later (ignoring destruction by tidal forces).  Now the question is which events happen where and when according to whom?

If we choose to fall in with the timer, we will see all the seconds tick and flash and be transmitted in sync with our own watches.  We'll see the flash go off at 02:00 as we cross the horizon while our own watches also read 02:00.  We'll also see 02:01, 02:02, 02:03, and then suddenly when we expect to see 02:04, it is destroyed in the singularity.  And so are we.

If we instead more wisely choose to only observe from far away, then we only receive information of the events up to 02:00.  The first several ticks and pulses are observed pretty much as we expect in tune with our own watches.  But then they come more slowly.  We get to 01:56 and find we must wait quite a while before observing 01:57.  Even longer for 01:58.  Longer still for 01:59.  An eternity for 02:00.  The light from this event is frozen on the horizon.  (Or at least the portion of the light that was emitted perfectly radially outward.  All of the rest of the light is pulled inwards and also ends up at the singularity.)  All events after that are never observed, for the light never reaches us.  We may say our device is frozen in time at the horizon, but we can't see it, and we never observe its ticks.  We won't even get to 02:01, let alone 02:04 (which happened at the singularity), or 02:05 (which never happened for any observer because the timer was destroyed before it could broadcast such a time).

Finally, if in a moment of mad desperation we try to put the paradox to the test by diving in after the timer sometime later, hoping to verify that it really is there frozen in time on the horizon, we will fail.  The timer will always be ahead of us, even as we sail through the horizon, even as we hit the singularity.  The timer and all the light from the events it ticked off within the horizon is gone from us, lost to the inward flow of space.

I'm not sure how well that answers your question but hopefully it helps a bit. :)  If it's still confusing don't worry because it was (still is?) a source of extreme confusion to the best thinkers of black holes as well.  I'll be happy to try to answer more if I can, and I can also recommend this section of a presentation by Leonard Susskind, on the apparent paradox of what happens to things falling through a horizon and the nature of Hawking Radiation.  In particular, from 30:00 to 37:30, though the whole thing is good.

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