Jump to content


Photo
- - - - -

Three Air Tight Reasons Why No Object Can Ever Reach An Event Horizon

General Relativity Black Holes

  • Please log in to reply
175 replies to this topic

#1 A-wal

A-wal

    Creating

  • Members
  • PipPipPipPipPipPipPip
  • 1316 posts

Posted 26 March 2019 - 05:50 AM

All you need to know about black holes to understand these is that no object can ever reach the event horizon of a black hole from a distance, an object falling towards the event horizon becomes increasingly time dilated and length contracted but never reaches the horizon.


1).
Given that no amount of time is enough for an object to reach the event horizon of a black hole from the perspective of an observer at a distance, can we accurately say from the perspective of an object falling towards a black hole that an infinite amount of time must pass on the watch of a more distant observer from the perspective of the falling observer before they are able to reach the event horizon?

If the answer is yes then although there would be a time on the watch of the falling observer when they reach the event horizon, how is any lifespan of the black hole long enough for an infinite amount of time to pass on the watch of a distant observer from the perspective of the falling observer before they reach the event horizon? If an infinite amount of time has to pass on the watch of the distant observer in the frame of the the falling observer as well as in the distant observer's frame then it never happens.

If the answer is no then from the frame of falling observer there is a time on the watch of the distant observer when they reach the event horizon but in the frame of the distant observer that time on their own watch passes and the falling observer still hasn't reached the horizon, they can still accelerate away in this frame but in the frame of the falling observer they're inside the event horizon and can't accelerate away once the distant observer's watch reaches that time.


2).
If two observers are falling towards a black hole, one behind the other then can the closer object reach and cross the event horizon from the perspective of the more distant observer before they themselves reach the horizon?

If the answer is yes then how does the closer object after crossing the horizon from the more distant observer's perspective then reemerge from inside the horizon if the more distant observer accelerates away before reaching the horizon themselves?

If the answer is no then all falling objects must reach the event horizon simultaneously so how could any object ever reach an event horizon if they can't reach it from the perspective of an observer falling in behind them?


3).
Gravitation is supposed to be time reversible, it's an attractive force either way. This doesn't hold once an object crosses an event horizon because then that object has to reemerge from inside the event horizon if the arrow of time is reversed and that shouldn't be possible with the arrow pointing either way.



#2 A-wal

A-wal

    Creating

  • Members
  • PipPipPipPipPipPipPip
  • 1316 posts

Posted 26 March 2019 - 05:58 AM

Post by Amplituhedron from the original topic before it was hijacked:

 

My understanding is that the observer outside the black hole would see you, falling into the hole, eventually stop at the event horizon, your clock frozen, and then see you red-shift out of the visible spectrum.

 

The falling person would — depending on how quickly she was approaching the event horizon — see the future history of the universe unfold, but not all of it before she crossed the horizon. Some of the light would not catch up with her; none of the light beyond the cosmic event horizon could reach the faller in any case, even if she didn’t fall into the black hole. So the situations don’t seem entirely symmetrical.

 

Here is what fascinates me: Black holes underscore the conflict between general relativity and quantum mechanics.



#3 A-wal

A-wal

    Creating

  • Members
  • PipPipPipPipPipPipPip
  • 1316 posts

Posted 26 March 2019 - 06:00 AM

My understanding is that the observer outside the black hole would see you, falling into the hole, eventually stop at the event horizon, your clock frozen, and then see you red-shift out of the visible spectrum.

Not quite. A distant observer never sees the falling observer reaching the event horizon. They see time dilation, length contraction and red shift of the observer continually increasing and approaching would what be infinite time dilation, length contraction and red shift at the horizon but the object is never frozen in time, contracted to no length or infinitely redshifted.

The important point here is that from the perspective of the distant observer, the falling object can always accelerate away from the black hole. Now can the falling observer can reach the event horizon in their own accelerated frame? It is true that they do reach the event horizon at a specific time on their own watch and of course time is progressing normally from their perspective.

The problem is the amount of time that passes on the watch of the distant observer from the frame of the falling observer before they reach the horizon. If it's a finite amount of time then this contradicts the fact in the frame of the distant observer the falling observer can still accelerate away from the black hole after the distant observer's watch passes this time.

The only conclusion is that an infinite amount of time has to pass on the watch of the distant observer before the falling observer reaches the horizon, from not only the frame of the distant observer but also in the frame of the falling observer so it's something that never happens in either frame. Although there is a time on the watch of the falling observer when they would reach the event horizon, it's a time that is never reached.

~And to link it to the second question.~

If the distant observer were to move towards the black hole then the falling observer will still never be able to reach the event horizon in front of them because if they did then they would have to reemerge from inside the horizon if the more distant observer were to move away again.

Also it well and truly shatters the time reversible aspect of gravity because again, an object would have to reemerge from inside the event horizon, this time if the arrow of time is reversed.
 

The falling person would — depending on how quickly she was approaching the event horizon — see the future history of the universe unfold, but not all of it before she crossed the horizon.

It would have to be the entire future history of the universe and that still wouldn't be enough time, no amount of time is enough. If there was a time when the falling observer reaches the horizon, say when the light from a distant supernova reaches the two observers then after this time it would be impossible for the falling observer to move away from the black hole but this would contradict the Schwarzschild coordinate system showing that from the frame of a distant observer it's always possible for them to accelerate away.
 

Here is what fascinates me: Black holes underscore the conflict between general relativity and quantum mechanics.

Thanks, I'll check that out.



#4 Amplituhedron

Amplituhedron

    Questioning

  • Members
  • PipPipPipPip
  • 129 posts

Posted 26 March 2019 - 08:16 AM

I browsed the physics stack exchange for more about this, and I get conflicting answers from presumed experts. As you say black holes have life spans and not last for an infinite amount of time — they evaporate away because of Hawking radiation. One answer presented the scenario of a clock falling toward the event horizon, ticking toward 12, at which time it is expected to cross the event horizon. An observer watching the clock will never see it fall in. From the clock’s point of view, billions of years will pass in the external world in the split second before the clock strikes 12, and before the clock passes the event horizon from its own point of view, the black hole will have evaporated away because of the aforementioned Hawking radiation. The reply invoked an unnamed cosmologist who said, “The black hole itself is only ever an approximation. When a bunch of matter collapses in on itself it very rapidly converges towards something that looks like a black-hole solution to Einstein's equations, to the point where to all intents and purposes you can treat it as if the matter is inside the event horizon rather than outside it. But this is only ever an approximation because from our perspective none of the infalling matter can ever pass the event horizon.” But, as I say, others disputed what seems to be the clear implication that nothing actually passes the EH from the point of view of either an observer or one falling to the horizon.


  • A-wal likes this

#5 ralfcis

ralfcis

    Explaining

  • Members
  • PipPipPipPipPipPip
  • 945 posts

Posted 26 March 2019 - 09:49 AM

You will get every answer under the rainbow for any question on the physics stack exchange. Just pick any one that appeals to you. BS to one person is absolute truth to another but less so for those that understand the math. And they say relativity is settled science when they can't agree on anything. 

 

I remember talking with Dr Don Lincoln on the SPCF forum begging him to take a look at my theory and he said do you know how many times a day people ask me to look at their theories and yours is wrong without me even looking at it if you reject length contraction. Relativity is settled science. Space and time  are the same thing. Well of course they are in relativity, that's what I'm trying to disprove. I asked him recently what forum he switched to and he's now not on any forum, too busy, he's missing out.


Edited by ralfcis, 26 March 2019 - 10:54 AM.


#6 A-wal

A-wal

    Creating

  • Members
  • PipPipPipPipPipPipPip
  • 1316 posts

Posted 26 March 2019 - 12:52 PM

I browsed the physics stack exchange for more about this, and I get conflicting answers from presumed experts.

You won't ever be able to get a real answer. You'll get people who say that observers can cross the event horizon from within their own frame but if you follow up with asking them how much time passes on the watch of a distant observer from the faller's frame before they reach the horizon, is it finite or infinite and if it's finite then it contradicts the fact that at that time on their own watch in the distant observer's frame the falling observer hasn't reached the horizon and never will but if it's infinite then that amount of time never passes on the watch of a distant observer from the frame of the falling observer then they'll either just slink away or go to great efforts to avoid answering the question.

 

As you say black holes have life spans and not last for an infinite amount of time — they evaporate away because of Hawking radiation.

It actually wouldn't matter if black holes did exist for an infinite amount of time because no finite amount of time is enough for an object to reach an horizon from the frame of a distant observer. Any time on that distant observer's watch that you want to ask 'have they reached the event horizon yet in this distant frame' the answer will always be no, when the watch of the distant observer reaches this time in the frame of the falling observer they still haven't reached the horizon yet.

 

One answer presented the scenario of a clock falling toward the event horizon, ticking toward 12, at which time it is expected to cross the event horizon. An observer watching the clock will never see it fall in. From the clock’s point of view, billions of years will pass in the external world in the split second before the clock strikes 12, and before the clock passes the event horizon from its own point of view, the black hole will have evaporated away because of the aforementioned Hawking radiation.

Yea and whatever lifespan the black hole has it won't be enough.

 

The reply invoked an unnamed cosmologist who said, “The black hole itself is only ever an approximation. When a bunch of matter collapses in on itself it very rapidly converges towards something that looks like a black-hole solution to Einstein's equations, to the point where to all intents and purposes you can treat it as if the matter is inside the event horizon rather than outside it. But this is only ever an approximation because from our perspective none of the infalling matter can ever pass the event horizon.” But, as I say, others disputed what seems to be the clear implication that nothing actually passes the EH from the point of view of either an observer or one falling to the horizon.

I completely disagree with both points. General relativity provides an entirely accurate model of what happens when matter collapses to the point that there's no outward pushing force to overpower gravity and it shows that objects can only ever be treated as outside the event horizon. When people claim that objects can reach the event horizon from their own frame it's a mistake in the application of that model. Reaching an event horizon is a frame independent event. It either happens or it doesn't, and it doesn't. It's the equivalent of accelerating past the speed of light.



#7 VictorMedvil

VictorMedvil

    The Human Shadow

  • Members
  • PipPipPipPipPipPipPip
  • 1404 posts

Posted 01 April 2019 - 08:14 PM

Well Photons still have Momentum thus they do fall into the black hole or infinitely circle in the photon sphere gravity still has the same effect on light as other things with mass, when hawking radiation happens photons do fall into the black hole.

 

The+Photon+Sphere.jpg

0b5ccbbd05167cc9fcd0016ed5391088.jpg


Edited by VictorMedvil, 01 April 2019 - 08:19 PM.


#8 Moronium

Moronium

    Creating

  • Members
  • PipPipPipPipPipPipPip
  • 2894 posts

Posted 02 April 2019 - 10:23 AM

This whole "airtight reasons" notion of Awol's has already been completely refuted in a couple of other threads, but he just won't give it up, eh?


Edited by Moronium, 02 April 2019 - 10:24 AM.


#9 Moronium

Moronium

    Creating

  • Members
  • PipPipPipPipPipPipPip
  • 2894 posts

Posted 02 April 2019 - 10:36 AM

Suppose I'm a villian who has tied a damsel to railroad tracks at 11 PM so the train scheduled to arrive at midnight can chop her body into three pieces.

 

I also leave her with a clock, so that she can watch the time tick away with an ever-increasing degree of distress as the moment of doom approaches.

 

But now suppose I forgot to wind the clock, and it just keeps slowing down until it finally stops completely when reading 11:29 PM.

 

Does the stopped clock save her life, ya figure?  Now midnight will NEVER show on her clock, eh?  Does that stop the oncoming train?


Edited by Moronium, 02 April 2019 - 10:43 AM.


#10 OceanBreeze

OceanBreeze

    Creating

  • Moderators
  • 1060 posts

Posted 02 April 2019 - 10:48 AM

And then along came Jones

 

Tall thin Jones

 

Slow-walkin' Jones

 

Slow-talkin' Jones

 

Along came long, lean, lanky Jones

 

 



#11 Moronium

Moronium

    Creating

  • Members
  • PipPipPipPipPipPipPip
  • 2894 posts

Posted 02 April 2019 - 10:56 AM

You forgot to include the audio demonstration to identify the source of your research, i.e., the great Coasters, eh, Popeye?  Here ya go:

 


Edited by Moronium, 02 April 2019 - 11:21 AM.

  • OceanBreeze likes this

#12 Moronium

Moronium

    Creating

  • Members
  • PipPipPipPipPipPipPip
  • 2894 posts

Posted 02 April 2019 - 11:00 AM

On a somewhat more serious note, way too many people seem to conflate the mechanical operation of a clock, which is designed to keep track of time, with time itself, eh?

 

Every day, all over the planet, various individual clocks stop for any number of reasons.  But, for some damn reason, I've yet to see such an instance make "time" stop for the entire universe..

 

As has been amply demonstrated empirically, so called "time dilation" (which should be called clock retardation), whether gravitational (GR) or due to speed (SR), slows down clocks.  But clocks are not time.  Time just marches on, undeterred and unaffected.

 

But don't try telling Awol that, eh?  Or anything else, for that matter.


Edited by Moronium, 02 April 2019 - 12:17 PM.


#13 Amplituhedron

Amplituhedron

    Questioning

  • Members
  • PipPipPipPip
  • 129 posts

Posted 02 April 2019 - 12:23 PM



On a somewhat more serious note, way too many people seem to conflate the mechanical operation of a clock, which is designed to keep track of time, with time itself, eh?

 

Every day, all over the planet, various individual clocks stop for any number of reasons.  But, for some damn reason, I've yet to see such an instance make "time" stop for the entire universe..

 

As has been amply demonstrated empirically, so called "time dilation" (which should be called clock retardation), whether gravitational (GR) or due to speed (SR), slows down clocks.  But clocks are not time.  Time just marches on, undeterred and unaffected.

 

But don't try telling Awol that, eh?  Or anything else, for that matter.

 

Holy ... I can't even ... this is a science forum???

 

Guess what, Mo ... in the relativistic scenario, clocks slow down because all physical processes, not just clocks, slow down!



#14 Moronium

Moronium

    Creating

  • Members
  • PipPipPipPipPipPipPip
  • 2894 posts

Posted 02 April 2019 - 12:26 PM

 

Holy ... I can't even ... this is a science forum???

 

Guess what, Mo ... in the relativistic scenario, clocks slow down because all physical processes, not just clocks, slow down!

 

Yeah, so?  Does that make "time" slow down or stop for the entire universe Mr. "Scientist?"  Suppose we put a guy into suspended animation, thereby slowing down all physical process, FOR HIM, for centuries while he "hibernates."  Does the entire universe then stop, until he is revived?

 

You "can't even" what?  Think, that it?


Edited by Moronium, 02 April 2019 - 12:58 PM.


#15 Moronium

Moronium

    Creating

  • Members
  • PipPipPipPipPipPipPip
  • 2894 posts

Posted 02 April 2019 - 12:44 PM

I can just see a guy on the verge of entering a black hole now, saying "My clock has stopped!" (not that he would ever say that, but let's just pretend, ya know?)

 

Then, just before swallowing him. the black hole says:  "Tough luck for you, chump, but guess what?  My gravity hasn't stopped.  Thanks for the snack."

 

But, wait...maybe there's a way to save him.  Suppose a guy millions of light years away comes to the rescue, like Jones.  The guy says to the black hole:  "Hey, you can't do that! Not on my watch!  According to my calculations, that guy's clock has stopped!"

 

I'm afraid the distant observer would get the same beatdown.  It wouldn't help.


Edited by Moronium, 02 April 2019 - 01:04 PM.


#16 Moronium

Moronium

    Creating

  • Members
  • PipPipPipPipPipPipPip
  • 2894 posts

Posted 02 April 2019 - 01:27 PM

Obviously, one insidious assumption underlying all of this "air tight reasoning" is that the subjective mental (or physical) thoughts, beliefs, opinions, perceptions, or other ideosyncrasies of a given individual serve to control all external objective reality.

 

As I've said before, this is just abject solipsism.  You can probably blame SR for the pervasiveness of this ridiculous assumption.


Edited by Moronium, 02 April 2019 - 01:34 PM.


#17 GAHD

GAHD

    Eldritch Horror

  • Administrators
  • 2669 posts

Posted 02 April 2019 - 04:48 PM

I'll just leave this here...

https://arxiv.org/pdf/0804.3619.pdf





Also tagged with one or more of these keywords: General Relativity, Black Holes