[geordief]

Are you taking the piss, in what universe does matter get stuck outside the event horizon of a black hole. Do you have a citation?

I heard that phrase "Are you taking a piss?" in the movie Kingsman: The Secret Service. What does it mean? I live in New England. Is that phrase a British thing?

Citation? Sure On the Influence of Gravitation on the Propagation of Light by Albert Einstein, Annalen der Physik[/b], 35, 1911.

Taking the piss is different from taking a piss (although you could do both at the same time)
It means "are you joking?" broadly.(with a side of "are you winding me up" or  "getting a rise"? )

Also you could use it for someone only pretending to make an effort.

[guest45734]

I heard that phrase "Are you taking a piss?" in the movie Kingsman: The Secret Service. What does it mean? I live in New England. Is that phrase a British thing?Citation? Sure On the Influence of Gravitation on the Propagation of Light by Albert Einstein, Annalen der Physik[/b], 35, 1911. Do you have a reason to claim otherwise?

Taking the piss, humourous slang for are you making fun, as Geordief states above. You had not made it clear you were talking about light, and not matter. I had a picture of a SS Enterprise being sucked into a BH, and using warp drive was not able to escape.

[guest45734]

I had a picture of a SS Enterprise being sucked into a BH, and using warp drive was not able to escape.

Warp drive goes well over light speed so Enterprise should have no trouble with our black hole if the plot should require such.  Physics definitely takes a back seat to entertainment here.

Damn I thought it was a documentary But even if they came under the influence of a BH they would still need to accelerate to above warp speed to break lose, something they have struggled to do on many occasions. Many inferior space ships without the ability to eject the warp cores etc don't fare so well and disappear over the event horizon, sometimes maybe to other universes existing in our theoretical multiverse.

By some weird curvature of space, can an infinite universe exist as a separate entity in a multiverse, without overlapping other universes in the multiverse. If we exist inside a BH would our spacetime appear infinite but still be contained inside a BH, etc etc please dont answer this random thought provoked by Bills question on space.

[PmbPhy]

While your quote is apparently accurate in the RF of the distant observer; would it not be true that in its own RF, the infalling matter not only reaches, but crosses the event horizon?

Correct.

[PmbPhy]

I heard that phrase "Are you taking a piss?" in the movie Kingsman: The Secret Service. What does it mean? I live in New England. Is that phrase a British thing?Citation? Sure On the Influence of Gravitation on the Propagation of Light by Albert Einstein, Annalen der Physik[/b], 35, 1911. Do you have a reason to claim otherwise?

Taking the piss, humourous slang for are you making fun, as Geordief states above. You had not made it clear you were talking about light, and not matter. I had a picture of a SS Enterprise being sucked into a BH, and using warp drive was not able to escape.

It applies to both light and matter.

[David Cooper]

This business of things stopping at the event horizon came up before in a discussion here. If the speed of light falls to zero at the event horizon, then nothing can cross the event horizon, ever. Light and matter simply goes more and more slowly, effectively stopping, although it's never technically a complete halt.

The reason many people imagine that a space ship could cross the event horizon of a large black hole while the people inside it continue to live normally is that the lack of Newtonian time in GR (and SR) leaves the "time" dimension as the only kind of time in the model, and that provides no mechanism to allow any clocks run slow, so for the people in the space ship their clocks must keep on ticking at full speed. However, they will be systematically annihilated before they reach the event horizon because they'll actually be stuck there for countless billions of years while the black hole gradually evaporates - the mechanism behind Hawking radiation will eliminate every single piece of their matter.

It looks to me as if the only matter that can ever get into a black hole is the matter that collapses to form a black hole, and most of the material of a collapsing body will miss the party and end up sitting just outside the event horizon of the first part to become dense enough to become a black hole. Also, if multiple parts form separate black holes during the collapse of the body, those separate parts may not be able to merge because there may be material around and between them which cannot reach/cross any of the event horizons, so I predict that you'd actually end up with a set of black holes stuck together which collectively form a sphere, but which remain distinct from each other (and the same would happen with any black hole merger).

All the above is dependent on the idea that the speed of light reaches zero at the event horizon. Perhaps it only reaches zero outwards though. If it remains higher than that inwards, then there would presumably have to be a mismatch between the speed of light up vs. down at all altitudes in a gravity well. Would such a mismatch be detectable, has it been detected, and is it predicted by GR?

[PmbPhy]

There's a great book out by Nobel Laureate Kip S. Thorne called Black Holes & Time Warps: Einstein's Outrageous Legacy.

Anybody who wants to understand general relativity and black holes should own a copy of this book!

[Halc]

This business of things stopping at the event horizon came up before in a discussion here. If the speed of light falls to zero at the event horizon, then nothing can cross the event horizon, ever. Light and matter simply goes more and more slowly, effectively stopping, although it's never technically a complete halt.

I agree that we’re probably wrong about painting the picture just like this. I’ve heard that the official physics line says that things actually do fall in, but a description of how/when from the POV of various frames is typically omitted.  The book from Thorne recommended above perhaps covers this.

From my naive view, one can drop some material ‘on’ a black hole, which gets stuck when time dilates to nothing, but drop anything else and the event horizon expands just enough and swallows the earlier material. That sounds pretty wrong, but at least it gets stuff in there, and allows the original hole to form in the first place.

On another note is the observed behavior of the merger of two black holes, where one gets to observe something big fall in.  The gravity waves come slow at first but with increasing frequency, getting higher and higher until a brief ‘chirp’ at the end when the waves cease abruptly.  That’s a view from a distant frame, and yet it speeds up at the end.  If it got stuck on the surface, wouldn’t the waves slow to imperceptibility instead of speeding up?  This pattern was predicted before it was first witnessed.

On the ‘freeze’ front, I think it was Hawking that was disturbed by the seeming violation of conservation of information when things fell into a black hole, but this was solved by realizing that from any external moment in time, the information never makes its way in, and is thus not actually lost.

I’m just pointing out what I see is evidence on both sides of this fence.

The reason many people imagine that a space ship could cross the event horizon of a large black hole while the people inside it continue to live normally is that the lack of Newtonian time in GR (and SR) leaves the "time" dimension as the only kind of time in the model, and that provides no mechanism to allow any clocks run slow, so for the people in the space ship their clocks must keep on ticking at full speed. However, they will be systematically annihilated before they reach the event horizon because they'll actually be stuck there for countless billions of years while the black hole gradually evaporates - the mechanism behind Hawking radiation will eliminate every single piece of their matter.

The surviving the crossing is hypothetical.  You’re right in that the radiation there (which is only considered Hawking radiation if part of it escapes permanently) would likely explode our traveler as he compresses years of intense radiation into a millisecond.  The gravitational field inside is even more intense, and barring a description of the physics there, it is guesswork if a biological being could exist. The comment was just to point out that little black holes kill you via tidal forces before you ever get that close. The big ones need to use different means to kill you.

The part of the ship clock ticking at full speed is correct.  Except for the clock exploding in a radiation cloud, there would be no discontinuity or anything from a temporal standpoint.

It looks to me as if the only matter that can ever get into a black hole is the matter that collapses to form a black hole, and most of the material of a collapsing body will miss the party and end up sitting just outside the event horizon of the first part to become dense enough to become a black hole. Also, if multiple parts form separate black holes during the collapse of the body, those separate parts may not be able to merge because there may be material around and between them which cannot reach/cross any of the event horizons, so I predict that you'd actually end up with a set of black holes stuck together which collectively form a sphere, but which remain distinct from each other (and the same would happen with any black hole merger).

By that logic, all black holes would be of no size, each preventing additional mass upon reaching the threshold.  For that matter, each would then immediately evaporate, preventing actual formation of black holes.

So the view of stuff getting stuck on the surface is probably wrong, at least when worded that way.  I’d appreciate if somebody more informed (perhaps the answer from the book) would chime in.

All the above is dependent on the idea that the speed of light reaches zero at the event horizon. Perhaps it only reaches zero outwards though.

I think the answer lies on this front.  The event horizon of a BH is very much like the edge of the Hubble Sphere.  Time there is stopped relative to us and the big bang is still banging, because space itself (not just the matter) is moving away at lightspeed.  That is dilation due to relative speed, not gravity, so the analogy might not be appropriate.  I know it is invalid to apply the rules of an inertial frame over distances large enough for space to not be flat.

If [lightspeed] remains higher than that inwards, then there would presumably have to be a mismatch between the speed of light up vs. down at all altitudes in a gravity well.

Doesn’t much matter if time is dilated to zero. Insufficient speed isn’t the problem.  Light speed going down could be 3c, but it isn’t going to help if it has no time to go anywhere.

Bottom line is I don’t know the answers.  I’m no GR expert.

[guest45734]

There's a great book out by Nobel Laureate Kip S. Thorne called Black Holes & Time Warps: Einstein's Outrageous Legacy.

Duly ordered from Amazon https://www.amazon.com/Black-Holes-Time-Warps-Commonwealth/dp/0393312763

I think at least two of the dimensions (the y and z I spoke of in the 'spinning' topic) are finite: You can see the back of your head if you look that way.  Light already orbits black holes well outside the event horizon, so finite space doesn't just happen within.  To escape a black hole that far out, going in those directions with maximum power will avail you not.  You have to go in the negative x direction to attempt escape.  This is counterintuitive to orbital mechanics where the best way to escape orbit is to thrust in the positive y direction.Sorry, I ignored your request, and took a stab at this answer.

I disapeared into a BH where time and space did not exist and reappeared via a wormhole inside an expanding white hole in new space time, when I first thought about this. For some it is quite an explosive idea, Big Bangs and QLG

For objects entering a Black hole time slows, it does not accelerate. A photon can not stop moving at light speed trying to leave a BH it simply is redshifted to death and ceases to exist, before reaching the event horizon.

An ER bridge represents a Back door in BH theory. The paper on ER bridges was published one month after the paper on EPR bridges. ER and EPR are generally thought to be equivalent.

A dimension/wormhole connecting different areas/volumes of space time back to a single point inside a BH where space time does not exist is an amusing thought. Is a big bang from a singularity existing inside a BH more likely to have occured through the event horizon of the BH or via a wormhole to all points in space time (appearing perhaps as dark energy governed by HUP, I guess maybe not, best read Petes book:) )

Jean Luc Picard of the SS Enterprise did eject his warp core causing a huge explosion allowing him to escape a BH, allowing him to return to base on impulse engines only.

[Colin2B]

Are you taking the piss, in what universe does matter get stuck outside the event horizon of a black hole. Do you have a citation?

I heard that phrase "Are you taking a piss?" in the movie Kingsman: The Secret Service. What does it mean? I live in New England. Is that phrase a British thing?

There are a few piss terms like piss-poor, and one is piss-proud which means false pride, no reason to be proud. So anyone knocking that false pride down was said to be taking the piss out of someone. It appears to have changed meaning over the years and now means making fun of, possibly because anyone knocking the false pride would tend to ridicule it. Also piss-proud has fallen out of fashion so the derivative has been left hanging.

[David Cooper]

...but drop anything else and the event horizon expands just enough and swallows the earlier material. That sounds pretty wrong, but at least it gets stuff in there, and allows the original hole to form in the first place.

If the speed of light is zero at the event horizon both outwards and inwards, any expansion of the event horizon may drive the material next to it further out rather than swallowing it, but even if it does swallow it, there is likely no further movement towards any singularity that might be in the middle. For a long time we've been given accounts of black holes (involving things falling in and joining a singularity at the centre) which were pushed as facts but which now look very dodgy indeed.

On another note is the observed behavior of the merger of two black holes, where one gets to observe something big fall in.  The gravity waves come slow at first but with increasing frequency, getting higher and higher until a brief ‘chirp’ at the end when the waves cease abruptly.  That’s a view from a distant frame, and yet it speeds up at the end.  If it got stuck on the surface, wouldn’t the waves slow to imperceptibility instead of speeding up?  This pattern was predicted before it was first witnessed.

I was hoping that gravity waves would show us something about the merger of two singularities, revealing what can't normally be detected, but that is apparently not the case - all we get is information from that about the event horizons merging, and almost all the mass of the black holes could be stored at those event horizons rather than deeper inside.

On the ‘freeze’ front, I think it was Hawking that was disturbed by the seeming violation of conservation of information when things fell into a black hole, but this was solved by realizing that from any external moment in time, the information never makes its way in, and is thus not actually lost.

I think he was onto something, but it's likely that most of the light and matter never makes it in either.

Also, if multiple parts form separate black holes during the collapse of the body, those separate parts may not be able to merge because there may be material around and between them which cannot reach/cross any of the event horizons, so I predict that you'd actually end up with a set of black holes stuck together which collectively form a sphere, but which remain distinct from each other (and the same would happen with any black hole merger).

By that logic, all black holes would be of no size, each preventing additional mass upon reaching the threshold.  For that matter, each would then immediately evaporate, preventing actual formation of black holes.

The event horizons would grow as material piles up against them. It may reach sufficient density there to produce its own event horizon, adding to a pile of conglomerated black holes that don't fully merge. If that happens, there could be a permanent barrier to them evaporating because Hawking radiation might only be able to come from material that's stuck outside the outermost event horizon. There is therefore no guarantee that a mini black hole created by a particle accelerator would immediately evaporate away - it could be a one-way process which only allows it to hold station or grow. We need to prove that that isn't the case before we do anything reckless.

If [lightspeed] remains higher than that inwards, then there would presumably have to be a mismatch between the speed of light up vs. down at all altitudes in a gravity well.

Doesn’t much matter if time is dilated to zero. Insufficient speed isn’t the problem.  Light speed going down could be 3c, but it isn’t going to help if it has no time to go anywhere.

We shouldn't take if for granted that GR or any other theory is correct. If you have a mismatch in the speed of light in opposite directions (faster down than up), then you may have some opportunity for things to continue functioning, allowing a light clock to cross an event horizon and to continue ticking while it does so. It would be good either way if we could rule that in or out, if anyone knows of any experiment that resolves the issue.

[evan_au]

The illuminous region around the BH's gravitational field represents it's external boundary

There is a region called the "photon sphere", which is outside the event horizon (at 50% greater radius). If you emitted a flash of light here, you would see a series of light echoes as photons from the flash repeatedly orbit the black hole.

Light emitted within the photon sphere eventually finds its way into the black hole.
By itself, the photon sphere does not emit any light, so you could not call this region "luminous".
However, matter in an accretion disk around a rotating black hole is subject to severe shear forces, which does emit a lot of light (including infra-red at the outer parts, and X-Rays at the inner edge).
See: https://en.wikipedia.org/wiki/Photon_sphere

The illuminous region around the BH's gravitational field represents ... is a reflection of the incoming light striking a mass.

If there is no infalling matter (eg from a closely-orbiting companion star) then there is no mass between the photosphere and the event horizon (...if you ignore the hypothetical, microscopically thin, microwave-shifted skin of star matter that fell into the event horizon when the black hole first formed).
For a black hole that is not actively consuming matter, there is no luminous region around it.

This reflection is similar to what occurs on a star, The cooler substrata below the star's surface creates a barrier that the hotter corona reflect off of. During a coronal () we see the cooler substrata mass.

I am not sure what "coronal" event you are talking about - maybe a Coronal Mass Ejection, or the Corona that is visible during an eclipse by the Moon?
But in any case, the density of the corona is so low, and the corona's total light output is so low that it is only visible from Earth's surface during a total solar eclipse. (Space telescopes can see it at other times using a coronagraph - but they don't need to battle Earth's atmosphere...)

Apart from solar eclipses, all that we see of the Sun is the lower layers of the Sun's atmosphere - the photosphere (not to be confused with the photon sphere around black holes!). We don't need to wait for some special coronal event to see it. The photosphere is not solid, and it tends to absorb light rather than reflect it.

The photosphere has almost a black body spectrum of around 5500C, overlain with fine emission and absorption lines from elements in the Sun. It does not reflect the spectrum of the corona (which has a temperature in the millions C).
See: https://en.wikipedia.org/wiki/Photosphere

[guest46746]

 excuse my dyslexia. I sometimes can proof read and still not distinguish my thoughts from what appears on paper. I was referring to a coronal hole. The cooler substrate acting as a barrier for the hotter surface, to reflect the outpouring  of light, as in a mirror with a black backing reflecting an image, it was a bad analogy. To compare the perimeter of the BH's gravitational boundary perimeter with the light reflecting off the mass of the Earth seemed a worst analogy, as it would cause greater confusion but for visualization  it goes to much to my point,. Incoming light reflecting off the greater mass. lol

[guest46746]

We shouldn't take if for granted that GR or any other theory is correct. If you have a mismatch in the speed of light in opposite directions (faster down than up), then you may have some opportunity for things to continue functioning, allowing a light clock to cross an event horizon and to continue ticking while it does so. It would be good either way if we could rule that in or out, if anyone knows of any experiment that resolves the issue.

As i iread this and attempted to formulate a response, the chirality of the BH came to mind. What if the chirality of the black hole was perpendicular to the lefthanded chirality of the Universe? Meaning it was not righthanded chiralty rather it's chiralty was up and down. It would operate the opposite of drawing water up a well. The draw would act as a downward pump and sucking light down a velocity enhancer. The opening and closing  creating a vacuum. lol

[guest45734]

Is it possible all the mass of black holes exists in the event horizon, beyond which is a wormhole, where time and space do not exist as we know it. A pre big bang state.

A link for numpties to get a clue at what I am driving at http://jila.colorado.edu/~ajsh/bh/schww.html

The event horizon is clearly very hot, and decomposing matter into gamma rays as evidenced by Pulsars. The event horizon is therefore decomposing matter, and reducing the overall mass of the event horizon. 

At the Big Bang as space time expanded is not possible that holes appeared where space time did not expand.

Is it possible that these holes still exist and are what we understand to be BH's today.

Is it further possible that gravity has a maximum where virtual particles cease to exist.

Black holes exist at the centre of all galaxies, can gravitational energy be converted to matter.

Edit after some googling I came across gravitational geons, which might answer can gravitational energy be converted to matter question.

[guest46746]

Is it possible that these holes still exist and are what we understand to be BH's today. Is it further possible that gravity has a maximum where virtual particles cease to exist.

Just my initial thought as reading. Space/time exist initially as having one D and two D dimensional property. This corresponds to hypothesis of folded space.   This time/space acts as an envelope for 3D mass, it inflates as mass enters. The uniformity of inflation is imperfect and residuals points/pockets of 1D and 2D space remain intact.   These space time points/pockets not possessing 3D properties don't abide by GR. They abide by a lesser attributes.  These lesser properties don't include 3D waves in attributes, but they accommodate 3D wave principles in expansion.  So, without 3D waves to open space/time, they accelerate possibly  folding back on themselves. To time travel would mean expanding 2D space along an already folded space/time acceleration. lol. 

As far as BHs providing a path to this folded space/time acceleration,  the space between the two could theoretically be adjoined or not. If the space/time  acceleration was adhering to our 3D universe then it would seem plausible that a entry could be possible. If the space/time acceleration fold was not adhered to our 3D universe, it seems possible that the BH in all likelihood would evaporate. lol

[guest46746]

These space time points/pockets not possessing 3D properties don't abide by GR. They abide by a lesser attributes. 

These space time points/pockets not possessing 3D properties don't abide by GR. They abide by a lesser attributes.

These points/pockets remanents could be Back Holes. These BHs could be impervious to 3D invasiveness. If so they are sealed artifacts of a monopole one and two dimensional time. lol

[Bill S]

Space/time exist initially as having one D and two D dimensional property.

My understanding is that 1D space (n=1) is a mathematical tool, but I would be interested to know of a physical example.

Surely, in order to act as a "pocket", 2D space would actually need a third dimension, so, would not be 2D.

[guest46746]

My understanding is that 1D space (n=1) is a mathematical tool, but I would be interested to know of a physical example.Surely, in order to act as a "pocket", 2D space would actually need a third dimension, so, would not be 2D.

A point is a physical example, theoretically a BH could be a single point making it a one dimensional singularity.

Space/time acceleration preceeds Light and/or gravitational waves as a fabric.  It travels as a 2D linear model. Imagine pre Light big bang, an acceleration of sub-elementary particles was transpiring, having no structure, the recombining period was essentially 2D. Yet, it was advancing/accelerating as time/space but w/o mass. Light eventually emerged  it did so as a product of the time/space 2D fabric. The Space/time fabric however didnot stop it's acceleration, it continued with Light constrained by its own speed of light limitation in the new 3D dimension, moving slower and in the wake of 2D acceleration. Being a product of space/time and literally tied to it's apron strings, it follows opening the faster and advancing 2D structure in a continuim fashion much like a zipper. lol

[guest45734]

My understanding is that 1D space (n=1) is a mathematical tool, but I would be interested to know of a physical example.Surely, in order to act as a "pocket", 2D space would actually need a third dimension, so, would not be 2D.

A point is a physical example, theoretically a BH could be a single point making it a one dimensional singularity.

Space/time acceleration preceeds Light and/or gravitational waves as a fabric.  It travels as a 2D linear model. Imagine pre Light big bang, an acceleration of sub-elementary particles was transpiring, having no structure, the recombining period was essentially 2D. Yet, it was advancing/accelerating as time/space but w/o mass. Light eventually emerged  it did so as a product of the time/space 2D fabric. The Space/time fabric however didnot stop it's acceleration, it continued with Light constrained by its own speed of light limitation in the new 3D dimension, moving slower and in the wake of 2D acceleration. Being a product of space/time and literally tied to it's apron strings, it follows opening the faster and advancing 2D structure in a continuim fashion much like a zipper. lol

Ref Singularities and missing dimensions at the point of the big bang expansion of space and time. Could the inside of a BH be similar in that time ceases to exist or time stops ticking forward for an object at  the assumed singularity at the centre of a BH.

Ref time travel, time can be slowed by gravity, but it can not go backwards. It is not possible to go back in time with todays lottery numbers and influence the outcome. From that point of view time travel is pretty useless. But it is key to maintaining the accuracy of GPS systems.