What Is Beyond The Observable Universe?

[Tenny]

Where ever you find yourself in the universe, you are both at its centre and at its edge.

Looking in any direction from any point in the universe is merely an observation into the history of the universe.

Einsteins equations tell us that it would take infinite energy to accelerate mass beyond c, so your kinda stuck with the first two statements.

"What is beyond the observable universe?" ...tomorrow is.





Thank you for describing my comments as poetry.

In a homogeneous and isotropic universe it could be said that, where ever you find yourself within it, your at it's centre.

Perhaps there is an assumption here that the universe is infinite and that Einsteins STR holds true.

Being at its edge and finding tomorrow beyond the observable is more cheeky i'll grant. But the universe has 4 dimensions (i'm sure someone will tell us it has more) and we live in its present, observe its past and wait for its future. So in that regard, we're at the edge.

Hi. Accepting that it has 4D's, 1 of time and 3 of space, isn't it a dodge to equate the edge with time ? What is it's spatial rather than it's temporal edge?

 

[nismaratwork]

Where ever you find yourself in the universe, you are both at its centre and at its edge.

Looking in any direction from any point in the universe is merely an observation into the history of the universe.

Einsteins equations tell us that it would take infinite energy to accelerate mass beyond c, so your kinda stuck with the first two statements.

"What is beyond the observable universe?" ...tomorrow is.





Thank you for describing my comments as poetry.

In a homogeneous and isotropic universe it could be said that, where ever you find yourself within it, your at it's centre.

Perhaps there is an assumption here that the universe is infinite and that Einsteins STR holds true.

Being at its edge and finding tomorrow beyond the observable is more cheeky i'll grant. But the universe has 4 dimensions (i'm sure someone will tell us it has more) and we live in its present, observe its past and wait for its future. So in that regard, we're at the edge.

I see your point, but doesn't that really imply that the notion of being at a center or edge is meaningless? Maybe that's your point. Consider that the universe, according to Hawking, has (from our point of view), a singularity at a Big Bang, and crunch. I'm not saying that is the case, but for the sake of using his globe model, lets. Our present exists at a definite point along time axis from BB->BC, or infinite expansion, it doesn't matter. We're not at an edge, or a center, but definite coordinates within a system we can't properly define, somewhere in the history, and future of the universe.

If you take away the future portion, then I see your point, in that for us the present is the leading edge of our experience in spacetime. If you consider spacetime as a complete structure with a past and future, we exist at a point in that structure, defined by our "when" which also defines our "where".

Being in a homogeneous and isotropic universe means that we cannot distinguish at large scales where we are in absolute terms, but in the strictest sense the time coordinate should solve that. I don't claim that this means that you could reach an "edge" to the universe and punch through that edge into something else. It might be better to say that no matter where you go in a homogeneous and isotropic universe, in spacetime, you'd eventually return to where and when you left, if you could travel in such a fashion.

I suppose my point is that you're speaking from our point of view, that of something embedded in this universe. It is entirely possible that beyond the observable universe, is nothing, or other universes, or cream cheese if we're being cheeky. As ants on the apple we can only deal with traversing this structure of (at least, as you say) spacetime in a particular way, but in an absolute sense, that doesn't remove the orchard.

Oh hell, you've gotten to me with your cheek and poetry. :p

 

[blandrew]

Hi. Accepting that it has 4D's, 1 of time and 3 of space, isn't it a dodge to equate the edge with time ? What is it's spatial rather than it's temporal edge?

Time could be said to be geometrically fundamental in regard to the universe.

I see your point, but doesn't that really imply that the notion of being at a center or edge is meaningless? Maybe that's your point. Consider that the universe, according to Hawking, has (from our point of view), a singularity at a Big Bang, and crunch. I'm not saying that is the case, but for the sake of using his globe model, lets. Our present exists at a definite point along time axis from BB->BC, or infinite expansion, it doesn't matter. We're not at an edge, or a center, but definite coordinates within a system we can't properly define, somewhere in the history, and future of the universe.

If you take away the future portion, then I see your point, in that for us the present is the leading edge of our experience in spacetime. If you consider spacetime as a complete structure with a past and future, we exist at a point in that structure, defined by our "when" which also defines our "where".

Being in a homogeneous and isotropic universe means that we cannot distinguish at large scales where we are in absolute terms, but in the strictest sense the time coordinate should solve that. I don't claim that this means that you could reach an "edge" to the universe and punch through that edge into something else. It might be better to say that no matter where you go in a homogeneous and isotropic universe, in spacetime, you'd eventually return to where and when you left, if you could travel in such a fashion.

I suppose my point is that you're speaking from our point of view, that of something embedded in this universe. It is entirely possible that beyond the observable universe, is nothing, or other universes, or cream cheese if we're being cheeky. As ants on the apple we can only deal with traversing this structure of (at least, as you say) spacetime in a particular way, but in an absolute sense, that doesn't remove the orchard.

Oh hell, you've gotten to me with your cheek and poetry. :p

Well, the faster than c expansion of the universe would presumably mean one would not return to the point of origin even if there is curvature.

"cream cheese" oh I do hope not, hate the stuff

 

[nismaratwork]

Time could be said to be geometrically fundamental in regard to the universe.

Well, the faster than c expansion of the universe would presumably mean one would not return to the point of origin even if there is curvature.

"cream cheese" oh I do hope not, hate the stuff

The +c issue is why I added the codicil, "if you could travel in such a fashion". The point about the geometry is possibly valid however. For cream cheese, how do you eat bagels? Cheesecake?! Bagels need cream cheese, they cry for it, and you would deny them this sweet offshoot of Neufchatel Cheese? No sir, I reject that premise; it's "[cream cheese] all the way down." :)

 

[Tenny]

Time could be said to be geometrically fundamental in regard to the universe.

I still don't get it. And earlier you posted ;

we live in its present, observe its past and wait for its future. So in that regard, we're at the edge

That would seem to me to be in the middle of the temporal dimension, not at the edge.

But why mix space and time ? Surely the three spatial dimensions I see around me are just that - three spatial dimensions! I don't feel I'm on the edge of the universe, though.

How can be ? I can see in all directions and there is more space. Isn't it shifting the goalpost to say I'm on the edge, but it's the edge in relation to time (which I still feel is a dodge) ?

 

[nismaratwork]

I still don't get it. And earlier you posted ;

we live in its present, observe its past and wait for its future. So in that regard, we're at the edge

That would seem to me to be in the middle of the temporal dimension, not at the edge.

But why mix space and time ? Surely the three spatial dimensions I see around me are just that - three spatial dimensions! I don't feel I'm on the edge of the universe, though.

How can be ? I can see in all directions and there is more space. Isn't it shifting the goalpost to say I'm on the edge, but it's the edge in relation to time (which I still feel is a dodge) ?

You mix space and time because that is a fundamental principle of Relativity. If you existed only in a space-like manner, you could not do anything, never mind looking around. There is a reason it's called "spacetime" and not "space and time".

 

[blandrew]

I still don't get it. And earlier you posted ;

we live in its present, observe its past and wait for its future. So in that regard, we're at the edge

That would seem to me to be in the middle of the temporal dimension, not at the edge.

But why mix space and time ? Surely the three spatial dimensions I see around me are just that - three spatial dimensions! I don't feel I'm on the edge of the universe, though.

How can be ? I can see in all directions and there is more space. Isn't it shifting the goalpost to say I'm on the edge, but it's the edge in relation to time (which I still feel is a dodge) ?

I guess this is the point of the homogeneous isotropic universe. It's only with the fourth dimension, that of time, that one can place oneself within it. In this context, I would equate "present" with "edge".

 

[blandrew]

The +c issue is why I added the codicil, "if you could travel in such a fashion". The point about the geometry is possibly valid however. For cream cheese, how do you eat bagels? Cheesecake?! Bagels need cream cheese, they cry for it, and you would deny them this sweet offshoot of Neufchatel Cheese? No sir, I reject that premise; it's "[cream cheese] all the way down." :)

Sultan-ed, sliced, toasted and buttered ...you can keep your "cream cheese" ... philistine! :)

 

[nismaratwork]

Sultan-ed, sliced, toasted and buttered ...you can keep your "cream cheese" ... philistine! :)

You sir, may be an excellent cosmologist, but when it comes to baked goods you are an unlettered barbarian. Without cream cheese, the lox cannot be properly ensconced in creamy goodness, and the scallions or red onion are too sharp. I believe this was known in the Neolithic period, when cave etchings clearly show our ancestors smoking salmon for bagels. I believe they preferred Philadelphia cream cheese too, but it's hard to translate as there was no Philadelphia at the time.

 

[Tenny]

I guess this is the point of the homogeneous isotropic universe. It's only with the fourth dimension, that of time, that one can place oneself within it. In this context, I would equate "present" with "edge".

I still don't get it. To equate the edge of the universe to time, seems to be just playing with language. To repeat once again, you said “we live in its present, observe its past and wait for its future. So in that regard, we're at the edge”

In what regard ? I am at the edge of the universe right now, according to earlier words here, including yours. But I certainly don’t feel like I’m at the edge of the universe. I can see the three dimensions around me, and I seem to be in the middle of them, not on some edge. And I can remember the past, and anticipate the future (to some degree). I certainly don’t feel like I’m at the edge of the universe in space, or in time, or in spacetime.

 

[Trenton]

It is highly probable our 'observable' universe is actually a black hole of radius 30, 40 or more billion light years (This is only the same as asking if it has enough mass to one day fall in on itself).

Outside this black hole will be yet more space with matter floating around and other black holes of course. (Purely my opionion, I can't prove it of course).

I don't buy this idea that outside the 'universe' is no time or space nor do I buy the multi-dimension idea

 

[DaveC426913]

It is highly probable our 'observable' universe is actually a black hole

Highly probable. Care to back that up with some references?

 

[blandrew]

I still don't get it. To equate the edge of the universe to time, seems to be just playing with language. To repeat once again, you said “we live in its present, observe its past and wait for its future. So in that regard, we're at the edge”

In what regard ? I am at the edge of the universe right now, according to earlier words here, including yours. But I certainly don’t feel like I’m at the edge of the universe. I can see the three dimensions around me, and I seem to be in the middle of them, not on some edge. And I can remember the past, and anticipate the future (to some degree). I certainly don’t feel like I’m at the edge of the universe in space, or in time, or in spacetime.

You kind of answer this yourself.

If I were to use an analogy. Let's say you've been reading a novel of indeterminate length for an indeterminate length of time. Well, you could say you were in the centre of the book and at the edge of the story.

I hardly think that's semantics.

 

[nismaratwork]

You kind of answer this yourself.

If I were to use an analogy. Let's say you've been reading a novel of indeterminate length for an indeterminate length of time. Well, you could say you were in the centre of the book and at the edge of the story.

I hardly think that's semantics.

In fact, knowing what is to come in the novel would still place you at the leading edge of whatever you know. There might be a middle, but you can also appreciate that in retrospect. Only seeing it as a complete structure with boundaries can allow you to overcome the homogeneity and isotropy, and that is definitely NOT how we live.

 

[Trenton]

Dave,

References no but only coz I don't get enough time to browse. The idea though, that we are in a black hole of perhaps 30 billion light years radius, maybe a lot more - is not that difficult to support. Much is made of so called 'missing mass' but when you look at the rudimentry approach to how mass is calculated it leaves a lot of room for inacuracy. Even without exotic theories (which I largely do not support) I suspect there is a lot more intergelactic gas, a lot more WIMPS and probably large numbers of 'failed galaxies' (which did not have enough rotational energy to avoid the entire ediface collapsing to a black hole). I could go on and on ...

 

[Trenton]

Further to the issue of the (observable) universe being a black hole; Should this turn out to be the case it is more likely that the galaxies are falling in rather than flying out. You can forget the 'current bun' model, it just would not apply. Instead the (apparent) expansion would be expalained better by progressive time dilation. Black holes are not wormholes (unless one is both an idiot and a fantasist) - but they are larger on the inside than on the out. You could fall into one and while away what would seem like years observing other infalling objects before hitting the singularity. The distance to the center would thus appear to be very large. This distance amplification would be very small in a large black hole but would be about the cosmological constant for a black hole of 30bn light years.

 

[George Jones]

The idea though, that we are in a black hole of perhaps 30 billion light years radius, maybe a lot more - is not that difficult to support.

Then support this with peer-reviewed mainstream references. Physics Forums Rules,

https://www.physicsforums.com/showthread.php?t=5374

in part, say

Overly Speculative Posts: One of the main goals of PF is to help students learn the current status of physics as practiced by the scientific community; accordingly, Physicsforums.com strives to maintain high standards of academic integrity. There are many open questions in physics, and we welcome discussion on those subjects provided the discussion remains intellectually sound. It is against our Posting Guidelines to discuss, in most of the PF forums or in blogs, new or non-mainstream theories or ideas that have not been published in professional peer-reviewed journals or are not part of current professional mainstream scientific discussion.

Personal theories are not allowed here.

 

[eha]

Some people still believes there is nothing beyond universe, and they don't even accept empty space or anything else. But they can't answer the question when you ask "How are you going to fill up the rest of the infite volume?" They can't realize the truth of "Black space extend forever". I wonder how many intelligent people are there can't see this fact? Isn't that hard to understand, am I wrong?

 

[DaveC426913]

...am I wrong*

Well, yes.

 

[nismaratwork]

Well, yes.

I believe you meant to say, "really really wrong."

eha: What exactly do you mean, because I find your wording vague, and you don't seem to offer obvious alternatives.

 

[Tenny]

You kind of answer this yourself.

If I were to use an analogy. Let's say you've been reading a novel of indeterminate length for an indeterminate length of time. Well, you could say you were in the centre of the book and at the edge of the story.

I hardly think that's semantics.

Definitely sounds like semantics or more.

How did you deterimine the centre of the book if it's length was INdeterminate ?

Edge of the story ? What does that analogise ?

 

[nismaratwork]

Definitely sounds like semantics or more.

How did you deterimine the centre of the book if it's length was INdeterminate ?

Edge of the story ? What does that analogise ?

I don't think you understand what it means that the universe is homogeneous and isotropic. I recommend a googling of the terms, and what they mean. The book analogy is really quite apt in 3+1 dimensions.

 

[eha]

Okay! What I say is; We are within a space which extends forever in 3D. Our universe occupies a certain volume within this infinite black space. We can't find even a one single atom outside our universe. I don't think there are another universe or universes around or in deep distant space. Our universe itself is a biggest miracle within endless space. The chance for another miracle is so slim, so slim nearly zero. I strongly believe these facts due to my knowledge in astronomy for 50 years and my logic.
I prefer to receive very short and very plain answers.
Thanks, love you all!

 

[Trenton]

George,

Less of the rules of overly speculative posts. The question of if there is sufficient mass to eventually arrest the expansion and lead to a crunch is an old one and all I am doing is re-phrasing it. It is mathematically the same as asking if the observable universe has a swartzchild radius large enough to contain it - ie is a black hole.

The story on this has to date been one of astronomers discovering more and more mass so it is quite probable more will be discovered.

Beyond that it is just a question of applying the relevant relativistic equations - which I either have got right or wrong.

It is not my fault people don't like the consequences of these equations.

 

[nismaratwork]

George,

Less of the rules of overly speculative posts. The question of if there is sufficient mass to eventually arrest the expansion and lead to a crunch is an old one and all I am doing is re-phrasing it. It is mathematically the same as asking if the observable universe has a swartzchild radius large enough to contain it - ie is a black hole.

The story on this has to date been one of astronomers discovering more and more mass so it is quite probable more will be discovered.

Beyond that it is just a question of applying the relevant relativistic equations - which I either have got right or wrong.

It is not my fault people don't like the consequences of these equations.

You agreed to rules when you joined, it's that simple.

 

[DaveC426913]

Okay! What I say is; We are within a space which extends forever in 3D. Our universe occupies a certain volume within this infinite black space. We can't find even a one single atom outside our universe. I don't think there are another universe or universes around or in deep distant space. Our universe itself is a biggest miracle within endless space. The chance for another miracle is so slim, so slim nearly zero. I strongly believe these facts due to my knowledge in astronomy for 50 years and my logic.
I prefer to receive very short and very plain answers.
Thanks, love you all!

eha, we do not entertain personal theories here; this forum is first and foremost a homework help forum and is conscientious about discussing established and accepted theories.

If you wish to submit a paper with your theories, there is a specific section for that with its own rules.

All this you agreed to when you signed up.

There are other fora where you can put up your personal ideas about the universe. This is not one of them.

 

[nismaratwork]

Okay! What I say is; We are within a space which extends forever in 3D. Our universe occupies a certain volume within this infinite black space. We can't find even a one single atom outside our universe. I don't think there are another universe or universes around or in deep distant space. Our universe itself is a biggest miracle within endless space. The chance for another miracle is so slim, so slim nearly zero. I strongly believe these facts due to my knowledge in astronomy for 50 years and my logic.
I prefer to receive very short and very plain answers.
Thanks, love you all!

Your basis is not scientific, but anecdotal. In short, this is your faith, and has no place here unless you can in some way support this with more than your espoused expertise. Words such as "miracle" are fanciful, not meaningful in this context. The argument that the universe is commonplace has been made as well, and nothing you've said refutes that. Care to rise to the challenge?

 

[Ich]

Beyond that it is just a question of applying the relevant relativistic equations - which I either have got right or wrong.

...which you have not done at all. So please provide references or the relevant equations.
Btw., swartzchild is not relevant, you might want to look up the vreedman equations instead.

 

[Tenny]

I don't think you understand what it means that the universe is homogeneous and isotropic. I recommend a googling of the terms, and what they mean.

I have a reasonable idea of what they mean. There was a statement made earlier by blandview (?) that we live at the edge of the universe. I queried this and was given some analogy, which I need to understand .. equally vague, in order to understand the former .. kind of circular, that!

Either that, or I'm just plain stupid and your intellect far surpasses mine - a possibility I'm ready to admit if readily shown. But all I've seen so far is circular argument and semantics - and the subtle changing of the meaning of words to suit.

The book analogy is really quite apt in 3+1 dimensions.

I am at the edge of the universe, (according to others previous posts) right ?

But I don't feel like I'm at the edge of the universe. I can see for miles in each direction - millions.

"Ah, the simpleton" I hear you say"

.. but anyway, you (and blandview more to the point) haven't 'splained it proply so far. And to say that the edge is the 4th dimension, time, kind of shifts the goalpost merely.

The present, is the futures past !

 

[blandrew]

I have a reasonable idea of what they mean. There was a statement made earlier by blandview (?) that we live at the edge of the universe. I queried this and was given some analogy, which I need to understand .. equally vague, in order to understand the former .. kind of circular, that!

Either that, or I'm just plain stupid and your intellect far surpasses mine - a possibility I'm ready to admit if readily shown. But all I've seen so far is circular argument and semantics - and the subtle changing of the meaning of words to suit.



I am at the edge of the universe, (according to others previous posts) right ?

But I don't feel like I'm at the edge of the universe. I can see for miles in each direction - millions.

"Ah, the simpleton" I hear you say"

.. but anyway, you (and blandview more to the point) haven't 'splained it proply so far. And to say that the edge is the 4th dimension, time, kind of shifts the goalpost merely.

The present, is the futures past !

"Blandview" i see what you done there.

Ok, this is what I originally posted:

"Where ever you find yourself in the universe, you are both at its centre and at its edge.

Looking in any direction from any point in the universe is merely an observation into the history of the universe.

Einsteins equations tell us that it would take infinite energy to accelerate mass beyond c, so your kinda stuck with the first two statements.

"What is beyond the observable universe?" ...tomorrow is."

-------------------

I think I've answered to, and explained this to the best of my ability in subsequent posts, so I'll not hijack this thread any longer.

I'm glad that I've aroused debate to some degree. Perhaps the issue here is the counter intuitive nature of the universe and/or the inadequacy of the English language.

 

[nismaratwork]

I have a reasonable idea of what they mean. There was a statement made earlier by blandview (?) that we live at the edge of the universe. I queried this and was given some analogy, which I need to understand .. equally vague, in order to understand the former .. kind of circular, that!

Either that, or I'm just plain stupid and your intellect far surpasses mine - a possibility I'm ready to admit if readily shown. But all I've seen so far is circular argument and semantics - and the subtle changing of the meaning of words to suit.



I am at the edge of the universe, (according to others previous posts) right ?

But I don't feel like I'm at the edge of the universe. I can see for miles in each direction - millions.

"Ah, the simpleton" I hear you say"

.. but anyway, you (and blandview more to the point) haven't 'splained it proply so far. And to say that the edge is the 4th dimension, time, kind of shifts the goalpost merely.

The present, is the futures past !

Yes, insult the people who are trying to explain a basic concept that you fail to grasp, that's going to provide strong motivation for anyone to help you. You're on your own.

 

[DaveC426913]

Yes, insult the people who are trying to explain a basic concept that you fail to grasp, that's going to provide strong motivation for anyone to help you. You're on your own.

nismar, I do not think he meant any insult (Note, by the way, that he did not actually make any insult). He is feeling frustration that he does not understand, though we seme to claim we are using simple words. It is most definitely not a "basic concept"!

See his frustration, don't take it as an attack.

 

[nismaratwork]

nismar, I do not think he meant any insult (Note, by the way, that he did not actually make any insult). He is feeling frustration that he does not understand, though we seme to claim we are using simple words. It is most definitely not a "basic concept"!

See his frustration, don't take it as an attack.

Generally manipulating a name (blandrew to blandview) is an insult, showing hostility. Frustration is understandable, but that doesn't mean this should degenerate into something hostile when the only reason the frustration exists at all is because the people he mentions are willing to engage at all.

If he doesn't understand, the best policy is to read, listen, research, and ask questions. Instead we get assertion after assertion, and pages of what appears to be a lack of independent inquiry.

I see his frusteration, and saw it earlier, but when that changed to something else I decided to walk away. I'm sorry, but "And to say that the edge is the 4th dimension, time, kind of shifts the goalpost merely..." is absurd, when that is in essence the point. He wants an answer that makes s certain kind of sense to him, rather than the correct answer, or best guess. How do you work with that, when there is no personal stake in his learning?

Out of respect for you Dave, Tenny: As far as you can see, and even beyond is a single time-like slice, and the next moment (t2) what is contained in that slice changes. Your place in the universe and your ability to see old light from a distance effects the range of space-like events you can observe in any moment. That is an edge in an indeterminant universe. To be in a center, you would have to define a beginning and end (to simplify), like the beginning and end of book. Then, with foreknowledge you say, "I'm at page 3 of 7"! In the universe, you can't tell how long the book is, and your position is bounded by your current position in spacetime.

 

[Trenton]

I did not mean to insult anyone and I appologise if I have done so. I conceed I lacked contrition when saying it was not my fault if people don't like the consequences of equations.

I am though baffled by the rules. No-one knows what lays beyond the observable universe and thus ANY thought we may have on the subject is speculative.

For the record I am not stating that the [observable] universe amounts to a black hole, meerly that it looks likely that it does - And if it does then there are other ways in which the cosmos can be viewed other than the presently entrenched version of the big bang.

On the subject in hand though, two things that are not speculative or a matter of opionion:-

1) The laws of physics and mathematics are valid regardless of weather or not there is anything to apply them too! For example 1+1=2 has always been and will always be true no matter if there is anything to count or an outside to the observable universe or not.

2) The radius of a black hole is proportional to it's mass.

One interpretation of (1) is that 'before and outside' are legal space-time coordinates.

And one interpretation of (2) is that black holes can be exceptionally large and have very low density and micro-gravity at the event horizon. It would still require light speed plus to escape to infinity.

I accept that this is a bit hard to get one's head round but unless it can be shown that gravity eventually departs from inverse-square, this interpretation is (at least mathematically) valid.

By contrast though, some of the solutions to the Einstein field equations are questionable because they yeild a singularity both at the center (valid) and at the event horizon (invalid). And yet some assertions about black holes seem to depend on the latter (eg an object falling into a black hole is seen to stop at the event horizon by an outside observer because time stops a this point). My interpretation of the horizon is that it is the point at which the escape velocity reaches C - which is not the same as saying an infalling object will reach C at this point (and anyway we all know it can't reach C). Any comments on this?

My interest in ultra-large black holes owes much to the fact that they illistrate quite clearly where these assertions are or seem to be faulty.

My best regards to eveyone - Trenton Maiers

 

[nismaratwork]

I did not mean to insult anyone and I appologise if I have done so. I conceed I lacked contrition when saying it was not my fault if people don't like the consequences of equations.

I am though baffled by the rules. No-one knows what lays beyond the observable universe and thus ANY thought we may have on the subject is speculative.

For the record I am not stating that the [observable] universe amounts to a black hole, meerly that it looks likely that it does - And if it does then there are other ways in which the cosmos can be viewed other than the presently entrenched version of the big bang.

On the subject in hand though, two things that are not speculative or a matter of opionion:-

1) The laws of physics and mathematics are valid regardless of weather or not there is anything to apply them too! For example 1+1=2 has always been and will always be true no matter if there is anything to count or an outside to the observable universe or not.

2) The radius of a black hole is proportional to it's mass.

One interpretation of (1) is that 'before and outside' are legal space-time coordinates.

And one interpretation of (2) is that black holes can be exceptionally large and have very low density and micro-gravity at the event horizon. It would still require light speed plus to escape to infinity.

I accept that this is a bit hard to get one's head round but unless it can be shown that gravity eventually departs from inverse-square, this interpretation is (at least mathematically) valid.

By contrast though, some of the solutions to the Einstein field equations are questionable because they yeild a singularity both at the center (valid) and at the event horizon (invalid). And yet some assertions about black holes seem to depend on the latter (eg an object falling into a black hole is seen to stop at the event horizon by an outside observer because time stops a this point). My interpretation of the horizon is that it is the point at which the escape velocity reaches C - which is not the same as saying an infalling object will reach C at this point (and anyway we all know it can't reach C). Any comments on this?

My interest in ultra-large black holes owes much to the fact that they illistrate quite clearly where these assertions are or seem to be faulty.

My best regards to eveyone - Trenton Maiers

4x5=10

How about quaternions?

 

[Trenton]

quaternions? Aren't they something to do with hamiltonians and complex numbers? Would you care to enlighten me as to where these might fit in? Hithertoo I was of the misapprehension that all one had to do was work out where to apply the Lorentz contraction.

 

[nismaratwork]

quaternions? Aren't they something to do with hamiltonians and complex numbers? Would you care to enlighten me as to where these might fit in? Hithertoo I was of the misapprehension that all one had to do was work out where to apply the Lorentz contraction.

My comment was in reference to your comment about the constancy of 1+1=2; it was meant to be a prod in the direction of the mutability of such things in different systems. You are correct that the relevance is in regards to commuting and non commuting operators.

 

[Tenny]

To mismaratwork, #281;

In post #279 I said ..

"There was a statement made earlier by blandview (?) that we live at the edge of the universe"

.. which you took as an insult, and said in post #283 ..

"Generally manipulating a name (blandrew to blandview) is an insult, showing hostility"

But "blandrew to blandview" was just a mistake on my part - as can be evidenced by the question mark (?) immediately following it. I was simply running on memory of what I had read earlier you see, and being relatively new, remembered the name wrongly. I was also on a dial up connection at that moment, (as I am right now) and you know how it is with dial up - to go back and forth, load several pages, etc, takes forever (just about).

Look - you even had some funnies in your #283 ..

“I see his frusteration”
(I hope not - I’m blushing, now)

“He wants an answer that makes s certain”
(not really - I see more certitude in ‘r’)

.. but I'm not too bothered. It's easy to make a mistake or two, isn‘t it ?

So you jumped the gun with YOUR hostility, but that's OK. Cheer up! You have no stake in my learning, nor did I ask for any from you. It is your choice however, to participate (or not) in an internet forum where many questions are bound to flow - even from dummies !

To blandrew #280

You said to me ..

"Blandview" i see what you done there"

I hope the above explains my error. No offence or hostility was intended on my part.


Thank you both for your responses. I'll have a good read of them and post later if I need to.

To Dave #282 - you said ..

“He is feeling frustration that he does not understand, though we seme to claim we are using simple words. It is most definitely not a "basic concept"!

Which really nails it, I think. Thanks.

 

[Trenton]

Good point nismar - I had not thought of that one. I shall mull that at length.

Another thing I am surprised I have not been pulled up on is event horizon disruption by neighboring black holes (and other outside mass). If the observable universe were a black hole among an infinite number of them randomly spaced, they would have to be very sparse to act as black holes.

Anyway in the meantime I am pondering a different matter. Hawkins radiation - Not at the event horizon but further in. Presumably the same mechanism would still apply. Of course the virtual particles would never escape but they would nonetheless mean that not all the mass of a black hole was concentrated at the center.

Has anyone else considered this or found any decent papers on it?

 

[nismaratwork]

Good point nismar - I had not thought of that one. I shall mull that at length.

Another thing I am surprised I have not been pulled up on is event horizon disruption by neighboring black holes (and other outside mass). If the observable universe were a black hole among an infinite number of them randomly spaced, they would have to be very sparse to act as black holes.

Anyway in the meantime I am pondering a different matter. Hawkins radiation - Not at the event horizon but further in. Presumably the same mechanism would still apply. Of course the virtual particles would never escape but they would nonetheless mean that not all the mass of a black hole was concentrated at the center.

Has anyone else considered this or found any decent papers on it?

Yes, but I also couldn't grasp the derivation, really HR is incredibly tough. I think the best way to think of the particle beyond the event horizon is the past of the particle which escapes. The math is really beyond me without sitting for specialized lectures, and even then I don't think I could grasp it.

 

[Max™]

http://news.nationalgeographic.com/news/2010/04/100409-black-holes-alternate-universe-multiverse-einstein-wormholes/

"What is new here is an actual wormhole solution in general relativity that acts as the passage from the exterior black hole to the new interior universe," said Easson, who was not involved in the new study.

"In our paper, we just speculated that such a solution could exist, but Poplawski has found an actual solution," said Easson, referring to Poplawski's equations.

Nevertheless, the idea is still very speculative, Easson said in an email.

"Is the idea possible? Yes. Is the scenario likely? I have no idea. But it is certainly an interesting possibility."

I'm not one to take exact EFE solutions lightly, it isn't proof, but it appears at least possible that this Universe is inside of a black hole in another Universe.

 

[Trenton]

Nismar,

I can't do the math either but before one even gets to that I can't properly picture the HR process in my mind.

Another example of my poor math is the above mentioned NAT GEOGRAPHIC article. It is obvious that time dilation gives rise to an 'inner universe' in black holes in that they are larger on the inside than the out - I was of this view more than 20 years ago but could not formulate a decent proof.

But back to HR - I have been contemplating something else though that may be HR related. The light emited from stars loses some of it's energy climbing away from the star's gravity. The star loses mass in producing the light of course but not all of that converted mass makes it out to infinity - part of it is lost to the redshift. Where does this missing mass end up? In the star in some other form than nuclear binding energy such a heat? And how?

Does anyone have a name for this conumdrum or know of any papers on it?

 

[Chronos]

The blackbody spectrum of the CMB is not a match to that expected from the interior of a black hole, Max.

 

[qmpash]

A big, nasty kid who is playing all kinds of jokes on us.

 

[ViewsofMars]

"What is Beyond The Observable Universe?" is the topic. Science only deals with the observable. We have The Big Bang Theory. It is extremely important to know what a theory means. Also, the following definition of a *theory* applies to every other scientific theory. Everyone should know this:

Theory
A scientifically testable general principle or body of principles offered to explain observed phenomena. In scientific usage, a theory is distinct from a hypothesis (or conjecture) that is proposed to explain previously observed phenomena. For a hypothesis to rise to the level of theory, it must predict the existence of new phenomena that are subsequently observed. A theory can be overturned if new phenomena are observed that directly contradict the theory.
http://map.gsfc.nasa.gov/site/glossary.html

 

[ViewsofMars]

What CMB blackbody spectrum would match a quantum particle sea of universes?
[/Color]

There are no "observable sea of universes."

 

[ViewsofMars]

If the Universe originated from a quantum particle, what CMB spectrum would match that?

The question is 'what is beyond the observable universe'?

A quantum particle sea of universes.
[/Color]

Orion, I already answered the questions. You need to read again and attempt to understand what I have previously posted. Also, a theory doesn't deal with "ifs." You need to first understand what a theory means. There are no universes. Period. End of story.

 

[Tenny]

Hello. I've read through the last several pages again recently, in an attempt to resolve the issue I was wondering about earlier. I still haven't been able to resolve it, and could even say I'm even more confused and mystified as to what's been said by some.

I have a reasonable understanding of what homogenous and isotropic means. And I ask again, how can it be said that I am, (and we) are at the edge of the universe ? I can see for countless millions of miles in any direction, so it certainly doesn't seem that I'm on any edge.

The analogy ..

'Lets say you've been reading a novel of indeterminate length for an indeterminate length of time. Well, you could say you were in the centre of the book and at the edge of the story (blandrew #263).

.. was given, but this merely confuses further, as it seems to be more vague than that which it is attempting to analogise. Worse, it seems to shift the meaning of the word 'edge' from a literal to a metaphorical one. I could say 'I'm at my wits end', or 'this is cutting edge stuff' but in both cases, I'm using a metaphor only.

In further posts it was suggested (I think) that time is the edge. But even with that, I can't see how I'm on the edge there either. We flow from the past to the future - and both past and future have a length (whatever that might be) so again, I do not feel I'm on the edge of time. In any case, I feel it is somewhat of a dodge (no hostility intended) to say that time puts me at the edge of the universe. It seems to me to be merely shifting the goalposts.

Please tell me how I'm at the edge of the universe, bearing in mind;

If you can't explain it simply, you don't understand it well enough.
Albert Einstein

Most of the fundamental ideas of science are essentially simple, and may, as a rule, be expressed in a language comprehensible to everyone.
Albert Einstein

 

[DaveC426913]

Please tell me how I'm at the edge of the universe, bearing in mind;

Keep in mind this is merely a spurious analogy, designed to show that sometimes "what we see" is not the only way to see things.

An ant is crawling on the surface of an balloon. Every direction it looks it sees more balloon surface - there are no boundaries, no edges. If the ant is not at the centre of this universe, it is certainly not near any edge.

I look down upon the ant from my vantage point. I can see that it is at the surface of the balloon. In fact, it is at the boundary of a sphere that is defined by the balloon's skin. Moreso, as I inflate this balloon, I can even say that the ant is on the leading edge of an expanding sphere that is defined by the balloon's skin.


The 2D surface of the balloon is analagous to our 3D universe (with one dminesion ignored). The expansion of the balloon in a radial direction is analagous to the movement of our 3D universe through the 4th dimension of time. The ant cannot go "forward" any more than the balloon expands. Outward is the future, inward is the past.

 

[Tenny]

Keep in mind this is merely a spurious analogy, designed to show that sometimes "what we see" is not the only way to see things.

An ant is crawling on the surface of an balloon. Every direction it looks it sees more balloon surface - there are no boundaries, no edges. If the ant is not at the centre of this universe, it is certainly not near any edge.

I look down upon the ant from my vantage point. I can see that it is at the surface of the balloon. In fact, it is at the boundary of a sphere that is defined by the balloon's skin. Moreso, as I inflate this balloon, I can even say that the ant is on the leading edge of an expanding sphere that is defined by the balloon's skin.


The 2D surface of the balloon is analagous to our 3D universe (with one dminesion ignored). The expansion of the balloon in a radial direction is analagous to the movement of our 3D universe through the 4th dimension of time. The ant cannot go "forward" any more than the balloon expands. Outward is the future, inward is the past.

Hi Dave. Thanks. Yes, I am familiar with your analogies above - very 'Flatland'.

Interesting that you to refer the 'edge of the universe' thing as a spurious analogy - I thought it was an actual proposition by other posters, and that analogies were given to explain THAT !

Anyhow, I need to think more about your, yes, clearer analogies.