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Author Topic:   What is "the fabric" of space-time?
Silent H
Member (Idle past 5820 days)
Posts: 7405
From: satellite of love
Joined: 12-11-2002


Message 106 of 327 (459103)
03-03-2008 10:23 PM


the gravity of general relativity
Looking for people to cure a bit of my own ignorance. As with the original poster, I (mis?)understood General Relativity (GR) to say that mass tells spacetime how to curve, and spacetime tells mass how to move. That creates an image of mass acting on spacetime, or let's say the "fabric" of spacetime.
I'm not so hung up on what that fabric is, as I get the idea of fields. But I am very curious about GR's actual tenets regarding mass v spacetime, what they mean, and why I am unable to make sense of (or accept) them so readily.
So first off, is my understanding correct or not? Does GR state or imply that mass acts on spacetime? I thought the idea was that GR replaced the concept of gravity as a force between objects, with gravity as a force between an object and spacetime.
If this is true so far, then what is the difference (mathematically and experientially) of a force acting between objects and one of a force acting on spacetime (such that it then effects the motion of other bodies). Wouldn't Occam's razor come in to play if there is no difference (beyond the math), and remove ST as a metaphysical intermediary?
I imagine issues such as changing time rates at different distances from an object's surface might be a measurable experiential effect.
There has been mention that physicists are seeking a "graviton" which would be the gravitational equivalent of the "photon". This confused me as it seems to inherently dismiss GR's implications for gravity, and reasserts the idea of gravity being a force between two objects. Where have I messed up, or is there a disconnect between gravitons and GR theory?
That's probably enough mistakes for now. I hope people understand I am not questioning the utility of ST as a mathematical tool for understanding observed phenomena, just that I'm having problems with understanding it as an actual "thing" which gets acted upon by objects and then acts upon other objects.
Edited by Silent H, : +by,actual
Edited by Silent H, : a/an

h
"Civilized men are more discourteous than savages because they know they can be impolite without having their skulls split, as a general thing." - Robert E. Howard

Replies to this message:
 Message 108 by cavediver, posted 03-04-2008 4:35 AM Silent H has replied

  
PaulK
Member
Posts: 17822
Joined: 01-10-2003
Member Rating: 2.2


Message 107 of 327 (459119)
03-04-2008 1:18 AM
Reply to: Message 105 by randman
03-03-2008 9:18 PM


quote:
"nothing but themselves" is still something PaulK. If matter and energy are derived properties from the field, what are the properties of the field?
But it's not your "non-physical" energy. And it means that it doesn't make any sense to ask what the fields consist of.
The properties of the fields are described mathematically. I'm sure that Cavediver would give you the mathematics if you asked. I don't think that either of us would really understand that, though.

This message is a reply to:
 Message 105 by randman, posted 03-03-2008 9:18 PM randman has replied

Replies to this message:
 Message 112 by randman, posted 03-04-2008 10:45 AM PaulK has replied

  
cavediver
Member (Idle past 3644 days)
Posts: 4129
From: UK
Joined: 06-16-2005


Message 108 of 327 (459131)
03-04-2008 4:35 AM
Reply to: Message 106 by Silent H
03-03-2008 10:23 PM


Re: the gravity of general relativity
As with the original poster, I (mis?)understood General Relativity (GR) to say that mass tells spacetime how to curve, and spacetime tells mass how to move. That creates an image of mass acting on spacetime, or let's say the "fabric" of spacetime.
Yes, this is a reasonable description of GR. GR treats space-time and matter as two different entities. I have been explaining the unified picture, where GR and matter are both aspects of some super-fundemental master field. It is the search for the consistent physical theory of this unification that is at the heart of much of modern theoretical physics.
I thought the idea was that GR replaced the concept of gravity as a force between objects, with gravity as a force between an object and spacetime.
Yes, this is true. But mass acting on space-time is very different. 'Forces' concern action-at-a-distance. Mass at a point acts on space-time at that point. The wider-area effect on space-time has nothing to do with the mass, but the properties of space-time. In the usual ball-bearing on rubber sheet, the ball creates the displacement in the sheet at the point of contact, but the surrounding depression is a result purely of that local displacement and the elastic properties of the sheet - it is nothing to do with the mass itself.
There has been mention that physicists are seeking a "graviton" which would be the gravitational equivalent of the "photon". This confused me as it seems to inherently dismiss GR's implications for gravity, and reasserts the idea of gravity being a force between two objects. Where have I messed up, or is there a disconnect between gravitons and GR theory?
A graviton is simply the smallest possible fluctuation in space-time, a result of applying standard quantum thinking to GR. In terms of the rubber sheet, it is essentially the quantum of displacement. This not so much brings GR 'down' to the level of force, as brings electromagnetism 'up' from a simple 'force' picture, to the level of a geometric theory. And this must happen as we expect all of the fields (space-time, electromagnetism, strong, weak, matter) to be different aspects of the one unified field.

This message is a reply to:
 Message 106 by Silent H, posted 03-03-2008 10:23 PM Silent H has replied

Replies to this message:
 Message 115 by Silent H, posted 03-04-2008 1:51 PM cavediver has replied

  
cavediver
Member (Idle past 3644 days)
Posts: 4129
From: UK
Joined: 06-16-2005


Message 109 of 327 (459134)
03-04-2008 7:17 AM
Reply to: Message 96 by randman
03-03-2008 3:44 PM


Please, no replies to this message that do not bear directly on the topic. --Admin
Randman, the reason I do not like replying to you is the because of the constant misrepresentation - either of myself or of the ideas I have presented. This becomes very tiresome, especially after two to three years of the same.
Just now you have repeatedly and falsely stated that I described the fields as 'nothing'.
Right here you have declared that
Different thread you did the same thing, insisting everything was deterministic.
when I have done no such thing.
You repeatedly ask me questions that I have already answered, claiming that I have yet to answer!
The questions I asked of you are:
...Call it information if you want. Call it X. It doesn't matter because I am just trying to get at what we do know about it. I think we know it's not physical, not matter and energy, but that it is potential.
How would you describe it?
Cavediver, they exist as something, right? Let's go with no energy and no mass, right? But they exist as something since they can be mathematically described, right?
How would you characterize that something? As mathematical principles and design?
Still waiting for your response.
No, you are not still waiting. You have been told repeatedly. I would describe 'it' mathematically, and characterise that 'something' as mathematics. That is all there is. If you want another word, then it would certainly not be design. If anything, in my mind, it would be inevitability.
How do you define physical?
Already answered. That that makes up the Universe is 'physical'.
Are you ever going to try reading my answers? Or do you just prefer to claim that I haven't answered them?
Edited by Admin, : Add a moderator request.

This message is a reply to:
 Message 96 by randman, posted 03-03-2008 3:44 PM randman has replied

Replies to this message:
 Message 111 by randman, posted 03-04-2008 10:27 AM cavediver has not replied

  
Admin
Director
Posts: 12998
From: EvC Forum
Joined: 06-14-2002
Member Rating: 2.3


Message 110 of 327 (459138)
03-04-2008 10:01 AM


A Word from Board Administration
Please let board administration deal with problem members. Because open discussion between moderators and members about moderator decisions was draining ever increasing amounts of moderator time, that entire approach was abandoned earlier this year and the moderator threads were closed, but one new one was added, Windsor castle.
The changes also included a decision to become much more mechanically "by the book" with regard to enforcement of the Forum Guidelines. Mature adults should be able to follow simple requests such as, for example, "Please address the topic and do not accuse people of dishonesty and misrepresentation." Those who cannot follow this or any such similarly simple instructions will be given short suspensions, though of course they become longer if the behavior continues.
I don't know why some people are the way the are. Ideally a moderator would suggest to someone that, for example, they tone it down a little, or that they learn a little about a topic before discussing it, or that they take a little care to express themselves more clearly, and they would do so. But in the real world people are for the most part who they are, and someone posting like an idiot is most likely doing so because, and pardon my shouting, HE'S AN IDIOT!
I used to say all the time that EvC Forum is not here to host nonsense discussions, and one thing that is impossible to do is to convince someone that their pet idea is nonsense. EvC Forum stands ready to entertain all ideas that are presented with evidence and rational argument, but without this approach the random idea that might pop into someone's head is just nonsense, independent of whether it is right or wrong. Here at EvC Forum, moderators make the decisions about what is and isn't nonsense.
Why this strong focus on what is fundamentally a scientific approach to examining ideas? It's very simple. EvC Forum exists to examine creationism's claim to be legitimate science. Those who don't know science from seance are in no position to make the scientific case for creationism, and we actually do creationism a favor by not permitting them to participate here, since they can only place creationism in a bad light.
--Percy
Edited by Admin, : Add thread link.

--Percy
EvC Forum Director

  
randman 
Suspended Member (Idle past 4899 days)
Posts: 6367
Joined: 05-26-2005


Message 111 of 327 (459140)
03-04-2008 10:27 AM
Reply to: Message 109 by cavediver
03-04-2008 7:17 AM


I would describe 'it' mathematically, and characterise that 'something' as mathematics. That is all there is.
This is the problem I have with your claiming I am misrepresenting you, or do not understand. Mathematics is not a quantum field, a universal field, or whatever. Mathematics is not even a physical science. Math is a field of study, however.
So when asked about what constitutes "it" which gives rise to space-time, the underlying fields or field that govern the physical world, giving rise to energy and matter and you say you would characterize "it":
as mathematics
And:
That is all there is.
Then you shouldn't be surprised if someone either questions that or restates in a manner you don't like, and that's because math isn't physical. Keep in mind you just didn't state you would describe it mathematically, but that it is math. You also stated it does not consist of "anything", and that it has no energy, nor mass.
So a layman's term for the things you described might well just be "nothing physical" based on your comments.
Math isn't physical, and you said that's all there is. Hmmmm......and yet you are "tired" of my comments?
You stated it has no energy, nor matter, right?
On your definition of physical, I followed up pointing out then that if God is real, He is physical.
Shouldn't physical things be subject to physical laws and properties such as energy and matter and local realism? I think if you define anything that exists, period, as physical, then if there are, just to use an example, angels, demons, God, souls, human spirits, spiritual forces like love, etc,.....they would all have to be physical, and that regardless, you are claiming fields are physical even if they have no mass, nor energy.
In fact, you are disagreeing with mainstream science because you are saying that math is physical, but in reality math is not a physical thing. You can say it describes a physical thing, but regardless, it is not itself physical. You contradict yourself then to say these fields are math and "that's all there is" and then try to suggest they are physical.
Edited by randman, : No reason given.

This message is a reply to:
 Message 109 by cavediver, posted 03-04-2008 7:17 AM cavediver has not replied

  
randman 
Suspended Member (Idle past 4899 days)
Posts: 6367
Joined: 05-26-2005


Message 112 of 327 (459145)
03-04-2008 10:45 AM
Reply to: Message 107 by PaulK
03-04-2008 1:18 AM


Unanswered Questions
Let's deal with some facts. Specifically, you admit that entanglement is real, standard QM, correct?
That entangled particles are spatially seperated with no physical connection between them, right?
I showed that because they act as one system instantly regardless of distance. There are no known particles that act faster than the speed of light to communicate between the particles, and the particle would have to always vary it's speed for instanct action, right?
So let's deal with that because it's a hard fact, observable and predicted by QM and relates specifically to the subject at hand.
This is how a prominent quantum physics scientist refers to the entanglement process:
The spooky effect at a distance is a process outside time and space that even I can't really imagine. But I believe that quantum physics tells us something very profound about the world. And that is that the world is not the way it is independently of us. That the characteristics of the world are to a certain extent dependent on us.
Anton Zeilinger, Mathias Plüss, Regina Hügli: Spooky action and beyond (16/02/2006) - signandsight
Please note his comment it "is a process outside time and space."
There is a reason he says that, and it's the same thing I am saying. Nothing within space-time can connect the particles due to certain limiting principles such as the speed of light and local realism.
Contrary to the derogatory comments offered here, all I am really saying on QM (as far as the science of it) is the same thing quantum physicists say themselves. For some reason EvCers just don't want to accept it, but this is mainstream stuff.
There is a reason Einstein called the process of entanglement "spooky", and there is a reason it has puzzled scientists ever since. We know it's real, but it shows that the particles are connected OUTSIDE TIME AND SPACE.
Now, you can define as cavediver wishes to something physical as anything whatsoever if it's in the universe, but that doesn't change the fact it has no physical properties under what is normally thought of as physical. Whatever word you wish to use, we have a field, or a connection or whatever, that is not strictly within space and time, or not only within space and time, and in reality, when you dig further than this little example, we see energy, mass, time and space are just products of whatever this is.
So lemme ask you something as an aise: step back for a minute and ask yourself where else you have heard that there are realms outside of time and space, where else you have heard that are non-physical (from a layman's understanding) realms?
What we have here are properties of a system, but a large part of that system is not confined to physical properties such as space, time, energy and mass.

This message is a reply to:
 Message 107 by PaulK, posted 03-04-2008 1:18 AM PaulK has replied

Replies to this message:
 Message 114 by Admin, posted 03-04-2008 1:32 PM randman has not replied
 Message 116 by PaulK, posted 03-04-2008 1:53 PM randman has replied
 Message 134 by bluegenes, posted 03-05-2008 2:08 PM randman has not replied

  
lyx2no
Member (Idle past 4717 days)
Posts: 1277
From: A vast, undifferentiated plane.
Joined: 02-28-2008


Message 113 of 327 (459162)
03-04-2008 12:14 PM
Reply to: Message 8 by cavediver
02-25-2008 2:59 PM


Definition please.
These munmps would then induce a bump in the space-time layer.
Being pathologically driven to make myself look like a complete idiot I can not resist asking, if by any wild chance it's not a typo, what are “Munmps”. There certainly would be stranger things within QM that I am ignorant of than a new term of art.
To later postings
cavediver:
Can I take it that since you’ve said it half a dozen times that “[These fields] aren’t made of anything.” is not the equivalent of “These fields are made of nothing.”?
And
Are you saying that the fields are currently purely mathematical constructs describing whatever it is that underlies matter and energy as we know it, and that if we could somehow delve into that realm we may or may not find the some-“thing” that comports to these equation as quarks did in their turn, yet are still accurate descriptions of whatever it is.
And to save postings.
randman:
You seem to be content by saying things are made of energy without having to ask what is energy. Would you be satisfied if these fields had a one word name for you to say that they were made of? I’d like to propose “munmps” if it's not already in use.
Edited by lyx2no, : To save postings.

Kindly
******
Fishing for complements without bait.

This message is a reply to:
 Message 8 by cavediver, posted 02-25-2008 2:59 PM cavediver has not replied

  
Admin
Director
Posts: 12998
From: EvC Forum
Joined: 06-14-2002
Member Rating: 2.3


Message 114 of 327 (459170)
03-04-2008 1:32 PM
Reply to: Message 112 by randman
03-04-2008 10:45 AM


Re: Unanswered Questions
Hi Randman,
When moderators request that people let the moderators handle moderation issues rather than dealing with it themselves, one of the consequences is that moderators are then committed to actually dealing with these issues. That's the only reason I'm posting this message to you right now, and not because I never have more fun than when I'm getting on your case.
Anyway, this is the second time I've spoken to you about something like this recently:
Let's deal with some facts. Specifically, you admit that entanglement is real, standard QM, correct?
I promise that if you continue treating people like hostile witnesses that I will continue suspending you.
And this is the second time I've spoken to you about something like this recently:
Contrary to the derogatory comments offered here...
If you have complaints about posts, the place to do that is Windsor castle. I'll save you the trouble this time and rule that I find no derogatory comments directed at you in this thread that you did not instigate yourself. You can't expect people to just sit back and say, "Oh, okay," after you accuse them of dishonesty and misrepresentation. The next time I see any variation of, "If you were being honest..." in any of your posts, you'll be suspended instantly.
No suspension this time. Focus your discussion on the topic and not on how horrible everyone else is, treat people with civility and respect, and you'll have absolutely no problems here, and I will definitely make sure you receive the same treatment from everyone else.
Please, no replies or references to this message. Just do it.

--Percy
EvC Forum Director

This message is a reply to:
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Silent H
Member (Idle past 5820 days)
Posts: 7405
From: satellite of love
Joined: 12-11-2002


Message 115 of 327 (459174)
03-04-2008 1:51 PM
Reply to: Message 108 by cavediver
03-04-2008 4:35 AM


Re: the gravity of general relativity
Man, you are awesome... and that's before we introduce the underwater cavediving aspect. The world could use more physicists like yourself in public arenas, carefully (and patiently) explaining how this works.
I have been explaining the unified picture, where GR and matter are both aspects of some super-fundemental master field. It is the search for the consistent physical theory of this unification that is at the heart of much of modern theoretical physics.
I think that was a critical element that I was missing in trying to understand the current discussion. Let me repeat what I am getting out of this and see if I have it right. GR replaced gravity (force at distance) with mass effecting another entity space-time, however physicists are now trying to merge both entities (mass and space-time) into specific operations of a singular entity which would be a "master field".
If this is correct, then I want to ask if this work is a mathematical exercise, that is to say the creation of the simplest mathematical tool (aka model) possible, or is it attempting to describe the "real" nature of natural phenomena? There is a huge difference between convenience and actual understanding.
If it is the latter, how are distinctions made between model and underlying reality, beyond calculations fitting results?
'Forces' concern action-at-a-distance. Mass at a point acts on space-time at that point. The wider-area effect on space-time has nothing to do with the mass, but the properties of space-time. In the usual ball-bearing on rubber sheet, the ball creates the displacement in the sheet at the point of contact, but the surrounding depression is a result purely of that local displacement and the elastic properties of the sheet - it is nothing to do with the mass itself.
Yes, I did understand this point already, which was a major difference between the two conceptually. But this does lead me to more questions.
As I understand it, if a mass were to suddenly "appear" (let's say an enormously massive particle falls out of an accelerator experiment), then it effects space-time at its what? Surface? Interior? And then the space-time "field" begins to effect other masses (and massless objects too right?) as its warping spreads out at the speed of light?
If this is so, how is gravity represented on that new object? Normally gravity is represented as a function of two masses, but if a new mass has just appeared, during a certain period of time its effect on space-time will not have reached another object. So is the measured gravitational effect different? And does that new mass still act as if it is effected by the other mass which already existed (and so who's space-time effects have already reached that location)?
A graviton is simply the smallest possible fluctuation in space-time, a result of applying standard quantum thinking to GR. In terms of the rubber sheet, it is essentially the quantum of displacement. This not so much brings GR 'down' to the level of force, as brings electromagnetism 'up' from a simple 'force' picture, to the level of a geometric theory. And this must happen as we expect all of the fields (space-time, electromagnetism, strong, weak, matter) to be different aspects of the one unified field.
This addresses another question I had waiting in the wings. If I understand your explanation correctly, this means that all forces would start to go the way of gravity, in that we would stop discussing them as actions at a distance between objects but rather as different phenomena within a single entity, which appear to us as two objects effecting each other at a distance? For example, we would not discuss em attraction as a result of exchanging photons, but as general field effects?
If this is correct, then (mirroring my earlier question) what is the evidential difference between the two ways of thinking? Also, could you describe the difference between a photon and a graviton in that theory?
I was originally thinking that discovering the "graviton" would undercut GR in some way, but now I am wondering if the opposite is true given attempts to move GR into the singular field theory as you have suggested. If we cannot find a graviton, would that pose a problem?
AbE:
I've decided to end this on a revelation of sheer stupidity. One thing which I never conceptually understood in GR, is what the space-time distortion is supposed to be, and so how it acts on masses. The rubber sheet analogy always worked for me on moving masses, so moving objects would have their motion bent by the distortion, perhaps so great as to circle into the mass creating the distortion.
However, I don't understand what is happening on an object which is not in motion. For example I pick up a stone and then let it go. What is space-time doing that makes the originally motionless stone start moving toward the surface? Why does it keep moving? For the purpose of this hypothetical we can imagine the earth does not spin or move in any other way (which would mean the stone is in motion). Force at a distance makes more sense to me at that point than motion of a motionless object across a curved space.
Edited by Silent H, : revealing underlying ignorance
Edited by Silent H, : quick fix

h
"Civilized men are more discourteous than savages because they know they can be impolite without having their skulls split, as a general thing." - Robert E. Howard

This message is a reply to:
 Message 108 by cavediver, posted 03-04-2008 4:35 AM cavediver has replied

Replies to this message:
 Message 135 by cavediver, posted 03-05-2008 4:20 PM Silent H has replied

  
PaulK
Member
Posts: 17822
Joined: 01-10-2003
Member Rating: 2.2


Message 116 of 327 (459175)
03-04-2008 1:53 PM
Reply to: Message 112 by randman
03-04-2008 10:45 AM


Re: Unanswered Questions
Despite the title there is no mention of unanswered questions in the text.
Now there should be no doubt that I accept entanglement. I don't disagree with mainstream QM. Just your ideas.
quote:
Now, you can define as cavediver wishes to something physical as anything whatsoever if it's in the universe, but that doesn't change the fact it has no physical properties under what is normally thought of as physical. Whatever word you wish to use, we have a field, or a connection or whatever, that is not strictly within space and time, or not only within space and time, and in reality, when you dig further than this little example, we see energy, mass, time and space are just products of whatever this is.
So lemme ask you something as an aise: step back for a minute and ask yourself where else you have heard that there are realms outside of time and space, where else you have heard that are non-physical (from a layman's understanding) realms?
What we have here are properties of a system, but a large part of that system is not confined to physical properties such as space, time, energy and mass.
I think that this illustrates your problem. You are still stuck in the thinking of classical physics. Because QM comes up with ideas that are strange to that you take it as essentially something supernatural. But that's wrong. QM isn't non-physical - it's a deeper insight into the nature of the physical. What is "commonly thought of as physical" is classical physics. But it is absolutely wrong to limit the physical to that and to exclude the deeper understanding offered by QM.

This message is a reply to:
 Message 112 by randman, posted 03-04-2008 10:45 AM randman has replied

Replies to this message:
 Message 117 by randman, posted 03-04-2008 2:48 PM PaulK has replied

  
randman 
Suspended Member (Idle past 4899 days)
Posts: 6367
Joined: 05-26-2005


Message 117 of 327 (459188)
03-04-2008 2:48 PM
Reply to: Message 116 by PaulK
03-04-2008 1:53 PM


Re: Unanswered Questions
I think that this illustrates your problem. You are still stuck in the thinking of classical physics. Because QM comes up with ideas that are strange to that you take it as essentially something supernatural.
When have I stated the process is supernatural? I have laid out specific facts very clearly. What specific physical mechanism is involved in creating what Einstein called "action at a distance."
It's clear that entangled particles act as one system, but whatever the connection that causes that is "outside time and space" as Zeilinger put it, and there is a reason he and other quantum physicists say that. Physical things have properties such as location (time and space), energy and matter. If you want to quibble with that, go ahead, but at least address the picture here.
There is no way that physical particles travel faster than the speed of light, or at least that's the current thinking, and to do so these particles would have to adjust their speed to create instant action at a distance, as Einstein put it.
So whatever medium is connecting the different particles is not something within space and time. It can be described mathematically as a wave-function, but that doesn't mean it has physical properties such as being limited to the speed of light, or definite locations within space-time.
You say, well, the field connects it. Ok, let's go with that. Why is the action instant?
Why does Zeiliner say it's "outside time and space"?
Those are the questions I am asking you. They are not claims of supernaturalness, but specific fact-based claims.
Think of a wave, say an ocean wave. When someone down the beach dives into the wave, the wave miles away doesn't instantly change, does it? Any measurable change would have to travel via physical mechanisms which take time. If a change doesn't take any time, as with the process of entanglement, then somehow that change is effected outside time and space. In other words, the process of entanglement is independent of time and space in terms of one particle collapsing to one state determining the state of the other particle.
I don't claim it is supernatural. I reiterate what someone like Zeilinger says and that is outside time and space.
Edited by randman, : No reason given.
Edited by randman, : No reason given.
Edited by randman, : No reason given.
Edited by randman, : No reason given.
Edited by randman, : No reason given.

This message is a reply to:
 Message 116 by PaulK, posted 03-04-2008 1:53 PM PaulK has replied

Replies to this message:
 Message 118 by PaulK, posted 03-04-2008 3:11 PM randman has replied
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PaulK
Member
Posts: 17822
Joined: 01-10-2003
Member Rating: 2.2


Message 118 of 327 (459190)
03-04-2008 3:11 PM
Reply to: Message 117 by randman
03-04-2008 2:48 PM


Re: Unanswered Questions
quote:
When have I stated the process is supernatural?
That seems to be what you're getting at.
quote:
t's clear that entangled particles act as one system, but whatever the connection that causes that is "outside time and space" as Zeilinger put it, and there is a reason he and other quantum physicists say that. Physical things have properties such as location (time and space), energy and matter. If you want to quibble with that, go ahead, but at least address the picture here.
I am addressing the picture. You are restricting "physical" to classical physics. And that's wrong. That isn't a quibble - it is a serious problem that invalidates your argument.
quote:
You say, well, the field connects it. Ok, let's go with that. Why is the action instant?
No, I don't say that. And I've told you why I don't say that. The quantum field doesn't respect your idea of locality.
Just a suggestion, but perhaps you should try considering how entanglement might work in the many-world model of QM ? I have.
quote:
Think of a wave, say an ocean wave. When someone down the beach dives into the wave, the wave miles away doesn't instantly change, does it? Any measurable change would have to travel via physical mechanisms which take time.
ANd that's classical physics again. QM doesn't work like that.

This message is a reply to:
 Message 117 by randman, posted 03-04-2008 2:48 PM randman has replied

Replies to this message:
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Son Goku
Inactive Member


Message 119 of 327 (459192)
03-04-2008 3:18 PM


Fields 3
First let me return to physics as it currently stands in addressing the question, “what is the fabric of reality”.
First of all, we have the basic revolutions of the 20th Century. Quantum Mechanics and Special Relativity. Quantum Mechanics is all about probabilities, e.t.c. I won’t go into it as it is tangential to the main issue here. Special Relativity is a theory which describes the structure of spacetime.
(Part 1)
Okay as it currently stands in physics the world is described by two theories, General Relativity and the Standard model. General Relativity is an example of a classical field theory and the Standard model is an example of a quantum field theory.
Classical field theory is a framework which describes fundamental forces using quantities defined everywhere in spacetime. An example is the electric field, which is defined at each point in spacetime and tells you the amount of Newtons per Coulomb, in a certain direction, at that location. How the field behaves is described by a set of equations, like Maxwell’s equations.
Quantum Field Theory is another framework. Unfortunately I can not give a snappy description like the one above for classical field theory. The best way, where by best I mean “will lead to the least confusion”, is that quantum field theory is a language or mathematical syntax in which it is impossible to write down something which contradicts the basic tenants of special relativity and quantum mechanics. To do this the language makes use of “field operators” as its basic grammatical components. These field operators behave very similar to the fields of classical field theory to some extent. Obviously, since it is impossible to contradict special relativity in quantum field theory, quantum field theory uses the spacetime structure of special relativity rather than the absolute space and time structure of old Newtonian theory. An important point to stress is that quantum field theory is a language for writing theories; it is not (despite its name) a theory itself. If a theory is written down in the quantum field theory language it is called a quantum field theory or a QFT.
(Part 2)
General Relativity updates the spacetime structure of special relativity to one where the shape of spacetime can change or be bent due to the presence of matter. The information regarding the shape of spacetime is stored in a quantity known as the metric tensor. This quantity is defined everywhere on spacetime and so General Relativity is a classical field theory, the field being the metric tensor.
However if one wishes to perform particle physics then effects due to gravity are negligible so we can use special relativity’s flat spacetime structure. Since we are dealing with particles (quantum) at high speeds (relativity) we need quantum field theory.
Let us say we want to describe electrons interacting electromagnetically, we will need to write down a quantum field theory of the electromagnetic force. Roughly since we are dealing with two objects, the electromagnetic force and electrons, we need two “field operators”. A magical consequence of the QFT language is that when we write down the field operator for electrons, the same field operator also describes another particle which has opposite charge to the electron.* This particle is the “anti-electron” or positron. When we write down the field operator for the electromagnetic force it describes a particle called a photon.
This quantum field theory of photons, electrons and positrons is called QED or Quantum Electrodynamics.
We then move on to the other forces and add field operators for quarks, neutrinos, e.t.c. As well as field operators for the other two forces, the weak and strong nuclear forces. Eventually we end up with a field theory with several field operators (17 or 20 in total, depending on how you count them**). This massive field theory is called the standard model and describes all particle physics ever observed.
However what if we wanted to look at particle physics when gravity is strong and spacetime is curved? Then the language of quantum field theory can be updated so that it works with the spacetime structure of general relativity. This new language is known as quantum field theory in curved spacetime, but it is seldom used practically.
This is where physics currently stands.
*Quantum field theory basically explains antiparticles as being a consequence of causality. If you want to keep special relativity’s causality when you add in quantum effects you need antiparticles.
**cavediver, I obtained this number by considering as a unique field, in the first case, each distinct rep of U(1)XSU(2)XSU(3). For matter this gives 16 fields. (2 fields per lepton generation, 3 per quark generation and Mr. Higgs all on his own) and all force fields as a single adjoint rep. The second figure is an attempt to be a little fairer to the forces and I’ve split the electroweak field into U(1)_e and the rest in order to reflect a little better the low energy world we live in.
Edited by Son Goku, : Change of number

  
randman 
Suspended Member (Idle past 4899 days)
Posts: 6367
Joined: 05-26-2005


Message 120 of 327 (459194)
03-04-2008 3:41 PM
Reply to: Message 118 by PaulK
03-04-2008 3:11 PM


Re: Unanswered Questions
I am addressing the picture. You are restricting "physical" to classical physics. And that's wrong. That isn't a quibble - it is a serious problem that invalidates your argument.
It doesn't invalidate the argument, nor am defining physical in any other way that science defines physical. Moreover, it's not the label I am trying to get you to address but the picture, the qualities and properties and processes involved. You can define physical as items outside time and space with no mass, nor energy, if you want, and we'd still be talking of a process outside time and space with no mass, nor energy. So let's address the specific qualities first to get an understanding of perhaps where we agree.
Wouldn't that be a better place to start?
We can discuss later whether physical or material things must have a location within space and time and whether they must have energy or mass. Obviously, I think calling things which have no location, no energy and no mass "physical" or "material" is inconsistent with how science defines those terms, but if you want to expand those terms to include anything, including God if He exists, so be it.
Let's first see if we can discuss the properties of the process involved.
ANd that's classical physics again. QM doesn't work like that
That's the point. It doesn't work via materialistic or mechanistic means within space and time.
[qs] Just a suggestion, but perhaps you should try considering how entanglement might work in the many-world model of QM ? I have.

This message is a reply to:
 Message 118 by PaulK, posted 03-04-2008 3:11 PM PaulK has replied

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 Message 122 by PaulK, posted 03-04-2008 4:04 PM randman has not replied

  
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