Naked Science Forum
Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: geordief on 20/06/2019 14:00:15
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Is it possible to say that the expanding/evolving universe creates "space" as a function of itself but that it expands "into" nothingness?
Also (separately but because these two thoughts occurred to me around the same time) is it possible for two objects to assimilate and become one object (I understand "objects" may be embedded in and part of the various fields)?
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Is it possible to say that the expanding/evolving universe creates "space" as a function of itself but that it expands "into" nothingness?
I suppose that one can say that expansion is the creation of a larger quantity of space from a given smaller quantity of it. There is nothing "into" (quotes or otherwise) that space is expanding. If there was, that would already be space, but just empty.
Vacuum (from the title, being not mentioned in the OP) seems to be a region with zero matter or possibly zero energy density. Sure, light can be detected from anywhere, but that requires a detector there. I am of the personal opinion that light doesn't change the state of what otherwise is vacuum. Such a statement would seem to be a counterfactual one, and I decline the principle of counterfactual definiteness.
Also (separately but because these two thoughts occurred to me around the same time) is it possible for two objects to assimilate and become one object (I understand "objects" may be embedded in and part of the various fields)?
That all depends on one's definition of 'object'. The word seems to be an abstract one with no physical meaning. It simply means this collection of <whatever> being considered/treated as a unit.
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That all depends on one's definition of 'object'. The word seems to be an abstract one with no physical meaning. It simply means this collection of <whatever> being considered/treated as a unit
Probably how I was using it ..It seems like a "one size fits all" description. A Field might also be an object , I suppose(and everything is part of the Field(s) isn't it?
So Fields do merge don't they and particles might be "one object" if they are all excitations of the one (combination of) Fields
.Hope I am not talking gibbonish ;-)
btw My last (unanswered thread) was "Does the Universe expand into itself?"
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A Field might also be an object , I suppose(and everything is part of the Field(s) isn't it?
A field can be treated as an object, but only as a convenient reference term, shorthand, etc. In reality it is a set of measurements/values at a location in spacetime - we’ve been through what fields are in other threads.
So Fields do merge don't they
Could you give me an example?
and particles might be "one object" if they are all excitations of the one (combination of) Fields
You’ve said particles (plural) might be ‘one object’ (singular). I’m not at all sure what you are asking.
.Hope I am not talking gibbonish ;-)
btw My last (unanswered thread) was "Does the Universe expand into itself?"
Looking at that question, you’ve thrown a lot of ‘bits’ into the OP. That probably put folks off answering as they weren’t sure what you were asking.
You’ve done the same in this OP. Rather than ask the title question you’ve actually asked 2 other very different questions, so we are up to 3 at once. Not easy to answer succinctly, and makes for a confusing thread.
As to your title question, quick answers:
Space, other than being the final frontier, is a set of 3 dimensions.
Vacuum can be: the common use meaning no air; QM use meaning lowest possible energy which means no particles inc photons; GR stress energy tensor is zero, hence no momentum, energy, fields etc. Basically, nothing there.
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Space is what is between objects. The definition depends on the objects and the context. The space between pebbles can be empty, or filled with air, or filled with sand.
The space between planets is mostly filled with nothing at all, with a few particles and molecules drifting about.
We can only make statements about the observable universe because its radius is limited by all the physics we know. There may be stuff or nothing outside, but as far as we know it has no effect on us because the observable universe appears to be expanding faster than any information from outside can reach us.
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Could you give me an example?
Well some have said that a Field is a set of measurements but others have said "no a Field is a thing in its own right".
From my lowly position in this "field" of knowledge ,I am not in a position to adjudicate.
However , in my question which you have addressed I accept I was treating Fields as objects in their own right.
So ,to give you the example I had(based on that possibly flawed understanding) it would go like this;
Suppose we have a charge in one location then it will have its own Electric Field .
Now ,if we have another separate charge it will also have its own Electric Field.
These two electric Fields will (per my understanding) interact with each other and it will be (again as I anticipate) possible to view the two separate Fields as one "conglomerate"
Any particles associated with this "combination Field" can (again in my possibly very flawed understanding) be attributed to either Field of both (actually,I would guess to both.)
Extrapolate to all the Electric Fields in the Universe and we have one Electric Field (to rule over all ;-) )
I took the Electric Field as an example. I assume the same might apply to any of the other kinds of Fields there are ...
Now that is what I had in mind (you did ask)
I hope not to be too embarrassed by your reply ;)
Oh and thanks for looking at the other thread I mentioned.
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Space is just that - 'space' - there is no word to describe it, emptiness.
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Fields have a source. These are particles for electromagnetic and gravitational fields. My question is what is the source of the Highs field?
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Well some have said that a Field is a set of measurements but others have said "no a Field is a thing in its own right".
The first is the correct definition, the second is treating it as an object.
A lot of this has to do with terminology and use of words as shortcuts for more complex sentences. With many types of field eg temperature field in a room, we can identify an underlying cause eg warm air, when we get to many of the QM/QFT fields we can’t see below them, at the moment they ‘just are’ hence we treat it as an object, a thing it it’s own right - easier than always having to say “field x which is a set of measurements but we don’t yet have an underlying cause”. (Takes deep breath).
Suppose we have a charge in one location then it will have its own Electric Field .
Now ,if we have another separate charge it will also have its own Electric Field.
These two electric Fields will (per my understanding) interact with each other and it will be (again as I anticipate) possible to view the two separate Fields as one "conglomerate"
Again this is a terminology issue.
We refer to particles having an electric field, and yes we refer to each one as having its own field, but their fields are only disturbances (variations of measured intensity at a point) of the same electric field. Imagine 2 loudspeaker in a room, each generates its own disturbance of the air in the room (which you can measure if you only switch on one at a time) but it is the same air in the room they are both disturbing.
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Is "Space" distinct from "nothingness"? (and the Vacuum)
My attempt:
A vacuum is when you have removed all the baryonic matter from a volume of space.
- You have to work very hard to ge a "good" vacuum, as atoms are always boiling off the container walls and seals.
If you really want nothing, you would need to remove light (not entirely possible above absolute zero), neutrinos (not possible with any shielding we can imagine), and Dark Matter (we don't even know what it is, let alone imagine a way to keep it out).
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Is "Space" distinct from "nothingness"? (and the Vacuum)
My attempt:
A vacuum is when you have removed all the baryonic matter from a volume of space.
- You have to work very hard to ge a "good" vacuum, as atoms are always boiling off the container walls and seals.
If you really want nothing, you would need to remove light (not entirely possible above absolute zero), neutrinos (not possible with any shielding we can imagine), and Dark Matter (we don't even know what it is, let alone imagine a way to keep it out).
OK so are we better just (re)starting from the position that a vacuum is not only impractical to create but that it is a misnomer and that we can only really talk about relative densities of whatever we are considering?
My first introduction to this idea of a vacuum was the "Nature abhors a vacuum" saying which made such perfect sense to me at the time.(with its seeming relevance to both physical and political events)
Time to cast "vacuums" into the bin of history?
"Nothingness" is clearly also a contentious subject (I think Odysseus got the better of one of his opponents with his "My name is Nobody " repartee).
I don't think we need to pick at that scab for now ;-)
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'Nothing' does not exist, because liminal matter constantly appears and disappears in the vacuum of space - does it not - causing the universe to expand?
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OK so are we better just (re)starting from the position that a vacuum is not only impractical to create but that it is a misnomer and that we can only really talk about relative densities of whatever we are considering?
No, just because something is unattainable doesn’t mean it couldn’t exist, or that the concept of it might not be a useful thing.
The calculation of the minimum energy in a QM vacuum is a useful tool.
liminal matter constantly appears and disappears in the vacuum of space - does it not - causing the universe to expand?
No it doesn’t, see https://www.physicsforums.com/insights/vacuum-fluctuation-myth/
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The emphasis of your negation belies Heisenberg's uncertainty principle I feel.
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The emphasis of your negation belies Heisenberg's uncertainty principle I feel.
The uncertainty principle says that we cannot measure the position (x) and the momentum (p) of a particle with absolute precision, the more accurately we know one of these values, the less accurately we know the other.
Nothing to do with particles popping in an out of existence.
Did you read the article?
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The emphasis of your negation belies Heisenberg's uncertainty principle I feel.
The uncertainty principle says that we cannot measure the position (x) and the momentum (p) of a particle with absolute precision, the more accurately we know one of these values, the less accurately we know the other.
Nothing to do with particles popping in an out of existence.
Did you read the article?
Yes, I am afraid it is beyond me. But the 'virtual particle' is a theory, I don't see that it can be proved or disproved beyond laboratory conditions, with all due respects to Mr Arnold Neumaier.
Reference https://www.physicsforums.com/insights/vacuum-fluctuation-myth/
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Yes, I am afraid it is beyond me. But the 'virtual particle' is a theory, I don't see that it can be proved or disproved beyond laboratory conditions, with all due respects to Mr Arnold Neumaier.
Virtual particles are not a theory, they are representations of mathematical models of internal processes in QM. Prof Neumaier has done a lot of work on the maths of QM and is keen to dispel some of the misunderstandings that arise due to poor interpretation of the maths and concepts.
Examples abound. There is one poor soul in new theories who is completely confused by his misunderstanding of observation, measurement, wave/particle duality, matter waves etc; such that he is unable to understand some very simple concepts.
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Virtual particles are not a theory...
The word 'theory' is used half a dozen times in that article, and a model is just a model & remains so until it can be proven or disproven & then discarded I feel.
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The word 'theory' is used half a dozen times in that article, and a model is just a model & remains so until it can be proven or disproven & then discarded I feel.
But have you really read and understood what the article is saying?
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Have I read the article? Please refer to post 16. You stated:
Virtual particles are not a theory...
However, I believe you are in error because a virtual particle is a transient quantum fluctuation that exhibits some of the characteristics of an ordinary particle, while having its existence limited by the uncertainty principle. The concept of virtual particles arises in perturbation *theory* of quantum field *theory*. Virtual particles are therefore *theoretical*, as is quantum field *theory*. I rest my case.
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the concept of (a vacuum) might not be a useful thing.
I would put it a different way...
The concept of a vacuum is a useful concept.
- We can't create a perfect vacuum
- But we can certainly create something that is usefully close enough to a vacuum for many practical purposes
- The LHC needs a pretty good approximation of a vacuum so they can inject their protons and expect them to make their way around all the ring
- While for some purposes (eg analysing radio wave patterns), normal atmospheric pressure is close enough to a vacuum to get excellent results
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Creating a perfect vacuum is as difficult as drawing a straight line, but who cares? Maths deals with straight lines, physics deals with weightless strings*, and in real life we just accept whatever is good enough.
*My father swore that he read an Indian exam paper with the phrase "you may ignore the weight of the elephant".
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Let's think about the vacuum. Before the big bang everything was densely packed. Not even particles, as we understand them, existed. You still had energy. What about the vacuum in this scenario?
When energy is that dense then it must flood the vacuum. There is no zero point energy. Then we have the big bang and a continuous drop in energy density. Whereas we hold that the big bang emerged out of the vacuum shouldn't it be the other way round?
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the concept of (a vacuum) might not be a useful thing.
I would put it a different way...
Thanks Evan, you’ve picked up the spirit of what I was trying to say. I view absolute vacuum in the same way as absolute zero, maybe not achievable but still useful to know it’s value and what happens as you approach it. Trying to get there gives us many benefits including discovery of superconductivity.
Let's think about the vacuum. Before the big bang everything was densely packed. Not even particles, as we understand them, existed. You still had energy. What about the vacuum in this scenario?
What form was the energy in?
You might be interested in this (popsci) article on quark soup - why does my mind think duck soup (quark, quark!). Haven’t read the original papers so not sure how accurate the reporting.
Whereas we hold that the big bang emerged out of the vacuum shouldn't it be the other way round?
no room for a vacuum? Interesting thought.
The concept of virtual particles arises in perturbation *theory* of quantum field *theory*. Virtual particles are therefore *theoretical*, as is quantum field *theory*. I rest my case.
Much better, ‘concept’ is ok. Remember I was responding to your original statement:
But the 'virtual particle' is a theory
We use a lot of concepts in a theory, but they are not theories in their own right, nor do the have a reality associated with them. In general physics these concepts are usually obvious as such, but in quantum theories they might not be so obvious. For example, we use the concept of an N dimensional phase space to help calculate the motion and characteristics of a particle, but no one would reasonably believe that this describes particles being in a real universe of N spacial dimensions.
When we come to the vacuum there are 2 concepts that help us with the calculations.
The first is harmonic oscillators - basically interconnected balls and springs at each point in space. The second is via virtual particles - not particles at all, but a calculation aid in Feynman diagrams - which were introduced to the public with the caveat “don’t take these literally. The problem is if I say to you imagine the vacuum to be full of little balls on springs, you would immediately recognise this as an analogy, but with virtual particles the public and popsci press immediately forget the caveat and do take it literally.
Nor should we refer to virtual particles as theoretical, any more than we would refer to balls and springs as such. It would be correct to refer to the Higgs Boson as theoretical, before it was discovered, because it had been predicted by a scientific theory. Virtual particles are not predicted to exist by any standard particle theory or to be tested/discovered in any lab.
I also think you may be mistaking a quantum energy/time relationship as being a Heisenberg uncertainty relationship, whereas it is in fact the uncertainty of an operator compared to the variation of its expectation value.
If you are interested there is a thread here which covers both issues in one. It’s worth noting that the misunderstandings around these topics is a constant source of irritation to those who understand quantum theories.
https://physics.stackexchange.com/questions/439946/heisenberg-energy-uncertainty
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folks you are confusing your selves and me not that that is difficult.
The vacuum of space is filled with virtual particles as is evidenced by the Casimir effect, and further evidenced by the dynamic Casimir effect. Space is not a empty vacuum. https://en.wikipedia.org/wiki/Vacuum_state
The only way you could possibly argue that the Casimir effect is not evidence off virtual particles is to ascribe it to the Van de Walls forces. The Dynamic Casimir effect can not be ascribed to anything but virtual particles. Hawking radiation depends on Virtual particles, are you denying that Hawking radiation is probable, but unprovable.
The Big Bang and Hot or Cold Baryogenesis relies on virtual particles become real due to inflation of space, this according to the standard model lead to Big bang nucleo synthesis. Are you all stating baryogenisis after the inflation epoch ever took place?
Fields are transmitted via virtual particles in QFT . ie Electrical fields are transmitted by polarisation of virtual particle pairs. virtual particles are often viewed as virtual photons, which "definately" do not have the same characteristics as real photons, ie they can transmit electric fields etc.
To state space is empty when looking at QFT and QED is WRONG. Maxwells equations depend on the ability to polarize space in QED this is done via virtual particles.
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You can't use "is" and "virtual" in the same sentence! Stuff is either actual (you can touch it) or virtual (you can model it mathematically). A good synonym for virtual is "as if".
Space is indeed an empty vacuum until you introduce real particles between which the Casimir and Van der Walls forces become apparent.
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@Colin2B I think you forgot the link to the article on duck a l'orange.
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Vacuum energy may well be the confusing factor here. It relates to the fields that permeate all of space. A bit of light reading may help. https://en.m.wikipedia.org/wiki/Vacuum_energy (https://en.m.wikipedia.org/wiki/Vacuum_energy)
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folks you are confusing your selves
No, we are not confused. We are drawing a distinction between calculations in perturbation theory and the popsci press tendency to portray these calculations as real particles ignoring the warning to ‘not take these literally” (as the words used in description of Hawking radiation). They have their place in discussion but only if used with suitable caveats.
I don’t have time to go through all of this, but would recommend you read and understand the link on vacuum fluctuation myth.
The concept of virtual particles arises in an approximation scheme in which interactions (forces) between actual particles are calculated in terms of exchanges of virtual particles which are shorthand terms for a series of processes and calculations within Feynman diagrams. The interpretation of an interaction as a sum of intermediate states involving the exchange of various virtual particles only makes sense in the framework of perturbation theory. In contrast, non-perturbative methods in QFT treat the interacting Lagrangian as a whole without any series expansion and do not introduce virtual particles.
The only way you could possibly argue that the Casimir effect is not evidence off virtual particles is to ascribe it to the Van de Walls forces. ..............The Dynamic Casimir effect can not be ascribed to anything but virtual particles.
Not so. Any non-perturbative analysis will not use Feynman diagrams and power series approximations.
Hawking radiation depends on Virtual particles, are you denying that Hawking radiation is probable, but unprovable.
Again, see the vacuum fluctuation article and associated virtual particle articles to understand how virtual particles should be viewed.. The same is true of the other examples you quote.
To state space is empty when looking at QFT and QED is WRONG
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No one was stating that space is empty. The vacuum energy can be modelled in QFT by quantum harmonic oscillators (ball-spring model) but no one suggests space is filled with little balls and springs. There is a difference between a model and what we consider as a reality.
Maxwells equations depend on the ability to polarize space in QED
Space is not polarised, and Maxwell’s equations do not depend on it being polarised.
QED starts with the free theory of the electromagnetic field and quantum theory gives rise to a photon with two polarisation states. This is done by using the Lagrangian for Maxwell’s equations in the absence of any sources, which gives an extended phase space (not a real physical space) with gauge orbits from which we can use Coulomb gauge (as in Maxwell’s equations) to identify 2 degrees of freedom which are the photon polarisation states.
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Don't mention degrees of freedom you will only confuse the chap.
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Don't mention degrees of freedom you will only confuse the chap.
I don't think I am the one who is confused, or misunderstanding what I wrote. :o
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I don't think I am the one who is confused, or misunderstanding what I wrote. :o
The confusion lies with the use of shorthand jargon by popsci press without expanding the caveats. Having worked with them on articles I can understand why; they have limited column inches and want to get as many wow factors into their pages as possible. They also know that their main audience has never studies quantum theories, and those who have will understand the reality of the jargon, and so they aim at the layman, but sometimes at a playschool level. The problem comes when speculation is made on the back of the top level statements.
We are not a popsci site, although we try to explain things for a non-science audience.
We are not saying that the term ‘virtual particle’ should be banned, what we are trying to do is make it clear that some things should not be taken literally as there is important detail behind the jargon.
This topic arose because of the comment about virtual particles popping in and out of existence. As one of the links you provided in a previous topic said “We routinely say things like "virtual photons ... are constantly being emitted and re-absorbed by the electron" but that isn't really what we mean. ..... Nothing at all is going on. The words about things fluctuating around are a rough way to convey one of the peculiar properties of quantum fields.”
Anyone who is interested in understanding the issue is welcome to read the links provided on vacuum fluctuations and the associated links on virtual particles.
It is also worth reading Prof Strassler’s article where he repeatedly says:
“Physicists often say, and laypersons’ books repeat, that the two electrons exchange virtual photons. But those are just words, and they lead to many confusions if you start imagining this word “exchange” as meaning that the electrons are tossing photons back and forth as two children might toss a ball.”
“The Feynman diagram is actually a calculational tool, not a picture of the physical phenomenon”
“One says "the electron emits and reabsorbs a virtual photon", but this is just shorthand for the physics “
“these quantum fluctuations are sometimes described as being due to two or more ‘virtual particles’, but this name really reflects a technical issue (i.e., how you can calculate the fluctuations’ properties using Feynman’s famous diagrams) more than it guides you as to how you should really think about them”
“The best way to approach this concept, I believe, is to forget you ever saw the word “particle” in the term. A virtual particle is not a particle at all. It refers precisely to a disturbance in a field that is not a particle.”
If anyone can get beyond the popsci descriptions there awaits a far richer description of what is happening which in the case of the dynamical Casmir effect lies on the border between quantum theory and relativity, but it does not depend on simplistic, jargon descriptions of virtual particles ‘popping in and out of existence’ because DCE does not prove the existence of virtual particles.
eg https://arxiv.org/pdf/quant-ph/9802017.pdf
It’s also worth noting that in Hawking’s paper on Hawking radiation he mentions virtual particles only once p. 202 but says at the bottom of the page: ''It should be emphasized that these pictures of the mechanism responsible for the thermal emission and area decrease are heuristic only and should not be taken too literally.''
What really happens is that the high energy of the gravitational field of the black hole creates real particle-antiparticle pairs - although before that event it could be viewed in terms of Feynman diagrams as virtual is completely irrelevant to his argument.
So, do you want to stay at the layman/playschool-of-physics stage or go deeper for a fuller understanding?
Let’s try and see what lies beneath.
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I don't think I am the one who is confused, or misunderstanding what I wrote. :o
The confusion lies with the use of shorthand jargon by popsci press without expanding the caveats.
So, do you want to stay at the layman/playschool-of-physics stage or go deeper for a fuller understanding?
Let’s try and see what lies beneath.
I think everyone wants to learn more. Incorrect pop science is often misleading. Over simplified answers are equally misleading. That is why I stated above I am not the one confused. Space is not empty nothingness, it has properties, and substance.
I went out and bought a good text book on QFT/QED, which starts out with the Quantum Vacuum based on Lagrangians and Hamiltonians and eigenvectors etc.
Does anyone have a recommendation for QCD, or is that limited to those with super computers who produce pop science links. like this one http://www.physics.adelaide.edu.au/theory/staff/leinweber/VisualQCD/Nobel/
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Most humans define "space" as that which has neither properties nor substance. Everything else is "stuff".
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I don't think I am the one who is confused, or misunderstanding what I wrote. :o
The confusion lies with the use of shorthand jargon by popsci press without expanding the caveats.
So, do you want to stay at the layman/playschool-of-physics stage or go deeper for a fuller understanding?
Let’s try and see what lies beneath.
I think everyone wants to learn more. Incorrect pop science is often misleading. Over simplified answers are equally misleading. That is why I stated above I am not the one confused. Space is not empty nothingness, it has properties, and substance.
I went out and bought a good text book on QFT/QED, which starts out with the Quantum Vacuum based on Lagrangians and Hamiltonians and eigenvectors etc.
Does anyone have a recommendation for QCD, or is that limited to those with super computers who produce pop science links. like this one http://www.physics.adelaide.edu.au/theory/staff/leinweber/VisualQCD/Nobel/
The problem you have is you try to come across as someone who knows what they are talking about. I learn something new here quite often. I have a lot to learn, an awful lot. Reading textbooks can be hard going. Ask some questions about what you have read. This will help to clarify some of the harder concepts.
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I dont try and come across as anything other than what I am. Sorry people think that.
I will stop answering questions, and leave that to others. I had hoped that by answering a few simple questions people might reciprocate and answer some of my musings. I may have waisted my time.
I might ask questions in the future ref the finer points of QFT, but at the moment, my maths is holding up, and I have been able to use google for clarification on points so far, it is good bed time reading zzzzzzzzzzzzz. My curiosity ref QCD is limited to pop science at the moment and a book recommendation to get me started.
Cheers
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Most humans define "space" as that which has neither properties nor substance. Everything else is "stuff".
Perhaps I am not human, but at least I am not an idiot.
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‘Outer space’ is the 'space of the Universe'. It has very low density and pressure, and is the closest physical approximation feature ‘perfect vacuum’.
There are still a few hydrogen atoms per cubic meter.
Observable universe is filled with large numbers of photons, the so-called cosmic background radiation, and quite likely a large number of neutrinos. The temperature of this radiation is about 3 K (−270.15 °C; −454.27 °F).
String theory is believed to have a huge number of vacua – the string theory landscape.
QED, QCD, Quantum vacuum state are different theoretical approaches to be used on the path of physical laws definitions.
Zero-point field is sometimes used as a synonym for the vacuum state of an individual field.
According to present-day understanding of what is called the vacuum state or the quantum vacuum, it is "by no means a simple empty space".
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" Is it possible to say that the expanding/evolving universe creates "space" as a function of itself but that it expands "into" nothingness? "
Why not define it as it 'extends' the laws, properties, as well as those other peculiarities, relativity and quantum mechanics, we find this universe to consist of? I think ES had something to say about it being solely fields, which I btw found pretty correct.
" Also (separately but because these two thoughts occurred to me around the same time) is it possible for two objects to assimilate and become one object (I understand "objects" may be embedded in and part of the various fields)? "
What does that mean?
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If we're talking about ZPE then I consider it a property of space. Zero point energy but it is probabilistic, I would not expect us able to tap it. The Casimir effect needs us to put boundaries on it to make itself known. And I can't call it a field, it's a property to me.
" The ZPE of the vacuum is infinite unless regularized by frequency cutoffs or other stratagems. In most electromagnetic phenomena, the ZPE can be canceled out or renormalized away. Casimir and Polder in 1948 proposed a physical situation in which the effects of ZPE might be directly observable. They considered two perfectly conducting parallel plates, with area , separated by a distance of the order of microns.
The electric field inside a perfect conductor equals zero, so this gives boundary values of zero for all modes at the surface. This perturbs the zero-point modes of the electromagnetic field, since modes with horizontal wavelength components greater than will be excluded from the region between the plates. They will lie in the ultraviolet and beyond and are shown as black waves. Modes outside the plates can belong to a continuum of frequencies. The result is a net attractive force "
https://demonstrations.wolfram.com/TheCasimirEffect/
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It builds from black body radiation and Planck scale, it uses Heisenberg's uncertainty principle as one way to define boundaries for it and Planck time as another. There are probably more ways to define it but those are the ones I'm used to.
and what I mean by us 'putting boundaries on it to make itself known' is that it should take more energy doing so than what we might gain from this 'virtually infinite' energy. Otherwise it would be magic to me.
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Also (separately but because these two thoughts occurred to me around the same time) is it possible for two objects to assimilate and become one object (I understand "objects" may be embedded in and part of the various fields)
What does that mean?
Yes,even I didn't understand that when I reread it (and I wrote it :) )
Well what I was thinking of was that particles are said to be an excitation of the field.
When two particles meet is impossible for them to "blend" and become one particle.?
And if the particles are viewed in terms of the field they are excitation of would the field interfere with itself to that two waves in the field become one wave ,(even a standing wave)?
I think I gave due warning earlier in this thread that I was probably talking "gibbonish",(ie nonsense) but you did ask.
:) :)
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Hi.
Yes,even I didn't understand that when I reread it (and I wrote it :) )
Well what I was thinking of was that particles are said to be an excitation of the field.
When two particles meet is impossible for them to "blend" and become one particle.?
And if the particles are viewed in terms of the field they are excitation of would the field interfere with itself to that two waves in the field become one wave ,(even a standing wave)?
I think I gave due warning earlier in this thread that I was probably talking "gibbonish",(ie nonsense) but you did ask.
* It sounds as if you're talking about Quantum Field Theory (QFT).
* You asked: When two particles meet is impossible it possible for them to "blend" and become one particle.?
Answer: Possibly. This depends on the field and the precise mechanics or model you are using.
For example, many of the fields are quantised and can only have certain energy states. It's not always possible to have two lots of an excitation of the field at the same location.
However, particles and anti-particles (something like a peak in the underlying filed and a corresponding dip in the field) can come together and combine but then they tend to pass their energy to another field rather than creating something in their own field. Example: An electron and a positron (the anti-particle of the electron) are disturbances in the electron field, if they come together and annihilate then they create an excitation in the electromagnetic field which looks like a pair of photons, while the electron field returns to the vaccum state.
I really wouldn't consider myself an expert in QFT, it's something I'll be reading more about soon.
Here's a short Pop Sci video that describes annihilation in terms of Quantum Fields reasonably well (takes about 7 minutes and some people may find the presenter a bit like "marmite" - you'll either like it or hate it). Personally, I'm not that keen on this style but the content is good and clearly explained so they can have my recommendation for whatever it is worth.
Best wishes.
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I really wouldn't consider myself an expert in QFT, it's something I'll be reading more about soon.
Here's a short Pop Sci video that describes annihilation in terms of Quantum Fields reasonably well (takes about 7 minutes and some people may find the presenter a bit like "marmite" - you'll either like it or hate it). Personally, I'm not that keen on this style but the content is good and clearly explained so they can have my recommendation for whatever it is worth.
I am lost for words.Perhaps ,if I watch that a few times I might retain a little acquaintance with the subject to help me out if it ever comes up again.
Anyway ,thanks for showing it :)
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Regarding vacuum. I might just add some to the article (literal explanations).
‘Outer space’ is the 'space of the universe'. It has very low density and pressure, and is the closest physical approximation feature to vacuum’.
Observable universe is filled with large numbers of photons, the so-called cosmic background radiation, and quite likely a large number of neutrinos. The temperature of this radiation is about 3 K (−270.15 °C; −454.27 °F).
String theory is believed to have a huge number of vacua – the string theory landscape.
QED, QCD, Quantum vacuum state are different theoretical approaches to be used on the path of physical laws definitions.
Terminology. In Einstein's theory of general relativity, the Schwarzschild metric (also known as the Schwarzschild vacuum or Schwarzschild solution).
https://en.wikipedia.org/wiki/Schwarzschild_metric
Regarding universe expansion.
Einstein recognized that the universe's imaginary grid wasn't fixed and wasn't absolute. Instead, it was like a fabric, and the fabric itself was curved, distorted and forced to evolve over time by the presence of matter and energy.
Alexander Friedmann showed that if you didn't add this extra cosmological constant, and you had a Universe that was filled with anything energetic (e.g. matter, radiation, dust, fluid, etc.) there were two classes of solutions: one for a contracting universe and one for an expanding universe.
The mathematics tells about the possible solutions, but you need to look to the physical universe to find which one of these describes us. Hubble was the first to discover that individual stars could be measured in other galaxies, determining their distance.
It's as though the fabric of space itself is getting stretched over time, and all the objects within that space are being dragged apart from one another. On small scales, like the scales of living creatures and below, the electromagnetic and nuclear forces dominate.
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Subspace, or God.
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Subspace, or God.
Stephen Hawking gave similar quote.
Still with technology that we have now and development speed that we have now,
there must be approach to more precise understanding. Going from literal abstractions to a set of solutions.
Maybe one day, with a new finding we will be surprised, 'why nobody thought of that [something we cannot explain now] before?'
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Subspace, or God.
Stephen Hawking gave similar quote.
Still with technology that we have now and development speed that we have now,
there must be approach to more precise understanding. Going from literal abstractions to a set of solutions.
Maybe one day, with a new finding we will be surprised, 'why nobody thought of that [something we cannot explain now] before?'
I'm in good company then.
If there are no particles distance has no concept. The plaque on the pioneer spacecraft gives measurement directly deducable by way of atomic qualities.
https://en.wikipedia.org/wiki/Pioneer_plaque#Symbolism
Perhaps in subspace there is a man/woman with is arms in an only 1 metre span encompassing the entire universe.
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ES, wouldn't you express the universe as a mathematical manifold? With us defining its coordinate system from relativity?
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Hi Yor_on,
I hope you are well.
ES, wouldn't you express the universe as a mathematical manifold? With us defining its coordinate system from relativity?
Sounds right.
I'm a bit lost about the context. The discussion seems to have moved on to a new area.
Also, just to be clear, that's not my idea. A (differentiable) manifold is the mathematical structure that underpins General Relativity and was developed by Einstein, Minkowski and others.
I'll re-read this thread later today and see what the general context was.
Best Wishes.
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Hi again.
Damaged thread
I've read through the thread from start to end. It was started a year ago and recently brought back to the top of the pile by someone (I'm not going to name them). Those comments seemed harmless but generic and didn't connect well with the previous posts. That's OK and this forum often has discussions that take sidelines. I think most other people re-engaged with the topic using the title and the perhaps the Original Post only.
There seems to have been one instance in another thread where the person who re-started or "bumped up" this thread was just keen to advertise some products (or "spam" this site). With this information it now seems easier to understand why their comments were so generic - they were probably trying to raise their profile enough to post active links on the forum. I don't know and I'm not judge and jury, it's not important. What matters is that for the moment it doesn't seem that many people are still interested in this thread.
@yor_on - you may be trying to answer questions and engage in discussion with someone who really wasn't interested in discussion anyway.
@geordief - If you still have questions or are seeking more discussion, just say something here. I'm sorry that your thread seems to have become complicated and difficult to follow.
Additional Confusion
I should also mention that you (Geordief) created a reply that confused me and probably "pinged" the wrong people to respond. Reply #40 features a quote which has all the header information to indicate that it was from Yor_on however the actual text within it looks more like something that @Colin2B had stated. I'm guessing that you used the quick-reply feature and then edited the quote by hand without realising that the wrong people would be notified (or not notified).
Conclusion
Some of the early answers in this thread were already very good.
I'm not sure it's worth talking about Manifolds since I don't think anyone really wanted to know.
Best Wishes to everyone.
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No Es, that's not true. 'A (differentiable) manifold' is quite interesting but also rather hard to melt for those of us not used to to the nomenclature :) I'm checking it out for the moment and I think it would be nice with a overview, maybe in another thread as this ones origin is quite old, just as you say.
https://en.wikipedia.org/wiki/Differentiable_manifold
as far as I'm concerned that is. Mathematics is what relativity builds on. Also, I'm afraid that it actually was me that Geordief answered to, although, I can't help finding it quite complimentary suggesting it was Collins :)
don't hesitate in using mathematics ES, just break it down for us if it gets too esoteric.
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geordief - If you still have questions or are seeking more discussion, just say something here. I'm sorry that your thread seems to have become complicated and difficult to follow.
Quite often ,I start a thread and ,after a few replies (if I get them) I have taken in all I can digest and so ,when others take over the thread ,so to speak I can lose interest as the conversation goes over my head
Sometimes ,as you may have observed someone can necro an old thread for perhaps not good reasons but in this case Yoron did ask me to clarify a passage I had written earlier (yes,a long time earlier)
Of course I did my best to explain my thinking
I don't think I accidentally misattributed any passage as Yoron correctly quoted me in post#38 and I then answered him in post#40.
(When I do quote anyone ,I often highlight the salient passages in the post and then look for the "quote selected" facility under the Actions tab at the top left of the post.
Simply using the "Reply" facility at the bottom of the post can imo often make for very long posts.)
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Hi again.
I don't think I accidentally distributed any passage as Yoron correctly quoted me.....
Sorry, my fault and misunderstanding.
No Es, that's not true. 'A (differentiable) manifold' is quite interesting...
Thanks Yor_on. That will be one person who thinks it's interesting (or is just being polite). I agree with you that another thread may be a better place.
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It's been interesting reading back through the thread from the beginning anyway. I'm still quite new here and this thing was started before I was a member. Thank you to everyone who has spent some time here.
Best Wishes.
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No Es, I'm finding it interesting. I think I might have looked at it a long time ago as I recognize some of it, but I'm definitely a layman when it comes to mathematics. https://www.quora.com/What-is-a-differentiable-manifold? contain some nice examples connecting it to a Euclidean space. It's just all those words that you don't recognize making it somewhat confusing.
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Is it possible to say that the expanding/evolving universe creates "space" as a function of itself but that it expands "into" nothingness?
Also (separately but because these two thoughts occurred to me around the same time) is it possible for two objects to assimilate and become one object (I understand "objects" may be embedded in and part of the various fields)?
I think the deep space that is between galaxies is probably the best definition of nothingness but I'm sure that there are particles even there. If we take a lead box and it is fully sealed and suck all the air out of it what do we have only the inside walls of the box in space we have the same nothing between the particles.
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If we take a lead box and it is fully sealed and suck all the air out of it what do we have only the inside walls of the box in space
We would have gravitational attraction between the pieces of lead that detach themselves from the wall and the remaining walls.(and themselves)
So something is happening within the space .
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If we take a lead box and it is fully sealed and suck all the air out of it what do we have only the inside walls of the box in space
We would have gravitational attraction between the pieces of lead that detach themselves from the wall and the remaining walls.(and themselves)
So something is happening within the space .
You make a very interesting point but then again I would expect there are different forms of radiation in the led box and throughout the whole universe so we can not escape there being something But this is the best definition for nothing now not before the big bang or whatever created everything. Mater created time and time creates mater this is the passage of reality before that there was no time no matter no empty space. As incredible as it is that there is a universe at all I think it is just as incredible if not more so that there was nothing at all but that seems to be the way it goes.
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If we take a lead box and it is fully sealed and suck all the air out of it what do we have only the inside walls of the box in space
We would have gravitational attraction between the pieces of lead that detach themselves from the wall and the remaining walls.(and themselves)
So something is happening within the space .
You make a very interesting point but then again I would expect there are different forms of radiation in the led box and throughout the whole universe so we can not escape there being something But this is the best definition for nothing now not before the big bang or whatever created everything. Mater created time and time creates mater this is the passage of reality before that there was no time no matter no empty space. As incredible as it is that there is a universe at all I think it is just as incredible if not more so that there was nothing at all but that seems to be the way it goes.
Can be also an alternative approach.
Attempts to unify space, time, and matter beyond general relativity introduce additional interactions and extra space-time dimensions.
The Casimir effect is a small attractive force that acts between two close parallel uncharged conducting plates. It is caused by quantum vacuum fluctuations of the electromagnetic field. The vacuum contains virtual particles which are in a continuous state of fluctuation.
According to the theory, the total zero point energy in the vacuum is infinite when summed over all the possible photon modes. The Casimir effect comes from a difference of energies in which the infinities cancel.
https://math.ucr.edu/home/baez/physics/Quantum/casimir.html
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Can be also an alternative approach.
It is possible that the big bang filled the remains of a previous and smaller big bang as a second big bang will have greater potential than the first. Your explanation is very interesting and very well thought out.
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Non-existence is a non-existent reality, but the cosmos still exists. Of course, some people still think that the earth is flat, but there is space.
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Non-existence is a non-existent reality, but the cosmos still exists. Of course, some people still think that the earth is flat, but there is space.
Yes, some say the earth is flat and some say we never went to the moon but reality is real having said that if we did not exist we would not know. Will fruit grow if there is no one to eat it.