Field Question

[MikeAL]

4 hours ago, Strange said:

Not really because the field is invented to describe exactly that sort of affect. 

I find this belief quite challenging. It seems to be what most of the forum is saying. Fields are an invention, a mathematical overlay across..... there's the tricky part....across a field? By creating the mathematical abstraction do you then deny that the overlay that was formed in now way represents anything real in space?

 

7 hours ago, Strange said:

8 hours ago, MikeAL said:

So, we are all prepared to accept that the permittivity of space does not change even though more of space is mushrooming out all the time and energy cannot be created or destroyed in our universe? That's interesting.

If that is what the evidence says, yes. 

And I really don’t understand your difficulty with that. 

In many situations, the vacuum state can be defined to have zero energy, although the actual situation is considerably more subtle. The vacuum state is associated with a zero-point energy, and this zero-point energy has measurable effects. In the laboratory, it may be detected as the Casimir effect. In physical cosmology, the energy of the cosmological vacuum appears as the cosmological constant. In fact, the energy of a cubic centimeter of empty space has been calculated figuratively to be one trillionth of an erg (or 0.6 eV).^[8] An outstanding requirement imposed on a potential Theory of Everything is that the energy of the quantum vacuum state must explain the physically observed cosmological constant.  https://en.wikipedia.org/wiki/Vacuum_state    

This sounds like new energy to me.

[studiot]

1 hour ago, Strange said:

Ideally, one would ignore the third dimension as we are talking intrinsic curvature

 

See above ...

But we are talking about dilation.

 

 

1 hour ago, Janus said:

By using non-Euclidean geometry.    The balloon analogy is a tool that's designed to simulate non-Euclidean geometry in a way that is easily visualized,  by imagining what it would be like to try to perform Euclidean plane geometry on the surface of a sphere.    In true non-Euclidean  plane geometry,  there is no 3rd dimension that the plane curves in, but the rules of geometry differ from Euclidean geometry, (the interior angles of  triangle don't add up to 180° etc.)    In the same way, the behavior of non-Euclidean 3 dimensional space simulates that of 3-d space curved through a 4 spacial dimension, but without the actual existence of a 4th spacial dimension.

Indeed so, but as noted, we are talking about dilation, which is a dynamic thing, not the static one both you and Strange are describing.

 

Is it not true that the intrinsic indicators of curvature will change with expansion?

For instance spherical excess on the balloon will increase as the balloon expands.

 

Further you are both ignoring my earlier comments about the subject.

 

[Strange]

11 minutes ago, studiot said:

Is it not true that the intrinsic indicators of curvature will change with expansion?

The universe appears to be flat, so no. (Yet another fatal flaw with the analogy!)

12 minutes ago, studiot said:

Further you are both ignoring my earlier comments about the subject.

Which ones?

[studiot]

7 minutes ago, Strange said:

The universe appears to be flat, so no. (Yet another fatal flaw with the analogy!)

You can't seriously be denying that surveyors on Earth have a different correction for spherical excess than hypothetical surveyors on Jupiter?

So are you saying that if the Earth expanded to the size of Jupiter, surveyors would notice no difference?

Edited May 6, 2018 by studiot

[geordief]

1 hour ago, Strange said:

You know, I did think about that, for quite a long time, and decided that, in this context, "affect" (which is the topic of discussion) was OK. But, you know ... language...

"affect" is a noun  practically always

http://web.ku.edu/~edit/affect.html

 

And to  think I was giving you the benefit of autocomplete syndrome doubt

 

(can't be wrong here surely,you can't have meant it as  a psychiatric term ??)

[Strange]

1 hour ago, studiot said:

You can't seriously be denying that surveyors on Earth have a different correction for spherical excess than hypothetical surveyors on Jupiter?

So are you saying that if the Earth expanded to the size of Jupiter, surveyors would notice no difference?

Not at all. Quite the opposite if anything. If the universe were curved like the Earth then the curvature would decrease with expansion. But it isn’t, so it doesn’t. 

22 minutes ago, geordief said:

"affect" is a noun  practically always

http://web.ku.edu/~edit/affect.html

 

And to  think I was giving you the benefit of autocomplete syndrome doubt

 

(can't be wrong here surely,you can't have meant it as  a psychiatric term ??)

But I was referring to the word “affect” as it appeared in your statement. A “use vs mention” distinction. 

[geordief]

6 minutes ago, Strange said:

 

But I was referring to the word “affect” as it appeared in your statement. A “use vs mention” distinction. 

I see what you mean now*. (Fields are more interesting ,though )

 

*stretching it a bit...

[Mordred]

 Wow has this thread gone down the garden path. Its truly amazing as one can assign any field to any region of spacetime under geometry. All that is required is a set of assigned values or functions under a geometry or coordinate basis.

 Roflmao this is done even with scalar fields such as temperature... 

 Why argue the detail that math is involved... How else can one possibly model relations of how A affects B without mathematics.

 So what if those mathematics describes measurable quantities. That is precisely the entire purpose in the first place.

 Lets not forget some common rational thought instead of getting sidetracked into "Is fields real or simply a mathematical descriptive". 

 The entire purpose in the first place is to accurately describe measurable quantities under a predictive and testable model....

 Do we argue against the validity of Newtons laws of inertia simply because it involves mathematics?

 So how is fields any different ?????

 Lol want a good sidetrack metaphysics debate discuss the meaning of physical....

 If you want a broad understanding of Fields try this 885 page article I have spent over 3 years just to understand half of it. Some good insights from this article such as a bosonic field i symmetric while a fermionic field is antisymmetric...

 

http://arxiv.org/abs/hepth/9912205 : "Fields" 

 Lol want a good metaphysics debate (another thread) define physical then look at the definition of physics...

Anyone that believes they can describe how particle A behaves under field condition B without mathematics is blowing fluff out their rear end. Let alone accurately plot the variations that occur on a field of any type LMAO 

 

 

 

Edited May 7, 2018 by Mordred

[Mordred]

8 hours ago, MikeAL said:

I find this belief quite challenging. It seems to be what most of the forum is saying. Fields are an invention, a mathematical overlay across..... there's the tricky part....across a field? By creating the mathematical abstraction do you then deny that the overlay that was formed in now way represents anything real in space

Answer how particle A behaves to reach point B without mathematics... Your objection is the use of mathematics itself. Does an engineer build a bridge that involves peoples lives without applying mathematics to the structural integrety?

 Why would you believe a physicist can predict dynamical motion and kinematics of how particle A behaves to go from one coordinate location to another without mathematics?

 Is ir sufficient to just use mere words?

 Here is an abstract field the inflaton field. Here we use a placeholder quasi particle not real and not virtual. It is a particle that merely exhibits particlelike behavior but does it actually exist ? Yet it is commonly used for inflation... meanwhile another quasi particle that dropped out of usage today that performed the precise same function is Parker radiation and the curvaton. Both of which had their own fields....

 Yes fields is a nathematical tool that is incredibly useful in physics but it is impossible to define any field without using mathematics. By define I mean describe its distribution and variations at every single coordinate however many coordinates you use is an arbitrary decision

Edited May 7, 2018 by Mordred

[beecee]

1 hour ago, Mordred said:

 Wow has this thread gone down the garden path.  

As generally a bystander observer, I found it interesting.

Quote

If you want a broad understanding of Fields try this 885 page article I have spent over 3 years just to understand half of it. Some good insights from this article such as a bosonic field i symmetric while a fermionic field is antisymmetric...

That means I have bloody buckley's chance! 

[Mordred]

4 minutes ago, beecee said:

 

That means I have bloody buckley's chance! 

Lol its been literally a study of dozens of articles simply to understand a single page in many cases.

 Lets try an example. Many of us have heard of SO(3.1) Poincare group for relativity. Yet I can describe this exact same group under SU(2)×SU(2)/Z_2 ). Then further that under SL(c/2) or under E(32). All of which involve different numbers of dimensions for the precise same dynamics and spacetime region.

 

Edited May 7, 2018 by Mordred

[MikeAL]

6 minutes ago, Mordred said:

Your objection is the use of mathematics itself.

No at all. My objection is having used the mathematics to model the universe, you then throw away the universe and say all that exists is the mathematics. We went and threw mathematics over the gravitation field so we could see how it works, now we have turn around and said the field is not really there at all,  it is just a mathematical abstraction (unless you mean extrapolation, which is different)

It seems to me you want to scrape off the icing and throw away the cake. 

[Mordred]

Tell you what describe how the universe evolves and plot the coordinate and proper distance of a galaxy from our observer point without mathematics.

 Define mass without using mathematics 

Edited May 7, 2018 by Mordred

[MikeAL]

I also like how, with the exception of BeeCee, everyone is staying well clear of the Art Hobson quotes.

Just now, Mordred said:

Tell you what describe how the universe evolves and plot the coordinate and proper distance of a galaxy from our observer point without mathematics

Once I am done with my description, and recorded all the wonderful and intriguing facets of the universe in mathematical language, will you then deny the whole thing exists?

[Mordred]

I like many of Art Hobsons works right until he hits metaphysics. Then I ignore him.

 Just as I did with Stephen Hawkings when he applied metaphysics.

 The purpose of physics is not the philosophy of reality. It is to make accurate and testable predictions of measurable events and quantities

Edited May 7, 2018 by Mordred

[MikeAL]

Well, I'm not that familiar with him outside of this book, but a quick search says he is: 

Art Hobson
Professor Emeritus of Physics

University of Arkansas

https://sites.uark.edu/ahobson/

I don't see how a professor of physics could get the basics so wrong. 

[Mordred]

Who stated he is necessarily right or wrong valid arguments can be made for any metaphysics argument. Those debates are endless circles of continous debates. Just like any other philosophical debate.

 Provide one example of a philosophical argument that ever reached a decisive conclusion...

I am more than aware of Art Hobsons qualifications. I have my own as well, what of it. Does that automatically mean everything I state is correct simply because of my masters degree? or that Hobson is correct everytime simply because he has a PH.D or Swansont with his PH.D ?

Edited May 7, 2018 by Mordred

[MikeAL]

So, like, when he said, "Fields are properties of space itself." P77,  or "Although we can’t see these fields directly, we’ll find they are physically real and not just something scientists invent to concoct theories and make calculations." P77-78 he was just speaking philosophically?

[Mordred]

Ever looked at the proper definition of space?

It is simply volume.

Spacetime is any metric where time is given dimensionslity of length in Natural units.

 How we describe spacetime is a mathematical treatment of arbitrary choice. Ie the Universe doesn't care how we measure it. 

 I can measure any volume of spacetime in a dozen different ways all equally accurate and valid using any arbitrary number of fields, subfields, rings, or dimensions.

 Roflmao I've even encountred theories where a 4d volume involved 465 dimensions. (though I doubt I can find the article today). Each dimension involving a different degree of freedom that can be accurately described as a different field...

 Every collection of particles of every type can be described with its own field, every interaction between these fields ie holonomy is also its own field. Every overlap, every connection every fibre bundle.

 Take the Higgs field as an example it involves not 1 but 4 seperate fields each describing a different interaction 

 If thats not abstract then what is ?

Edited May 7, 2018 by Mordred

[MikeAL]

1 hour ago, Mordred said:

If thats not abstract then what is ?

abstract

adjective

 

ˈabstrakt/

1. 1.

   existing in thought or as an idea but not having a physical or concrete existence.

    

   Although we can’t see these fields directly, we’ll find they are physically real and not just something scientists invent to concoct theories and make calculations. P77-78 Tales of the Quantum, Understanding Physic’s Most Fundamental Theory – Art Hobson.

    

   I do take your point Mordred. At the end of the day though this little old planet of ours keeps doing elipses around the sun and it ain't touchin' it. Something is out there... do you agree, or is it just volume?

[Strange]

1 hour ago, MikeAL said:

So, like, when he said, "Fields are properties of space itself." P77,  or "Although we can’t see these fields directly, we’ll find they are physically real and not just something scientists invent to concoct theories and make calculations." P77-78 he was just speaking philosophically?

As soon as you start discussing whether something is "real" or not, you are doing philosophy, not science.

For example, in Newtonian theory, gravity is a force and you would assume that force is real.

But along comes GR and the force no longer exists. Gravity is described as the curvature of space-time geometry. So is that real?

Maybe. Or maybe another theory will come along describing gravity in a different way and perhaps in that theory space and time don't exist at all. 

So physics doesn't deal with reality (whatever that is) but with descriptions of what we observe. 

[MikeAL]

1 hour ago, Strange said:

As soon as you start discussing whether something is "real" or not, you are doing philosophy, not science.

I think you guys are the philosophers. I am not pondering the meaning of the word 'real' and having existential epiphanies as I chant mantras under a waterfall. I am referring to the sharp distinction between mathematics and physics. In physics, mathematics is an overlay, that attempts to explain what is in our universe. It is not the other way around. The universe is not an abstract imaginary form used as an overlay for mathematics. 

1 hour ago, Strange said:

But along comes GR and the force no longer exists. Gravity is described as the curvature of space-time geometry. So is that real?

Maybe.

There is a difference between something being right or wrong, knowing and not knowing, existing or not existing. 

We know something we call gravity is causing objects with mass to be attracted toward each other. Our current best theories tell us this is because of a gravitational field. If you tell me the field is not real, then what you are in effect saying is that the theory is incorrect.

1 hour ago, Strange said:

So physics doesn't deal with reality (whatever that is) but with descriptions of what we observe. 

This is incorrect. Physics uses as it's primary tool mathematics, in order to explain our universe - our very real universe. If you need a frame of reference for real, start with yourself and your world, and take it from there.

 

Edited May 7, 2018 by MikeAL

[Strange]

34 minutes ago, MikeAL said:

In physics, mathematics is an overlay, that attempts to explain what is in our universe.

Exactly. 

35 minutes ago, MikeAL said:

We know something we call gravity is causing objects with mass to be attracted toward each other. Our current best theories tell us this is because of a gravitational field. 

Our previous best there told us it was a force. That theory still works in most cases. So, in most cases, we can consider the force to be real (it certainly feels real). In other cases, we consider the curvature of space-time to be real and the force to be a fictitious force. 

36 minutes ago, MikeAL said:

If you tell me the field is not real, then what you are in effect saying is that the theory is incorrect.

No because a theory is correct when it works. Both Newtonian gravity and GR are correct, within the areas where they apply. For the early universe and black holes, we probably need yet another theory. But that won't make the others wrong, even if the new model is completely different again.

38 minutes ago, MikeAL said:

This is incorrect. Physics uses as it's primary tool mathematics, in order to explain our universe - our very real universe.

Although some philosophers might argue about whether the universe is real or to, I won't. But I would say physics describes, rather than explains, the universe. It tells us how it behaves, not what it is ultimately made of.

 

[MikeAL]

19 minutes ago, Strange said:

No because a theory is correct when it works.

I disagree. A theory is correct when it is correct. Any other time, a theory is simply a convenience.

22 minutes ago, Strange said:

But I would say physics describes, rather than explains, the universe. It tells us how it behaves, not what it is ultimately made of.

Well, Quantum Mechanists may argue the point with you on that one, but even is physics is a little too pointed a definition, certainly science will try to tell us what the universe is made of. I mean, if it doesn't then what are we waiting for, let's start a new branch of science right now.

[swansont]

9 minutes ago, MikeAL said:

I disagree. A theory is correct when it is correct. Any other time, a theory is simply a convenience.

That's a tautology. How do you tell if it correct? It's correct when it works. And then, it only tells you about behavior, not fundamental truth or reality.

9 minutes ago, MikeAL said:

Well, Quantum Mechanists may argue the point with you on that one, but even is physics is a little too pointed a definition, certainly science will try to tell us what the universe is made of. I mean, if it doesn't then what are we waiting for, let's start a new branch of science right now.

It already exists as philosophy. If it were science, you would need a way to test to see if it were true. How do you do that?