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originally posted by: ImaFungi
originally posted by: mbkennel
How about learning about 1-d wave equation and then classical acoustics first, it's simpler then EM having only a scalar pressure field.
OK, let's start more basic. Do you know what an ordinary differential equation is? In particular, an initial-value problem for describing equations of motion? Do you understand the concept of a 'differential equation of motion' in physics? If not, start there before complaining about how to intuitively grok quantum field theory.
Is reality composed of differential equations of motion? And that is the quantitative comprehension of the quality of what is doing the motion? And then the particle and field aspect is the attempt to ascribe a qualitative understanding to the bare raw symbolism the math provides?
Im just very concerned for the state of physics that it cant tell me what 'that which exists in/as empty space' is. It is said empty space is pure fields. EM field, gravity field. So do you imagine that in space there are lines, field lines, that are made of EM? And the gravity field is field lines made of gravity essence?
How do these 2 fields exist in relation to each other? Holographically on top? next to? Entwined?
How does one field exist as itself. What is in between the field lines? Or are the field lines all touching, as to make a field fabric or sheet? Are they touching length wise and height wise and width wise? Are the field lines made of particles?
If the field lines are not touching, how are they held together? What exists between them?
Fields only exist where matter exists you need a particle to have a field period.
Well there you have it, dragonridr may be right after all if the definition of matter is so muddled we aren't sure what it is anymore.
Before the 20th century, the term matter included ordinary matter composed of atoms, and excluded other energy phenomena such as light or sound. This concept of matter may be generalized from atoms to include any objects having mass even when at rest, but this is ambiguous because an object's mass can arise from its (possibly-massless) constituents' motion and interaction energies. Thus, matter does not have a universal definition, nor is it a fundamental concept, in physics today.
And this is from the physics branch of about.com so one would think a physics-specific definition would be used. I think the term matter isn't well defined anymore.
Definition: Matter has many definitions, but the most common is that it is any substance which has mass and occupies space. All physical objects are composed of matter, in the form of atoms, which are in turn composed of protons, neutrons, and electrons.
Photons have no mass, so they are an example of something in physics is not comprised of matter. They are also not considered "objects" in the traditional sense, as they cannot exist in a stationary state.
originally posted by: Arbitrageur
a reply to: dragonridr
This may be the way physicists now think of it, but the way the general population thinks about it, and ordinary dictionaries aren't entirely consistent with these definitions, hence the confusion. For example:
physics.about.com...
And this is from the physics branch of about.com so one would think a physics-specific definition would be used. I think the term matter isn't well defined anymore.
Definition: Matter has many definitions, but the most common is that it is any substance which has mass and occupies space. All physical objects are composed of matter, in the form of atoms, which are in turn composed of protons, neutrons, and electrons.
Photons have no mass, so they are an example of something in physics is not comprised of matter. They are also not considered "objects" in the traditional sense, as they cannot exist in a stationary state.
By any chance do you have a better definition than this?
originally posted by: ImaFungi
Is reality composed of differential equations of motion?
And that is the quantitative comprehension of the quality of what is doing the motion? And then the particle and field aspect is the attempt to ascribe a qualitative understanding to the bare raw symbolism the math provides?
Im just very concerned for the state of physics that it cant tell me what 'that which exists in/as empty space' is. It is said empty space is pure fields.
EM field, gravity field. So do you imagine that in space there are lines, field lines, that are made of EM?
And the gravity field is field lines made of gravity essence?
How do these 2 fields exist in relation to each other? Holographically on top? next to? Entwined?
How does one field exist as itself.
What is in between the field lines? Or are the field lines all touching, as to make a field fabric or sheet? Are they touching length wise and height wise and width wise? Are the field lines made of particles?
If the field lines are not touching, how are they held together? What exists between them?
And this is from the physics branch of about.com so one would think a physics-specific definition would be used. I think the term matter isn't well defined anymore.
originally posted by: Arbitrageur
er, in the form of atoms, which are in turn composed of protons, neutrons, and electrons.
Photons have no mass, so they are an example of something in physics is not comprised of matter. They are also not considered "objects" in the traditional sense, as they cannot exist in a stationary state.
By any chance do you have a better definition than this?
originally posted by: mbkennel
And this is from the physics branch of about.com so one would think a physics-specific definition would be used. I think the term matter isn't well defined anymore.
originally posted by: Arbitrageur
er, in the form of atoms, which are in turn composed of protons, neutrons, and electrons.
Photons have no mass, so they are an example of something in physics is not comprised of matter. They are also not considered "objects" in the traditional sense, as they cannot exist in a stationary state.
By any chance do you have a better definition than this?
A good translation of the intuitive term "matter" would correspond, in physics, to particles with non-zero rest mass, and conservation laws on their number. This excludes bosons like photons (which have zero mass and can be created/destroyed at will), and includes matter like electrons and nuclei, which, thanks to laws of physics, can sit still and don't easily go away, as the interactions to create or destroy them are very rare in practical human life.
Light Changed to Matter, Then Stopped and Moved
CAMBRIDGE, Mass., Feb. 8, 2007 -- By converting light into matter and then back again, physicists have for the first time stopped a light pulse and then restarted it a small distance away. This "quantum mechanical magic trick" provides unprecedented control over light and could have applications in fiber-optic communication and quantum information processing.
Not to mention theres still a debate on if photons have mass.
The only difference really between light and matter is matter cant travel at the speed of light.
originally posted by: DenyObfuscation
a reply to: dragonridr
Not to mention theres still a debate on if photons have mass.
Why? If the following is true,
The only difference really between light and matter is matter cant travel at the speed of light.
Help?
originally posted by: DenyObfuscation
a reply to: dragonridr
On your phone? Save your thumbs. Remember I'm real simple with this stuff, like this
I thought it was impossible for mass to reach lightspeed. If a photon has mass that would mean a photon could not travel at lightspeed.
Is that the thinking on neutrinos, that they have mass so are traveling the speed of light but maybe such a small hair under that we can't measure the difference?
originally posted by: dragonridr
that little bit of mass that it does have would slightly slow it down we could be talking .999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999 the speed of light
originally posted by: mbkennel
Lines are a graphical technique to display properties of a field for human visualization.
In modern physics gravity is believed to be special and not necessarily "in" the fields as Yet Another Field. Somehow the future unification will fix this but we don't know what that looks like.
originally posted by: dragonridr
originally posted by: DenyObfuscation
a reply to: dragonridr
On your phone? Save your thumbs. Remember I'm real simple with this stuff, like this
I thought it was impossible for mass to reach lightspeed. If a photon has mass that would mean a photon could not travel at lightspeed.
Ok ill explain it this way lets say photons do indeed have a slight mass. What we call the speed of light is simply than the lowest mass that can attain what we would call the speed of light. Higher frequencies would have even a smaller mass and move enev faster. The only problem is the difference we would be talking about would be so small that light would have to travel trillions of light years for us to even notice. So what we assume to be the speed of light without mass is actually the speed of light with almost no mass. This of course means heavier particles will again travel slower than that.
originally posted by: DenyObfuscation
a reply to: dragonridr
Frequency doesn't affect velocity. EM radiation travels at lightspeed, period, or I'm done with science!!
No matter how *small* the mass, either SR or GR or both say no lightspeed for mass. Mass increases with velocity I'm told, requiring more energy to accelerate it. Acceleration of mass to lightspeed would approach infinite mass requiring infinite energy... or something like that.
Not trying to be difficult but this is thoroughly confusing.
originally posted by: ImaFungi
originally posted by: mbkennel
Lines are a graphical technique to display properties of a field for human visualization.
So do physicists know what the lines represent in reality? Do the lines in their graphical technique = lines that exist in reality?
If not, what are the lines representing? (and I understand either way that answer will entail, energy, they are representing an area or volume of energy that is a space of the universe that is the universe but,)
How do physicists think the fields they represent with lines, really physically exist? I read bellow you say the field lines are like those of geographical contortion. So 'there is something there', the something that is there is what I am trying to comprehend, what it is. You are now saying field theory is not in anyway a fundamental replica of reality, but a tool of measuring the fundamental of reality? Like reality is not composed of inches and feet and miles and seconds and minutes and hours, but we can place these tools of measurement on top of reality, to organize our understanding of it, and watch how it moves under our measuring restrictions to compare its parts to its parts.
Ok so what do you mean by in the fields. Do physicists really think that there is an entire universally encompassing field for each of the hundreds of fundamental particles? Or is there a general consensus that there are only a handful of all encompassing universal energy fields (EM, Gravity, Higgs, quark, electron, etc.)?