Ask any question you want about Physics

originally posted by: ImaFungi
a reply to: dragonridr

Respond to all of my questions; you are not speaking from a place of rationality, or clear and concise desire to purely seek the Truth.

Sorry the universe diesnt have to follow your rules and what you believe to be true. As in everything in life there are always alternatives. And just because you believe some truth doesn't mean the universe will agree with you. Every day we make discoveries that defy logic and reason which is why figuring out what is actually going on is difficult.

There are no easy answers in physics see you want to attack a particular interpretation without realizing others even exist. Bottom line is we can observe the universe and we see what it does and than in physics we try to figure out the why. Problem is your arguments directly contradict observation. So we know your standard interpretation of physics doesn't work. In fact if it did we wouldn't have built the LHC for example we would have all the answers .

originally posted by: ImaFungi


The electron does not 'have its own field', there is only one EM field, the electron locally (locally meaning, most surrounding the electron) effects the the EM field, wherever the electron is, to a degree greater than the EM field is effected when no charged particles are near, but to a degree comparable to when a charged particle is accelerated, thus even away from the charged particle, while 'viewing' an area of EM field, it is possible to detect 'instabilities', which his refereed to as EM radiation.

What you mean by 'virtual particles popping in and out of existence' is; Due to the nature of nature, the electron cannot avoid being coupled to the EM field, and the EM field cannot avoid being non trivially effected by the existence of the electron locally and its motion.

I don't know where you are getting your information but the electron has a field.
According the most accurate theory ever constructed by anyone ever, QED says "For example, quantum electrodynamics (QED) has one electron field and one photon field; quantum chromodynamics (QCD) has one field for each type of quark;" From Wiki quantum field page.

Your description of virtual photons is ok but vague as it doesn't explain why they interact. When I said "virtual photons" I meant virtual photons. That is the actual description of what is happening. The electron causes virtual photons to be exchanged with the EM field. That is how they interact.

All this is explained in Feynman's QED book.

Anyone can get someone to make a 'gravity field contour map' of what 3d/4d energy density gradient must appear as according to the appropriate comprehension of how that planets orbit the sun and how the gravity field exists?


themetapicture.com...

a reply to: ImaFungi
First, that animation is wrong as it shows the ecliptic at 90 degrees from the plane of the galaxy and it's only about 60 degrees.

Second, if you do what I think you're suggesting to scale, you won't see much besides the sun. The mass of the solar system is 1.0014 solar masses, which means that the planets have only a tiny fraction of the mass, and Jupiter by far has most of that 0.0014, so the rest of the planets have next to nothing in comparison.

Third, most solar system illustrations are not to scale. The animation in the following video probably is, but you can't even see any of the planets after the Earth disappears after 2 minutes, we only see curved lines representing the planets' orbits rather than the planets, and you'd have the same problem with your proposed illustration. It's not surprising we have a distorted perception of the solar system since almost every illustration we ever see of it is distorted, including the one you posted.

So, do you want it to be accurate, or do you want to be able to see something? Getting both is next to impossible on a solar system illustration, which is why almost all are inaccurate; the following is an exception.

Cosmic voyage (note the solar system to scale at 2 minutes, you can't see the planets)

a reply to: Arbitrageur

According to theory, there is an energy dense medium termed 'the gravity field' which the sun 'effects in some very non trivial way', which results in the planets 'following the sun'. If the accurate simulated depiction of sun travel and planet follow was shown as a means to highly the nature of the energy dense medium that is the gravity field, considering the way in which the planets appear to must follow the sun, how would the contour gradient of the suns effect on the gravity field appear?

a reply to: ImaFungi

The "dumbed down" illustration commonly used reduced the 3D gravitational field to a 2D representation of a rubber sheet and it shows the sun as a big ball on the rubber sheet making a dent in it.

General theory of relativity

Space-time is represented in this diagram geometrically, as it is in the general theory of relativity. Space-time is shown as a flexible sheet that is distorted by the presence of masses. The large mass creating a space-time "crater" in the center is the Sun, around which the Earth rotates

Once again this is a concept drawing. The scale is not accurate.

If you look at the sun's gravitational field from the perspective of an observer stationary with respect to the sun, and you can visualize the 3D effect reduced to 2D in the above illustration, that's it.

Now if you change the observer's position to someone stationary with respect to the Milky way as the reference frame, they will see the sun moving.

In relativity both reference frames are equivalent to each other and you can translate from one to the other using techniques you can learn in a course on relativity.

Tie a string to a ball and twirl the ball. Do it while you're standing still or do it while you're walking. Twirl the ball at any angle you want. It doesn't get left behind just because you're walking.

originally posted by: ImaFungi

originally posted by: mbkennel

Yes, electrons are excitations of "the electron field" and photons are excitations of "the electromagnetic field" and the two objects are distinct entities/constructions in accepted quantum field theory. It so happens that there are conservation laws on the number of leptons (like electrons) and not on photons so the excitations of the electron field (namely electrons) are quite a bit more persistent.

It would be nice if you responded to my reply to you, though I do not mind you responding to this as such, my reply to others of course, the one to you would be nice as well.

I dont get what you mean by 'more persistent'..

Can the electron field be measured where there are no electrons?

Can the EM field be measured where there are no photons?

Yes, you find that there are no electrons and no photons because your measuring devices made of matter don't show interactions.

If not, are there theories about its average energy density, mass, at every point where there is no excitations, excitations assumedly being greater than average?

Yeah, it's called quantum field theory and gets pretty complicated fast. You can't understand it until you first understand plain old quantum mechanics and that isn't easy.

And yes, in quantum field theory there is a notion of the 'vacuum state', the lowest energy/excitation state, which is not necessarily a mathematical zero.

The Higgs field is special as it seems to have cooled off after the Big Bang into a fixed non-trivial non-zero value and this interaction causes 'effective mass'. (The Higgs particle is the self-excitation of this special field).

What came first, the electron or the electron field? If the electron field came first, in what way were all the electrons excited/created?

What do you mean 'first'? I guess you say the field structure and particular interactions was created in the BIg Bang. Electrons and all other particles are created and destroyed according to the laws of particle physics which, in its best known approximation is called the Standard Model. This shows how the various fields interact. A huge amount of it is not derivable by "thinking upon it" but by experimental measurement.

Are the areas of non excited electron field able to interact with each other?

In Standard Model, not very much, no.

Can multiple electrons interact strongly enough to excite another one into existence?

I don't know details, depends on the particular interactions. Electrons interact electromagnetically and by the weak force too, so there could be interactions. If you shoot a very high energy electron and positron at one another in a particle accelerator there are some interactions which can create additional particles. You'll probably get leptons (electrons, positrons, muons) and neutrinos in various combinations. It gets very complicated and what you see is a whole mish-mash of all possible interactions probabilisitcally.

Is every fundamental field a different version of the same concept? (as perhaps it can be said every atom is a different version of the same concept, due to an altering of quantity, which unavoidably alters quality)

No each fundamental field is somewhat different (otherwise it would be the same) but there are definitely similarities, like muons are like electrons but are heavier, and these two are definitely different from quarks.

Does electromagnetism interact with the non excited portions of the electron field, how?

You'll have to ask a better expert on quantum field theory but I think the answer is likely to be 'if it does, it is a very very small amount', as it's an interaction of photons with virtual electron/positron pairs. In principle for very high energy gamma rays there may be some very very small "vacuum polarization" which is in effect an interaction of electromagnetism with 'virtual electrons', which means in practice the electron field but one without any real electrons already existing.

Maybe if you have extremely high energy gamma rays whose energies exceed the rest mass of electron plus positron you might start to have an effect. This means, for virtually all normal circumstances, "no, the interaction is essentially zero".

originally posted by: joelr
Right but the problem here, with quantum mechanics, is that the math works but the picture it paints violates common sense. It violates either local realism or causality.

Ditch local realism. The experiments keep saying the same thing over and over again. Eventually people will get the message. In the classical limit you have locality, but in full entangled QM you don't.

Sure, it's not common sense, but even Newtonian mechanics isn't common sense to a caveman. Start believing the experiments.

Locality emerges in the decohered classical limit, and the transition to that limit is very rapid in almost all practical circumstances, unless you arrange delicate quantum experiments.

originally posted by: mbkennel

originally posted by: joelr
Right but the problem here, with quantum mechanics, is that the math works but the picture it paints violates common sense. It violates either local realism or causality.

Ditch local realism. The experiments keep saying the same thing over and over again. Eventually people will get the message. In the classical limit you have locality, but in full entangled QM you don't.

Sure, it's not common sense, but even Newtonian mechanics isn't common sense to a caveman. Start believing the experiments.

Locality emerges in the decohered classical limit, and the transition to that limit is very rapid in almost all practical circumstances, unless you arrange delicate quantum experiments.

Could it not be that local realism appears to not exist, because the earth is spinning 'very' rapidly, revolving 'very' rapidly, and revolving again (around center of galaxy) 'very' rapidly, and traveling linear through ultimate space time ( as the galaxy itself is moving yet again in another direction dragging the earth along with it) 'very' rapidly.

How does the truth of these conditions not effect the playing with particles?

A related question regarding vacuum;

Gravity field 'exists'. It assumedly would have some general average energy density away from all mass, and then its energy density incrementally changes as the quantity of mass incrementally changes.

A galaxy is seemingly one of the dominant, macro, systems of 'massive mass collection'.

Relating to the statement prior to the statement prior to this one, it can be seen that a galaxy must create quite a change compared to the average energy density of gravity field.

So, compared to the average (outside and far away from galaxies, unless as my personal theory suggests, an opposite effect of the gravity creation inside the galaxy, this is to say, the mass in the galaxy excavates or displaces the energy density of the average gravity field, and that energy is then really existing in greater quantity outside the galaxy, and this might be what dark matter and/or dark energy is, I am probably right) nature of gravity field, any where in the galaxy will be different, because we potentially only have access to the displaced gravity field.

Moreover; the sun than displaces again the displaced gravity field, yes albeit of a extremely relatively smaller degree, but everything counts.

And then again the earth displaces the displaced gravity field of the sun; so then, my question is, we are on earth, and we take a chamber and make a vacuum;

Are we 'touching' the displaced displaced displaced gravity field? Or are we removing any gravity field, from vacuum, and so when we create a vacuum on earth we are creating a chamber of pure nothingness, or when we create a vacuum we are creating a chamber full of all the fields, minus there excitations?

originally posted by: ImaFungi

Could it not be that local realism appears to not exist, because the earth is spinning 'very' rapidly, revolving 'very' rapidly, and revolving again (around center of galaxy) 'very' rapidly, and traveling linear through ultimate space time ( as the galaxy itself is moving yet again in another direction dragging the earth along with it) 'very' rapidly.

How does the truth of these conditions not effect the playing with particles?

Special relativity forbids any statement like that to be true. We could just as easily say we are standing still and the galaxy is moving around us.
I don't see how that would effect quantum fuzzyness anyhow?
But the particles reference frame is the same as ours, we cannot prove we are in motion without looking out at objects in space.

originally posted by: ImaFungi

Gravity field 'exists'. It assumedly would have some general average energy density away from all mass, and then its energy density incrementally changes as the quantity of mass incrementally changes.

A galaxy is seemingly one of the dominant, macro, systems of 'massive mass collection'.

Relating to the statement prior to the statement prior to this one, it can be seen that a galaxy must create quite a change compared to the average energy density of gravity field.

So, compared to the average (outside and far away from galaxies, unless as my personal theory suggests, an opposite effect of the gravity creation inside the galaxy, this is to say, the mass in the galaxy excavates or displaces the energy density of the average gravity field, and that energy is then really existing in greater quantity outside the galaxy, and this might be what dark matter and/or dark energy is, I am probably right) nature of gravity field, any where in the galaxy will be different, because we potentially only have access to the displaced gravity field.

Moreover; the sun than displaces again the displaced gravity field, yes albeit of a extremely relatively smaller degree, but everything counts.

And then again the earth displaces the displaced gravity field of the sun; so then, my question is, we are on earth, and we take a chamber and make a vacuum;

Are we 'touching' the displaced displaced displaced gravity field? Or are we removing any gravity field, from vacuum, and so when we create a vacuum on earth we are creating a chamber of pure nothingness, or when we create a vacuum we are creating a chamber full of all the fields, minus there excitations?

A gravity field is a mathematical vector field. Gravity is only described right now as space-time and the curves put onto it by "matter". There is no average density, just space-time and curved space-time. You cannot remove curved space-time so it's impossible to block gravity in any way.
Two bodies near each other produce mutual curves toward each other including objects on Earth like people and buildings.
At the subatomic level the curve on space-time caused by particles is so negligible that it effects nothing.

On the large scale there is curved space-time everywhere to some degree because super super clusters orbit around each other.

a reply to: joelr

Your right no matter where you are gravity waves are there. You can't remove them and to our knowledge no way to stop it.

New Question

This one may be of interest to ATS members who play the electric guitar (or bass).

Does the thickness of an electric guitar string affect either the volume or the timbre of the note produced?

I'm thinking volume not so much, timbre maybe, though you wouldn't hear much of a difference if the guitar had humbucking pickups. 'Humbuckers' are pickups that use adjacent coils out of phase to cancel unwanted hum, but they tend to cancel out some high harmonics too.

originally posted by: Astyanax
Does the thickness of an electric guitar string affect either the volume or the timbre of the note produced?

It's got to affect the timbre. I'd also guess the thicker the string, for the same material, the lower the volume, if you pick them identically.

a reply to: Astyanax

Ha! I remember this from my freshman physics lab in college. The effect on volume is minimal since we humans tend to compensate automatically for the bigger force needed to move the thicker string. But the relationship between lenght and thickness at a given tension does affect the harmonics, that is, the timbre. The thicker the string the "rounder" the sound.

Changing the point where you pluck the string has a bigger effect, I seem to recall.

a reply to: Pirvonen

But the relationship between lenght and thickness at a given tension does affect the harmonics, that is, the timbre. The thicker the string the "rounder" the sound.

This is what I thought too; the extra diameter of the string should induce a higher current moving through the magnetic field of the pickups, but since the relative difference between thick and thin strings is quite small, the effect should (I think) be more clearly audible in terms of higher harmonics. But I recently heard a demonstration in which the difference was pretty well inaudible.

Here's the demo, for those interested. Lots of unnecessary preamble, I fear, and 20min or so in all.

a reply to: Arbitrageur

Imagine an electron not moving existing in empty space.

How is it attached to the EM field? What does the EM field appear like surrounding it?

Electrons can never be not moving, electrons intrinsically vibrate, for...no...reason?

Imagine an electron intrinsically vibrating in empty space.

How is it attached to the EM field? What does the EM field appear like surrounding it?

Is the electron just moving in place up and down? How and why?

An electron alone in empty space would vibrate...how and why?

If an electron alone in empty space could stand exactly still, what would be the minimum quantity of non nothing (substance) that you would have to introduce into the region of this lone electron, to get it to move, thus defaultly produce EM radiation?

Once you choose the substance you wish to use, imagine that substance traveling towards the lone electron, planck length by planck length, and keep note of how the substance itself is attached the EM field, and how the EM field appears surrounding it, as it approaches our electron.

If the substance you have chosen is producing EM radiation, we can imagine that before the substance physically touches our lone electron, its EM radiation it is producing, which you know how it is appearing surrounding the substance and how the EM field is attached the substance, so you should also know how the lone electrons em field is appearing surrounding itself, and therefore how the substances EM radiation will interact with the lone electrons local EM field.

So play by play, we are all carefully watching this event unfold, planck length by planck length, so we get all the details, and we see the substances em radiation heading towards the lone electrons local EM field...

and does the substances em radiation interact with the lone electrons EM field?

or does it interact with the physical body the electron itself?

When the substances EM radiation finally interacts with the lone electron/lone electrons local field; is the lone electron moved in the direction the substance was traveling, and the substances EM radiation was traveling?

When a substance is traveling forward is EM radiation produced traveling forward?

When the substances EM radiation finally interacts with the lone electron/lone electrons local field; and the lone electron is subsequently accelerated in (what direction?) some direction; where does the EM radiation which caused the lone electron to accelerate, go exactly, how is its path altered, direction altered?

And; how exactly does the local EM field surrounding the lone electron respond to the lone electron being accelerated via EM radiation from the substance? In which directions surrounding the lone electron at T exactly prior to lone electron acceleration through T exact instance of lone electron acceleration, does the EM radiation generated from the acceleration of the lone electron propagate?

I watched these videos on youtube a while ago. " The Primer Fields " it is a must watch and give you something to think about.. i recommend watching

a reply to: Bedlam

Not a Guitarist but I AM a Bassplyr.

String thickness does effect timbre and it does lower the volume of what frequencies are exhibited by the string. Along with how much energy it takes to get any volume out of the string. More mass more energy required.

For instance listen to Les Claypool's (primus) bass playing. He uses only very light gauge strings. He has a thin clanky crisp sound to his instrument. The fundamental and the lower end frequencies are quieter and roll off and aren't heard as easily.

Listen to Marcus Miller. He uses a heavier gauge string. Somewhere in the middle actually. He has a much more punchier sound focusing on frequencies somewhere around 400-600 hertz. The middle range of the bass spectrum. The high end sound rolls off in volume and so does a little of the lower frequencies.

As for me I like a sweeter sounding high end that's softer so I use heavy gauge strings for my G and C strings so that the treble rolls off a bit. (I have a 6 string bass tuned B,E,A,D,G,C) I use regular gauge strings for the E,A,D strings and I buy one lighter gauge. B string my lowest string. Not Les Claypool light. The thinner B string is to exhibit the upper spectrum harmonics of the B which can get as low as 60 hertz on the open b or something like that. SO to make it sound less muddy I use the thinner gauge on that one string to make the lower notes more focused and crisp sounding.

But I also increase the length of the string from standard 34 inches to 35 inches to maximize the fundamental frequencies so that they don't get obliterated by the upper harmonics. It sounds complicated but it's not.

It then gets more complicated because everything in the universe is effected by something else. So then one has to carefully select which density woods and materials you are going to use as they will absorb vibrations of certain frequencies and sculpt the instruments sound too. This is especially important in the bridge and other hardware on the instrument.

Then you have to deal with the room you are playing in and it's dimensions and what frequencies they resonate with. You have to dial back certain frequencies on your own instrument to prevent the resonance with the rooms dimensions from overtaking all the other frequencies and giving you a muddled mushy sound or one that shakes the walls at inappropriate times in the song.

SO it's like one giant circle between the string gauge, the wood, the hardware of the instrument, the room dimensions and the instrument again to sculpt desired vibrational effects.

I'm figure all of the universe operates on similar principles and relationships. Or in a word relationships matter.

Long story short just listen to Marcus Miller. www.youtube.com...

originally posted by: ImaFungi
a reply to: Arbitrageur

Imagine an electron not moving existing in empty space.

How is it attached to the EM field? What does the EM field appear like surrounding it?

Have you looked through the textbooks and videos I suggested before?

It looks like a point charge (radial electric field) plus a point dipole on the magnetic field.

Electrons can never be not moving, electrons intrinsically vibrate, for...no...reason?

Imagine an electron intrinsically vibrating in empty space.

I don't know what you mean by intrinsically vibrating. Since an electron has no internal structure it's not clear what that would mean.

How is it attached to the EM field? What does the EM field appear like surrounding it?

Is the electron just moving in place up and down? How and why?

An electron alone in empty space would vibrate...how and why?

It wouldn't.

If an electron alone in empty space could stand exactly still, what would be the minimum quantity of non nothing (substance) that you would have to introduce into the region of this lone electron, to get it to move, thus defaultly produce EM radiation?

That amount would be very low. You would essentially be scattering electromagnetic radiation off a charge (the re-radiation and change 'counts' as the radiation made by the electron) and you could do that for arbitrarily low (long wavelength) EM waves.

Once you choose the substance you wish to use, imagine that substance traveling towards the lone electron, planck length by planck length, and keep note of how the substance itself is attached the EM field, and how the EM field appears surrounding it, as it approaches our electron.

Are you talking about a different particle and not a photon?

If the substance you have chosen is producing EM radiation, we can imagine that before the substance physically touches our lone electron, its EM radiation it is producing, which you know how it is appearing surrounding the substance and how the EM field is attached the substance, so you should also know how the lone electrons em field is appearing surrounding itself, and therefore how the substances EM radiation will interact with the lone electrons local EM field.

So play by play, we are all carefully watching this event unfold, planck length by planck length, so we get all the details, and we see the substances em radiation heading towards the lone electrons local EM field...

and does the substances em radiation interact with the lone electrons EM field?

or does it interact with the physical body the electron itself?

The EM field is produced by adding up contributions from ALL charges in the universe. So if you have an accelerating particle which emits EM radiation because it's charged, then yes the EM radiation could conceivably get there to the other charged particle before the particle itself does.

When the substances EM radiation finally interacts with the lone electron/lone electrons local field; is the lone electron moved in the direction the substance was traveling, and the substances EM radiation was traveling?

The electron will be accelerated in whatever direction the electric field is *AT* the target electron's location plus something perpendicular to both the target electron's velocity and the magnetic field at the target electron's location. You don't need to know where the source electron once was or what it used to do, just what the E & B fields are *now* and *here* to get the force *here*.

The entire point of a field theory is that to compute the effect on the target particle you ONLY need to know the values of the field at the particle and not specifically all the other particles. The chain of causality is one electron accelerates and makes EM waves, and those EM waves propagate and then they hit another charged particle which then accelerates.

When a substance is traveling forward is EM radiation produced traveling forward?

If you consider the direction of EM radiation to be the direction of energy propagation (most sensible definition):

No, generally EM radiation is produced most efficiently in a propagating direction perpendicular to the direction of motion of the charges. (and the E and B fields in a EM wave are pointing in a direction perpendicular to the direction of propagation)

Think of a TV antenna---the old school kind which had a grid of poles. You pointed the antenna so you caught the signal with the elements *perpendicular*. Think of a water wave coming into shore. If you faced out to the ocean and held out your arms perpendicularly, you would feel the wave the most that way. In the antenna, by pointing it this way you accelerate electrons in the antenna perpendicularly most efficiently and you can pick that up in the receiver. Since it's symmetrical accelerating electrons to broadcast works the same way.

When the substances EM radiation finally interacts with the lone electron/lone electrons local field; and the lone electron is subsequently accelerated in (what direction?) some direction; where does the EM radiation which caused the lone electron to accelerate, go exactly, how is its path altered, direction altered?

The new E fields are the sum of the old ones plus whatever is created by the new motion of the target charge.

And; how exactly does the local EM field surrounding the lone electron respond to the lone electron being accelerated via EM radiation from the substance? In which directions surrounding the lone electron at T exactly prior to lone electron acceleration through T exact instance of lone electron acceleration, does the EM radiation generated from the acceleration of the lone electron propagate?

Think of it this way. You shoot a plane wave from left to right in free space where it hits a lone charge.
Say now that the polarization of this wave is such that the electric field is up and down. From the viewpoint of the target charge, it is now subjected to a local E field which accelerates the electron in a wiggly way in the up and down direction as well. Since the electron is itself accelerating it will produce EM waves as well, and the resulting EM field will be the sum of the incoming plane wave plus new waves created by the accelerating charge. These can cancel and reinforce.

Because the electron has a non-zero mass it cannot be accelerated instantaneously, i.e. it has inertia, so its motion will lag the incoming plane wave. It means that the radiation it produces will be partially phase delayed from the incoming one, and so you can get constructive & destructive interference.

A laser is a situtation, when using quantum mechanical behavior, you get 100% constructive reinforcing behavior and all the waves sum up to make a giant coherent wave.

a reply to: BASSPLYR

Physically I'd guess that this means that for a thicker string vs thinner string, the higher frequencies are damped faster, so that the the lower frequencies are heard more in the sustain of the note.

The damping comes from frictional flexing in the string, as well as the connection to the ends and body which also provide resonance & damping.

I don't know exactly how an electric bass works---is there a magnetic induction & dissipation going on as well? Is the decay entirely mechanical or does it involve the electric system?