Why electricity flows

Originally posted by Bedlam

The weakest of these forces totally swamp out inter-atomic gravity. However, if you've got a lot of material, and a lot of time, and not much else really disturbing the pot, then gravity will cause the material to coalesce. That's how stars are formed.

edit to add:

When you've got enough of them in one place, you obviously can observe a mass of atoms attracting another mass of atoms - which is why you have weight. But on an atom by atom basis, it's not a big factor in how they interact.

edit on 14-11-2012 by Bedlam because: (no reason given)

why is it gravity that coalesces the lot of material to for stars, and not electromagnetism and the nuclear force/s?
if atoms attract,, and many atoms attract many atoms,, because of forces other then gravity.... why is it that when a star forms, it is not out of atomic attractions,, but because of gravity?

reply to post by ImaFungi


Well, most atoms are neutrally charged. That sort of ends the electrostatic attraction part over a distance. The dipolar forces are more short-ranged than gravity.

reply to post by ImaFungi


I don't think so. If you get down to very tiny distances with the right materials, you get Casimir forces which are attributable to a vacuum. But it's tough to spot.

Originally posted by Bedlam
reply to post by ImaFungi

 

I don't think so. If you get down to very tiny distances with the right materials, you get Casimir forces which are attributable to a vacuum. But it's tough to spot.

if there are those forces on very small materials at small distances,, why dont you think that force would be multiplied with much larger materials at a relatively similarly ratioed tiny distance?

but i dont think you answered any of my questions about if non dense matter regions of space have mass or energy or are entirely composed of particles etc.? meaning there is no such thing as empty space....

another thing i was just thinking about, wondering if you know,, if not i will google about it....

say we have an absolutely perfect vacuum the size of a show box.. and somehow emit millions of photons into this vacuum "enlightening" the vacuum... what will happen to the photons? will they remain lighting this vacuum for a relative while? if not where will they go? what will happen to their energy? to what will it dissipate/transfer?

what if the vacuum walls were perfect mirrors?

Originally posted by ImaFungi

if there are those forces on very small materials at small distances,, why dont you think that force would be multiplied with much larger materials at a relatively similarly ratioed tiny distance?

Because it doesn't work that way. The only time you see them is when you start excluding virtual particle flux between the particles, to do that, you have to be close and wee.

but i dont think you answered any of my questions about if non dense matter regions of space have mass or energy or are entirely composed of particles etc.? meaning there is no such thing as empty space....

Vacuum is vacuum. Way way way down at the Planck level, you've got virtual particles popping in and out, but that sort of thing is not easily explained without a lot more background in place. If, for instance, you ask me about spinors and ambitwistors, and you don't know algebra, I'm going to have to meatball it as "it's a math operation". Similarly, if you want to know about virtual particle fluctuations, I don't have a really good way to explain that verbally. mbkennel might do better, I can't do it very well. Trying to explain some of this verbally just doesn't work well. You can also get into other esoteric crap like time-linked energy and the like, not for the faint of heart.

And, then, too, you might wonder other things that seem like 'why is the sky blue' questions, but when you get into creepy starting constraints you have to ask them. Like, why is c c? Why that value? Why are the values for permittivity and permeability anything at all in a vacuum? Why are they the numbers they are? Does that ever change? Why is e e? Pi pi? Are we in a deSitter or Machian universe? Is space negatively curved? Or does that fluctuate depending on where you are? Is the cosmological constant? Or is it a cosmological variable depending on the concentration of dark matter in the area?

say we have an absolutely perfect vacuum the size of a show box.. and somehow emit millions of photons into this vacuum "enlightening" the vacuum... what will happen to the photons? will they remain lighting this vacuum for a relative while? if not where will they go? what will happen to their energy? to what will it dissipate/transfer?

The problem is poorly constrained. What is a "show box"? What are its characteristics? What sort of photons? Are they placed randomly? Etc. Etc.

For a relative while - yes. For the time it will take them to propagate across it. Then they aren't in the box anymore, unless it's reflective. Then you get into other issues. They retain their energy - if the box is conceptual - as they leave it, they take their energy with them. Remember, you can't "see" the photons unless they whack you in the eye. So from an observer outside the box, if you put them in the left side heading for the right, and you're looking in at the top, you will see...nothing.

what if the vacuum walls were perfect mirrors?

Go look up Einstein's box. I'll be back in a couple of hours - it's time to hit the town.

reply to post by Bedlam


cool,, thanks for the replies.. show box = shoe box.. shoe box sized vacuum,..,.,

if the photons are sent straight across from left to right is it only because this is occurring in a vacuum, that when we view from overhead they are not visible?

say we are on a plane,, and travel over a lighthouse with its high beam on streaming horizontal... we can see the entire beam because from every point of the beam there are photons that simulteanously travel straight horizontal in the focused beam,, but also ninety degrees (and every other degrees) into our eye?

regarding your questions on what kind of photons and how they are placed in the vacuum... I want to say there is some photon emitter embedded in one of the walls,, and it can emit photons while still sealing off anything beyond the vacuums containment.... if thousands of photons are emitted into this shoe box sized perfect vacuum,,, where will the photons and their subsequent energy go?

Originally posted by ImaFungi
how does the mass of 3 individual quarks compare to the mass of a proton?

The rest masses of the three quarks in a proton summed is much smaller than the mass of them in combination of a proton. Most of the mass of the proton comes from its binding energy from strong nuclear force (gluon exchange).

This is contrary to the situation of atoms being bound into molecules. There the rest masses of the atoms contribute nearly all of the total mass of the molecule, the mass equivalent of the binding energy is small and in the opposite direction (bound energy is slightly smaller than total sum).

Originally posted by ImaFungi?

regarding your questions on what kind of photons and how they are placed in the vacuum... I want to say there is some photon emitter embedded in one of the walls,, and it can emit photons while still sealing off anything beyond the vacuums containment.... if thousands of photons are emitted into this shoe box sized perfect vacuum,,, where will the photons and their subsequent energy go?

edit on 14-11-2012 by ImaFungi because: (no reason given)

It depends on what the walls are made out of and do. Photons propagate without losing any energy or changing frequency if they don't interact with charged particles, so unless there's further constraints, the best answer is "nowhere, nothing happens".

Originally posted by Bedlam

Vacuum is vacuum. Way way way down at the Planck level, you've got virtual particles popping in and out, but that sort of thing is not easily explained without a lot more background in place. If, for instance, you ask me about spinors and ambitwistors, and you don't know algebra, I'm going to have to meatball it as "it's a math operation". Similarly, if you want to know about virtual particle fluctuations, I don't have a really good way to explain that verbally. mbkennel might do better, I can't do it very well. Trying to explain some of this verbally just doesn't work well. You can also get into other esoteric crap like time-linked energy and the like, not for the faint of heart.

And, then, too, you might wonder other things that seem like 'why is the sky blue' questions, but when you get into creepy starting constraints you have to ask them. Like, why is c c? Why that value? Why are the values for permittivity and permeability anything at all in a vacuum? Why are they the numbers they are? Does that ever change? Why is e e? Pi pi? Are we in a deSitter or Machian universe? Is space negatively curved? Or does that fluctuate depending on where you are? Is the cosmological constant? Or is it a cosmological variable depending on the concentration of dark matter in the area?

ok,, i believe you that the virtual particles popping in and out of existence isnt easily explained,, its something i see brought up often though,, with what i take as a sense of ode to chaos.. but anyway... im wondering if there is any general or semi simple way you can describe where these virtual particle come from? what effect they have on particles and matter? am i wrong to assume that virtual particle is a substitute for "actions that occur on small scales where we can as of now not accurately determine exactly what is going on"? virtual particles are to micro physics,as invisible and undetectable fields are to macro physics?

why is c c is an interesting one.... can you imagine a physical system existing with no limits to velocity? imagine a physical component with the highest velocity, for example c... any other physical component related to this system, traveling slower,, would naturally appear and function differently i would assume...because all known physical things do not travel at infinite velocities and beyond... there is a known, measurable, hierarchy that has arisen, and followed in result of the inability for what prime energy is to travel over c,, and what energy that travels less the c is and can become... I agree im talking jargon here,, but maybe i am touching upon some relevance,, im just trying to think about these things.... why does light exist at all.. why is light able to be created... what is the most primal form of energy/matter?

for the question about why the values of permittivity and permeability are what they are in a vacuum,,i dont know but maybe this has to do with my photons in a shoebox question,, if a natural aspect of a vacuum is the ability for particles to pop in and out of existence,,maybe the popping in and out of existence is a result of electromagnetic energy being in a contained vacuum and having no place to go, so the virtual particles is its method of dissipating,,, or else would they just collide and make heat or explode or something?
also with permittivity and permeability of electromagnetism in a vacuum.. how can a photon travel billions of light years,, can it travel indefinitely? why can a photon from a star travel billions of light years in the vacuum of the universe,,, and not billions of light years in my shoe box? is it because the walls of the contained vacuum would absorb the photon,, so thats why i asked about the mirrored vacuum? gonna look up Einstein's box...

Originally posted by mbkennel

Originally posted by ImaFungi
how does the mass of 3 individual quarks compare to the mass of a proton?

The rest masses of the three quarks in a proton summed is much smaller than the mass of them in combination of a proton. Most of the mass of the proton comes from its binding energy from strong nuclear force (gluon exchange).

This is contrary to the situation of atoms being bound into molecules. There the rest masses of the atoms contribute nearly all of the total mass of the molecule, the mass equivalent of the binding energy is small and in the opposite direction (bound energy is slightly smaller than total sum).

so when 3 quarks come together to form a proton,,, they magically level up and gain more total mass then they are when separate? as in the mass of 3 separate quarks < a proton... because when 3 separate quarks are together,, the attraction force of , strong nuclear force adds extra mass to the 3 quarks? where are gluons before the quarks bind? how are they exchanged once the quarks are bound?

Originally posted by ImaFungi

if the photons are sent straight across from left to right is it only because this is occurring in a vacuum, that when we view from overhead they are not visible?

Yes, for the most part, more explanation after...

say we are on a plane,, and travel over a lighthouse with its high beam on streaming horizontal... we can see the entire beam because from every point of the beam there are photons that simulteanously travel straight horizontal in the focused beam,, but also ninety degrees (and every other degrees) into our eye?

Ok. The truth on this one is that you only see a tiny part of the light from overhead. And the only reason you see even THAT is that there is dust in the air, and for a lighthouse there are suspended particulates, mostly water vapor and microcrystalline salt. If the air were perfectly clean and dry, you wouldn't see anything. In fact, you can measure the level of contamination in the atmosphere by measuring the dispersal of light in a beam. In a vacuum, there's no gas to speak of, although you can still get the occasional bit of particulate crap that will twinkle in a laser in space.

regarding your questions on what kind of photons and how they are placed in the vacuum... I want to say there is some photon emitter embedded in one of the walls,, and it can emit photons while still sealing off anything beyond the vacuums containment.... if thousands of photons are emitted into this shoe box sized perfect vacuum,,, where will the photons and their subsequent energy go?[

Better than I could ever do, there are a bazillion discourses on Einstein's Box, which address this question exactly. Like this one. The short answer is that the photons transfer energy into the box itself. (although I think the answer has to be framed in terms of momentum, lest mbkennel smite me in his wrath)

Originally posted by ImaFungi

ok,, i believe you that the virtual particles popping in and out of existence isnt easily explained,, its something i see brought up often though,, with what i take as a sense of ode to chaos.. but anyway... im wondering if there is any general or semi simple way you can describe where these virtual particle come from? what effect they have on particles and matter? am i wrong to assume that virtual particle is a substitute for "actions that occur on small scales where we can as of now not accurately determine exactly what is going on"? virtual particles are to micro physics,as invisible and undetectable fields are to macro physics?

It has to be real for gauge bosons to work. You can also get them to instantiate in certain circumstances. There are some very clever bits of optics work that won't go without virtual particles either.

Originally posted by buddhasystem

Originally posted by Blue Shift
It's relatively well understood how it flows, but the explanations as to why it flows are quite a bit fewer and not quite as convincing.

You lost me here. There is a field, and the prime property of an electric charge is that it will experience force when a field is present. The force will cause a change in momentum. What's there to be convinced about???

You use the word "field" like it automatically imbues reality with some kind of inherent property that causes certain specific things to happen. You might as well say "god" or "fairies." Why does that happen in a field? That's the difference between knowing how things act and why they act that way.

Originally posted by Bedlam


Ok. The truth on this one is that you only see a tiny part of the light from overhead. And the only reason you see even THAT is that there is dust in the air, and for a lighthouse there are suspended particulates, mostly water vapor and microcrystalline salt. If the air were perfectly clean and dry, you wouldn't see anything. In fact, you can measure the level of contamination in the atmosphere by measuring the dispersal of light in a beam. In a vacuum, there's no gas to speak of, although you can still get the occasional bit of particulate crap that will twinkle in a laser in space.

what about the dust and particulates allows you to see the light from overhead?

Originally posted by Blue Shift
You use the word "field" like it automatically imbues reality with some kind of inherent property that causes certain specific things to happen.

That's pretty much the definition of a field.

You might as well say "god" or "fairies." Why does that happen in a field? That's the difference between knowing how things act and why they act that way.

Ah, a Socratic reduction attempt.

Originally posted by ImaFungi

what about the dust and particulates allows you to see the light from overhead?

They scatter the light. The photons hit the floaty crap and bounce randomly, some will depart the beam at right angles, just right to go into your eye.

Originally posted by Bedlam
Ok. The truth on this one is that you only see a tiny part of the light from overhead. And the only reason you see even THAT is that there is dust in the air, and for a lighthouse there are suspended particulates, mostly water vapor and microcrystalline salt. If the air were perfectly clean and dry, you wouldn't see anything. In fact, you can measure the level of contamination in the atmosphere by measuring the dispersal of light in a beam. In a vacuum, there's no gas to speak of, although you can still get the occasional bit of particulate crap that will twinkle in a laser in space.

Not to split hair, but there can also Rayleigh scattering in the gaseous medium. So clean air will still scatter radiation. And Delbruck scattering happens in (technically) vacuum, although of course a source of electric field is needed.

Originally posted by Bedlam

Originally posted by ImaFungi

what about the dust and particulates allows you to see the light from overhead?

They scatter the light. The photons hit the floaty crap and bounce randomly, some will depart the beam at right angles, just right to go into your eye.

but if only some were to be scattered,,, you wouldn't be able to detect a constant beam of light like you most likely would ( it probably helps to imagine this scenario at night).. when you say some do you mean billions scatter every second?

Originally posted by buddhasystem

Originally posted by Bedlam
Ok. The truth on this one is that you only see a tiny part of the light from overhead. And the only reason you see even THAT is that there is dust in the air, and for a lighthouse there are suspended particulates, mostly water vapor and microcrystalline salt. If the air were perfectly clean and dry, you wouldn't see anything. In fact, you can measure the level of contamination in the atmosphere by measuring the dispersal of light in a beam. In a vacuum, there's no gas to speak of, although you can still get the occasional bit of particulate crap that will twinkle in a laser in space.

Not to split hair, but there can also Rayleigh scattering in the gaseous medium. So clean air will still scatter radiation. And Delbruck scattering happens in (technically) vacuum, although of course a source of electric field is needed.

do/can photons interact with one another?