Ask any question you want about Physics

originally posted by: greenreflections
If I enclose esotropic radiator into solid shell... I mean, really, why not?

I have no idea what you're talking about. I don't know what esotropic is and I don't see any solid shell. You can make a thought experiment with a solid shell if you want, but since there's no solid shell in the diagram I posted such a thought experiment seems to have no relevance to that diagram.

originally posted by: greenreflections

thank you, I didn't know we can manufacture a slit that is smaller than photon wave function and still call it a slit))
It would be no slit at all. Energy quanta will be absorbed or excite first atom it meets, deflected or what ever but will not get through. Am I right with this?

Nope

Photons will only interact with atoms if the electron energy levels allow it or in a somewhat rarer case a direct electron photon scattering event occurs.

Best example of this i can think of is a Photomultiplier tube. Its active surface has a very low work function. Imagine a lightbulb, except on the inside of the glass you have a few atoms thick. The structure of this material means it will absorb photons with any more than a few eV of energy... so it can absorb photons and produce electrons anywhere between roughly green to blue light.

Now, if you were correct, the photons would be absorbed at 100% efficiency.

Reality is that the efficiency is closer to 25-30% and the layer is less than 1 wavelength thick. The model behind this can be found in Professor Mark Fox's book, Optical properties of Solids. Light... is more interesting than you might initially think or predict... While his book is roughly £30 (when i bought it) his lecture notes are free www.mark-fox.staff.shef.ac.uk...

originally posted by: Arbitrageur


Synchrotron radiation

Radiation cone of photons generated by an electron package is shown in yellow

If the electrons direction was altered at a sharp angle, that image might be accurate, but I would think, that the electron would cause radiation from the moment its curve began, to the moment its curve finished; which might result in not such a pointalistic starting point of the cone, but maybe multiple cones, or rectangular pyramid.

Or perhaps this idea is expressed in the fact that it is a cone and not a cylinder, or no... the cone aspect (mouth getting ever larger area) is expressed now I recall due to the fact that there are multiple electrons in the example, so they each make their own EM impact, which due to minor differences, result in a coning, or just because it is something of a collision event, and the result of the collision cannot be expected to propagate away in a balanced even manner like a cylinder, so the image is expressing that each photon quanta, is propagated in a slightly different direction;

Who you are arguing with about this; you are simply saying, it is most likely, that direction is just not from where the electrons were, or to the sides, or up and down, but as the image depicts, a singular cone beam, I personally would love to see the image with a single electron (as I am interested always, first and foremost, or absolutely, the most fundamental understanding of the most fundamental aspects of nature possible). Single electron around the track create single photon?

originally posted by: ImaFungi
If the electrons direction was altered at a sharp angle, that image might be accurate

The first clue that the sketch exaggerates some things is that we can't see electrons in the way it shows electrons.

I would think, that the electron would cause radiation from the moment its curve began, to the moment its curve finished; which might result in not such a pointalistic starting point of the cone, but maybe multiple cones, or rectangular pyramid.

If you accelerate charged particles around a big circle they will emit radiation all the way around and the LHC certainly gets some of this type of effect. However we don't have a big circle in the subject illustration, and I suspect the angle of the electrons' deflection is greatly exaggerated for this illustration. Think about it this way, the electron is traveling at nearly the speed of light so from its frame of reference the thickness of the bending magnet might be something like a sheet of paper, so I think eccentricity of the cone is minimal for that reason.

the cone aspect (mouth getting ever larger area) is expressed now I recall due to the fact that there are multiple electrons in the example

There are multiple electrons but that's not the reason the cone gets wider, you can see the math for that in this link.

Who you are arguing with about this; you are simply saying, it is most likely, that direction is just not from where the electrons were, or to the sides, or up and down, but as the image depicts, a singular cone beam,

GreenReflections said the photon had a spherical wave function so I posted a sketch of photons making a cone and asked where is the sphere? Then he invented a solid sphere that's not in the illustration. By the way relativity plays a role in the answer to this question.The lab has one reference frame and the electron has another one, which not only makes the bending magnet seem very thin to the electron, but also the apparent geometry of the radiation varies by reference frame, and anybody who was paying attention to this thread would have seen the illustration I posted of this a few pages back.

I personally would love to see the image with a single electron (as I am interested always, first and foremost, or absolutely, the most fundamental understanding of the most fundamental aspects of nature possible). Single electron around the track create single photon?

Wouldn't it make sense that the number of photons would be a function of numerous parameters which you didn't specify, such as the electron energy? The above link has a formula which relates photon flux (something like the number of photons per second) with variables like electron energy etc.

Also I would argue that you're not getting a good understanding by looking at one photon, because even if you did configure the experiment so it emitted one photon, the energy of that one photon would not be representative of the entire spectral bandwidth that will be observed when larger numbers of electrons are used to emit larger numbers of photons.

originally posted by: Arbitrageur

Consciousness is an interesting topic, but I don't know what you mean by "how light might play its role in the mind", as I don't think it does, directly.

I meant light as the colloquial EM radiation, which I do believe plays a, maybe obviously major role (though I know with these things its silly to say, major, sometimes, since, often all aspects are entirely necessary for what exists to exist), which can simply be proven by stating; even imagine if EM radiation still existed outside of the body, and in the body in every way it does; but that EM radiation of no kind were to occur in the head or brain, in this thought experiment; would you not agree the human would not function; dont cat scans relay on this type of stuff, electrical signaling of neurons, EM radiation is fundamental and pivotal in the universe, and it seems in human body and relation to the environment, and it seems in the processes of mind and cognition.

If you thought I meant only 'visible light' by the usage of the term light, that is my fault, and perhaps we agree now.

So then; the visible light, em radiation, enters the eye, and it is eventually transformed into non visible light spectrum, and you are possibly rightly suggesting with your reply to me, that the brain, mind, consciousness, does not utilize EM radiation of the visible light spectrum, that is interesting if so, and it would be interesting to know what parts of the spectrum it does utilize. I obviously intuit it is a power thing, and force thing, and the brain is not producing gamma rays, maybe... maybe it is not about power, or maybe it is about powers, magnitude, that something on that very small level, because you also scale down all the other terms and variables, though EM is always its own scale compared to all events which can possibly create EM so I do not know.

A related topic that interests me is how easily our minds are fooled with optical illusions. I think evolution left us with a mind that provides for some good survival skills, but it has plenty of flaws in the way things are perceived where there was probably no evolutionary pressure for those flows to be corrected so we still have them.

I am awe struck by the existence and abilities of the mind (and body)( I could not imagine designing and creating a working mind, part of the reason I am interested in AI/AC, and physics and philosophy really, because I am impressed by the actuals and potentials of nature to a high degree). I do not know how much you have looked into transhumanism, but it seems nature would say, you think you can do a better job than me, be my guest, as intelligence increases, it increases its participation in evolution, when we can alter our genes, and clone, and make android and ai, stronger bodies, etc. then we can no longer blame nature for its short comings, we can only be thankful for the ridiculous opportunity of human life, and if we are so intelligent, we will make ourselves better brains and bodies.

It's not really a problem until people mistakenly think that their eyes and brain record things like a video camera and that their brain stores information like a hard drive, when neither is the case and both human systems have far more flaws than comparable video cameras and memory chips.

it depends what you mean by 'like'; it might be that those things are more alike each other than anything else. Context.

If you accelerate charged particles around a big circle they will emit radiation all the way around and the LHC certainly gets some of this type of effect.

Is this because radiation is constantly being added 'into the arena' which is the method of charge particle acceleration, so constantly being added so the electron goes faster/maintains its speed = radiation being able to be detected all around circle.

However we don't have a big circle in the subject illustration, and I suspect the angle of the electrons' deflection is greatly exaggerated for this illustration. Think about it this way, the electron is traveling at nearly the speed of light so from its frame of reference the thickness of the bending magnet might be something like a sheet of paper, so I think eccentricity of the cone is minimal for that reason.

So the picture is hardly accurate in any way, accept the most most general depiction of ; electro magnet, electron, radiation; you are saying now there is no circumstance in which an electron would pass a single small electro magnet and produce a single cropping of em radiation?

If you are saying there are circumstances in which an electron, or electrons, would pass a single electro magnet, to theoretically and beyond comprehend the resulting em radiation, quantity, quality, direction; then that image would not properly depict such?

I am attempting to state, to probe, about something fundamental about the concept of 'alteration of direction', requiring angles and/or curve;

You met this point with the speed and paper-like remark;

which is good; which gives the single electro magnet, a strong wicket like reality, like a pin ball bumper;

well, you know, then we get into, why the electron goes 1 direction rather than another when it interacts with the elector magnet field; and part of that answer is the spin of the electron? Part of that answer is the orientation and/or spin of the electro magnet field?

There are multiple electrons but that's not the reason the cone gets wider

If there was 1 electron, there would be no cone, and no cone getting wider;

If there are multiple electrons, the cone represents multiple photons, and the fact that multiple electrons colliding with a EM field which covers a multitude of spatial points, would likely not collide with the EM field, and propagate photons, in a perfect, cylinder straight line like matter, so the cone represents the smallest bit of displacement, the fact that each photons trajectory when created by each electrons trajectory, are not aligned parallel, but they are resulted from enough of the same momentous direction, to propagate in the same direction.

but also the apparent geometry of the radiation varies by reference frame,

(do you include optical illusions, as valid reference frames, or is part of the point, that all reference frames have inherent optical illusion?)

Would you agree, that even if humans do not know, even if humans could not know, even if humans did not exist, there would still exist, in theory, in actuality, in reality, 'all possible reference frames', and such is the meaning of the objective reality, reality as an object truth.
(obviously yes; so if you rule out all optical illusions, you are left with all possible reference frames of light as it actually exists in reality; for classical example, well, the blind men feeling the elephant, there are different reference frames, but the blind men would be wrong in presuming that there was no objective ultimate reference frame of all possible reference frames that they did not have access too)

Wouldn't it make sense that the number of photons would be a function of numerous parameters which you didn't specify, such as the electron energy?

Yes, there are a ton of parameters, strength, volume of electro magnet, etc. I was asking questions about specifically about the direction of propagation, related to the trajectory of an electron prior too, beginning, through, and out of any and all possible electro magnet field variables. Well we wont go through all possible etc. but general knowledge of what occurs in varying circumstances, can lead to general understanding of such fundamental principle.

Also I would argue that you're not getting a good understanding by looking at one photon, because even if you did configure the experiment so it emitted one photon, the energy of that one photon would not be representative of the entire spectral bandwidth that will be observed when larger numbers of electrons are used to emit larger numbers of photons.

I would argue that if you do not fundamentally understand one electron, and one photon you wont fundamentally understand many. (key word: Fundamentally)

originally posted by: ImaFungi
Is this because radiation is constantly being added 'into the arena'

Energy is added.

So the picture is hardly accurate in any way, accept the most most general depiction of ; electro magnet, electron, radiation; you are saying now there is no circumstance in which an electron would pass a single small electro magnet and produce a single cropping of em radiation?

I'd say it's fairly typical of a conceptual sketch. The purpose is to show concepts, not to allow you to put a ruler to the sketch and try to make measurements. I don't know what "a single cropping of em radiation" means.

If you are saying there are circumstances in which an electron, or electrons, would pass a single electro magnet, to theoretically and beyond comprehend the resulting em radiation, quantity, quality, direction; then that image would not properly depict such?

I don't comprehend your question. Again I'd say it's fairly typical of a conceptual sketch. It's about as accurate as it's intended to be to illustrate concepts. For one thing, the angle of the cone is not fixed, since it can vary with the amount of electron energy.

well, you know, then we get into, why the electron goes 1 direction rather than another when it interacts with the elector magnet field; and part of that answer is the spin of the electron?

You already asked this question and I already answered. No, again. The spin affects the polarization in synchrotron radiation, not the direction of travel. How many times are you going to ask the same question?

Part of that answer is the orientation and/or spin of the electro magnet field?

Again, already answered, and I think you already know a charged particle curves when traveling through a magnetic field. How can you read the Wikipedia article on electromagnetism 50 times and not know this?

If there was 1 electron, there would be no cone, and no cone getting wider;

who told you that? Even if there's one electron and it emits one photon the photon will have a probability of being somewhere in that cone, so in effect the cone still exists in the wave function.

(do you include optical illusions, as valid reference frames, or is part of the point, that all reference frames have inherent optical illusion?)

I don't consider switching from one frame to another an optical illusion. Each frame can observe things differently and all are equally "correct".

Would you agree, that even if humans do not know, even if humans could not know, even if humans did not exist, there would still exist, in theory, in actuality, in reality, 'all possible reference frames', and such is the meaning of the objective reality, reality as an object truth.
(obviously yes; so if you rule out all optical illusions, you are left with all possible reference frames of light

Light doesn't have a reference frame. Light is observed by observers in other reference frames and the observers have mass so they can't travel at the speed of light. In the case of a synchrotron the electrons can travel at close to the speed of light, but not quite. They would need an infinite amount of energy to travel at the speed of light.

as it actually exists in reality; for classical example, well, the blind men feeling the elephant, there are different reference frames, but the blind men would be wrong in presuming that there was no objective ultimate reference frame of all possible reference frames that they did not have access too)

I've already answered that question before too. If you want to pick an arbitrary "ultimate" reference frame the CMB might do, but there's nothing in relativity that infers that and in fact Einstein died long before the CMB was discovered so he didn't know about it. We generally prefer to use something more familiar to us, like our reference frames here on Earth.

I would argue that if you do not fundamentally understand one electron, and one photon you wont fundamentally understand many. (key word: Fundamentally)

If you spin a roulette wheel one time, you don't fundamentally understand all the possible statistical outcomes from that one spin. You have a similar problem with a single electron or photon, since you don't know exactly where it will go. But spin the roulette wheel enough times and you can understand its statistical behavior, same with electrons and photons. You can predict what a population of them will do, not what a single one will do exactly, only as a statistical probability.

Also by studying a single electron, you would not fundamentally understand any of the following:
-The chemistry of all non-ionized atoms except hydrogen.
-Electron degeneracy pressure, that phenomenon keeping your rear end from sinking into your chair.
-The operation of semiconductors including whatever you're using to post messages here.
-The correlation between the wave functions and large populations of particles. For example the most likely location for a single photon from a single electron in the synchrotron would be inside the yellow cone somewhere, but with one particle, you won't be able to observe the cone nor determine the angle of the cone.

a reply to: Arbitrageur

I will reply to that later.



That is 7 points with concentric circles drawn around each of them;

I did not draw, or attempt, though maybe I will try but it seems very hard, maybe, to accurately draw the circles how if they were matter, field, would interact with one another;

but still the image might give one the idea, of how complex the geometry of a space might be, which contains 100,000 particles, millions... more, in a much smaller depicted area than that paper; also which might go to show why gravity is so weak; because it is likely thinking of such tiny quanta, that their concentric circle will die out rather quickly; this is ignoring where EM field might come into the picture as well;

originally posted by: ImaFungi
I did not draw, or attempt, though maybe I will try but it seems very hard, maybe, to accurately draw the circles how if they were matter, field, would interact with one another;

but still the image might give one the idea, of how complex the geometry of a space might be, which contains 100,000 particles, millions...

I can't even draw the Hilbert space illustrating the (near?) instantaneous correlation between two particles separated by kilometers, and yes multi-particle analysis gets quite complex, far more than that drawing.

more, in a much smaller depicted area than that paper; also which might go to show why gravity is so weak; because it is likely thinking of such tiny quanta, that their concentric circle will die out rather quickly; this is ignoring where EM field might come into the picture as well;

I don't see how it explains why gravity is so weak, because you could draw circles for gravitation and electric fields and they both follow the inverse-square relationship, which sort of explains why they both get weaker with the square of the distance. However it's the magnitude of the interaction at any comparable distance being so much weaker for gravity that's related to the "hierarchy problem" which is one of the greatest unsolved problems in theoretical physics today.

a reply to: Arbitrageur

Read the thought experiment about schrodingers cat. The cat is in a box and is neither dead nor alive until someone opens the box and sees it. This collapses the wave state and the cats out come becomes apparant.. Thing i never got about this was. What happens to get cat. Cant the cat collapse the waves and see if its dead or alive itself.

Always wondered if QM was like a pc game. You know one of those big worlds you can run about exploring and see vast words and forests. What happens to that world when you turn your pc off. Its not gone it just in a different form because you are not looking at it.

a reply to: Arbitrageur

yeah, you are right. Of course you don't know coz I miss spell it. It should read 'isotropic'.
Wiki refers as following:

'..An isotropic radiator is a theoretical point source of electromagnetic or sound waves
which radiates the same intensity of radiation in all directions. It has no preferred direction
of radiation. It radiates uniformly in all directions over a sphere centred on the source.
Isotropic radiators are used as reference radiators with which other sources are compared.'

I know it is theoretical concept, although my initial interest was triggered as to how photon is emitted.
When it is part of an atom it is everywhere within it. If I only assume atom has form (it will be a sphere),
I ask myself from which part or area of that sphere and in what direction photon is being emitted.
Came to mind theoretical RF transmitter where EM pulse is emitted everywhere in all directions.
The wave fits best this description. Its frequency is how 'deep' (fat) that spreading donut is.

That is isotropic radiator.

But that's fine. Your answer was as usual sharp and down to the point.

a reply to: purplemer
To observe a state of superposition of the radioactive particle decay state so we don't know if it's decayed or not until it's observed, we have to work very hard to isolate such a quantum system.

The cat isn't isolated and any large quantum mechanical system tends to interact with its environment leading to more classical-like behavior, which is why you never observe a cat in a state of superposition of being alive and dead at the same time.

Supposedly the thought experiment causes us to question the role of an observer and what constitutes an observation, such as your question about the cat being an observer. From my point of view, it is the size of the system and how much larger systems interact with their environment which is the key issue, more than defining the role of observer or observation. To put it another way, one way to think of an "observation" is any interaction with the environment and then the importance of the meaning of "observer" or "observation" becomes moot if it is really just interaction with environment that's relevant.

The interesting question to me isn't what really happens in the Schrodinger cat thought experiment since I don't really have doubts or questions about that, the interesting question is, as explained in the opening post video by Sean Carroll, how do we interpret quantum mechanics in general? In Carroll's preferred explanation, which I don't really like but I'm not closed-minded to it as a possibility, there are two universes, one in which the cat is alive and one in which the cat is dead, and we don't know which universe we are in until the box is opened. In that Everett "Many Worlds" model, there is no wave function collapse as in the Copenhagen interpretation we teach in schools, but we don't know if that's the correct interpretation. It's one of several possibilities.

a reply to: Arbitrageur

In Carroll's preferred explanation, which I don't really like but I'm not closed-minded to it as a possibility, there are two universes, one in which the cat is alive and one in which the cat is dead, and we don't know which universe we are in until the box is opened. In that Everett "Many Worlds" model, there is no wave function collapse as in the Copenhagen interpretation we teach in schools, but we don't know if that's the correct interpretation. It's one of several possibilities.

I like to look at nature and to me nature has an amazing efficiency and intelligence to it that we are only beginning to understand.

It seems like to have lots of universes requires a lot of energy. Is it not a lot simpler if its just an observer observing themselves.

How do we know that we are interacting with an outside environment at all. When i open the box with the cat in it. Is it possible that I am choosing on some level if the cat lives or dies.

:-)

originally posted by: purplemer
It seems like to have lots of universes requires a lot of energy. Is it not a lot simpler if its just an observer observing themselves.

I'm not sure if more universes require more energy according to Everett's interpretation, I'm thinking probably not. If there was some kind of energy drain for the extra universes why couldn't we use that to rule them out?

In the context of Schrodinger's cat experiment, the decaying uranium atom can't observe itself. It only needs to interact with a Geiger counter inside the box for the decay to have actually occurred. You won't know whether it has or hasn't until you open the box, but if it did decay that already happened when the Geiger Counter detected the decay, before you opened the box.

How do we know that we are interacting with an outside environment at all. When i open the box with the cat in it. Is it possible that I am choosing on some level if the cat lives or dies.

See previous answer. While there may be some nuances in pinning down exactly what is meant by interaction versus non-interaction, here are some general clues:

1. You and the cat are both mammals. Mammals need to breathe to live, so if you're not breathing for more than a short time, you're dead. If you are breathing, that's one way you're interacting with your environment.

2. Temperature. You and the cat are warm blooded, meaning your atoms jiggle a lot and radiate infrared radiation into the environment, and probably vice-versa unless you're out in a snowstorm and getting cold. In contrast, many of the experiments I see where quantum systems are isolated into states of superposition are done at very cold temperatures, as a means of isolating thermal interaction with the environment.

Max Tegmark used this temperature relationship to debunk some of the fringier claims about the role of quantum entanglement inside the human mind, by explaining that decoherence occurs quite rapidly at such high temperatures as found inside warm-blooded mammals.

What are the main factors that determine the shape of a snow flake? Subatomic particle motion, coupled with molecular motion surrounding, coupled with water density, are snow flakes frozen rain drops?

themetapicture.com...

a reply to: ImaFungi

Hydrogen bond angles.

originally posted by: Bedlam
a reply to: ImaFungi

Hydrogen bond angles.

What are the main factors in determining hydrogen bond angles?

originally posted by: ImaFungi

originally posted by: Bedlam
a reply to: ImaFungi

Hydrogen bond angles.

What are the main factors in determining hydrogen bond angles?

They are what they are. But what determines them is the electron distribution around the oxygen atom in water. On another level, the answer is 'electrostatic forces and geometry'.

a reply to: Bedlam
Yes,the fact that you always see 6 sides is a result of the bond angles.

a reply to: ImaFungi
Nice pics

I would say small hail is more like frozen raindrops than snowflakes.

The speed at which the snowflakes form which is mainly related to temperature, but also some other factors, has a lot to do with the shapes they form:

Snowflake Chemistry

Generally, six-sided hexagonal crystals are shaped in high clouds; needles or flat six-sided crystals are shaped in middle height clouds; and a wide variety of six-sided shapes are formed in low clouds. Colder temperatures produce snowflakes with sharper tips on the sides of the crystals and may lead to branching of the snowflake arms (dendrites). Snowflakes that grow under warmer conditions grow more slowly, resulting in smoother, less intricate shapes.

32-25° F - Thin hexagonal plates
25-21° F - Needles
21-14° F - Hollow columns
14-10° F - Sector plates (hexagons with indentations)
10-3° F - Dendrites (lacy hexagonal shapes)

a reply to: Arbitrageur

What would happen if a single photon hit one of those single snowflakes? (for the picture to even happen, millions of photons were hitting it, when reflected into the camera? shows potentially how subtle and small photons are and can be? (unless its electron microscope, but still something small bouncing off object) How millions of photons are just redirected and or 'absorbed' by these crystal objects, if information was sent in the form of photons (as is done in radio for example) would it be effected by interacting with that snow flake, or are you gonna say something like it passes right through it without interacting at all, millions of them right through, like a person going through a metal detector?