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When a photon is released, which way does it head?


tar
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That is, do the two ends of the train move at the same time? Would this not mean that you could send information from the area of the solenoid coils, to the other end of the plunger extension, before you could send information along the same route, using light?


Absolutely I agree that events that are simultaneous for one are not for another. Like the shouts at the stadium.

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Absolutely I agree that events that are simultaneous for one are not for another. Like the shouts at the stadium.

 

No, that is purely a delay, due to the speed of sound, that causes them to hear things at different times (because they are at different distances). If they took the distance and the speed of sound into account, they would all agree on the time the shouts happened.

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But we had a simultaneous event we started with, at the stadium, figuring that seeing the clock was instantaneous relative to the speed of sound, which would take some time to travel. If we are talking about occuring and seeing as two different things, then the position of our reference clock would be crucial. There is a lag between the occurence of something and when the photons from it get to an observer. You could take this idea right down to the atomic level, and I think it would still be true.

 

When something touches our foot, we figure it touched just now. We know what that means, even though there is a little slop in there in terms of the time light took to get from the event to our eye and through the brain synapses to our model of the world, and even though the electrical signals coming up from our foot arrived at our model in our brain at a different time than the light hit our eye, we know, from experience how to sort that all out, and what it means, in terms of the thing just now touching our foot.

 

We don't have a lot of experience on the atomic level, of seeing a distant thing and touching it, at the same time. Nor do we have a lot of experience at seeing and touching a distant galaxy at the same time, but the analogy can be made, and the distances and times figured, to merge the event into one particular thing, that happened at one place, at one time.

 

Regards, TAR

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Yes, but relativity of simultaneity is NOT about the delay between something happening and when it is perceived.

 

It is about the result when that delay is taken into account to work out when the events actually happened. That is what is different for the two observers.

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So, similarly if you take the speed of light into account the woman and the guy can agree on when exactly and where exactly the lightning strikes, occurred, and this knowledge would fully explain to them both why the other saw it differently.


My caution here, is that one can fully use the analogy of speed of light to speed of sound, and call them both delay, except one does not have anything faster that light with which to carry the analogy fully out, but the speed of thought. And it is only with this instantaneous viewing mechanism that one can have the strikes occur before they are seen. And this instantaneous view, obtainable only in ones imagination, is the kind of thing we do when we judge a thing touching our foot, "at the same time" as we see it and feel it.

 

So which is "really true". The star in the sky that we see, or what that star is doing "now" that we will see in two years?

 

You have to agree that you need both nows, to operate, and understand the thing, and the model of the thing.


The now that you see, witness and experience. and the now you know must be presently occuring, inorder for you to be seeing now, distant thing, which have been delayed in arriving at your eye.

 

We are used to saying that thunder happens a certain time after we see the lightning.

Only our understanding can have the lightning happening a certain time before we see it.

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So, similarly if you take the speed of light into account the woman and the guy can agree on when exactly and where exactly the lightning strikes, occurred, and this knowledge would fully explain to them both why the other saw it differently.

 

Yes. But I am still not sure (because of your waffle) that you agree that one of them will determine that the two flashes happened at the same time, and the other will calculate that they happened at different times.

 

 

My caution here, is that one can fully use the analogy of speed of light to speed of sound, and call them both delay, except one does not have anything faster that light with which to carry the analogy fully out, but the speed of thought.

 

Why do you need anything faster than light? We know the speed of light, so we can work out how long it takes light to travel a given distance.

 

And the "speed of thought" (in so far as it means anything) is much, much slower than light. Slower than the speed of sound, even.

 

 

And it is only with this instantaneous viewing mechanism that one can have the strikes occur before they are seen.

 

Everything occurs before it is seen, because of the finite speed of light. It doesn't need any mythical "instantaneous viewing".

 

 

The star in the sky that we see, or what that star is doing "now" that we will see in two years?

 

This has nothing to do with relativity.

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Strange,

 

Relativity, at its basis, is the understanding that reality consists of judgements true and consistent in one frame of reference, that would be otherwise judged from another frame of reference.

 

But here, we have a tendency to require a "big picture" that both observers can be seen, observing, within.

 

There were many that hypothesized an ether through which planets and stars and photons and particles moved.

This was disproved with some mirror experiments, and interference fringes that showed there did not seem to be such a ocean we are floating through.

 

Much of "relativity" seems to me to be concentrating on proving that we can't know reality or find a refererence point from which to judge what is true from both an inertial frame and a frame that is subject to some acceleration.

 

My thought, consistent with the thread title, is that there is a geometry within which a photon and any other particle must exist in a particular position, at a particular time. And this particle postion is exactly defined by its relationship to every other particle in the universe.

 

So tracking photons is possible, but only from an imaginary viewpoint, that does not require seeing the photon, just requires "knowing" where the thing is. As we know where the distant galaxy is currently, even though we will not see it there for millions or billions of years. For this to be possible, it requires that photons are physically on their way here, now, at every position that exists between here and there...all the way back to the actual current position of the galaxy.

 

But it is impossible that any photons exist that have not been emitted yet, so there must be a current situation, a current arrangement of matter and energy, a current geometetry of space, where everything is in a particular spot in relationship to everything else. By definition, you can not "see" this arrangement in any manner other than the one that presents itself to us, but you can imagine it and model it, if you "visualize" without looking, and without expecting photons to inform you of the arrangement.

 

The speed of thought I was alluding to, was not the actual completion of some synaptic arrangement in ones brain, but of our ability to switch grain size, and get "outside" a scene, to view it, far faster than a photon could change position to that degree.

 

So we have limitations, but also great analogy power, and can make any transforms we need to. Just good to carry ALL elements we can think of, through, during the transform, and not leave any out that allow us to imagine an impossible thing.

 

The arrangement the universe is currently in, is by definition, emmense and not modelable. We don't have enough synapses within our relatively tiny heads to put every item in motion, at its proper and true and real relationship to everything else. We can just sort of estimate the thing.

 

But for me, tracking photons, is a good back check, and a good predictor.

 

Regards, TAR

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So,

 

Which way a photon heads when it is released, engenders the corelary question, of which direction did a photon that hits your eye or a sensor, come from.

 

imagining a random surface as big a a pupil, placed anywhere out in the open, faced in some direction other than the surface of the Earth, and picking a day or night with good visibility and no clouds or buildings or trees or other obstructions, it would be reasonable to suspect that this small surface would be hit by a large number of photons streaming in from all directions. Enough photons for instance to see a starry night if you attached the pupil to a brain.

 

Reasonable to assume that every position in space, out away from the planet is similarly populated by photons coming in from all directions. And each photon was released a certain time before arriving at the spot, consistent with the distance between the emitter of the photon, and the spot. So a spot, or position only has one configuation of photons, coming in from all directions, but that particular collection of photons has photons in it from our Sun, and from a nearby star. A different spot will also have photons in it from our Sun and a nearby star. If you draw lines back to the Sun and the nearby star you can judge the postion of the spot, and the other spot in relationship to each other and the Sun and the nearby star.

 

Now the question is WHEN are you taking the particular collection of photons from spot A and spot B. My suggestion is that you take the collection NOW, no matter where you are. Take the collection in the universal now, and then add distances back or forward, depending on your purpose. To establish a time baseline, for determining this NOW, I suggest using the age of the universe, because every item in the universe, has to have a history exactly that long. And every spot in the universe has to have been there for exactly that length of time with the same amount of intervals for taking the collection of photons, as any other "current" spot, has to have had.

 

So if one can estimate the age of the universe, one has established ones own age, and at the same time, established the age of every other spot and thing the universe has.

 

In this regard the traveling twin, even though she is moving at relatavistic speeds, cannot help but move into areas that are exactly the same age as she is. There is a light travel time complication happening between her and her twin back home, and clocks will look like they have slowed or sped up and such, and distances measured by the one will appear to be different and such, but the twin can not help but stay in the unversal now. Everywhere she goes, it will be now for her, and every spot she will be in will be exactly as old as the universe, all the time, at every check. The photons from the Sun and the nearby star will still locate her position, and the photons that were on the way here from the nearby star, will be the ones she is running into on the way to the star, just getting to them sooner than we will receive them, and at a faster frequency. Probably when she looks forward toward the star the visible light from the star would be shortened in wavelength and increased in frequency to gamma waves or something, but she has to run into them, because all the spots she is going through are already populated by the photons from the rest of the universe. Time on the planet circling the star she is headed for would have to look to her, to be in fast motion as the photons from the events are coming to her at a rate much faster then they were released. And on the way back to Earth, the reverse would occur and the photons from Earth that were stretched out, reddened and slowed, on the way out, would be compressed and quickened on the way back, and when she got back, it would still be now, and she would be exactly as old as everywhere she was, and still as old as her twin.

 

But that would make sense and be contrary to the predictions of the equations of relativity.

 

So what's a fellow to do?

 

Regards, TAR

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Strange,

 

Ok, we will put my problems with dark matter, and forshortening, and the twins aside. Those things are already agreed upon, and not in my favor, for the most part.

 

"It goes in a random direction. When you have enough of them you see light transmitted in all directions."

 

Was your original answer to the thread title.

 

I am wondering though if it has to be true. Could the surrounding matter and energy and fields affect the initial direction of a photon. For instance if the electron that released it, was on a particular "course" because of other electrons, around its atom or nearby ones that were repelling it in a certain direction, then the release, though possibly random in time might be limited in direction. For instance if you had a steel ball you were swinging around your head on a thread, the thread would break at some random time, but the ball would go off only in certain possible directions, not ALL directions. Your feet are in the way, so you can not describe a circle around your head, that includes where your feet are. And if we would place a powerful electro magnet somewhere in the vicinity, the Randomness of the release, would be put somewhat in question.

 

Regards, TAR

Edited by tar
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And the time of the breaking might not be random, either. The energy of the electron was boosted up at a particular time, there might be a certain time it takes to get rid of that packet of energy, and a limit to how long it can hold on the packet.


There thus could be a relationship between the incoming direction of the photon that boosted the electron up, and the consequential release direction, relative to the circumference of the electron's route averaged between the lower orbit and the upper.


In fact, it might not be random at all and could be very dependent on the incoming photon's energy and vector. After all, only a certain photon, with a certain energy can even be absorbed by a particular electron on a particular level. This is what contributes to the quantum nature of the energy absorbtion and reemission anyway, so the mechanics might result in a certain pattern of possible "out" routes, dependant on the "in" route.

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Strange,

 

But is it random enough to have an equal distribution in any and all directions?

 

I am thinking that how the photon that excited the electron comes in, might have something to do with how the photon departs the atom. As you said, the reemitted photon in some situations is in phase with the absorbed one. And since photons of the wrong quantum number just won't get caught by a certain electron, of a certain energy on a certain level of a certain shell, some photons just fly right by, or perhaps even through the cloud the several electrons describe around a nucleus. Not impossible to consider that the timing is important, in terms of "where" the electron is in its orbit, in respect to the incoming photon. Don't know whether it would make more sense if an electron picked up the energy from a photon "going its way" or by "running into it", but the release direction may be partially dependent on the vector of the incoming photon. Like you said, random, but perhaps a little less than completely random. Like trying to hit a spinning baseball, coming in at 94 mph with a round bat, its sort of random which way the ball is going to leave home plate, if you hit it at all. Could go foul or fair or up or into the ground, but its "less random" enough by virtue of the batter's intent, to shift your 3rd baseman into the most likely spot the hitter will "place", the ball.

 

If there is not a requirement that an even distribution in all directions must take place, and environmental factors of nearby masses and electric and magnetic fields, along with which direction the exciting photons came in from, can influence the direction into a less random distribution, then judging the energy of a distant glowing thing, might be error prone, since you might be in a high probability direction and over estimate the things power output, or be in a low probability direction and underestimate the thing's photon output. Specially possible with distant things like galaxies, because you have no way to move around and take a reading from all vectors. Just the one in this direction, is the only one you have access to.

 

Even possible that light tends to travel along the strings of galaxies, rather than through the voids, like electrons in a wire, or water and soap in the areas surrounding and between the "voids" of the bubbles.

 

Photons just might have "preferred" routes away from the electron/atom that launched it. Depending on the environment the atom is in.

 

Regards, TAR


Just thought of something.

 

If a photon comes in and then goes out, it really can't be held for any length of time, because that would require the "pulse" which was traveling at C, grind to a near stop, and then upon release, resume its light speed trek. Seems easier to consider the pulse traveling right on through in some "natural" way, like a comet coming into the Sun's immediate vicinity and being released or slingshot around, "right away".

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But is it random enough to have an equal distribution in any and all directions?

 

In a laser, the direction is not random. If you want to know more about lasers, I suggest you ask in the appropriate part of the forum.

 

The rest of your post is just the usual random nonsense. What if photons got a taxi part of the way? What if photons wore little plaid jackets? What if they were strawberry flavoured?

 

Even possible that light tends to travel along the strings of galaxies, rather than through the voids, like electrons in a wire, or water and soap in the areas surrounding and between the "voids" of the bubbles.

 

If light didn't travel in straight lines, then we wouldn't be able to see what was around us. Lenses would not work. And, in the case you suggest, we would not be able to see clear image of galaxies.

 

 

 

Photons just might have "preferred" routes away from the electron/atom that launched it. Depending on the environment the atom is in.

 

A "distant glowing thing" is not a laser. It requires materials to be specially engineered to get lasing effects. I don't know if there are natural lasers (another interesting question you could ask in the Physics section) but if so they are rare and not what we see from stars.

 

Even if the direction of emission from a single atom is not random (and I don't know if that is the case or not) that is hardly relevant as the light we see comes from gadzillions of atoms all of which are moving. So the direction will be fully randomized.

 

 

If a photon comes in and then goes out

 

Comes in and goes out of what?

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Strange,

 

Into the vicinity of the entity we consider the electron, and back out. The Sun/comet thing was not meant to be a direct analogy, just the idea of coming in and going right back out.

 

Sorry for the whimsical thoughts, but they are, at least to me, not completely random. Perhaps a little like Strawberry jackets, but there are aspects of the world that are very big and hard to check on, very far away and hard to check on, very slow in developing and thusly hard to check on, very tiny and quick and thusly hard to check on, very numerous and thusly hard to envision and so on.

 

I am not suggesting that "anything goes", I am suggesting that the place does not need to be completely homogeneous and can have differences on different scales, that do not "have to" average out 100% of the time.

 

The universe is known to bend light, excuse me, light always goes in a straight line through curved space (whatever that means.)

 

There is room to entertain some strawberry jackets out there. Black holes are entertained, where physical laws are somewhat bent out of shape, and we don't know exactly how they act in different situations because we have not been able to poke and prod and turn the thing around and write down what happens and take temperature and pressure readings and model its movement and such. So I just entertain thoughts that would be consistent with what we know, make sense if looked at from an imaginary perspective, that we are incapable of taking in actuality, and that "add back" in terms of explaining what we see and experience.

 

Like the universal now, that I think we already assume and know about, that you figure does not exist.

 

How else would we be able to say that the star in the sky was "really" 3 lys away and what we were seeing "really" happened 3 years ago, unless, three years ago, what was happening there, and what was happening here, were happening at the same time?

 

Regards, TAR

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  • 3 weeks later...

So,

 

The double slit experiment has a directional inconsistency, if a photon heads off, away from a molecule in a particular direction.

 

That is, a particular photon would either be heading for the one slit or the other, on the way out from the source.

 

If, at the source, only photons headed directly toward the center of the left slit were allowed to proceed, then the screen on the other side of the slit, would be hit a lot in a direct line between the source and the left slit. The area on the screen in a direct line between the source and the right slit, would not be hit much, since the precision of direction at the source has already been designed.

 

So the question becomes, how precisely can a photon be directed? Can it be aimed at one slit or the other? And how big is the path of the photon? Can it be directed to go though the center of the slit and not hit the edges?

 

If such precision is possible, and only one photon could be released in this precise direction at a time, why would there be a question as to which slit the photon passed through? It would have to go through the slit that is was aimed at.

 

Regards, TAR

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If you only illuminate one slit, then there will be no interference pattern because the pattern is caused by the interference of the light that has passed through the two slits (and therefore have different path lengths and hence phase relationships at each point on the screen).

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Strange,

 

So if you can illuminate either the left slit or the right slit, on purpose, when you fire the photon, then you already know which slit the photon is going to go through.

 

Regards, TAR

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Strange,

 

So if you can illuminate either the left slit or the right slit, on purpose, when you fire the photon, then you already know which slit the photon is going to go through.

 

Regards, TAR

 

Exactly.

 

You will not get an interference pattern (because you have changed it to a single slit experiment). Anything you do in order to know which slit an individual photon (or electron, etc) goes through will prevent an interference pattern forming for the same reason.

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Strange,

 

So, when you launch the individual photon, the direction that the photon is heading has to be only in the general direction of the two slits, not toward the one or the other?

 

To understand what is happening to the photons, in a particular launch situation, could you not launch a few billion toward the screen with no barrier and inspect the shot pattern on the screen, then repeat the experiment with a plate as wide as the distance between the slits, then add a plate to the right with a separation as wide as a slit, then one to the left as wide as the slit?

 

It seems that in the second situation most of your photons would hit the barrier and not continue to the screen at all. So the question would not be which slit would they have gone through, but if they would even make it to the screen. So if you do not know, at launch which slit you are going through, chances are good you are going to hit the barrier between, or to the right, or to the left. It seems to me, the emergence of the interference pattern could be understood by knowing your shot pattern with no barriers and seeing what happens to the shot pattern as you apply plates of various widths inbetween, with varying gaps between a left and right plate.

 

My thought is that you will get an interference pattern with only one slit, as I just held two of my fingers very close together and saw many black lines inbetween in the gap, running parallel to my fingers. If the back of my eye were the screen, there would be areas where photons were hitting and areas were photons were not. The areas where the photons were not, would be consistent with the black lines.

 

Important I think, to know how big the source is, in comparision to the slit. That is, it would be physically impossible for the source to be a point source and a photon would thus be heading toward the slit from the left limit of the source sometimes, and someimes from the right limit of the source sometimes. It might be instructive to inspect the shot pattern from a single slit, then block exactly half of the source. Inspect the shot pattern and then block exactly the other half of the source and inspect the shot pattern.

 

Regards, TAR

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So, when you launch the individual photon, the direction that the photon is heading has to be only in the general direction of the two slits, not toward the one or the other?

 

Yes, you will get the strongest pattern when both are equally illuminated (or when they have an equal probability of a photon going through them).

 

To understand what is happening to the photons, in a particular launch situation, could you not launch a few billion toward the screen with no barrier and inspect the shot pattern on the screen, then repeat the experiment with a plate as wide as the distance between the slits, then add a plate to the right with a separation as wide as a slit, then one to the left as wide as the slit?

 

I can't quite visualise what you are doing here. But clearly changing the setup will change the pattern.

 

It seems to me, the emergence of the interference pattern could be understood by knowing your shot pattern with no barriers and seeing what happens to the shot pattern as you apply plates of various widths inbetween, with varying gaps between a left and right plate.

 

If you look at individual photons, each one will be random. But if you look at a large number, then the effect is identical to shining a continuous light.

 

My thought is that you will get an interference pattern with only one slit, as I just held two of my fingers very close together and saw many black lines inbetween in the gap, running parallel to my fingers. If the back of my eye were the screen, there would be areas where photons were hitting and areas were photons were not. The areas where the photons were not, would be consistent with the black lines.

 

You are right. You do get a similar interference effect with a single slit, because light is diffracted from each edge.

 

http://physics.stackexchange.com/questions/61455/how-can-a-single-slit-diffraction-produce-an-interference-pattern

 

(I am not quite sure that that is exactly what you are seeing with your fingers; that might be something to do with the overlapping unfocussed images in the eye. But I really don't know. And well done for spotting it!)

 

Important I think, to know how big the source is, in comparision to the slit.

 

I'm not sure about that. Ideally, the light should be a plane wave when it hits the slits, which implies a wide source. I think this is normally approximated by having the source some distance from the slits.

 

That is, it would be physically impossible for the source to be a point source and a photon would thus be heading toward the slit from the left limit of the source sometimes, and someimes from the right limit of the source sometimes.

 

That shouldn't matter. The slits are small enough that each behaves as a new point source.

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