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

[tar]

Strange,

 

Well, here is the problem. If it is undetectable when its here and now, what makes it detectable when its over there, then?

 

And number 2, if its over there, then, what connection does it have with us, here, now? That is, what does it matter?

 

It seems to me, that mathematically, doing the arithmetic, the time lag between a photon arriving here from the front of a galaxy 250 million lys from here and one coming from the back of the same galaxy would be highly significant. Grainsize wise, in your calculations of dark matter density in said distant galaxy, you figure the whole galaxy at once. I am suggesting that this is not actually possible. What is happening at the front of the galaxy and what is happening at the back, according to the photons we receive today, are not contemporary events. Not contemporary with events here, now, and not contemporary with each other. The photons received from the front were released 250,000,000 years ago, the photons received from the back where released 250,100,000 years ago. 100,000 years is a significant portion of the lifetime of the universe if the universe is just 3,800,000,000 years old.

 

There hence are several ways that one can imagine that distant galaxy, all of them being incorrect in one way or another. Either the place is considered one grain at one time, in which case one is not taking into account the immense size of the thing, and the separation between events at the front and the back, or the thing is considered a massive collection of massive stars, spread out over a hundred million lys distance, in which case talking about its density at any particular time, is a misnomer, because you have not identified the moment in which you are taking the measurment.

 

For instance, let's take two examples of things that scientists have said about the universe.

 

One, I remember somewhere hearing that based on calculations and extrapolations of the ideal gas laws, one can figure the exact amount of atoms in the universe. Really? Number of atoms then, or number of atoms now? Before a heavier element was forged in a stellar furnace, or after?

 

Two, I remember hearing that based on current observations, and calculations, the expansion of the universe is accelerating.

What does that mean? If we are basing our calculations on current observations, we are basing them on old news, and the old position of material that released photons a long time ago. If we are basing our calculations on the projected positions of all the material that hypothetically exists currently in the universe, we are speculating, because we will not recieve any evidence of the correctness of our projection of what and where an item 250 million lys from here is currently, until 250 million years from now.

So what exactly could the statement "the universe's expansion is currently accelerating" be based on? Speculation, with is speculation, or observation which is not of current affairs?

 

Regards, TAR

[swansont]

One, I remember somewhere hearing that based on calculations and extrapolations of the ideal gas laws, one can figure the exact amount of atoms in the universe. Really? Number of atoms then, or number of atoms now? Before a heavier element was forged in a stellar furnace, or after?

 

If anyone actually claimed the number was exact, they were wrong; that's sloppy. The number that was quoted would not have been an exact number and you could tell: if there were trailing zeroes, it was not exact.

 

As far as good estimates go, the fact that hydrogen and other atoms fuse into heavier elements is a small correction. The vast majority of atoms in our solar system are hydrogen. The correction (reduction) to account for heavier atoms is of order 1%.

[Strange]

Well, here is the problem. If it is undetectable when its here and now, what makes it detectable when its over there, then?

 

Sigh. The difference is volume. If you did a bit of basic arithmetic, it might make more sense.

Given the density of dark matter (for simplicity, assume it is constant everywhere) work out the mass of dark matter within the Earth's orbit and how much gravitational effect it will have on the Earth. For simplcity, you don't even have to work out the last bvit (it might involve something advanced like squaring a number). Just work out the mass of the dark matter relative to the Sun. See, it is a really tiny number.

 

Now do the same thing for the galaxy and work out the mass of the dark matter compared to the mass of the stars See a much larger number.

 

Now you can see quite clearly why it has a noticeable effect on the scale of the galaxy and no noticeable effect on the scale of the solar system.

 

And actually, it is worse than that. The density of dark matter increases towards the center of the galaxy, making the effect on galactic scales even greater.

 

 

And number 2, if its over there, then, what connection does it have with us, here, now? That is, what does it matter?

 

It depends what you mean. It doesn't matter in any practical sense. But it is part of understanding how the universe works.

 

 

It seems to me, that mathematically, doing the arithmetic, the time lag between a photon arriving here from the front of a galaxy 250 million lys from here and one coming from the back of the same galaxy would be highly significant.

 

OK. If you have done the arithmetic, can you show the results and explain why you think it is significant?

 

 

Two, I remember hearing that based on current observations, and calculations, the expansion of the universe is accelerating.

What does that mean? If we are basing our calculations on current observations, we are basing them on old news, and the old position of material that released photons a long time ago.

 

Correct. By looking at more distant galaxies we are effectively looking back in time as well as at things which are some distance away. That is how we know when the expansion started accelerating. By looking at recessional velocities at different times.

 

Are you surprised that scientists already know this and take it into account?

[tar]

Strange,

 

No I am not suprised that scientists already know the stuff I think about. It is primarily because of what other people (scientists) have figured out and observed that I have facts to deal with to begin with.

 

It is the implications of and combination of the facts that I am trying to address here. Normally, as I mentioned before, things are true in more than one way. That is, things fit, and balance and trade off. You take the thing away from there and put it here and it subtacts from there and adds to here and everything still adds up.

 

You keep asking me to do the math and this is fine, the math is good, but the problem needs to be set up. The constraints of the problem need to be defined. You have to tell me over what time frame you are figuring the number of atoms in the universe, and also tell be what your boundry conditions are, in terms of how far out, you are counting. Are you assuming we are counting atoms in the observable universe or in the entire universe. And how are we handling stuff that used to send photons to this location but now have receeded from us, due to the expansion of space to the point where a photon released today will never reach this location? Is there not at least two ways to account for such an atom? In the one sense, we will never see photons it is releasing now. In the other sense, we are still seeing photons it released before. So there is likely material that used to be in a causal relationship with us, that is no longer in such a relationship. How are we handling that stuff, in the count.

 

A math equation is fine, but if you apply the ideal gas law to something the size of the universe, you have to tell me how you are handling the vast distances involved and still imagining the thing happening at once.

 

How many instances of a particular atom are you entertaining in any particular consideration. Lets say we are talking about the atoms in a nearby star. Are you talking about how many there are now, or are you talking about how many there were releasing photons toward us two years ago when they released them. Just like know the definitions and make sure that one set is being held throughout the calculation, so that there is no double counting or anything missed.

 

Regards, TAR

[Strange]

You keep asking me to do the math and this is fine, the math is good, but the problem needs to be set up.

 

Arithmetic. Not even math.

 

 

The constraints of the problem need to be defined.

 

I thought they were reasonably well defined: average density of dark matter (easy to look up), volume within Earth's orbit (easy to calculate), compared to the mass of the Sun (easy to look up).

 

The other question you were worrying about was the time delay for light from the near and far edges of a galaxy. This is even easier: you can take our galaxy as typical and divide its diameter by the distance you suggest (100,000 / 250,000,000). You will get a tiny percentage (0.04%). So it is up to you to show how that minute difference could be significant. I would guess it is less than the margin of error in the distance.

 

 

You have to tell me over what time frame you are figuring the number of atoms in the universe, and also tell be what your boundry conditions are, in terms of how far out, you are counting.

 

I never said anything about the number of atoms, so I don't know what you are referring to.

Edited August 22, 2014 by Strange

[tar]

Strange,

 

I didn't mean you. I meant one that was describing the density of dark matter...etc.

 

My "problem" with the percentage volume of dark matter, within the solar system and then the galaxy and then the galaxy 250 million lys from here, and then the universe as a whole, is that one can not see the universe all at once. One can imagine it all at once, but one can not see it all at once. Since seeing a thing has a lot to do with photons, it has direct relationship to the "direction" question raised in this thread. And imagining the way the universe works has something to do with keeping track of photons. Where they were emitted and in what direction, and at what point in time, as in how old was the universe, when the thing was emitted, and where is that atom now, and what is it currently doing.

 

With this "image" being structured in my mind. one can not easily flip back and forth in grain size and consider the density of a thing so large as to not all be happening at once. The same equation can not be employed on two different scales, without making the propler transformations. And these transformations require clear definition of what material you are considering, when you make your densitiy announcement. That is to say, that there is only one instance of a particular atom, or particle of dark matter and you have to be clear as to when you are counting it, in reference to another.

 

Example.

 

Let's take one atom of hydrogen in our Sun and call it atom 1,989,489,384,809,847. This singular particular atom is releasing photons at the incredible rate SwansonT described earlier. It has been doing so in a similar fashion for 13.8 billion years. Its photons are spread out throughout the universe, and are reaching, and have reached, and will reach disparate atoms, or "observers" all over the universe. Let's take atom 1,989,489,384,809,847 and consider the photons it released yesterday at 3am for the one second between 3am and one second after 3. Those particular photons exist in a spherical shell 186 thousand miles thick, about 20 billion miles in radius, centered on the position of the Sun at 3am yesterday.

 

Every photon atom 1,989,489,384,809,847 ever released can be imagined as existing somewhere in the universe, in an appropriate position consistent with where it was released and when it was released, and it what direction it was released.

 

We on Earth only see certain of these photons released by atom 1,989,489,384,809,847 at 3am yesterday, and we only see the ones we see for a second at 3:07am yesterday. The others are elsewhere now, far away and getting farther every second. They still exist, and are part of the present of some other observer.

 

The photons we recieve from some star in a galaxy whose motion we are observing, to determine the density of gravitationally involved matter, also came from a particlar atom in a particular Sun, at a particular time and was released in a particular direction, that wound up here in some recording device of ours at a particular time. And an atom on the other side of that distant galaxy also released a photon that wound up at our recording device about the same time...except that photon was released 100 thousand years prior the one from the front.

 

Under these circumstances, stating "how" that galaxy is rotating is somewhat ambiguous. And saying that you need some "extra" non photon emitting material to account for this motion, is somewhat arbitrary.

 

My suggestion here, is not that we do not see what we see, but that what we say what we see means it not necessarily properly and completely thought out, and does not completely fit together.

 

The density of a Galaxy would have to be figured in relationship to some volume and said volume would have to be "frozen" in time, to ensure that no two particles were counted twice, or missed. To do this properly one would have to entertain formulae that corrected for distance and time lag, in some concentric sphere shell manner, starting from some defined point in space and time.

 

I would think, anyway. It just seems to me that these considerations are NOT built into the equations that force the requirement for dark matter to exist, and I would feel better about dark matter, being a requirement, if I did not feel that the huge size of distant galaxies, and the inability to "freeze" such immense areas into one moment, was an unfactored, consideration.

 

Regards, TAR

[Strange]

 

My "problem" with the percentage volume of dark matter, within the solar system and then the galaxy and then the galaxy 250 million lys from here, and then the universe as a whole, is that one can not see the universe all at once.

 

You don't need to see the whole universe. One reason science (and engineering) works is because we can (using mathematics) determine what is significant and what isn't.

 

You are trying to use some sort of poor grasp of physics, your instincts and not much else to make bad guesses about the way things work.

 

 

Under these circumstances, stating "how" that galaxy is rotating is somewhat ambiguous.

 

Prove it.

 

You can make any old vague claims you like. But as you appear to have approximately zero understanding of the science involved, and are not even prepared to do kindergarten-level arithmetic to test your ideas, I see no reason to take your thoughts seriously.

 

On the other hand, a lot of people have worked very hard to develop and test models of the way the universe works. Your "I'm too lazy to try and learn anything so it must be wrong" whinging is just pathetic. Even for a 14 year old.

Edited August 23, 2014 by Strange

[tar]

Strange,

 

Well, I seem to be frustrating you. So I will stop.

 

My intention was to provide an another angle with which to attempt to explain the motion of distant galaxies, by requiring a mapping and keeping track of each photon, first from what we see and second by where and when the thing was that released it, and third by where and how we might imagine that source being currently arranged in the universe.

 

The switch between there and then, here and now, and there now is not an easy one for me. The transformations are very complicated and each aspect of the transformation needs to be thought out. I am pleased to hear that scientists have these aspects all figured out.

 

I am glad it all makes sense to you.

 

I will leave you with your crystal clear view.

 

Regards, TAR

[Strange]

 

 

It is your refusal to do even the simplest test of your ideas that is frustrating.

 

Even if someone else does the simple arithmetic for you to show that there is a minute 0.04% difference between the front and the back of a distant galaxy, you simply ignore it. Can you explain how it is significant? I assume not. You just want to believe that science must have it wrong for no reason.

[tar]

Strange,

 

But it isn't that I don't see it is a small percentage. It is that I disagree that a small percentage means it can be disregarded and not factored in, as to the meaning and consequence.

 

You are a small percentage of the population of the planet, but whether you drive or walk, or waste a thing or recycle it, makes a difference. There was once a saying, that no single snowflake feels responsible for the avalanche.

 

The difference between the front and back of a distant galaxy is a tiny percentage of the distance between us and the front of the galaxy...so why consider the distance between the front and the back?

Because it takes photons 100,000 years to make that trip, which one has to take into consideration, when attempting to describe the rotational motion of the huge area of space being viewed. If we were one foot away from the front of the galaxy in question, the 100,000 lys disparity would be a significant multiple of the distance between us and the front of, as in our example it is a tiny percentage of. Does this make our description of what we see, any different? Should it? Does being "right on top" of a galaxy or viewing one at 250 million lys distance, give us a better or worse perspective on the situation? I do not think that just because we see the thing at a very small angle we can think of it as a point source, where the distance between front and back can be discarded.

 

If scientists DO think this distance can be ignored in the calculations of the rotation of the galaxy in question, and they think it can be conceptually considered in the equations as happening all at once, then perhaps they should not.

 

If scientists already do take this huge time lag into consideration in their equations, then tell me that. Not that the percentage difference is too small to matter.

 

Regards, TAR

The thickness of the crust of the Earth is just a small percentage of the distance between the center of the Earth and the far reaches of our atmosphere. It is in some ways analogous to pond scum building up at the downwind end of a pond. It morphs into mountains and folds, and wears down and changes shape as per the effects of wind and water and bulldozer and dynamite. The continents have shifted and grand motions are at foot as plates progress this way and that and India plows into Asia and lifts the highest mountains on Earth...yet we dig two feet into soil, lay concrete, build a foundation and a house on top and call it stable, raise a family and live a lifetime in it.

 

Small percentages do not mean insignificance. Especially at the scales we are talking here.

[Strange]

Because it takes photons 100,000 years to make that trip, which one has to take into consideration, when attempting to describe the rotational motion of the huge area of space being viewed.

 

Then please demonstrate, quantitatively, that it makes a difference and what that difference is.

 

Please also demonstrate, quantitatively, that this difference is greater than the error in the estimate of the distance to the galaxy.

 

Simply repeating "it has to be taken into consideration" (without doing so and showing that you get a different result) is just not very convincing I'm afraid.

 

 

Does this make our description of what we see, any different?

 

Well? Does it? It is up to you to answer this.

 

 

If scientists DO think this distance can be ignored in the calculations of the rotation of the galaxy in question, and they think it can be conceptually considered in the equations as happening all at once, then perhaps they should not.

 

You need to provide a reason why they should not.

 

 

The thickness of the crust of the Earth...

 

But the thickness of the crust has no effect on things at a sufficiently large scale. For example, it is irrelevant to calculating the orbit of the Earth around the Sun. (If you are going to challenge that, then please provide a quantitative argument instead of "but maybe it is".)

 

 

Small percentages do not mean insignificance. Especially at the scales we are talking here.

 

You have that almost exactly the wrong way round.

[tar]

Stange,

 

I have to get ready for work. Will think about it a bit, read up on what forcing reasoning dictates the presence of dark matter, and formulate an alternative explanation based on the thickness of galaxies presented as evidence. Track the photons and prove they do not present a momentary state of a huge thing and its rotational characteristics.

 

Later.

 

Regards, TAR

[tar]

OK,

 

Maybe a lot later.

 

Have not found the proof yet.

 

Here are the areas that I am considering.

 

Photons emitted from the column of space through a distant galaxy in a particular direction (toward Earth) are from diverse times, such that they do not all correspond to a singular position/configuration of said galaxy. Said column is not clearly defined, as it is not stationary, nor reproducable, nor does the one end of it, represent the same epoch as the other. Being such, the information gleened from a particular photon coming from said column, can only be trusted to NOT represent the current position of the atom that emitted it. And to truly state the rotational characteristics of said galaxy, one cannot be certain they are saying a true thing, unless the immense size of the galaxy in question, and the immense distance and uncertainies involved are fully defined, as well as the perspective from which, any claims about it are made, is clear.

 

Second area of uncertainty is the non compliance of observation of item's motions within a galaxy with Kepler's laws of planetary motion. Over the last thrity years, this problem has been solved by adding a halo of dark matter of uncertain characteristics to galaxies, with mostly consistent results, but not complete success. Other solutions are still entertained. Adjusting the laws of motion at that scale is one consideration and one I am currently entertaining, Especially in referrence to the photon travel time differencial between the sources at face of a galaxy, as opposed to the ones comings from the wings. With sources traveling a thousand miles a second, the position differential this would cause over 50,000 years is substantial. Adding all the motion back, to come up with a positional model of the galaxy, at any figured point in time, is a tremendous challenge.

 

Third area of possibility is that ordinary matter acts in ways that we are not considering, when veiwing distant stuff. Especially not considered is the fact that material in a distant galaxy is more likely to have characteristics that the Milkyway had a million years ago, than those the Milkyway has currently. And "currently" any evidence we get of what is happening at the other end of the Milkyway is 100,000 year old news. Bottom line, there are many areas of conjecture, like considering a model of a galaxy with high porportions of large bodies consisting of metallic hydrogen (as in Jupiter) and factoring what this would mean both in gravity and in internal light absorbtion of a galaxy. Photons from behind such a body would not get here, thus rendering the photon emitting source "dark" to our eyes. And considering the size of a Galaxy there is a tremendous amount of a distant galaxy that is "hiding" behind a "Jupiter" on the near side, at any particular moment.

 

Regards, TAR

To say nothing of the tremendous amount of photons that are "blocked" by huge light emitting items at the near side of viewed galaxies. We ourselves can not see through the center of our own galaxy. Thus a large portion of our own Galaxy is "dark" to us. Same with a distant galaxy. Any item will block any item behind, from our view. Photon travelwise.

How one is to figure this shadow, over time is very complex. What volume of M33 is blocked from our view, by a Jupiter placed at M33's nearest point? And considering the shadow of this "Jupiter" is moving like a negative beam, for each other lightsource in M33, the "shape" of each of the beams singulary would be hard to figure over time, and all together a really knotty problem. For just one "Jupiter". For billions? I am afraid someone else will have to do the math. I simply can not. Not laziness. Just lack of ability.

[Strange]

1. Unless you can quantify these supposed "uncertainties" there is nothing to discuss.

 

2. There is little value considering individual photons in this context as almost nothing is measured from individual photons(*). It is much more practical to use the classical view of light.

 

(*) About the only example I can think of is the measurement of the position of the moon using the Apollo reflectors. In this case, of the octobazillions of photons from the laser on Earth, just a handful are reflected back to the detectors.

[tar]

Strange,

 

I will work on the quantification and the geometry, but I don't think nothing is implied from a single photon. Read at one time that the large collectors of photons, looking into deep deep space at really distant stuff, collect one photon at a time, have to wait minutes for the next, and record everything and build back the image of the thing based on the results.

 

Classical view of light may be most practical, considering the numbers and varied calculations that one would have to entertain, otherwise, but I am currently concentrating on what is actually happening, what is actually possible and considering the gaps inbetween photons, both in time and in spread. A particular source of photons, however big, only has a finite number released every second. Those photons need to go in ALL directions. There are very many directions. More directions than photons. A singular photon must have a "shot pattern", that is, a span, as in "with its arms extentended" what size imaginary whole would it punch in an imaginary membrane. How close would it have to be to an atom to hit an electron on it, and boost it up to another energy level? The creation of, the travel time and path of, and the destruction of a photon, must occur. Thusly, there are actual photons "on their way" to Earth, from the nearest star. Some that will reach my left eye, some that will reach my right, in enough abundance that I will sense the arrivals as continuous. and the star as visible, and present, there, right there in the sky.

 

I cannot however reach out and touch the thing and verify its position and sync it up with my other senses, like I could the lamp on the other side of the room. Several switches of grain size and models have to be entertained to grasp that star as true in two senses. The sense that it is right there, NOW in the sky at that spot where I am pointing now, AND it is true that it is in another spot, that it has traveled to, in the 2 years it took the photons that I am judging its position by, to get here. AND it is true that the photons I saw coming from the star two years ago, were telling me the exact and actual direction the star would be in today.

 

I apologize, but I fell into this requirement to track photons several years ago, with considerations of the twin paradox, and the thought that one could mentally imagine how both twins would view a distant pulsar during the trip of the one, and "count" the pulses. Upon the return of the twin, the counts would have to be equal.

 

Regards, TAR

[Strange]

 

Upon the return of the twin, the counts would have to be equal.

 

I don't think so. They have observed the pulsar for different amounts of time and so will have different counts.

[Spyman]

 

I don't think so. They have observed the pulsar for different amounts of time and so will have different counts.

I think you should reconsider, if one event takes place is one frame then it should happen in all frames, it can not vanish from one view.

 

From my limited understanding I think they can disagree on the time between events and their duration but their counts must be the same.

 

If one twin can see the others clock and both twins counts how many times this clock ticks forward, can they really end up with different amounts of ticks for this particular clock when they reunite?

 

 

[Strange]

Yes, you are right. I was wrong. Again. The pulsar can be considered a clock in the Earth-bound twin's frame of reference. The other twin will see it "tick" faster (overall) and so get the same number of pulses.

[tar]

Strange,

 

Overall?

 

The "overall" would be the reality that included both the traveler and the stay at home. Since as Spyman put it, neither ever left reality, and had the pulsar in view the whole time, then any ticking faster on the way out would have to be matched with a ticking slower on the way back, or vice a versa, depending on which frame you are considering, and whose count you are going by at any particular time.

 

My thinking, in the "keeping track of photons" mode, is that any progress toward the pulsar on the traveling twin's part would indeed speed up the arrival of the photons and be experienced as a blue shift, as if the pulsar was approaching. And on the way home, there would be a corresponding red shift in the frequency or the ticks. This could be measured in reference to any onboard clocks the traveling twin might have, and there is some crazyness in trying to figure whose onboard clocks are running at what relative pace in reference to the other, the simple act of traveling, even at near light speed, can not change the ticks of the pulsar. That pulsing pattern of photons is already laid down, those waves are already on the surface of the lake, and traveling anywhere on the lake in any direction, with, against or along a trough or peak, will not change the count.

 

I know this is contrary the experiment with the clocks flown East and West and reunited only to be on different ticks, sped up and slowed down appropriately by velocity aided and abetted by the spin of the Earth, and gravity well considerations as the clock that stayed home stayed deeper in the well...but all three clocks could have been judged against the quasar's pulse, and a deternination made of when and how each clock ticked faster or slower than one or the other, or the other. Time itself, as referenced by the waves laid down on the lake, by the quasar was not, and could not have been affected.

 

Ones reference point might be inadvertently mislaid, but the ticks of the quasar cannot be undone.

 

As an aside, such keeping track of photons, speaks strongly against time travel. While one can easily change ones position on the lake, and concurrently separate themselves "in time" from another, getting infront of, or behind a wave experienced by the other, if one is interested in getting back in sync with the other, they have to make the reverse trip. Thusly they have never affected time and space a whit, only their position in it. You can leave and come back to a spot in space, time on the other hand, marches on. The arrangement of the entire universe would have to be reconstructed to "return" to a moment in time. This is not a possibilty. Time is one way, in this regard. Any calculation that allows time to flow in the opposite direction is in error. The photon waves from every photon release...ever...are not registered on a device that can be rewound and replayed. Its already done.

 

Regards, TAR

[Strange]

Strange,

 

Overall?

 

The "overall" would be the reality that included both the traveler and the stay at home. Since as Spyman put it, neither ever left reality, and had the pulsar in view the whole time, then any ticking faster on the way out would have to be matched with a ticking slower on the way back, or vice a versa, depending on which frame you are considering, and whose count you are going by at any particular time.

 

The faster and slower ticking rates would not be matched. The travelling twin has seen the same number of ticks in less time so, on average, more ticks per unit time.

[John Cuthber]

You may find it interesting to note that the direction in which a photon is emitted may depend on whether or not there is a mirror nearby. This also affects the emission half- life.

http://newton.ex.ac.uk/research/emag/pubs/pa_thesis.pdf

[tar]

John Cuthber,

 

Thank you for the Piers Andrew's submission. I did not read through the whole thing, and the "math" I do not know well enough to appreciate, but I scanned through and read some of the summaries and such. Interesting to me in regards to this thread was this sentence from the final summary.

"

By fitting the

angle dependence of the emission to a simple model which considered the

interference between the direct emission from the dipole and the reflected field

from the mirror, it was shown that the 614nm emission arose from an electric

dipole transition, and the 592nm emission from a magnetic dipole transition, in

agreement with studies by previous workers [Drexhage (1974)]." Piers Andrew 1998

 

 

Suggests that it may be other than randomly that a photon is emitted. I will have to learn what an electric dipole and magnetic dipole are, but that is the beauty of Wiki, I will know such, by my next post. Also this suggests that the particular electron falling from a particular height that yields a certain frequency photon may depend to some extent on the angle of incidence and the phase of the photon that boosted the electron up in the first place.

 

Not particulary related to the paper, but the fact that timing was studied, made me consider that there may be a preferred time that an excited electron might "hold on" to the energy before it "immediately" released it. Enough time perhaps in the quick and tiny world of an electron, for the electron to have traveled a certain angular distance around the nucleus, or a certain amount of times around, at which point it would prefer to cough up the energy as a photon.

 

Strange,

 

Back to the shorter amount of time to count the same number of pulses. If this were the case, the traveling twin would have to see the beats of the pulsar as "faster" than she knew before she left they were. Also the frequency of light during each pulse would have to be measured as faster and the wavelengths shorter. If she was traveling tangent to the pulsar, what physical law would allow this difference?

 

Regards, TAR

Edited August 31, 2014 by tar

[John Cuthber]

It's certainly well documented that the polarisation of an emitted photon isn't (always) random.

http://en.wikipedia.org/wiki/Depolarization_ratio

http://en.wikipedia.org/wiki/Fluorescence_anisotropy

 

 

The fluorescence lifetimes of the europium complex they were using is about a millisecond.

That's long enough for the electron to go round the entire lab, never mind the atom.

[tar]

John,

 

Did not look at the links yet, but the long fluorence lifetimes may or maynot describe an individual electron's grasp on a packet of energy. And if it was figured to be a single electron's hold, "about a millisecond" does allow for it to "let go" of the energy in any random direction (considering the electron would have the opportunity to be in any particular position in its "higher" energy level, in reference to a direction from the nucleus, many many times, before it let go.

 

However, two situations seem to make it hard to figure the geometry. The experiments are sort of gross approximations, taking large amounts of transitions over large amounts of time, where averages and implications hold greater sway than actual measurements of individual photon trajectory. (as opposed to "I hit said electron with this amount of energy at that point in time and it released this amount of energy at this point in time" So tiny and so fast.

 

By the way my quick foray into electric and magnetic dipole transitions did not leave me as knowledgable on the subjects as Schrödinger Hamilton and Pauli would consider sufficient.

 

Regards, TAR

FRET is analogous to near-field communication, in that the radius of interaction is much smaller than the wavelength of light emitted. In the near-field region, the excited chromophore emits a virtual photon that is instantly absorbed by a receiving chromophore. These virtual photons are undetectable, since their existence violates the conservation of energy and momentum, and hence FRET is known as a radiationless mechanism.

 

 

Forster (o with an umlat) resonance energy transfer, (off John Cuther's last link) seems another way for an electron to transfer its energy to another closer range atom than the photon route, although the two seem to be versions of the same mechanism.

 

The "direction" in which the recepient atom is oriented in reference to the donor would still pertain to the thread question.

 

As that an atom in a molecule or matrix of molecules does not have a nearby atom at every direction, but only certain ones consistent with the arrangement of the molecule, this FRET mechanism seems to indicate that the energy can be transferred in a general direction, general enough to "hit" the neighboring atom and in particular, one of its electrons. Taking exact aim on a neighboring atom's electron, would be a highly improbable act, otherwise.

that first paragraph after my signature is supposed to be in quotes being from a Wiki article (I am having trouble with my edit feature)

[Strange]

Back to the shorter amount of time to count the same number of pulses. If this were the case, the traveling twin would have to see the beats of the pulsar as "faster" than she knew before she left they were. Also the frequency of light during each pulse would have to be measured as faster and the wavelengths shorter.

 

Yes. Because she experiences less time (has aged less) than her twin on Earth.

 

If she was traveling tangent to the pulsar, what physical law would allow this difference?

 

If she is travelling tangentially to the pulsar, then she is orbiting it (1), in which case she is accelerating continuously (2). Which accounts for the difference.

 

1) If she were travelling in a straight line then her velocity would only be tangential for an instant. Before that she would be getting closer and after that she would be getting further away

 

2) Strictly speaking, in GR she is not accelerating but the stationary twin on Earth is.