Does light have a mass?

[James R]

137,

From a historical point of view, which appears to be your interest, I agree that there was a slow break-away from the ether idea, driven by the need to reconcile Maxwell's equations with changes in reference frames, and also the seeming independence of the speed of light on the frame of reference.

<i>But [light] is not constrained to any coordinate system was my contention. Am I wrong?</i>

No, you're right, but your statement is applicable to everything. You can describe the motion of any object in any coordinate system you like. A coordinate system is simply a point of view.

The speed of light is constant in any inertial coordinate system.

<i>I assume you mean the Crank site link?</i>

No, I meant your "What is the mass of a photon?" link. If you read the current thread, you'll find that I explained all of the information in that link earlier in this thread.

 

[thed]

Wahey, the lads

Originally posted by Adam
We space monkeys only throw energy balls back and forth when paid to do so, and we make no claims regarding such activities and the nature of physics.

It looks like Adam might be a working implementation of the Infinite Monkey Protocol Suite. Explains a lot

 

[Adam]

RFC2795 is about but one of many activities undertaken by space monkeys.

 

[137]

Stir the pot

Some random thangs [as I continue my reading of historics around proto-relativities through contemporary ]:

As I look for consistent evidence of gravitational lensing, I still find a predominance of Eddington's 'proof' based on the solar eclipse of 1919. The more recent claim is a Hubble telescope image claiming proof positive that gravitational lensing is duplicating galaxy images.

1]If there is consistent data on gravitational lensing, then it should be catalogued appropriately. Does anyone know a source? From Eddington to the present, I am not finding SCIENTIFIC data that discusses data/observation/measurements of proported gravitational lensing with associated discussion of the elimination of all other variables as affecting measurements.
For example[and this has been brought up before] the atmosphere of the sun is a broiling stew of elements, plasma, magnetic emanations. Has a refractive index[range] been determined for the sun's 'atmosphere?' and this index as a variable been eliminated.[Note: it is a weak argument to say, 'oh I am sure they took that into account.' Perhaps they did, but good science does not leave this out of the findings, no?]

2]Is there or has there been any development of a gravitational index of refraction? There must be some formula to predict this based on the mass of a stellar object [or averaged amount based on speculation of massive bodies between a viewed object and the observer.]

3] On gravity bending light: The following is the argument as my feeble mind has read it --> relativity predicts that gravity will bend light. The bend is due to light following a geodesic--> A geodisic path is due to the physical properties explained in relativity. Circular argument is not acceptable. I will accept ignorance as the accusation, but only if the accuser can expound upon the reasoning that results in this prediction. Light is so fast that weak-old gravity would have to work mighty fast in a short amount of space to affect any bending. I can see where people love to use the outdated 'relativistic mass of light' because it semantically creates a massive particle that can interact with gravity. Electromagnetic waves and gravity interaction experiments would be insightful...any sources....anyone...anyone?

4] The anthropomorphising of relativity predictions are a major hurdle. If Einstein had described the twin paradox using two atoms, then the instinctive 'what the hell?' reaction would never have occurred. He tread on the concept/mystery of time as existence. The argument seems to fly in the face of all investigations of time from Xeno to the present. The twin paradox calculations seem very similar to the mathematical paradox-->
a]Take any two points A and B with a distance x between them. b]Step 1/2x from A to B.
c]Reset your new position as A and the new distance between A and B as x.
d]go to a]
Mathematically, you approach 0 but will never reach it. So this proves that given the use of this formula, you can never reach another point.

5] The ability on paper/thought to abstract our reality and 'stop time' for a measurement, seems to be thrown out the window in regards to relativity, unless we a priori accept that relativity is true! If we perform the twin paradox and try to use 'antique' reasoning, we think,'Hey if some one goes away at near the speed of light and returns near the speed of light then the total round trip from earth's perspective should only take as long as it takes to go and return. The person who goes away on the trip may have screwy clock readings, but this is the appearance of time, not time or asynchronous aging. If we abstract thought stop time and consider a person who is one minute[earth atomic clock time]from death and their twin who is 'out there' near the speed of light who is also one minute from death[near speed of light time with a clock that is doing who the hell knows what depending upon the various gravitational interactions, or lack there of at near speed of light time] and in that stopped instant, we take a God's eye view of these two people an earth second at a time. We think -step through the 60 seconds and the only thing that changes is the distance between the two. At the 60 second tick on the earth clock, both twins are dead. They are in two vastly different places, but dead nevertheless. If we continue them on their respective frameworks and velocities, their existence is smeared out over varying distances, momentums and directions, but this begins to look like a macro version of quantum physics. You can either know the location[or rather statistically predict the locations] or calculate their velocities...but this becomes yet another tangent....
The fact that no human being..no twins, in probably many lifetimes, will ever be able to test the theory makes this all the more fodder for nonsensicals. As previously stated, I think there would be no complaints if Einstein had not used a human as the test pilot of his aging/time dilation thought experiments.

6] Similar case as '5]' with the shortening of rods. Einstein and his explaineers[spelling intentional] seem to be using appearances, or rather the time it takes for light to reach the observer from a rod's ends as the explanation of the shortening of rods. Lorentz's papers speculate from a more grounded position of the velocity of a rod affecting the atomic interactions, possibly causing a compression of sorts. Again, the move from atomic, and smaller, interactions to the distortion of time and space has created what many consider a counter-reason environment to physics.

7] I read somewhere a person saying that the thought experiment of Einstein where a person on an elevator in space[at the right acceleration] would not know the difference between Earth's gravity was incorrect in its assertion of equivalence. Th person stated that gravity vectors converge at the Earth's center while the force vectors felt by the elevator rider are parallel. One can imagine modern equipment able to measure this difference. Does anyone see a flaw in this argument, or is it one more of those 'little things' that do not quite hold up in the baseline explication of Relativity?

What do people think of the idea of a 'catalogue of proofs?' Modern science demands that a consistent body of repeated experiment to both test a theory and to further hone the ability to make predictions is created and that the findings are presented for peer review. There are enough solar eclipses around the world on a trackable basis that the starlight deflections due to the sun's gravitational lensing should have a consistent record. I am having no luck finding any such data.

Hope all are well. Back to my delving into the calculations of history [of physics]

137:bugeye:

 

[Crisp]

Hi 137,

You did some fine researching . I'm afraid I can't help you in your quest for the original sources of some of the experimental verifications you look for, but I could give you a hint where to look for them.

First of all, you could consider looking into recently published papers on eg. gravitational lensing. Most "peer reviewed" magazines don't allow online consulting of their articles, but you could try http://xxx.lanl.gov , which holds preprints of quite a number of published articles. A search on gravitational lensing returned <a href="http://lanl.arXiv.org/find/hep-ph,cond-mat,physics,hep-th,hep-ex,gr-qc,hep-lat,nucl-th,nucl-ex,quant-ph,astro-ph,math-ph/1/abs:+AND+gravitational+lens/0/1/0/past,all/0/1">this</A>. You can read these papers online, perhaps one contains a link to the original Eddington article, or references to articles that discussion a scientific study of gravitational lensing (the later will be no problem to find by just skimming through some introductions).

Secondly, you could try some books on science philosophy, those tend to extensivily study the historic context in which scientific discoveries were made, and mostly contain references to original books and papers. I somehow seem to have lost some references I had over here (you should see the mess I have in my working chamber ), but I am sure you'll find a good book on the history of relativity in the science philosophy field.

Bye!

Crisp

 

[James R]

Re: Stir the pot

137,

<i>1]If there is consistent data on gravitational lensing, then it should be catalogued appropriately. Does anyone know a source?</i>

There is an immense literature on gravitational lensing, and a segment of the scientific community dedicated to researching it. If you want original sources, the primary source is physics journals. On the other hand, books have been written on the subject.

<i>From Eddington to the present, I am not finding SCIENTIFIC data that discusses data/observation/measurements of proported gravitational lensing with associated discussion of the elimination of all other variables as affecting measurements.</i>

Then I don't think you're looking hard enough.

<i>Has a refractive index[range] been determined for the sun's 'atmosphere?' and this index as a variable been eliminated.</i>

Yes and yes. Most gravitational lensing examples involve lensing by <b>galaxies</b>. The atmospheres of stars, as normally defined, do not extend into interstellar space. The lensing by galaxies must be due to mass, not refractive effects of gas.

<i>2]Is there or has there been any development of a gravitational index of refraction?</i>

Yes. You can assign an "index of refraction" to a particular lens if you like. However, it's not like a homogeneous medium, so I doubt that such a concept is very useful.

<i>3] On gravity bending light: The following is the argument as my feeble mind has read it --> relativity predicts that gravity will bend light. The bend is due to light following a geodesic--> A geodisic path is due to the physical properties explained in relativity. Circular argument is not acceptable.</i>

The argument actually goes like this:
1. We observe bending of light (for example, by the sun).
2. Relativity accurately predicts the amount of bending we should observe.
3. Therefore, we conclude that relativity accurately describes the observations.

No circularity there. Observation - hypothesis - conclusion.

<i>Light is so fast that weak-old gravity would have to work mighty fast in a short amount of space to affect any bending.</i>

Relativity describes gravity as the curvature of spacetime itself. There's no speed involved.

<i>If Einstein had described the twin paradox using two atoms, then the instinctive 'what the hell?' reaction would never have occurred.</i>

I don't think so. The predictions of relativity are counter-intuitive no matter how you look at them.

<i>The twin paradox calculations seem very similar to [Zeno's paradox]... So this proves that given the use of this formula, you can never reach another point.</i>

Wrong. Zeno's "paradox" ignores the fact that to cover a shorter and shorter distance requires a shorter and shorter period of time. In the limit as the distance goes to zero, so does the time, which resolves the apparent paradox. Even Newton understood that.

<i>If we abstract thought stop time and consider a person who is one minute[earth atomic clock time]from death and their twin who is 'out there' near the speed of light who is also one minute from death[near speed of light time with a clock that is doing who the hell knows what depending upon the various gravitational interactions, or lack there of at near speed of light time] and in that stopped instant, we take a God's eye view of these two people an earth second at a time. We think -step through the 60 seconds and the only thing that changes is the distance between the two. At the 60 second tick on the earth clock, both twins are dead.</i>

Wrong. Time dilation effects mean that the travelling twin dies later, as seen by the Earth clock.

<i>The fact that no human being..no twins, in probably many lifetimes, will ever be able to test the theory makes this all the more fodder for nonsensicals.</i>

The twin paradox has been tested with atomic clocks flown in aircraft.

<i>6] Similar case as '5]' with the shortening of rods. Einstein and his explaineers[spelling intentional] seem to be using appearances, or rather the time it takes for light to reach the observer from a rod's ends as the explanation of the shortening of rods.</i>

No, that is a common misconception. In the case of length contraction, any light travel times are taken into account in deriving the contraction. The contraction is a relativistic effect which has no dependence on light travel time.

<i>Lorentz's papers speculate from a more grounded position of the velocity of a rod affecting the atomic interactions, possibly causing a compression of sorts. Again, the move from atomic, and smaller, interactions to the distortion of time and space has created what many consider a counter-reason environment to physics.</i>

Only the many who do not understand relativity. Lorentz did not have the benefit of almost100 years of thought about this, remember, so <b>he</b> can be forgiven.

<i>7] I read somewhere a person saying that the thought experiment of Einstein where a person on an elevator in space[at the right acceleration] would not know the difference between Earth's gravity was incorrect in its assertion of equivalence. Th person stated that gravity vectors converge at the Earth's center while the force vectors felt by the elevator rider are parallel. One can imagine modern equipment able to measure this difference. Does anyone see a flaw in this argument, or is it one more of those 'little things' that do not quite hold up in the baseline explication of Relativity?</i>

There is no problem at all with that argument. It is correct. In fact, if you follow it through to its logical conclusion, as Einstein did, you arrive at the General Theory of Relativity. It's not a problem for relativity, but rather a base for the theory.

<i>What do people think of the idea of a 'catalogue of proofs?' Modern science demands that a consistent body of repeated experiment to both test a theory and to further hone the ability to make predictions is created and that the findings are presented for peer review. There are enough solar eclipses around the world on a trackable basis that the starlight deflections due to the sun's gravitational lensing should have a consistent record. I am having no luck finding any such data.</i>

I do not have the information at hand, but I suspect that the gravitational deflection of starlight by the sun is well confirmed.

At the risk of giving you cannon fodder, let me say this: In fact, the original Eddington experiment was probably not sensitive enough to measure the predicted relativistic deflection of light during an eclipse. However, the experiment has since been repeated using appropriate equipment and the effect is confirmed.

 

[137]

Many thanks...to be continued

Crisp: Thanks for the links. I will begin a-looking over the information. Oodles of books including science philosophy and history are on my bookshelves and I pick up others from the library. I have lately been trying to read up on the 'biggies' first hand writings, but am trying to find the 'counter-point' physicists who test the claims...and I mean legitamate physicists not cranks.

James R: I know I am not looking hard enough...that is why I ask on the forum ! I was hoping that instead of general 'the data is there' that someone would know of sources. I guess I am going to have to build a public catalogue...if I can find the time....

Most gravitational lensing examples involve lensing by galaxies. The atmospheres of stars, as normally defined, do not extend into interstellar space. The lensing by galaxies must be due to mass, not refractive effects of gas.

**NOTE**I did read your response about the data at the end of your post...more at bottom***
As our equipment advanced, obviously the search for gravitational lensing moved beyond our sun. BUT, for starters, what I am trying to find out is the actual data for one case study, i.e., the predicted gravitational lensing by our sun and the resultant claims of proof. If I start with the Eddington photographic proof of the eclipse of 1919 and the claim that his proofs were faulty - from earlier post **Columbia University astronomer C.L. Poor in 1922,'26 & '30 gave unassailable refutations of the claims of Eddington "Thirty-three photographic plates taken during the eclipse of 1919 show star images; of these thirty-three, seven only give results even approximating towards the Einstein predictions. And to make even these seven fit the hypothesis, the relativist is forced to invoke the aid of the Sun to distort the camera in a particular way and by just the right amount!" ..... "The relativity theory may be true, but no substantial experimental proofs have yet [1922-1990] been submitted by any of its adherents."*** -- this leaves me with a few questions to be answered.
1. Was Eddington correct or was Poor's refutation correct?
2. Does the sun have the ability to 'measurably lens?
3. If 2 is true, there should be reams of data proving unequivocally that gravitational lensing occurs?
4. If the sun can gravitationally lens light, then shouldn't there also be reams of data that also elaborate on how the sun's corona affects light passing through?

The argument actually goes like this:
1. We observe bending of light (for example, by the sun).
2. Relativity accurately predicts the amount of bending we should observe.
3. Therefore, we conclude that relativity accurately describes the observations.

And I am looking for the data/proof for 1, 2 and 3.
When I delve back into the Lorentz/Einstein and begin the Minkowsy I will have more of a groundwork to actually talk about this

Relativity describes gravity as the curvature of spacetime itself. There's no speed involved.

The counter-intuitive kicks in...light approaching a gravitational lens from a myriad of source each curves according to the curved spacetime in the locale of a massive object. It smacks of analogy as opposed to reality. I will concede that I do not know enough of why the curvature of spacetime is a mandatory component of Relativity...I will continue in my study. But at the root of the argument, am I correct that the realm of relativity would say that I adhere to the earth because of local[earth] curvature of spacetime?

I don't think so. The predictions of relativity are counter-intuitive no matter how you look at them.

If molecules/atomic/sub-atomic particles exhibit different behaviors, i.e. decay rate of a radioactive isotope is advanced or retarded by proximity to certain EM fields, curved spacetime or lack thereof, then we are talking about the root of physics. When we talk of sending a person out into space at near light speed, we are talking science fiction or analogy[at the very least, for many lifetimes until humans could even begin to attempt this.] I may try an atomic twin paradox with more detail another time... I was hoping to be ceded the point that if you talk about asynchronous time regarding humans you will unavoidable receive argument, if you rather discuss an atom, no one would peep.

Whoops I X'ed the Z. Zeno's paradox still stands, mathematically,as an appropriate illustration of what can be proved mathematically. The problem with understanding it is that it is counter-intuitive to human experience; distance and time can approach zero without end from a mathematical standpoint. Even Newton understood that. You MUST concede that mathematically, a formula can be set up to approach zero, but never reach it. I am intentionally being flippant to illustrate the point. Feel free to cite me the Newton that discusses how time resolves this. If it is in the Principia, I've it on my bookshelve and I will dive right in.

Wrong. Time dilation effects mean that the travelling twin dies later, as seen by the Earth clock.

Now when you say the 'as seen by the Earth clock, are you talking about when the light signal from the travelling twin's clock reaches earth? IS this to say that from a God's eye view of the universe that the two instances of dying twins are non-silmultaneous? What I am aiming for is to make sure I understand whether relativity is saying one of the following:
1. Near speed of light travel demands that the near speed of light traveller has a slower existence than a slower, or earth bound citizen
2. a mid point can be found, between the two travellers that is speeding fast enough towards the travelling twin that both clock light signals reach him at the same time and only for this person does the silmultaneity[sp?--to lazy to look it up] of death occur
3. Communications is limited by the top speed wave front we can modulate. Therefore lightspeed is the fastest we can communicate. This wavefront is affected by speeds of transmission and reception, distance, and wavelength.
Before I go further with this thought..I would like to see a response.

Only the many who do not understand relativity. Lorentz did not have the benefit of almost100 years of thought about this, remember, so he can be forgiven

So don't forgive me
This is another arena of many I am having to delve into. I am still trying to find time to contrast and compare Lorentz's thoughts on contraction and Einstein's...so once understood, if I jump for joy at relativities elegance, please forgive me. I am still reserving judgement as I endeavor to understand it fully.

Thanks for the insight on the follow through leading to GTR. I am still on the fringes of STR...GTR will have to wait[sounds like a movie title.

I am adamant, for my own understanding and pursuit of this knowledge, that on gravitational lensing related to our sun, that I delve into as much data as possible and verify the chain of prediction and observation from Eddington to the present. For the sake of this information, I am going to ignore all other stellar body claims to gravitational lensing.

thanks James R for responding so thouroughly to my statements/questions/ponderings. I hope others find it useful.

Cheers,
137

 

[137]

thanks crisp

Crisp,

Just another thanks for the second link which is the search for gravitational lensing. I am happy you posted it since the proxy at my workplace will not allow me to link to any URL with 'xxx' in it. Thought you would get a chuckle over that one.

regards,
137

 

[Crisp]

Funny! Just incredible how paranoid some employers can get

 

[James R]

137,

<i>1. Was Eddington correct or was Poor's refutation correct?</i>

As I said, I suspect that the refutation was correct.

<i>2. Does the sun have the ability to 'measurably lens?</i>

Yes. And it has been measured. There's another experiment you might also like to look up, which concerned the light travel time of a signal between Earth and Venus, which was observed to change when the signal had to travel near the sun.

<i>3. If 2 is true, there should be reams of data proving unequivocally that gravitational lensing occurs?</i>

Yes.

<i>4. If the sun can gravitationally lens light, then shouldn't there also be reams of data that also elaborate on how the sun's corona affects light passing through?</i>

I suspect (I'm not an expert on this) that the corona has very little effect on light passing through. In terms of refraction, the corona is not a very optically dense medium.

<i>The counter-intuitive kicks in...light approaching a gravitational lens from a myriad of source each curves according to the curved spacetime in the locale of a massive object. It smacks of analogy as opposed to reality.</i>

Why do you think that?

<i>[A]m I correct that the realm of relativity would say that I adhere to the earth because of local[earth] curvature of spacetime?</i>

Yes. According to general relativity, the Earth's surface is continually accelerating upwards, pushing you up with it.

<i>Zeno's paradox still stands, mathematically,as an appropriate illustration of what can be proved mathematically. The problem with understanding it is that it is counter-intuitive to human experience; distance and time can approach zero without end from a mathematical standpoint. Even Newton understood that. You MUST concede that mathematically, a formula can be set up to approach zero, but never reach it. I am intentionally being flippant to illustrate the point. Feel free to cite me the Newton that discusses how time resolves this. If it is in the Principia, I've it on my bookshelve and I will dive right in.</i>

Suppose you want to move something 1 metre, at a speed of 1 metre per second. At that speed, to cover 1/2 a metre takes 1/2 a second. To cover 1/8 of a metre takes 1/8 of a second, and so on. To cover the 1 metre, you have to first cover 1/2 a metre, then 1/2 the remaining distance (1/4 of a metre), then 1/2 of that (1/8) and so on. The total distance covered is:

1/2 + 1/4 + 1/8 + 1/16 + ... = 1 metre

The total time taken for the journey is the sum of the times for each segment:

1/2 + 1/4 + 1/8 + 1/16 + ... = 1 second

There's no problem with that. The total journey takes only 1 second, even though there are an infinite number of distance intervals to be covered in that time.

Do you still need Newton to believe that?

<i>Now when you say the 'as seen by the Earth clock, are you talking about when the light signal from the travelling twin's clock reaches earth? IS this to say that from a God's eye view of the universe that the two instances of dying twins are non-silmultaneous?</i>

The effect of relativistic time dilation is above and beyond the delaying effect of the finite travel time of light from one point in space to another. When I say that two events occur simultaneously, that doesn't mean that two spatially separated observers will see them at the same time, since light might take longer to travel from one event to the observer than from the other. Two events are simultaneous if they have the same time coordinate.

In this sense, the events of the twins dying are not simultaneous. The travelling twin dies at a later time than the Earthbound twin, in the reference frame of the Earth. That's even after the travel time of the light from the travelling twin to Earth has been subtracted from the equation.

To put it in more concrete terms, let us say that the twin on Earth dies at time T and the "real" time of the death of the travelling twin is T'. The light from the travelling twin takes time dT to travel from the travelling twin back to observers on Earth, arriving back on Earth at time T2. To find out the "real" time of death of the travelling twin, observers on earth calculate T2 - dT = T'. What they find is that T' is greater than T. In other words, the travelling twin "really" died later than the Earth twin. The time difference T' - T is due to relativistic time dilation, as opposed to the time dT, which is due to light travel time.

<i>1. Near speed of light travel demands that the near speed of light traveller has a slower existence than a slower, or earth bound citizen</i>

Only from the point of view of the Earth-bound person. From their own point of view, the traveller experiences time at the normal rate.

<i>2. a mid point can be found, between the two travellers that is speeding fast enough towards the travelling twin that both clock light signals reach him at the same time and only for this person does the silmultaneity[sp?--to lazy to look it up] of death occur</i>

No. The events will not be simultaneous from his point of view, either.

<i>3. Communications is limited by the top speed wave front we can modulate. Therefore lightspeed is the fastest we can communicate.</i>

Yes.

<i>Thanks for the insight on the follow through leading to GTR. I am still on the fringes of STR...GTR will have to wait</i>

Special relativity, as the name suggests, is just a special case of the general theory. Specifically, special relativity applies in the case of so-called "flat" spacetime. That means that it describes relative motion, but not gravity. GR adds gravity.

I'd advise tackling SR for a start, then worry about GR later.

 

[137]

and on it goes

Howdy, James R:

Yes. And it has been measured. There's another experiment you might also like to look up, which concerned the light travel time of a signal between Earth and Venus, which was observed to change when the signal had to travel near the sun.

I am still finding scarce data for sun lensing. The Crisp link does have plenty to look through, but the recent journals that assure the reader that the sun's lensing is a given footnote this with, once again, references to Eddington. We are talking journal of physics within the last 5 years. So I still have my work cut out for me. Venus will have to wait. The sun will be the focus for lensing.

I suspect (I'm not an expert on this) that the corona has very little effect on light passing through. In terms of refraction, the corona is not a very optically dense medium.

A little effect means a great deal, perhaps in the favor of Eddinton's photographic data. The plasma within the corona is whipped around by the magnetic field eruptions and a soup of particles is constantly being jostled around. There are journal articles discussing the effect on EM waves. If the corona shimmers the light, this does not BY NECESSITY eliminate the possibility of gravitational lensing. The photo plates that did NOT support lensing could have been a result of coronal refraction. I am reserving judgement, but the corona is a phenomena that affects EM transmission.

Why do you think that?

Because that is what it seems to be. IS your question rhetorical, because it IS understood to be an analogy? So far in my reading, there is no formula that logically concludes that 'Aha, spacetime curves!!' it is an attempt to illustrate the mysterious gravity. It could have been called uniform suction of consolidated matter, but that doesn't sound as swell.

1/2 + 1/4 + 1/8 + 1/16 + ... = 1 metre
The total time taken for the journey is the sum of the times for each segment:
1/2 + 1/4 + 1/8 + 1/16 + ... = 1 second
There's no problem with that. The total journey takes only 1 second, even though there are an infinite number of distance intervals to be covered in that time. Do you still need Newton to believe that?

The paradox lay in the elipses for both time and distance... Unless the human mind puts reasonable limits on a formula/paradox of this sort, it never ends. No amount of summing a continuous halving of remaining distance will ever total one; without limits, mathematically the number will ALWAY total as less than one. The sum of fractions will ALWAYS = n-1/n. This holds for endlessly halving time, MATHEMATICALLY. The paradox illustrates where certain mathematical postulates descend one into nonsense.

To put it in more concrete terms, let us say that the twin on Earth dies at time T and the "real" time of the death of the travelling twin is T'. The light from the travelling twin takes time dT to travel from the travelling twin back to
observers on Earth, arriving back on Earth at time T2. To find out the "real" time of death of the travelling twin,observers on earth calculate T2 - dT = T'. What they find is that T' is greater than T. In other words, the travelling twin "really" died later than the Earth twin. The time difference T' - T is due to relativistic time dilation, as opposed to the time dT, which is due to light travel time.

If we remove the signalling of death component, since this concerns ONLY the ability to communicate an event, we are left with the faster twin living in slower time in comparison to the stay at home twin. This comparison presupposes the neutral mind of the physicist theorizer. The neutral abstracted from any framework physicist, can sit down and map out 'snapshots' of locations and times of each twin.
If we remove the clocks from both twins sight, and so remove the physical device that they are trying to read from, what is dialated? Let us also remove any desire for the twins to communicate their positions or their times of death. How is existence slowed down? For the theorizer can sit in front of graph paper and plot positions and time[ lets assume uniform linear motion for the travelling twin.] This is what is at the root of time dialation,as it is expounded; that existence slows down more and more the faster one goes. If the time dialation component is merely an illustration of the limits of communication of location and time, then you have a believer of sorts, right here and now. My understanding, though, is that time dialation is treading on the grounds of a mathematical paradox.
When I preset my dying twin paradox with a 'they will die in one minute' and send them on their merry way, the time dialation generality is that the travelling one will die later. What if I said, instead, 'the twins will die at the same time? There is a paradox for you. Then you would have to pick a point in space for both twins and say, 'Here and here are where the twins were when they died.' Now what happens? If you do not know the preset synchronous nature of the twins dying, you do not necessarily end up with an asychronous solution. A snapshot of the universe at a given moment could reflect two synchronous events. When we stop time in order to analyze events in an abstract way, we are removing not only time, but velocity and their effects and fix coordinates for analysis. When we do so, the calculations of time dialation seem to reside SOLELY with the limitation of communication issues. Please tell me you are not saying, 'Time dialation is real and does not depend on light communication, and here are the results of twin dyings: The relativistic formula shows that the light signal of death proves the twin died later than 60 seconds.' Either the formulas predict actual time dialation or we are being asked to a priori accept that time dialation occurs on faith and the formulas are merely presenting the time delay in communicating this truth. More on this later.
As usual, I will be re-reading the formulas that present this paradox as a factual account of the implications of Relativity...everytime I do it is very unsatisying...


Yep...SR is and has been my focus.

good evening to you...[did everyone else leave this thread?

137

 

[137]

wee update

Howdy anyone who is left,

1. There is still no body of sun deflection of light data, though I continue to search. It seems that the contemporary references point to the sun's deflection of X-rays to prove local[solar] deflection of light by gravity[space-time curvature.] Even in this case, there are references to the 'there are studies that show' made - not data. Meanwhile, the data from solar scientists abound with the turbulence of the corona, magnetic plumes, oxygen and hydrogen atoms 'surfing' on magetic emanantions, the magnetosphere variations involving the sun, plantets, moon and earth, the solar wind, etc. There are quite a bit of EM affecting effects that need to be taken into consideration before unequivocally stating that sun's gravity measurably bends light.

2. I still contend that it is an absolute necessity to test for gravity's affect on light. Does anyone have any feedback on the possibility of the following experiment.
>>> If light could be kept in a gravitational field for an extended length of time, there should be a measurable affect on the path of the light. A ground based evacuated tube [high vacuum] of a certain distance is constructed and stablized. Precision mirrors are set at either end parallel to each other with as little deviation as possible. A laser emits light that is to, initially, bounce pack and forth perpendicular to the mirrors. The light is then, theoretically, subjected to the earth's gravity for an extended period of time. Eventually, the light's path should degrade from the perpendicular in a measurable amount.
Depending upon the precision of the equipment, the experimenters accounting for errors, and the experiment conducted exhaustively, this should put to rest the question of whether light is affected by gravity. The desire to test the theory is valid. If anyone objects, or says we do not need to test this, then they are not scientists nor interested in what science, physics inparticular, is supposed to be about.
a] Are there any flaws in the idea behind this experiment?
b] Does anyone want to venture the calculations using Earth's gravity as to how much distance/time a light beam needs to remain 'active'[bouncing back and forth] in the tube for gravity's effects to be measured?
c] Has this experiment been performed?
d] In the event that the thought is 'the earth's gravity is too small [though this is the point of the experiment's keeping and controlling a light beam bouncing back-n-forth] then there should still be a calculatable amount of affect that a given amount of gravity[space-time curvature] has on light.

3. Another version of the twin paradox.
>>>Two twins. One goes off at near the speed of light and returns. When he returns who is older? By relativity's own standards it does not matter who is the 'go-er.' Each framework can be equally referred to as the one who is moving off near the speed of light. So the relativity answer should be, either one of them could be the older one. And herein is the contradiction that cannot be glossed over. The only reconciliation is that, as the wisest of relativity proponents state, we are talking ONLY of measurements, nothing more. The formulas use light speed as the speed limit of communicating events, not the passage of real time. By the necessity of mathematics, as the speed approches the speed of light, the answer moves closer and closer to zero, but this zero is a mathematical paradox, whose resolution is in its application towards the fastest known communication device, light, not in its application to existence or actual dimensions.

As usual...more later, after the tirade of responses.
137

 

[Prosoothus]

137,

The experiment with the two mirrors sounds very interesting.

It appears that the only problem would be calibrating the mirrors, and making sure that there aren't any imperfections in the mirrors.

Tom

 

[(Q)]

Each framework can be equally referred to as the one who is moving off near the speed of light. So the relativity answer should be, either one of them could be the older one. And herein is the contradiction that cannot be glossed over.

It is true that one or the other can appear to be moving off near the speed of light since no absolute frame of reference exists. However, the one that moves off near the speed of light is bathed in a pseudo-universal-gravitational field due to acceleration relative to the rest of the universe. The 'go-er' must also decelerate, turn around and accelerate back to the Earth. According to GR, clocks tick slower in a gravity well, which is what the 'go-er' experiences during his trip. He will therefore age more than the twin on Earth.

No contradictions to gloss over.

 

[Prosoothus]

137,

On second thought, the device with the two mirrors would not work.

To measure the earths gravity using this device, the light would have to bounce off the mirrors at least a million times. If there is even the smallest imperfection in the mirrors, the imperfections would cause errors that would be amplified during every "bounce". The cumulative errors would be to great to measure the gravity accurately.

Tom

 

[Prosoothus]

Q,

It is true that one or the other can appear to be moving off near the speed of light since no absolute frame of reference exists. However, the one that moves off near the speed of light is bathed in a pseudo-universal-gravitational field due to acceleration relative to the rest of the universe. The 'go-er' must also decelerate, turn around and accelerate back to the Earth. According to GR, clocks tick slower in a gravity well, which is what the 'go-er' experiences during his trip. He will therefore age more than the twin on Earth

How do we know what the acceleration of the rest of the universe is? The observer moving at close to c may actually be at rest, while the universe is moving away at close to c.

Where is the gravity well in this case?? Does the universe create a gravity well or does the observer create it? In other words, does time slow down for the observer or for the universe??

Tom

 

[(Q)]

How do we know what the acceleration of the rest of the universe is?

Relative to what ?

The observer moving at close to c may actually be at rest, while the universe is moving away at close to c.

The moving observer IS at rest inside the ship and cannot tell he is moving or the universe is moving.

Where is the gravity well in this case??

Inside the ship as it accelerates away from the Earth. Remember GR ? You cannot distinguish acceleration from a gravitational field.

Does the universe create a gravity well or does the observer create it?

The ship creates a pseudo-gravitational field relative to the rest of the universe as it accelerates, decelerates, turns around and accelerates back to the Earth.

In other words, does time slow down for the observer or for the universe??

Time slows down for the moving observer at rest in the accelerating ship.

 

[137]

The parameters

Hi Q,

However, the one that moves off near the speed of light is bathed in a pseudo-universal-gravitational field due to acceleration relative to the rest of the universe. The 'go-er' must also decelerate, turn around and accelerate back to the Earth. According to GR, clocks tick slower in a gravity well, which is what the 'go-er' experiences during his trip. He will therefore age more than the twin on Earth.

a]Who ever said the twin Must be on earth? What happens to your solution if the 'rest' twin is taking a psuedo-universal-gravitational bath at rest with respect to the earth[the earth merely being a convenient observable body by rest twin] but is not on earth, or is in null gravity[floating in space?][Or if floating, I guess it should be NOT taking a bath!]
b]Einstein did not consider the acceleration/deceleration to matter in his writings on SR.
c] SR is the home of the Twin paradox. Are you saying the SR is incorrect for the Twin Paradox[and by extension the clock slowing and rod shortening] and can only be corrected by the GR?:bugeye:

Hi Prosoothus

To measure the earths gravity using this device, the light would have to bounce off the mirrors at least a million times. If there is even the smallest imperfection in the mirrors, the imperfections would cause errors that would be amplified during every "bounce". The cumulative errors would be to great to measure the gravity accurately.

Did you calculate the number of times [just curious] or did you guestimate. I hope to see the actual calculation, with an assumption of a perfect setup. Given modern technology and computational power, my assumption is that a device could be built. If there is a standard and repeated error, it would be possible to calculate for this to see if statistically there is still a non-calibration error tendency for the light to descend due to gravity. I know that there may be insurmountable issues of degradation of signal, funding issues, standardization of testing, etc. I wonder what the device makers would say about these issues? The fact that we are hurling subatomic particles and tracking the impact trajectories and resultant targets, and sub-targets, would lead me to believe that it is within the realm of possiblility. Unless of course, as with many modern measurings, we are dealing more with simulations and projections to interpret data. This would mean a danger of too much reliance on pre-conceived outcome-based computer models.

Q,

You cannot distinguish acceleration from a gravitational field.

Gravitational vectors for a planet or star would converge towards a center point. Gravity vectors of Psuedo-gravity created by acceleration would be parallel. This is how one would be able to tell the difference. Pendulum tests to determine, perhps?

***Only by nature of the formulas, that set up a proportion with light speed as its top limit do we end up with calculations of time slowing and rods shortening. The atomic clocks on planes and GPS show a slowing of decay rates, but I am still not seeing conclusive proof that this is due to either of the relativity's calculations. This is a legitimate question: Do the computers on board planes, supersonic or otherwise, or satellites, or computers also slow down? The root cause should be investigated, as opposed to just saying SR & GR did it. As stated in a previous post, a NASA site that discusses GPS states that 'the affects of relativity are negligible.' I am curious if batteries, electricity, CMOS gates, etc., all slow down? If so, is the slowing rate consistent? What is the pattern and how close to the predictions of relativity does this pattern come? A cascading circuit consisting of an electronic clock, triggered by an electronic clock could be strung together. Given x number of clocks, there should be an ever increasing delay that is caused. I would be interested in seeing the data dump of the parameters and results of an experiment such as this, too! Anyone have any links to studies on the affect on electronic circuitry in orbit/space?

On yet another thought toss out; lets say that Einstein was born in the time of the Neaderthal. He was the younger brother of Lorentz. As a Child Einstein imagined running as fast as a wave along the river he lived by. Aha, for the wave to continue being a wave, it must not be affected by my speed. A wave will always measure the same speed no matter what speed I go. He quickly used his older brothers tree vine wave formula and plugged in the measured top speed of water wave [established and studied by cro-magnons, Maxwell, Fizeau, Fresnel, Michelson, Morley,etc...] and low and behold, if you calculated what happens the closer someone moves to the speed of the wave, the shorter it becomes!! The forula proves this!!! And if someone took a reed boat and paddled close to the speed of the wave and returned, 'Zounds, ' he is younger than the river bank twin!!!
>>>If you replace the speed of light with any other top speed, what happes? What happens if we take a faster than light speed particle and use this top speed, instead of light? The reason why this does not make logical sense to do so, is because we are talking strictly about the ability to communicate information.

regards,
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[(Q)]

Who ever said the twin Must be on earth? What happens to your solution if the 'rest' twin is taking a psuedo-universal-gravitational bath at rest with respect to the earth[the earth merely being a convenient observable body by rest twin] but is not on earth, or is in null gravity[floating in space?]

No problem. But I think you're misunderstanding. The 'stationary' twin can be on Earth or floating in space, it doesn't really matter. It is the twin that is accelerating away in his ship who is at rest in a gravity well.

Einstein did not consider the acceleration/deceleration to matter in his writings on SR.

He didn't need to consider it, SR shows there is no paradox. What I've stated is that GR can also show there is no paradox.

SR is the home of the Twin paradox.

No. The Twin Paradox was contrived by those who did not understand SR.

Are you saying the SR is incorrect for the Twin Paradox[and by extension the clock slowing and rod shortening] and can only be corrected by the GR?

Both SR and GR can easily show there is no paradox.

 

[Prosoothus]

Q,

I think you misunderstood my question.

If an observer travels faster, relativists will claim that time slows down. However if the speed of the observer decreases, they say that time would speed up again.

The question is how can relativists say that something speeds up or slows down, when they claim that there is no obsolute frame of reference? In other words, what do you compare the observers speed to.

Example: If the observer speeds up while the universe is at rest the time will slow down for the observer compared to the universe. However, if the universe is travelling close to c with the observer, and the observer speeds up relative to the universe(in reality he slows down), won't the observer's clock run faster than the clock moving with the universe???

Tom