Twin Paradox: Definitive Proof That It's SR?

[Tensor]

Say, by the way, do you know the physical classical reason why a bottle rocket goes higher with compressed air and water than with just compressed air alone?

Well, if the paper around the bottle rocker were burning, thats heat so it's lighter than the air. So, it rises faster. Yeah, that's why a bottle rocket goes up. Of couse Newton thought that heat rise's faster if it curves around the earth, cause of stuff near the earth that cause it to go up faster. Here's the equation Stuff = up faster. I don't know much math so I'll do it this way.

Laser Jock,
Well, since you couldn't answer my question, I thought maybe someone else could.

Hey, he's answered 4 or 5 times already. Why don't you make up your own answer, or ask Sean (sorry Sean) to answer it, or search for his earlier answers. He's busy

[SeanF]

=D> Tensor

Now, do you see how the water bottle rocket proves that Einstein made a mistake in his 1905 paper? He had to reveal the correction stealthily, though, which is why he put it in a bottle and rocketed it into the atmosphere.

[Sam5]

As to your question about why a bottle rocket might move higher with a "fuel" mixture with water and air rather than air alone, it might be because, assuming the water is just turning to steam, that the water generates more energy on expanding. It is after all heavier than the oxygen and nitrogen in air, and will thus have more momentum on exiting the nozzle, assuming it reaches the same temperature as the air does. It takes more energy to heat it, but without knowing what was doing the heating -- black powder? -- it's hard to tell. The phenomenon is similar to when you spit out water from your mouth -- a mouthful of air is lighter and has much less momentum than a mouthful of water moving at the same speed. But someone tell me if this explanation is wildly of base (I don't think it is).

Unlike what Herr Gehrcke did to me, I will not laugh at your response.

OUCH! That plastic bottle is so hot at the nozzle!!!!

[Sam5]

=D> Tensor

Now, do you see how the water bottle rocket proves that Einstein made a mistake in his 1905 paper? He had to reveal the correction stealthily, though, which is why he put it in a bottle and rocketed it into the atmosphere.

So you don’t know either, huh? =D>

Do you think if I pump up the air enough, I can turn all the water into steam, or would that melt the bottle? What would CM say about this?

[Sam5]

Emspak,


No hot stuff is used. It’s just compressed air inside a 1 liter bottle with some water in it. The bottle doesn’t go very far with just compressed air alone. It goes farther with some water in it. It’s related to mass and inertial in some way. In what way?

This is a big fad “science fair” project at some 4th – 6th grade schools today.

[SeanF]

Unlike what Herr Gehrcke did to me, I will not laugh at your response.

You think you're going to claim the high ground now by not laughing at someone? Go back through this thread and see how many times "lol" shows up in your posts.

=D> Tensor

Now, do you see how the water bottle rocket proves that Einstein made a mistake in his 1905 paper? He had to reveal the correction stealthily, though, which is why he put it in a bottle and rocketed it into the atmosphere.

So you don’t know either, huh? =D>

I don't feel the need to know everything, Sam5. I do know that the reason a water bottle rocket goes farther with some water in it than with just air (but also farther than with lots of water and little air) has nothing to do with the "twin paradox" in SR, though.

And I know that the reason you're talking about the water bottle rockets is because you're desperate to feel smarter than us about something.

[Sam5]

You think you're going to claim the high ground now by not laughing at someone? Go back through this thread and see how many times "lol" shows up in your posts.

I'm sorry. I thought we were supposed to be having fun.

[Emspak]

To continue with the water bottle dsicussin - I thought Sam5 meant a bottle rocket like the fireworks we played with as kids. But the point is still the same. A given volume of water is heavier, so if I put, say X pounds of pressure behind it it will smack into something a lot harder than air will.

Remember also, in a bottle, say, that holds 1 liter, that's only about -- what, a milligram? Less? of air even under pressure. Water weighs 1 kg at that volume.

Nothing to do with the SR discussion, tho.

[alexh110]

SR applies only to inertial frames, and hence it CANNOT be used here at all.

This site would tend to disagree, and so would I.
Can Special Relativity handle accelerations?

It's true that SR can be used to make approximate calculations of the time dilation effect in this case, by doing an infinite series of Lorentz transforms on the time coordinate. GR would give you a more accurate result, since it also allows for the effects of gravity wells.

The problem is that conceptually the Twin Paradox does not make sense within the framework of SR. That's why it's a paradox in the first place!

It is the nature of acceleration in SR which causes the problem, because how do you know which of the twins is accelerating and which is in an inertial frame?

GR resolves this by giving you a universal reference from which to measure acceleration.

[Sam5]

To continue with the water bottle dsicussin - I thought Sam5 meant a bottle rocket like the fireworks we played with as kids. But the point is still the same. A given volume of water is heavier, so if I put, say X pounds of pressure behind it it will smack into something a lot harder than air will.

Hi. Yes, that’s basically correct. But there is an even more fundamental and simple explanation based on mass and inertia. Like which has more mass when the water is in the bottle, and which has more mass when just the air is in the bottle, figuring we have three items, the bottle, the air, and the water. What happens when the air goes out and what happens when the water goes out.

Evidently I bore some people with these most fundamental explanations, but I love them. 19th Century and earlier physics books are filled with them. Like with Galileo’s weights and the Pizza story, and his rolling the round spheres down inclined planes. What a brilliant way to slow down the weights so he could see what was happening to them. They moved so fast when he dropped them, but he figured out that he could roll them down an inclined plane and literally slow down the speed of the acceleration of the gravity pulling on them.

Actually, I think the bottle rocket thing can teach us a good lesson in relativity, since I think it is important for everyone to understand what is fundamentally going on in relativity. Too many people don’t know. They have not a clue. They just know the jargon, but they don’t actually know what’s going on. That's why so many different people use a different technique to solve the twins paradox mystery. They just don't know what's going on with that thought experiment. Like the people who don’t think light slows down when it passes the sun. They just don’t get it.

[Sam5]

The problem is that conceptually the Twin Paradox does not make sense within the framework of SR. That's why it's a paradox in the first place!

It is the nature of acceleration in SR which causes the problem, because how do you know which of the twins is accelerating and which is in an inertial frame?

GR resolves this by giving you a universal reference from which to measure acceleration.

That’s exactly right. He left out acceleration in SR, and, in the first half of the paper, that turned out to be a mistake. It wasn’t so bad in the second half, since he tended to be using the Lorentz force and the Lorentz ether theory in the second half. But in the first half he had no "force" applied to any of the clocks to cause them to slow down. What he added to the theory in 1918 was the gravitational field to the k frame, and that added the "force" that was missing in 1905.

[daver]

The problem is that conceptually the Twin Paradox does not make sense within the framework of SR. That's why it's a paradox in the first place!

The twin problem can be handled in SR; it is an apparent paradox, not a real paradox. The problem can be reformulated so that there is no acceleration to mess things up.

It is the nature of acceleration in SR which causes the problem, because how do you know which of the twins is accelerating and which is in an inertial frame?

The problem is that there are three inertial frames involved in the twin problem.

[Sam5]

The problem is that conceptually the Twin Paradox does not make sense within the framework of SR. That's why it's a paradox in the first place!

The twin problem can be handled in SR; it is an apparent paradox, not a real paradox. The problem can be reformulated so that there is no acceleration to mess things up.

It is the nature of acceleration in SR which causes the problem, because how do you know which of the twins is accelerating and which is in an inertial frame?

The problem is that there are three inertial frames involved in the twin problem.

In the first of his “peculiar consequence” thought experiments, there are only two inertial frames, and the motion is a relative “v”. That’s the origin of the clock paradox.

[SeanF]

In the first of his “peculiar consequence” thought experiments, there are only two inertial frames, and the motion is a relative “v”. That’s the origin of the clock paradox.

There are only two inertial frames in the original "peculiar consequence" thought experiment, but there is a clear lack of reciprocity. The "Clock at A" is specifically identified as changing inertial frames. That's why there's no paradox.

[milli360]

Milli,

Say, by the way, do you know the physical classical reason why a bottle rocket goes higher with compressed air and water than with just compressed air alone?

We talked about it over on the Space and Mystery Board, remember?

[Tensor]

=D> Tensor

Now, do you see how the water bottle rocket proves that Einstein made a mistake in his 1905 paper? He had to reveal the correction stealthily, though, which is why he put it in a bottle and rocketed it into the atmosphere.

=D> Sean. What's scary is that almost made sense.

[SeanF]

Sam5, in this post in another thread, you said:

But the general myth in American schools today is that only “Einstein’s relativity, gravity, and acceleration” can change clock rates.

Can you clarify what you mean by "only" in this sentence, please?

[Laser Jock]

Sam5, in this post in another thread, you said:

But the general myth in American schools today is that only “Einstein’s relativity, gravity, and acceleration” can change clock rates.

Can you clarify what you mean by "only" in this sentence, please?

In the same post he says:

You can find the subject of clock slowdowns due to acceleration and gravitational fields in classical physics books of the 19th Century and earlier.

I take that to mean that the observed changes in atomic clock tick rates for clocks in different gravitational potentials can somehow be explained classically. Don't ask me how though.

[SeanF]

What I'm wondering is exactly what he's accusing the schools of teaching:

A) "Relativity" can cause clock changes all by itself.

B) "Relativity" is the only thing that can cause clock changes.

[Jobe]

C) Water bottle rockets that 12 year olds build can cause clock changes

[Kaptain K]

C) Water bottle rockets that 12 year olds build can cause clock changes

[John Cameron Swayse voice] It takes a licking, but keeps on ticking (only slower). [/John Cameron Swayse voice]

[Sam5]

C) Water bottle rockets that 12 year olds build can cause clock changes

[John Cameron Swayse voice] It takes a licking, but keeps on ticking (only slower). [/John Cameron Swayse voice]

LOL! These kids won't know what you are talking about.

[Jobe]

C) Water bottle rockets that 12 year olds build can cause clock changes

[John Cameron Swayse voice] It takes a licking, but keeps on ticking (only slower). [/John Cameron Swayse voice]

LOL! These kids won't know what you are talking about.

Well, since your impressive physics resume entails talking to physicists and explaining physics problems aimed at 12 year olds in your quintessential self proclaimed 'classicist' terms, perhaps you could explain. #-o

[SeanF]

[John Cameron Swayse voice] It takes a licking, but keeps on ticking (only slower). [/John Cameron Swayse voice]

LOL! These kids won't know what you are talking about.

Well, since your impressive physics resume entails talking to physicists and explaining physics problems aimed at 12 year olds in your quintessential self proclaimed 'classicist' terms, perhaps you could explain. #-o

I'm thinking about taking bets on how long Sam5 will ignore this question before he starts claiming to have answered it "a long time ago."

How about it, Sam5?

[Grey]

Welcome back, Grey!

Thanks! As you can see, I'll still be participating in the discussion only occasionally, but I'll try to throw some thoughts in now and again.

I don't think I understand your response here. All I'm saying is that if two observers who are moving differently make measurements of the electric and magnetic fields, they'll get different answers. However, because of the way the mathematics describing electrodynamic interactions work, they will make precisely the same predictions about how the particles move, and those predictions will be borne out by experiment. Do you disagree with that statement?

I already know that if a student moves close to an open flame, he will feel warmer, but his motion away from the open flame doesn’t make the open flame disappear from the room.

For your statement to have any relevance to the discussion, I'd have to agree with your unspoken assertion that an electric or magnetic field is like a flame, and I don't.

It's tempting to consider an electric field to be some thing that fills space; I do it too when working with classical electrodynamics. But let's take a step back and remember what it really "is". This is pretty basic, so please don't take offense, but you seem to have forgotten some of it. Electric charges exert forces on each other, proportional to the strength of the charges. So, if I have some distribution of charge, and I put a test charge nearby, it will experience some force. But that force is proportional to the charge of my test object itself, and I'm usually concerned with just the effects of the charge distribution I'm interested in, so I divide the force experienced by the test object by its own charge, and that gives me the strength and direction of the electric field and that point in space (and time, if it's not a static charge distribution).

Let me make this clear: the electric field isn't really some "thing", it's a mathematical construct for us to describe how a charge distribution will influence other electric charges. Similarly, the magentic field is just a description of how a moving charge distribution (an electric current) will affect other charges. So, there's nothing particularly wrong with these fields "appearing" or "disappearing", since all that's changing is our way of looking at the situation. What's actually there (that is, the actual events involving the electric charges themselves) doesn't change.

Remember, if we wanted to describe the situation using the most precise model we currently know about, we'd have to dispense with Maxwell's laws entirely, and use quantum electrodynamics. I expect the calculations for a macroscopic Faraday-type experiment would be fiendishly difficult, probably beyond our computational capability at this point, but it's still possible in principle. In that case, there aren't any fields at all, just charged particles interacting through the exchange of virtual photons, along with other exchange particles. It's not necessary to believe in fields at all to accurately describe what happens in an electrical or magnetic interaction, but even if you use them in your description, that doesn't necessarily make them "real" in the same sense as the charged particles.

Of course, once we start dealing with quantum mechanics, we may start questioning just how "real" the particles are, but we can leave that for another discussion.

We're in deep space, and the magnet and coil are moving relative to each other. We're curious about what the strength of the magnetic and electric fields are, so we'll set up some detectors. One of them is stationary with respect to the coil. In that case, the magnet is moving, and so we detect a changing magnetic field. The other one is instead stationary with respect to the magnet, and so it reads a constant magnetic field. Which one of them is right? My claim is that there's no way to determine, and that therefore either can be seen as equally correct. If you tell me that I should be measuring with respect to the coil, and ignoring the reading with respect to the magnet, why is that the case?

Well, of course. That’s classical electrodynamics. Both students are right about the magnetic field.

Exactly! You've got it! Whether the magnetic field is constant or changing depends on how you're moving relative to the object generating the field.

The problem is not with the “magnetic field” but with the “disappearing electric field”. If it is present at the magnet if you are moving a certain way, it does not “disappear” at the magnet if you move a different way.

Well, you had it for a moment. So why is it alright for the magnetic field to be different depending on how the students are moving, but not the electric field? Remember, there's nothing particularly special about the difference between a zero and a nonzero field. The former just means that the electric charge distribution is such that a charge placed there would feel no net force, not that there are no electrical effects at all on such a charge.*

...I had, for many years, worked in an industry in which we had two very important pieces of equipment that we needed to constantly keep “synchronous” and “synchronized”, and those two pieces of equipment were in fact two completely separate “inertial frames” that often moved “relatively”. In those days (mainly in the 1960s and ‘70s) we did not have any good computer clock or motor speed controls or crystal speed controls or any way to link the two machines together, all the time, when we used them in battery-operated portable conditions. I, and many other people in my industry at that time, had plenty of problems trying to keep the two “clocks” (one in each “frame”) perfectly synchronized.

During my first few years in the business I learned that the main cause of our two-system clock de-synchronization problem was due to various “inertial” forces being placed on one, or the other, or both of the “clocks”, especially when they were moved in certain ways, and that (the “inertial forces”) caused their rates to drift apart and, thus, the two separate machines became non-synchronous. Also, there were two other occasional reasons for the lack of synchronism: low voltage going to one or both of the “clocks”, and uneven “friction” on the bearings of one or both of the “clocks”.

I also learned that just “relative motion” alone could not possibly slow down either clock, and could not make the two of them “non-synchronous”.

Although this is all interesting, I hope that you realize that unless you were moving the clocks around at an appreciable fraction of the speed of light, the effects you were noticing had nothing whatsoever to do with the validity or lack thereof of special relativity. The mechanical effects of jarring clocks as you move them simply is not relevant to a discussion of relativity. If you were moving the clocks that fast, please tell me the name of the company so I can invest in their stock, since they are obviously more technically advanced than they've let on.

The “constancy of the speed of light” postulate in the 1905 paper is flawed

Thank you very much for responding directly to my question about this. Would you care then to cite some experimental evidence, showing the measurement of the speed of light in a vacuum as something other than the accepted value of c? Remember, no using experiments involving gravitational fields or cosmological distances, since we already know that we need general relativity to handle such situations, so any such measurements would not be testsof the validity of special relativity.

In SR theory, Einstein mentioned only “v” and a clock “slowdown” whether or not “v” is positive or negative. If H-K noticed any “SR kinematical effect”, their clocks would have slowed down the same amount in both directions of travel, since the “relative motion” would have been –v and +v relative only to the “surface of the earth”, and Einstein said in 1905 that both directions of relative motion would slow down a clock. He never said that +v would slow down a clock while –v would speed it up. That is another flaw in the 1905 theory.

I'm afraid that's not correct. Observers will see a clock moving relative to them to slow down, provided that they are in an inertial reference frame. But the surface of the Earth is not an inertial reference frame, it's accelerating toward the center as it rotates. So the calculation ends up being a bit more complex. Also, I'm a bit perplexed. You'd said:

I hear people say all the time that “the traveling twin ages more slowly”, but can you actually show me a traveling twin that aged more slowly? All of Hafele’s flying atomic clocks ticked more rapidly, when their final readouts were compared to earth-based clocks that did not travel.

But in fact the eastward moving clock did tick more slowly, and by exactly the amount predicted (within experimental error, of course), after taking into account both special and general relativistic effects.

* Of course, it's highly unlikely that there are actually any places that really have such a precise balance of electric forces, given a universe filled with an inhomogeneous distribution of charged particles, but certainly it's common enough for the net field to be small enough to be neglible in many cases, depending on exactly what sort of experiment we might be performing.

[Sam5]

I'm thinking about taking bets....

[-X

[Sam5]

C) Water bottle rockets that 12 year olds build can cause clock changes

[John Cameron Swayse voice] It takes a licking, but keeps on ticking (only slower). [/John Cameron Swayse voice]

LOL! These kids won't know what you are talking about.

Well, since your impressive physics resume entails talking to physicists and explaining physics problems aimed at 12 year olds in your quintessential self proclaimed 'classicist' terms, perhaps you could explain. #-o

John Cameron Swayze was an early TV news anchor for (I think) NBC news, in the early 1950s, and his sponsor was Timex watches. The slogan, which he spoke on every newscast was, “Timex, it takes a licking [a beating] but it keeps on ticking”.

So that was a funny “catch phrase” of the 1950s.

[SeanF]

I'm thinking about taking bets....

[-X

And yet you still don't answer the question . . .

[Sam5]

Let me make this clear: the electric field isn't really some "thing"...

Tell that to the coil and the magnet.

As far as the magnet and the coil are concerned the changing magnetic field is a thing, a thing called a “force field”, and if the students don’t carry with them enough of their own magnetic field or electrical field, then their motion relative to the magnet and the coil isn’t going to make any electric field at the coil “disappear” from the room, not any more than the moving student in Sumatra will. It is a fundamental error in the Kinematical part of SR theory that makes some people think that just “relative motion” alone can make certain “things” disappear from far off places and can make clocks change their rates without any “force” being placed on the oscillating mechanism of the clock.

Remember, if we wanted to describe the situation using the most precise model we currently know about, we'd have to dispense with Maxwell's laws entirely...

No, that’s a mistake, and that’s part of today’s problem in science classes in our public schools. The schools have replaced “action at a distance” with “spooky action at a distance” and I don’t believe in spooks in physics.

Of course, once we start dealing with quantum mechanics, we may start questioning just how "real" the particles are, but we can leave that for another discussion.

A few months ago I read a news article on a message board that said a modern philosopher, using quantum mechanics principles, gives us only a 50-50 chance of actually being here. So I suppose that maybe either you or I don’t really exist, under the new rules of “science” that are being taught in school today.

Whether the magnetic field is constant or changing depends on how you're moving relative to the object generating the field.

No, we still disagree about this. What the two students measure at their location has nothing at all to do with what the magnet and the coil measure at their location.

So why is it alright for the magnetic field to be different depending on how the students are moving, but not the electric field?

The magnetic field at the students can be “different” or measured as being of different value for each student, but the field at the student has nothing to do with the field at the coil. In other words, I suppose that in your way of thinking, you must always consider the coil to be one of the “students”. So, if it has an electric field at it (and at the magnet) when the coil moves relative to the magnet and a current is flowing through the coil, then it will have an electric field at it (and at the magnet) when the magnet moves relative to the coil. Just forget about all the other students. “Observers” don’t have anything to do with what goes on at the coil and the magnet.

Although this is all interesting, I hope that you realize that unless you were moving the clocks around at an appreciable fraction of the speed of light, the effects you were noticing had nothing whatsoever to do with the validity or lack thereof of special relativity.

No clock rate ever changes due to “relative motion”. Einstein realized that by 1918 and he added the gravitational field to the k frame in the SR theory. Just because the vast majority of physics professors don’t know that fact of life, that fact of physics, and that fact of history, matters naught.

If you were moving the clocks that fast, please tell me the name of the company so I can invest in their stock, since they are obviously more technically advanced than they've let on.

Well, uhh, the problem is... all these companies are existing inside superluminal galaxies, and there is no way for you to contact them. They can call you, but you can’t call them.

Would you care then to cite some experimental evidence, showing the measurement of the speed of light in a vacuum as something other than the accepted value of c? Remember, no using experiments involving gravitational fields or cosmological distances, since we already know that we need general relativity to handle such situations, so any such measurements would not be testsof the validity of special relativity.

Well sure, see the Davis Lineweaver paper or the Ned Wright website. The Vtot speed of a photon relative to the earth, coming from a superluminal galaxy is believed to be less than c while it is traveling in the vacuum of space in between the superluminal galaxy and the earth.

The thing is, Einstein discovered in 1911 that the speed of light is not “constant” in all parts of the space thorugh which it travels. That’s why he said in his 1916 book:

“A curvature of rays of light can only take place when the velocity of propagation of light varies with position.”

Don’t you believe in that? I do.

But in fact the eastward moving clock did tick more slowly, and by exactly the amount predicted (within experimental error, of course), after taking into account both special and general relativistic effects.

SR theory predicts a total time slowdown, with either -v or + v, either Westbound or Eastbound. The total time observed on all the flying clocks totaled an overall gain, not a loss.

The Eastbound clock ticked an average of - 59 nanoseconds more slowly over 41.2 hours, while the Westbound clocks ticked an average of + 273 more rapidly over 48.6 hours, due to the Lorentz Effect of the Lorentz electrodynamic theory, not due to Einstein SR theory. Einstein 1905 SR theory predicted an overall "lagging behind" in both directions of travel.

[Sam5]

And yet....

What question are you talking about? Look, son, I don’t have time to devote all my time to you, so stop bothering me. I’m talking to other people on this message board and on the internet. They usually ask me to answer a question only once, but you ask me to answer the same question 50 times, so I just give up after I answer the same question 5 to 10 times for you. So stop bothering me. Go troll someone else. Go talk about Bob and Ann with CM.