to carry out a large public experiment of slowing down times; That is, an experiment that will compare two clocks - one on the International Space Station and the other on Earth.
March 14 is Einstein's birthday and also the National Science Day.
As you know from the theory of relativity, time passes at different rates in different gravitational potentials and at different speeds. That is, time will pass faster in space than down here on Earth. But a clock on top of a very fast moving rocket will appear to yield more slowly than a clock at rest. This effect is known as "time dilation" and Albert Einstein predicted it in the theory of special and general relativity almost a hundred years ago.
The lengthening of times since then has been proven in experiments and the GPS systems have to compensate for any time mismatch between the satellites of the global positioning system and the receivers on the ground.
Although the lengthening of time is considered a known physical result, consider the so-called festival IdeaFestifal To be held in September 2011, along with Discovery Channel
Let it be an original and exciting idea to carry out a large public experiment of slowing down times; That is, an experiment that will compare two clocks - one on the International Space Station and the other on Earth.
The focus of the experiment is the non-profit space organization known as "Kentucky Space", which will have access to the International Space Station. http://www.kentuckyspace.com/
The organization is planning a unique time extension event that will give people the opportunity to experience Einstein's great idea. We know the physics but we don't know the feeling yet, and that's exactly the idea. Therefore the lengthening of time should be a matter of experience.
Experiments have been carried out since the Haifley-Keating flights in 1971 - when four atomic cesium clocks were flown on regular jet flights around the world - and they all confirmed the time-dilation effect, depending on the speed of the flight.
But instead of simply proving in another such experiment the phenomena of special and general relativity and demonstrating again the properties of space and time, Kentucky Spice wants to create a connection of love between the public and space, between the physics behind the universe and our experiences.
The device that will measure time and will be used by Kentucky together with its partner called "Nano Rax" will be a device that combines a rubidium atomic clock with a modulus unit called CubeLab, which is manufactured by the company. http://www.nanoracksllc.com/
The two companies will take care of building the experimental interface and the data handling systems, integrating everything in the payload so that the clock that will be placed on the space station will be suitable for the flight to it and will work in harmony with the "Nanorocks" system.
A clock identical to the one that will fly on the space station will be maintained at the Space Center at Morehead State University. http://www2.moreheadstate.edu/ssc/
The predicted time of the clock in orbit will be displayed - but measuring the time of the clock on the space station in orbit will be prohibited. For comparison this measurement of the clock's predicted time in orbit will be displayed next to the clock's time reading at the center of space. Then, as the Discovery Channel writes, people will look and look... and the screen will show that the clock on the space station lags behind the clock on Earth. While accelerating relative to the clock on the ground and still experiencing less gravity, the clock aboard the space station will begin to slow down relative to the clock on the ground.
While the final decision regarding the duration of the watch's stay in the space station has not yet been made, there is no reason why the watch in orbit should not remain in the station for an extended period of time before returning to Israel for the final inspection and until the practical time difference is verified.
And here you are called for help as you are the inhabitants of the world and invite you to tweet on Twitter or enter Facebook and help make the effect of time dilation accessible to the world.
http://www.facebook.com/pages/Kentucky-Space/358521859592
68 תגובות
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Gali, what do you think of all of those objections to time dilation
In fact, from what I read and understood (and thanks for the links) we will not measure temperatures lower than that of the CMB even in closed cells, and even more so in Einstein's cars and elevators. So in all practical respects, in certain areas of space, especially in the eternal steppes that extend into the twilight zone between the finite and infinity, the formula in 27 is applicable to space itself.
Let's go back to the relationship. In 55 you say "Cesium and temp clocks agree only in one inertial system - the resting CG of the CMB." If our car is at rest relative to the CMB, the cesium and temp clocks in it will always agree. If we managed to get the car to clock 1 on the road when all the clocks, on the road and in the car, show the exact same time, then in the next clocks on the road the temp clocks in the car and on the road will show the same time, (they always show the same time) and therefore also the cesium clock in the car.
If, as you said in 12, the cameras will see that the cesium clock in the car lags behind the cesium clock on the road, it turns out that the cesium clock on the road is speeding up relative to the temp clock, and this is contrary to relativity and your words at the end of 55 "They don't agree, and it looks like the temperature is dropping too fast." (I interpret this sentence as follows: the cesium clock moves slower than the temp clock).
If I extended, it is because of the need to be clear and precise. Like all of Israel, since the time of the patriarchs, the desire of my soul is Rachel, your little daughter. (Not yours, Adi).
Israel,
What is space itself? The particles in space? Everywhere in space the temperature is different. Also like Earth in space, and it has a different temperature than the sun, which is also in space. The gas in the gas clouds has a temperature that varies over a huge range of values, which depends on its composition, on its location (not exactly close/far from a star, there are many other considerations).
And in short - no.
Michael,
It is an inertial system in which the cosmic background radiation is anisotropic (the same in every direction), that is, one that does not move through the same radiation.
Besides background radiation, doesn't space itself have a temperature that can be measured with a simple Kelvin thermometer? And isn't temperature a continuous function of the time that has passed since the big bang?
Sorry. what is the cmb system
with gratitude
aka
Israel,
When you want to measure the cosmic background radiation temperature, you basically measure this:
http://en.wikipedia.org/wiki/Black_body_radiation
If you don't have the strength to read, the first graph shows everything - it is a radiation spectrum, where the wavelength emitted the most corresponds to the temperature of that "black body". This is how temperature is measured.
I'm not looking for "contradictions". It's very possible that I didn't understand something. Here I am in the room, I'm not measuring any radiation, and the thermometer shows 25 degrees Celsius. A Kelvin thermometer will show about 298K. What is the temperature (approximately) that the same Kelvin thermometer will see now in a shaded chamber in space? And 10 billion years ago?
Israel,
(58) No. The thermometer is not enough. You have to look outside, measure the cosmic background radiation (the electromagnetic radiation is not with you in the car but comes from a long way away), and see from its spectrum what temperature of black body radiation it corresponds to. This is the desired temperature.
(59) "And if the car is at rest, the road clocks will fall behind" after the car clock? No. In the past I have already referred to the bilocality of the events. A clock that is not in front of the car, for him the time on the car's clock, and the time at the point that is in front of it in the car system (which is represented by the CMB temperature at that point because the car's temperature = CMB temperature) is not the same time, because these events are not simultaneous in the road system! There is a distance between them, therefore there is also a time difference between them. It's really not a simple matter that you try to understand on one foot. So here, I have shown you that you are wrong in this case, but it will not be difficult for you, due to a lack of understanding, to find other "contradictions" in a matter so contrary to our intuition.
It also follows that if the road is at rest relative to the CMB system, then the car clocks will lag behind the road clocks, and if the car is at rest, the road clocks will lag behind.
Doesn't this contradict principle of relativity number 1:
The principle of relativity:
"The laws of physics do not change when moving from one inertial frame of reference to another inertial frame of reference. Thus, for example, a person in a sealed train car cannot, through any experiment or physical measurement, determine whether the car is moving at a constant speed or standing at rest."
After all, one can easily, without "looking outside" (53), know the difference between the systems. All you need is a watch and a thermometer.
Israel,
Everything has already been written, I don't know how to explain it better.
Why?
(short enough?)
Israel,
Sorry, for some reason I thought you were confusing concepts and calling the system of the CMB a non-accelerated system and the system of the car moving relative to it at a constant speed an accelerated system.
So let's not include accelerations at all and talk about private relativity only (why did you suddenly decide to introduce accelerations?). Response 52 is too long so I will summarize:
Cesium and Temp clocks agree only in one inertial system - the resting M of the CMB. In all other inertial systems (moving at a constant speed relative to it) they do not agree, and it looks from the content as if the temperature drops too fast.
Adi
If, as you say, "all the first part is true", then the first part includes the sentence: "If we put a "temperature clock" and a cesium clock side by side, and calibrate them to an agreed time in a non-accelerating system, even after a million years a photograph of both will show exactly the same time in both" . (52)
How does this agree with: "During the car's journey, indeed, the "temperature clocks" will be the same inside and outside, but, a cesium clock inside the car will not agree with the "temperature clock" inside the car, and will lag behind it" (53)?
After all, the car is not an accelerated system.
Israel,
The first part is all true. The last part has a problem:
During the car's journey, indeed, the "temperature clocks" will be the same inside and outside, but, a cesium clock inside the car will not agree with the "temperature clock" inside the car, and will lag behind it.
Before you jump and say "Ahhh! So there is a way to distinguish between inertial systems and discover absolute speed contrary to what Einstein said about the principle of relativity!", I remind you that the CMB is not part of the closed system. The principle of relativity means that the laws of physics are the same in every inertial mass. Galileo came up with the first principle of relativity and explained it to his friend as follows: "Imagine that you are in the belly of a ship moving smoothly at a constant speed. No matter what physical experiment you do, you will not be able to discover that you are in motion." Of course, all that passenger has to do is glance out the window at the waves, and he will be proven to be in motion. Likewise in the relativistic case, only that it is electromagnetic waves that surround us (I didn't just give examples of oceans and swimmers 🙂 )
By the way, my analysis in 51 is incorrect, because I referred to temp = time in the twin position, which is of course a mistake, but what is important is the idea - temp and time do not agree.
Thanks Adi. You are helping me a lot, and I'm sorry if I confuse you too much. But it is very important, for the regular and proper operation of the universe, that we reach an agreed solution. Someone must take into account these fateful problems, and what should we do as the only responsible adults in the field? We are always on command.
So he immediately went to work. Like Meir, the twin paradox concerns me less than the problem of the lengthening of time in a non-accelerating system, special relativity.
I claim that "temperature clocks" will always show the same time at a given moment and at a given place in the universe. They do not require any synchronization between them and if we take some of them out of the packaging, they will immediately, without any adjustment, show the exact same time: the time that has passed since the big bang.
Unlike normal clocks, including cesium clocks, temperature clocks are not affected by accelerations. If we put a "temperature clock" and a cesium clock side by side, and calibrate them to an agreed time in a non-accelerating system, even after a million years a photograph of both will show exactly the same time in both. Conversely, if the system is accelerated, the cesium clock will lag behind the "temperature clock", and since the mechanism of life works like a cesium clock, everyone in the same system will age more slowly. This works especially well with twins.
Temperature clocks are the fulfillment of Einstein's vision of clocks in space, because as mentioned two of them will always show the same time at the same point in space. Ordinary clocks, on the other hand, can show different times, but these times are not real, and are only good for the system they are in, and it is possible for two of them to show completely different times at the same point in space at a given moment. To the same extent, if we separate two young carrots and put one of them in the refrigerator, it seems to age more slowly than its brother, and with it all its reference system (the other vegetables in the refrigerator). Despite this, this does not constitute a "paradox of the carrot twins". The time of the vegetables in the refrigerator is simply not correct, and this will be proven to them by any clock that is with them.
So much for my argument. If you agree with him, you will see that a problem arises in response (6).
Because if in this system, which is not accelerated, we add temperature clocks to the normal clocks, then if the temperature clock in the car shows the same time when it passes temperature clock number 1 on the road, it will also show the same time on the other temperature clocks on the road. And if a cesium clock is attached to it, and it also shows the same time as clock 1 on the road, it will see the same time in the car as the temperature clock in the car for the entire trip (a system that is not accelerated), therefore also the same time of all the clocks that the car passes by, temperature and cesium, on the road .
And this is contrary to what is expected according to the theory of relativity, as expressed in response 12 (yours).
Israel,
I understood what was bothering you. Since you didn't set up experimental conditions well, let's examine the twin effect again. You stay and I go out in the spaceship and come back. During my drive, I notice that the temp drops more slowly than I expect, then all of a sudden it drops a lot (when I turn around) and then drops again more slowly than I expect. When I come back she has gone down more than I expected.
And the cameras? What will they see?
ZA when two systems - cars for example - pass by each other and the cameras in both photograph the thermometers in both and the clocks in both. If the photographs show the same temperature in both, what will the clocks show?
Israel (48),
The temperature indicates a unique time in a certain reference system - both will agree on the time in this reference system. This does not mean that the elapsed time for one of them cannot be different from the elapsed time in the aforementioned reference system.
It will help if you stop thinking of time as an absolute value, like temperature, and start thinking of it as a "distance" you travel/gain in another "dimension". Therefore, natural time becomes the "distance" traveled by all those who were in the aforementioned reference system. There is no stopping someone else from traveling a different "distance" in their travels.
Adi (45)
How exactly will they agree on the temperature and not the time if according to the formula a unique temperature gives a unique time?
Meir
If you are a fan of conspiracy theories, go to the site:
http://www.wbabin.net/science/mueller.pdf
And my previous response was addressed to Israel (what will happen?)
You can read about the temperature of the cosmic background radiation all over the link, I saw a reference there at the very beginning. You can read about radiation radiation there in the CMBR dipole anisotropy section, although I admit not much. You can continue on Google with reference frame of the CMB, I'm sure you'll be fine 🙂
I think I answered your question. They will agree on the temperature, and the twin who has flown and returned will say "Wow, what a story, 14 years have passed with me and in a system where there is no movement relative to the CMB, the one where you stay, 50 have passed. It's time for coffee." Just as there is nothing miraculous about the returning swimmer counting more rods than his fellows who drifted in the time stream of the ocean universe.
My previous response is aimed at Meir.
Adi (34)
I looked at the site you referred me to, but I didn't see anything to do with a "preferred inertial system" - M.A. in which there is no motion relative to the cosmic background radiation (whose temperature is measured), or motion at all. Maybe I missed something.
I don't see how you answered my question (33). Let's define exactly what the question is:
In (27) there is a reference to the site with a continuous function for the interdependence of the temperature and the time that has passed since the big bang. At the bottom of the site is a "calculator" with one simple principle:
Input: temperature of the universe at a given point and time.
Output: Time elapsed since the Big Bang at that point and time.
So, if we go back to the twin paradox: how can the twins (after their meeting, when they are together, drinking tea together in space on the same planet) claim that each has its own time, as long as they agree on the same temperature.
Will the twins not agree on the temperature as well?
First, I don't think anyone (at least not me) has directed questions to you.
Second, changing an inertial frame of reference requires, by definition, the changer to feel accelerations (I hope that's clear). What the book (and with all the required modesty I also) claims is that you don't need general relativity (which deals with accelerations) in order to explain the effect, everything can be explained within the tools of special relativity. But you can't claim symmetry in changing reference systems and certainly the book doesn't claim that.
Meir:
Again - your words here also differ from what is stated in the link.
There is also no difference between a GPS satellite and a Boeing or any other body that moves under the influence of gravity, therefore according to you - the clock of a body that falls into a black hole does not slow down because its fall is offset by gravity.
All this is of course in contradiction to the theory of relativity, but I don't think I will be able to convince you.
I don't think anyone ever claimed that twins' clocks wouldn't be the same again if they worked symmetrically.
There are scripts (thought experiments) that describe a twin paradox without acceleration, but even there there is no symmetry between the twins because one of them is actually created in a simulation by two people who pass each other in opposite directions and switch roles.
Even here - although there are no accelerations - there is no symmetry, because it is clear that the twin who changed direction (by switching) notices the Doppler effect immediately after the switch, while the other (the inertial one) notices it only after the light from the twin that changed direction reaches him.
jewel,
One of the two: or the transition from one inertial system to its companion causes the time differences due to the deceleration and acceleration involved in the exchange, and then it is indeed the traveler (and not the Earth) who is exposed to the accelerations associated with the exchange (and this alternative is ruled out on page 28 of the book you recommended)
Or the accelerations are negligible (as the book claims), and the time differences result from the very exchange of reference frames.
But, if the mere change of frame of reference is the determining factor (as the author of the book claims), then symmetry is preserved, because the flying twin is allowed to see itself at rest (ignoring the momentary discomfort of acceleration) while the Earth flies away from it for 25 years, and then changes frame attribution and returning to it. I know that this claim was not addressed by the author of the book, but if so I assume that the questions should be directed to him and not to me.
Michael,
It is clear that the GPS calculations must take into account gravitational differences because a clock on the Earth's surface is subject to the effect of gravity g, while a clock suspended in weightlessness in a free orbit around the Earth is not exposed to it.
Regarding the lifetime of unstable particles - I have no comments. I did not claim that an observer at rest would not measure a relative slowing down of clocks moving relative to him. What I argued was that if two synchronized clocks left one point their clocks would still be found synchronized upon their return (unless they were exposed to accelerations or gravitational fields in such a way that the symmetry was broken.
Israel,
The subject of the preferred frame of reference does not necessarily concern the cosmic background radiation (or Mach's "distant stars"). One of the claims used to invalidate the conclusion of the famous Michelson-Morley experiment is that every massive body (such as the Earth) drags the "ether" with it. Hence, for small bodies that are in motion relative to the Earth, the preferred frame of reference is that of the Earth and the earth dragged along with it. That is, according to this claim, if you are in motion relative to the Earth, you are also moving relative to the site, and therefore the symmetry between you and the Earth is broken in your relative motion. I don't have a link but I guess you'll find a reference to it on the wiki regarding Michelson-Morley (and maybe regarding the Sagank effect)
Also, at the end of Michael's message 23 there is a link to an article by Dr. Tom van der Flandren in which he refers, among other things, to the difference between a relative frame (Einsteinian relativity) and a preferred frame (Lorentzian relativity).
Meir (30):
I have to say that your words are quite puzzling to me.
It doesn't matter at all what Flandern thinks about anything in the world. I brought the link to point out the fact that the GPS calculations (which work) take gravity into account.
I found the claim that gravity has no effect in the plane scenario (and we didn't talk about other scenarios) throughout all of your responses, including in response 24 where you wrote:
"Regarding a clock in a circumferential orbit around the Earth - the radial acceleration and gravity are equal and opposite in direction and therefore offset."
If this were true - it would not be correct to consider the gravity differences in the GPS calculations.
As I said - the twin paradox is not a phenomenon that someone noticed just like that and then decided that an explanation had to be found for it.
This is a paradox predicted by the theory of relativity (which is an explanation) and only then were all kinds of experiments invented to illustrate it.
Of course, after it was predicted and understood by the theory of relativity, it was easy to use it to understand how it is that unstable particles created in collisions of cosmic radiation with the atmosphere manage to cross it all before disintegrating, even though it is known that the time they spent there is longer than their lifetime.
These particles fly fast and their time passes more slowly (for us) - something that allows them to cross the entire atmosphere while for them they live the normal amount of time and only the atmosphere has contracted.
Meir, sorry, you're missing the point. My analogy is not perfect and does not come to replace the theory of relativity. I illustrate to you with mileage what happens over time, which is a "preferred" coordinate in 4-dimensional Minkowski space. I have already told you that there is no symmetry between the one who stayed on Earth and the one who traveled and returned - the one who traveled and returned changed inertial systems. The one that remains in the DHA remains in one inertial system. Therefore, the one who traveled and returned, accumulated "more mileage" - less time.
jewel,
According to the theory of relativity, the fact that your mileage shows a difference, does not mean that you have driven. You can with the same degree of justice consider the other driver (whose car is standing on the earth with the handbrake raised) as traveling along with the entire earth and thereby turning the wheels of your stationary car, from which the odometer cable in your car is turned.
Therefore, in any case that you find yourself moving at a constant speed relative to your friend, the symmetry is maintained and you should not measure a time difference on your return.
I don't think Meir addressed your question, I just made a mistake and directed my answer to him by mistake.
I don't really know where to direct you on the subject, except: http://en.wikipedia.org/wiki/Cosmic_microwave_background_radiation
The entry in Hebrew is clearly unusable due to its brevity.
To your question - the fact that there is something that can be compared to, does not mean that there cannot be different readings of the measured size. Your problem stems from the fact that you are used to the fact that for you time is something that is no more absolute than that.
I will try to illustrate how absurd your question is:
Let's say at a certain moment in the past we all at once began to float on a huge ocean, which always flows in one direction at a constant speed, like a corridor, on the sides of which there are poles marking the distance after every meter. All we know is just float. No matter how we look to the sides, everyone floats at the same speed, the natural speed we called it, the speed of the ocean waves, and everyone travels the same distance together. The amount of rods we have passed so far we called "time". And of course we immediately received a natural time as well - the number of poles we passed since we started floating. At a certain point, suddenly some genius invents fins and starts moving away from us. And the brat starts reporting to us that he has already counted 500 rods while we only counted 480! How can he have his own "time"? "Time" not "natural"? "Time" different from ours? Then he turns and starts swimming against the current while continuing to count the rods that are passing him in the opposite direction now. When he comes back to us, he tells us that his time is 600, while our time = natural time = 520.
Meir, Adi, what you say about a "preferred" inertial system - MA in which there is no movement relative to the cosmic background radiation (whose temperature is measured), is very interesting to me, and I confess that I have never heard of it. I would appreciate it if you could send me a link.
Now for the twin paradox. The paradox speaks to the fact that the twin returning from the journey is really younger than his brother. How does this work with absolute time? It is said that before the journey they both checked their "thermometer watches", which showed a number of seconds equal to 13,573,567 years 124 days 14 hours 32 minutes and 43 seconds from the big bang. It was decided between them that this time corresponds to November 29, 2011, exactly 1900. After the journey, the young man claims that only one year has passed, while his brother claims that fifty have already passed. But the temperature clocks show both of them the same temperature, equal to the time, to an accuracy of seconds and more, corresponding to exactly one time that has passed since the big bang, so you can clearly see that at least one of the twins is wrong. How can it be said that both are right, and each of them has their own time?
Meyer,
Excellent! Just allow me to correct a little - all of the above has an effect, but I wouldn't say that it determines. The fact that in a certain scenario the clocks converge does not mean anything about anything. And again an analogy - let's say we both leave from the same point, in opposite directions at the same speeds in our cars. After an hour we turn around and come back. We compare the odometers in our cars and find that there is no distance difference between us at all - we converged to the same distance. Now I stay standing, you drive, turn around after an hour and come back. Compare odometers - there is a difference! And if you drive at the same speed for two hours and not an hour before turning around? The difference will be greater. So does it matter how long you've been driving?
Adi (28),
I actually understand the explanation very well. But if we have already come to an agreement that at the end of the trip the clocks converge back to synchronization, my question repeats itself: why is Dr. Gali Weinstein interested in her article above, what will be the duration of the airborne clock's stay in space. What determines is the turn back, accelerations, and gravity, but not the duration of the flight.
Michael,
I don't know where you found in my words that gravity has no effect on time. The movement around the earth also has an effect on time (but not according to relativity which holds that there is no preferred inertial system). Einstein's theory of relativity is not the only theory that explains the effects of motion on time measurement.
Precisely the link you attached to comment 23 is of one of the more famous critics of Einstein's theory of relativity, and therefore an outsider who is boycotted by mainstream scientists. The author, Tom Van Flandren, (who is the founder of the entire website) and in this very article that you brought, he claims that the findings obtained from the GPS system do not distinguish between Einstein's theory of relativity and Lorentzian relativity and certainly not in Einstein's favor. Here it is in his own words:
But it is important to realize that none of the 11 independent experiments said to confirm the validity of SR experimentally distinguish it from LR — at least not in Einstein's favor.
(Among other things, according to Tom van der Flandren, gravitation spreads at a speed of at least 10^10 times the speed of light).
Regarding the twin paradox, the article in the link I provided in message 24 was written by Nick Percival, a physicist who has been engaged in the study of the twin paradox for 47 years and the various methods of presenting and solving it. His approach is that relativity has a problem, and his approach is supported by quite a few physicists.
You say that there is an explanation for the twin paradox, only that I still don't understand it, and I say that there are many explanations for the twin paradox and many of them are understandable to me, and that is exactly the problem. Each of the many principled solutions to the paradox is attacked and rejected by those who have the other solutions, because each solution contradicts the correctness of the others. Nick Percival brings in his summary at least 15 different solutions to the paradox - none of which can be agreed upon by most mainstream physicists.
Apparently it is a very small challenge to present the paradox and point to a solution accepted by all, if there is one. In the meantime, it does not seem that anyone can respond to this simple challenge, and in the meantime dozens of textbooks around the world present different and varied solutions.
Sorry, my answer to Meir (27) was of course aimed at Israel.
Meir (25):
I disagree. When you read in the book about the twin effect you will also understand why, the explanation there is also valid here. I'll tell you what will happen, and I'll tell you why too, but I'm afraid you won't really be able to understand right now. And again I completely neglect accelerations due to their lack of necessity.
What will happen is that as long as the twins have not turned around each will measure that the other's clock is moving slower and therefore getting more and more behind. During the instant rotation, the twins, to their surprise, will measure that their twin's watch, Suddenly jumped forward in time many years at once. That is, immediately after the round, the second's clock, which until now was lagging behind, is suddenly years ahead. From this moment on, the other twin's clock (each twin and its other twin) will again move more slowly, and will slowly reduce the gap it opened, until at the moment of the meeting they will see exactly the same time.
The reason for this is that at the moment of the rotation, each twin abandoned its inertial system, and jumped into another inertial system, performing a kind of instantaneous "rotation" in space-time and this is what caused the second twin's clock to jump forward in time immediately.
The above problem illustrates how difficult it is to discuss relationships without having the appropriate tools for it - you only see part of a complicated picture.
Meir (27):
Indeed, the universe has a "preferred" inertial system, if you can call it that - in which there is no movement relative to the cosmic background radiation (whose temperature is measured). So what? The laws of physics are the same in this system as any other system. So you have a "convenient" mechanism that shows you anywhere in the universe the exact time (not really, but for the purpose of the discussion here) of a certain inertial system. This is Einstein's vision come true. He defined an inertial system by placing clocks at every point in space and synchronizing them. So here, he was provided with one such system.
And yet, in any other system there will be a different time. I hope that answers the question of how relativity copes, as there just isn't that much to deal with.
There is something fundamental about the whole subject of time slowing down that I can't understand.
In Einstein's original article on relativity
http://www.fourmilab.ch/etexts/einstein/specrel/www/
The first chapter deals with the problem of the simultaneity of events. On the face of it, a perfectly legitimate question. If you travel in space in a closed cabin (Einstein liked examples with closed cabins and elevators), how can you tell what time it is? or today? Or this year?
Even if you have a clock and a calendar. How would you know they're hooking up with another space traveler? What will happen when you meet and compare the times between you? Who can tell which of you is the "real" time, even if the difference between the two of you's times is many years?
It's different if you don't agree on the pressure or temperature. If your thermometer shows that the temperature outside is 270 - Celsius and your friend maintains that it is not, the temperature is 25 and the pressure is one atmosphere, politely suggest that he go outside and check, but without a suit, and let nature settle the differences.
But time? There is no way to settle a dispute. Everyone has their time. From here the path to intoxication through light rays, the speed of which is the same for every measurer, is short, and the path to private relationship is paved.
This is what Einstein claimed in 1905. And he is absolutely right - in 1905, when the image of the universe is of a static universe containing only the Milky Way.
Today the accepted description is that of the "big bang" theory, of an expanding universe. Einstein could not have known this, (see the "cosmological constant"), but this theory contains a "natural clock". We read about a universe about 14 billion years old, about the "first three seconds" of the universe. We do not know the exact age of the universe, but there is no doubt that such an exact age does exist, and it is the same at every point in the universe.
Furthermore: the age of the universe is expressed in physical factors such as density, radiation and temperature. On the website:
http://hyperphysics.phy-astr.gsu.edu/hbase/astro/expand.html#c3
You can find the formula for the dependence of the age of the universe on temperature, which is a continuous function, and at the bottom of the page there is a small calculator that, if you enter a certain temperature, you will get the approximate time of the universe plus or minus a few tens of millions of years.
And hence the question: if we have a thermometer as accurate as we want, connected to a computer, won't we get a kind of "natural clock" that will show us the time that has passed since the big bang with any precision we want, at any point in outer space, and this is simply by measuring the temperature?
How can we talk about "private time" for each traveler or for each surveyor, if such a natural time does exist in the universe?
And how does relativity deal with such a question?
I would be very happy to receive an answer.
Meir:
I do not accept your arguments.
The twin paradox was predicted by the theory of relativity - that is - it had an explanation even before it was encountered and the findings in the experiment only confirm the predictions.
We may not have been able to explain the matter to you, but that does not mean that it has no explanation, but only that it is not yet understood by you.
Acceleration/gravity must be taken into account and the fact is that this is exactly what the GPS satellites do (if you read the link I attached to my previous response you will see that the effect of speed is offset by the effect of reduced gravity) which they should not have done if your words were true.
jewel,
Thank you for your recommendation about the book. I got it and I will learn it.
At the same time, whatever the approach of its author, there are still many different approaches as described in the link in message 24, and this indicates a problem.
Regardless of the twin paradox (with or without quotation marks as you choose), I offer again the thought experiment I mentioned in message 21:
Two clock-synchronized twins take flight, symmetrical in every turn, only in opposite directions. After 25 years they change direction and return to the starting point where they meet at the end of 50 years. All this time (with the exception of accelerations at the beginning, at the reversal of direction and at the end) they fly at a constant speed.
Based on your understanding of the theory of relativity (special/general - your choice) do you agree or disagree that one twin will measure the time on his friend's watch as slower, and therefore as accumulating an ever-increasing lag throughout the years of flight?
Michael,
In response 19 I referred to Adi's words in response 18.
Regarding an airplane, it is clear as you said that the clock flown in it is subject to the influence of gravity.
Regarding a clock in a circumferential orbit around the Earth - the radial acceleration and gravity are equal and opposite in direction and therefore offset.
Regarding the twin paradox, I recommend reading the summary here:
http://worknotes.com/Physics/SpecialRelativity/TwinParadox/page2.aspx
A point that should be taken into account (given in the above link) is that each of the many experts on the theory of relativity gives a different solution and/or explanation to the paradox, but it is not possible that all of them are right.
It turns out that there is no blanket agreement among relativity experts, neither regarding the formulation of the paradox, nor regarding its settlement in any formulation. Therefore the claim that there is no problem in the theory of relativity is problematic.
It is not possible for a consistent theory to allow each expert to use different basic assumptions while taking into account different physical effects, in order to reach the same result at the end of the day. If any physical effect contributes to the existence of a phenomenon, it should be reflected in each of the calculation methods. The fact that each expert chooses a different way and takes into account other influences indicates a problem.
Meir:
I assumed that you also refer to the theory of relativity itself and not just to the article because at the end of response 19 you seem to be summarizing a scenario in which you think nature would behave in contradiction to the theory of relativity. It doesn't belong in the article.
Acceleration and gravity have and do have a role in the story of the plane.
The clock on earth is constantly subject to a gravitational field.
The plane's motion is not in a straight line and is therefore accelerated. The acceleration is indeed caused by gravity, but that does not change the fact that it exists. You can consider this acceleration or gravitation but not ignore both.
They are equal to each other and do not cancel each other out.
You can get a fairly complete picture of the subject here.
http://metaresearch.org/cosmology/gps-relativity.asp
I repeat - there is no need to use accelerations and gravity fields. That is, if you really feel like it, you can involve it and make the problem unnecessarily complicated. The twin "paradox" appears within the framework of private relativity, and is resolved very nicely within it. The use of accelerations to solve it usually appears in people who are not that well versed in the material.
Meir, I'm sorry you didn't understand, it probably means you've never seen a space-time diagram, then really the illustration in two-dimensional space was wasted. Unfortunately, it will be very difficult for me to explain it to you - it will require a very large investment (to introduce you to basic concepts) within this forum.
The book I recommended to you does this very well in less than 30 pages ("The Twin Paradox" appears on page 28) and if you want I will send you a computerized copy of it.
Beyond that, you will have to accept the fact that you currently do not have the tools to deal with the problem and you only see a small part of it (but as I said, only 28 pages separate you from understanding it).
Michael,
In my previous message (No. 16) I wrote that if the explanation lies in the accelerations, as you say, then it is not clear why the author of the article attaches importance to the delay time of the airborne clock in the planned experiment. This is not a question addressed to the theory of relativity but to the author of the article.
I understand from your words that in your opinion the duration of a delay in a circular route can be important. I don't think this is so, firstly because the clock in the circular orbit is weightless (the acceleration of the Earth is offset against the radial acceleration), and secondly, what determines the degree of relative delay is not the speed of the orbit, but the relative speed between the terrestrial clock and the airborne clock. Since the distance between them is close to constant (radius of the circle), the relative speed between them is small or negligible.
As a matter of fact, I completely agree with you that the time differences measured at the end of experiments of this type are due to exposure to gravitational fields and accelerations (which are equivalent to gravitational fields), and not from the flight speed.
Time differences resulting from the flight speed are ruled out as can be deduced from the twin paradox. The twin paradox can be described in a symmetrical system where two clock-synchronized twins take flight, symmetrical in every aspect, only in opposite directions. After 25 years they change direction and return to the starting point where they meet at the end of 50 years. All this time (with the exception of accelerations at the beginning, at the reversal of direction and at the end) they fly at a constant speed, and as long as this is the case, each of them sees the other's watch as falling behind. Despite this, it is clear (because of the symmetry) that at the final meeting the clocks will be found synchronized. Hence, the slowing down of time in the theory of relativity is relevant and measurable only while in relative motion, and hence the time differences measured after any clocks have returned from a state of relative motion to a state of rest in a common reference system originate from the differences in their exposure to gravitational fields and accelerations.
Meir:
I'm not trying to go into the details of your response because going into the details requires checking the facts you report on and performing complex calculations.
The scenario you describe belongs to general relativity.
The plane goes through a lot of accelerations (taking off, just flying in a circular path, landing) and all the clocks are in (different) fields of gravity.
There is no problem in the theory of relativity and certainly not a problem that can be convinced of its existence by waving hands.
jewel,
Thanks for the explanation. Unfortunately, I still don't understand.
I repeat the question of the cosmonaut: according to the predictions of the theory of relativity, every moment during 500 days (both on his way out and on his way back) the cosmonaut will see (through the telescope) the terrestrial clock lagging behind the airborne clock adjacent to it. But the results of the experiment showed exactly the opposite, that is, at the end of the journey, the airborne clock actually lagged behind by a second. The results of the experiment show that if the cosmonaut had indeed looked at the terrestrial clock through a telescope throughout the journey, he would have seen it speeding up relative to the clock next to him (exactly the opposite of the theory of relativity).
Meir, indeed, a mistake on your hands. The twin paradox, which like the other paradoxes in the theory of relativity is not really a paradox, is solved in many ways without the need to use the acceleration explanation and I can refer you to the literature if you wish. There is a very beautiful and elegant rigorous solution that Satan likes in Schultz - A first course in general relativity.
I personally like a nice illustration in our space, normal two-dimensional. Imagine a group of people who know how to move on a two-dimensional surface in only one dimension - along a line. Every day they go out with their carts from point A to point B and travel in a straight line. At the end of each day they compare the odometers on their carts and always find the same size X. One day, one of the men left point A and drove sideways to point C in a straight line, immediately turned around and drove in a straight line to point A. At the end of the day the people discovered to their surprise, That man's odometer shows X+20.
What is the reason for this? Is the reason the sudden acceleration he experiences at bank C when he turns? of course not. He just traveled a greater distance. The same thing happens in space-time, only that time behaves strangely there - the faster and farther you travel, the smaller it will be compared to those who don't travel!
What is beautiful about this explanation, is that anything you want to bring up as a "paradox" can be metaphorized in the above story.
You say - the spacecraft sees the earth's clock moving slower, and in Israel it is the other way around. Right. Now think about the cart - for those who travel in a straight line from A to B, they see the guy to C traveling diagonally, therefore he travels more distance than them with each step they take. And what about the guy? As far as he is concerned, all the people move diagonally relative to him, that is, they are the ones who travel more distance with each of his steps!
Israel (13) You understood everything correctly, and in the case you describe, indeed, depending on the position of the observer (standing on the road or standing on the train) he will see that the clocks passing by him are rushing (of the train or the road respectively).
It is not clear to me how the Boeing experiment and/or the public experiment that is the subject of this article and/or the Russian cosmonaut's atomic clock experiment are supposed to support the theory of relativity.
At any given moment, the time on the earth clock measured in the cosmonaut's reference system must lag behind the time measured on the airborne clock (which is at rest in the aforementioned reference system). What is the great joy of the cosmonaut to discover after 500 days that his watch is behind the terrestrial time? Happy Eid?
And to further illustrate: suppose the cosmonaut is equipped with a powerful telescope that allows him to continuously and simultaneously monitor the progress of the hands of the two clocks. According to the theory of relativity, as long as there is movement between the cosmonaut and the earth, he should see the terrestrial clock lagging behind the clock in his hand. The lag is accumulating during 500 days of movement, so when he returns to Israel the national clock should lag behind.
The truth that the theory of relativity brings out is lost in any result, because everything that is true about the airborne system is inversely true about the stationary system.
So it is true that it is called the Twin Paradox, and it is true that one of the excuses for the Twin Paradox is that the airborne clock experienced accelerations and therefore the symmetry between the airborne clock and the earthly clock was violated. But then, the dominant phenomenon in the whole story is not the slowing down of time due to relative motion, but the slowing down of time resulting from accelerated motion (which is considered to be at rest in a gravitational field), and if so, it is not the duration of the delay in space that determines it, but the existence of accelerations on the way out and on the way back (and it follows from this that in experiments of this type to confirm or deny the classical time slowing down phenomenon of the theory of relativity, which results from movement at a constant speed).
In light of this, it is not clear why Gali attaches importance to the time the clock stays in space, in the public experiment that is the subject of the article.
Apparently, the thing that needs to be tested in such experiments is the predictions of the theory of relativity for the slowing down of the time of the airborne clock considering the accelerations (the size and duration of exposure to which are known to the flight planners) that it goes through.
Am I wrong?
A much more interesting attempt has already been made regarding the lengthening of time:
A Russian cosmonaut who spent more than 500 days in space and took with him an atomic clock that corresponds to an atomic clock in Israel - atomic-twin-clocks.
When the watch returned to his hand, "it was a second or so late compared to the clock in KDA."
due to the high speed.
Israel Shapira:
I was busy and didn't turn around to answer, but to your question in comments 10 and 11 the answer is yes.
Thank you Adi, you are not hurting me at all. On the contrary, I prefer girly things.
With your permission, I will continue the argument. Let's say that the car is actually a locomotive, followed by a long train that is also checked every 150,000 km between them. The clock on the locomotive will now be "clock 1 on the train" followed by "clock 2 on the train" etc. On the road we will receive "1st watch on the road", "2nd watch on the road" etc.
The systems are now completely symmetrical (in my opinion, of course), because the road can actually be seen as a second train, with each train seeing the other relatively subordinate to it, while it itself is at rest.
According to your argument, if I understood correctly, when "clock 1 on the train" passes "clock 2 on the road" the shots on the train and on the road will show the train clock behind. The delay will increase in the following hours, and when "hour 1 on the train" reaches "hour 200 on the road" for example, we will already have a significant delay of dozens of seconds on the train.
Because of the symmetry, when "clock 200 on the train" reaches "clock 1 on the road" we will get the same delay of tens of seconds, but this time for the road, since it can be argued that the train is actually standing still and the road is the one that is moving.
It therefore follows that only when "clock 1 on the train" passes by "clock 1 on the road" will the photographs show the same time on the clocks, and then each system will see the second as slower. did I understand correctly?
Thanks in advance for the reply.
Israel, you are wrong about one of the basic mistakes in analyzing the situation. Before I continue, I don't say this to offend you, God forbid, relativity confuses us a lot because we are not used to the phenomena that occur at the high speeds of my daily life. However, this kind of mistake is a basic mistake that many make when starting out, so don't feel bad.
The difference between the moving car and the road is that the time is measured in the system in the car in one place - the clock is inside the car and does not move from its place on the dashboard, relative to the car. That is, all the events of reading the clock in the car are where locals. On the other hand, in the road system, the events are measured by different clocks, that is, the events are present In various places. This difference is very important, and it is the one that breaks the symmetry. The simple formula of the lengthening of time, therefore, is applicable only for the "self-system" - the one in which the clock does not move - the car system - in which time will pass the slowest in relation to any other system moving relative to it. For the road system, each camera, and therefore also each event, has a different location, therefore, in calculating the photo times, you must use the full Lorentz transformation, and if you do this, you will find that the times of the cameras are ahead of the car's clock.
Therefore, what will really happen is that the camera in the car will film the clocks outside moving faster, and the cameras outside will film the car's clock moving slower - in perfect coordination.
Let's try this, say the car also has a camera.
According to Lorentz transformations, at half the speed of light the time difference between the system resting and moving is about 15%. At this speed, the car's lag time at each clock is about a billionth of a second. At the 60th hour, the camera in the car will photograph both clocks when the clock on the road lags by about 10 seconds, while the camera almost next to it in the blink of an eye, the one on the road, will photograph the opposite?
Let's try it. It is said that the car also has a camera.
Since its speed is about half the speed of light, the time difference between the road and car clocks according to the Lorenz equations is approximately 15%. And the time the car spends next to each clock on the road is about a billionth of a second.
Let's take the eighth watch for example. The time difference already reaches a full second. According to the camera on the road, the car is behind and according to the camera in the car, the clock on the road is behind. However, the photographs were taken with cameras that were practically next to each other in the blink of an eye, and in fact they can even be exchanged between them. How could they see such a significant difference? And what will happen to the 10th camera, when the difference increases to 090240 seconds? The camera on the road will show 090230 on the road and XNUMX in the car, and the camera almost next to it in the blink of an eye, the one in the car, will show exactly the opposite?
Israel:
it's simple:
According to your description, the measurements are carried out by elements of the road system and therefore the system is assumed.
She will think that time in the car is slower and this will be reflected in the fact that the car's clock will seem slow to her.
In the car's system, things will look different (among other things, it will think that the distances on the road are shorter).
If the photographs were taken by the car, things would look different.
Thanks Michael, but that won't help. Which is the drive system, the car or the road?
Try to give an accurate answer. I did not succeed. If the car is moving, then its clock will lag. If the road is moving, then its clocks will lag. If both are stationary, where is the time dilation? If each sees the other as slow, what will the unequivocal shot show?
Israel:
Take the formulas
http://en.wikipedia.org/wiki/Special_relativity
Place and think.
Suppose that on a very long road large clocks are installed 150,000 km apart. The clocks are sugared between them. A high-resolution camera is installed above each watch. A car travels along the road at a speed of half the speed of light relative to the road. On the roof of the car is a large clock. Every time the car passes under the camera, the camera captures the speedometer in the car and the two clocks together: on the roof of the car and on the road
If in camera 1 the photo shows the exact time 0900.0000 both on the road and in the car, and the mileage is 1000,000 in the car, what will the photo show in cameras two and three? J
Thanks
Another theory of relativity takes place in the bank accounts of each and every one of us.
It is possible to notice the phenomenon that the money that is inside the bank account grows at a slower rate than the money that enters it from outside. In other words, there is a clear violation of symmetry that is accepted by the general public. Therefore it is a new theory.
Let me summarize:
Another experiment to test the dilation of time, only this time at the same time a clock is placed on the ground simulating the clock on the spaceship.
Big Wop.
Gali Weinstein:
In the event of an earthquake there is a problem:
Because on the one hand time on the bottom floor slows down compared to the 100th floor
But if the shaking is strong and fast then the movement on the 100th floor is much greater than on the ground. But in this case the secretary's time will slow down due to the speed of the traffic.
Say Weinstein and Einstein are the same?
Here too, of course, everything is relative and the element of time comes into play... either time is lengthening or perhaps shortening...
In any case Einstein, luckily or maybe not, and probably because of his genius, discovered two theories of relativity (really the twin paradox, two relativistic twins).
So he did publish the first in 1905, but he published the second ten years later.
And here it turns out that according to the second, clocks tick at different rates depending of course on which office you sit. That is, it depends on where the secretary sits, whether she sits on the first floor of the skyscraper or whether she sits on the hundredth floor up in the sky. And it's also obviously not healthy for the latter in case an earthquake occurs.
A little more about the shortening of time: Einstein did not predict these things "almost 100 years ago" - but a little more than a hundred years ago (the article was published in 1905).