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Thread: Does Time exist?

  1. #201  
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    Quote Originally Posted by Strange View Post
    Quote Originally Posted by sigurdV View Post
    When I heard that there was an age to our universe I immediately raised the question if that was in conflict with the theory of relativity.
    No conflict because the expansion of the universe is described (and predicted) by relativity theory.
    Where did I discuss the expansion of the universe. I simply raised the question if the fact that there is a definite age of the universe in some way contradicts the theory of relativity. I never claimed that the expansion of the universe is NOT described (and predicted) by relativity theory. Are there any more irrelevant points you want to raise?
     

  2. #202  
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    How do you think the age of the universe was derived?

    From the expansion.
     

  3. #203  
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    Quote Originally Posted by sigurdV View Post
    Where did I discuss the expansion of the universe.
    Determining the age is only possible because it is expanding; we can trace back the expansion to an (apparent) time zero.

    Are there any more irrelevant points you want to raise?
    Are there any more demonstrations of your ignorance you want to make?
    Without wishing to overstate my case, everything in the observable universe definitely has its origins in Northamptonshire -- Alan Moore
     

  4. #204  
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    Quote Originally Posted by SpeedFreek View Post
    Quote Originally Posted by sigurdV View Post
    And you dont get the fact that when you look out the windows on a ship travelling close to the speed of light then you see the universe growing older faster than it should werent you travelling so fast... you would see the birth and death of a star within seconds without having the need of using any universal frame!
    Such arrogance! Please, drop the attitude. You are just digging yourself in deeper.

    You obviously don't get that nobody ever sees anyone else's clock run faster due to relative motion. With time-dilation due to relative motion, the other clock is always seen to run slower. What you might be thinking of is the shift of simultaneity during acceleration.

    And you obviously don't get that when you are travelling close to the speed of light and actually measure the speed of light in your own frame, you will find the speed of light is still ~300,000 km/s faster than yourself. You are always at rest in relation to the speed of light. You only have velocity relative to the speed of light to someone else, never to yourself.

    And you obviously don't get that the age of the universe in cosmology is a gross idealisation, based on a completely theoretical series of comoving cosmological clocks, always at rest in relation to the expansion of the universe and always in the region of greatest gravitational potential (i.e. always as far away from any source of gravitational time-dilation as possible). Such a series of clocks if they were to physically exist, would actually have to be constantly accelerated in order to keep them in a comoving frame, as gravity would inevitably move them from their comoving frame otherwise.

    So, there is no theoretical observer or clock in the whole universe that could actually measure cosmological time.

    But your argument is all a straw-man anyway. Even if the universe were to have a definite age, it would not change the fact that time itself is not absolute. The universe itself might be a useful or intuitive frame in which to base your measurements, but there are no frames of reference where the laws of physics apply more than in any other frame.
    I have no attitude to drop. I am honest! I write what I think. I dont discuss clocks yet.
    I just look out the window of a ship travelling close to the speed of light. I think I see a star born from a stellar cloud and turning nova within seconds. Are you telling me that there will be no such strange sights through that window? That the universe will behave just as it does when we look at it at home on Earth?
    Will I (or you for that matter) not realise that time is running slower within the ship than outside the ship.
    I never thought much about this but shouldnt planets appear to move too fast around their sun to be able to remain in their orbits? I have difficulties in believing that it is impossible to verify the fact that one is time dilated by looking at what is going on outside the ship! Is that what you claim or not?
     

  5. #205  
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    Quote Originally Posted by sigurdV View Post
    I have no attitude to drop.
    Why not let others be the judge of that?

    I just look out the window of a ship travelling close to the speed of light. I think I see a star born from a stellar cloud and turning nova within seconds. Are you telling me that there will be no such strange sights through that window?
    No. It will be the other way round.

    Will I (or you for that matter) not realise that time is running slower within the ship than outside the ship.
    No, it will be the other way round.

    I never thought much about this but shouldnt planets appear to move too fast around their sun to be able to remain in their orbits?
    No, they will go slower.

    I have difficulties in believing that it is impossible to verify the fact that one is time dilated by looking at what is going on outside the ship! Is that what you claim or not?
    You would be able to see other clocks running slower than yours. How hard is that to understand?

    Of course, you might be confused by the fact that the people on Earth, say, would see your clock running slower than theirs. Funny old universe, isn't it.
    Without wishing to overstate my case, everything in the observable universe definitely has its origins in Northamptonshire -- Alan Moore
     

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    Quote Originally Posted by SpeedFreek View Post
    How do you think the age of the universe was derived?

    From the expansion.
    And how does that apply to my argument?

    First I stated that the age of the universe ,u1, was measured at the time t1
    and then I proposed that another measure of the age of the universe, u2,
    should be made at the time t2
    and that the result should be put in the form (u2-u1)/(t2-t1)
    for short: u/t.

    The details I left for the experimenters. If you find them to be of importance
    then perhaps you should explain why? I might agree with you...
    Last edited by sigurdV; January 9th, 2013 at 05:16 PM.
     

  7. #207  
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    Quote Originally Posted by sigurdV View Post
    Quote Originally Posted by SpeedFreek View Post
    How do you think the age of the universe was derived?

    From the expansion.
    And how does that apply to my argument?
    Do try and keep a logical sequence ideas going, it makes dialog so much easier.

    Sigurd: "When I heard that there was an age to our universe I immediately raised the question if that was in conflict with the theory of relativity."

    Strange: "No conflict because the expansion of the universe is described (and predicted) by relativity theory."

    Sigurd: "Where did I discuss the expansion of the universe. "

    All together: "THE AGE IS BASED ON EXPANSION WHICH IS PREDICTED BY GR SO THERE CANNOT BE A CONFLICT BETWEEN GR AND AGE"
    Without wishing to overstate my case, everything in the observable universe definitely has its origins in Northamptonshire -- Alan Moore
     

  8. #208  
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    Quote Originally Posted by Strange View Post
    Quote Originally Posted by sigurdV View Post
    I have no attitude to drop.
    Why not let others be the judge of that?
    Because they can not see my inside. Or are you saying they can?

    I just look out the window of a ship travelling close to the speed of light. I think I see a star born from a stellar cloud and turning nova within seconds. Are you telling me that there will be no such strange sights through that window?
    Quote Originally Posted by Strange View Post

    No. It will be the other way round..
    You mean the strange sights will observe me.
    I observe you and you are ridiculous.



    Will I (or you for that matter) not realise that time is running slower within the ship than outside the ship.
    No, it will be the other way round.[/QUOTE]

    So the faster a ship travels the faster time passes within the ship. Heh!
    Are you sure? Can you repeat it a couple of times?
     

  9. #209  
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    Quote Originally Posted by Strange View Post
    Quote Originally Posted by sigurdV View Post
    Quote Originally Posted by SpeedFreek View Post
    How do you think the age of the universe was derived?

    From the expansion.
    And how does that apply to my argument?
    Do try and keep a logical sequence ideas going, it makes dialog so much easier.

    Sigurd: "When I heard that there was an age to our universe I immediately raised the question if that was in conflict with the theory of relativity."

    Strange: "No conflict because the expansion of the universe is described (and predicted) by relativity theory."

    Sigurd: "Where did I discuss the expansion of the universe. "

    All together: "THE AGE IS BASED ON EXPANSION WHICH IS PREDICTED BY GR SO THERE CANNOT BE A CONFLICT BETWEEN GR AND AGE"
    No the age is not based on the expansion but measuring the age is. Try to get your facts correct.
    Yawn! Its late. See you tomorrow little troll.
     

  10. #210  
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    Quote Originally Posted by sigurdV View Post
    Because they can not see my inside. Or are you saying they can?
    No, we can only judge you by the attitude you project. You may think you are charming, subtle, witty, intelligent and and an all round nice guy. It may not always come across that way to pother people.

    So the faster a ship travels the faster time passes within the ship.
    No. The faster you travel, the slower you will see other people's clocks. Your own time will always pass (for you) at the same rate.
    Without wishing to overstate my case, everything in the observable universe definitely has its origins in Northamptonshire -- Alan Moore
     

  11. #211  
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    Quote Originally Posted by sigurdV View Post
    No the age is not based on the expansion but measuring the age is.
    How do you propose to measure the age of the universe then?
    Without wishing to overstate my case, everything in the observable universe definitely has its origins in Northamptonshire -- Alan Moore
     

  12. #212  
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    Quote Originally Posted by sigurdV View Post
    I dont discuss clocks yet. I just look out the window of a ship travelling close to the speed of light. I think I see a star born from a stellar cloud and turning nova within seconds. Are you telling me that there will be no such strange sights through that window?
    There are indeed strange sights out of the window, they are not what you think they are. And you are talking of clocks whenever you describe time. If you think you would see a star born and then die, you are referring to the lifetime of the star. Think of the star as a very large glowing clock!

    The sights you will see are the aberration of light (objects in front of you look more distant than when you were at rest, whilst the faster you go the more of what was behind you comes into your field of view!) combined with the relativistic Doppler effect, You will not, however, see the time-dilation of the universe "running fast" in relation to yourself. You do not see time-dilation or length contraction, you have to calculate that, based on your knowledge of your own acceleration relative to the universe around you.

    What you might calculate, during the non-inertial phases of your flight, are the results of time-dilation and length contraction - a shift in simultaneity. In the classic "paradox of the twins", one way to analyse the situation is that each twin calculates the others clock to be running slower during the inertial phases of the flight, but during the non-inertial phases, when one twin accelerates (and thus constantly changes frames of reference) is when the difference in their final ages occurs, due to a large shift in simultaneity between them.

    Not as simple as you thought, eh?

    (Note that in that aberration of light website there are also descriptions of both Doppler effect and time-dilation, but the time-dilation is what is calculated rather than what is actually seen).

    Quote Originally Posted by sigurdV View Post
    Will I (or you for that matter) not realise that time is running slower within the ship than outside the ship.
    Only if you calculate it properly, based on your knowledge of how you accelerated. But you won't simply see it.

    Quote Originally Posted by sigurdV View Post
    I never thought much about this but shouldnt planets appear to move too fast around their sun to be able to remain in their orbits?
    They don't appear to be moving fast.

    Quote Originally Posted by sigurdV View Post
    I have difficulties in believing that it is impossible to verify the fact that one is time dilated by looking at what is going on outside the ship! Is that what you claim or not?
    Oh, you will know that there is something strange going on, due to the apparent aberration of light and the relativistic Doppler effect of the universe around you. But you won't actually see the "clock of the universe" running fast.

    With those pesky relativistic twins, where one stays at home whilst the other moves off very fast, turns around and comes back again, the "moving" twin is time-dilated - his clock is running slow in relation to the stay at home twin. But the stay at home twin sees him Doppler redshifted "running slow" as he moves away and blueshifted "running fast" as he comes back again. That Doppler shift is not the cause of the difference in their ages - it is not the time-dilation itself you are seeing with relativistic Doppler shift. The twin isnt ageing slower on the outbound trip and ageing faster as he returns, he is ageing slower the whole time, due purely to his relative speed. It does not matter in which direction that speed is.
     

  13. #213  
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    Quote Originally Posted by sigurdV View Post
    Quote Originally Posted by Strange View Post
    Quote Originally Posted by sigurdV View Post
    Quote Originally Posted by SpeedFreek View Post
    How do you think the age of the universe was derived?

    From the expansion.
    And how does that apply to my argument?
    Do try and keep a logical sequence ideas going, it makes dialog so much easier.

    Sigurd: "When I heard that there was an age to our universe I immediately raised the question if that was in conflict with the theory of relativity."

    Strange: "No conflict because the expansion of the universe is described (and predicted) by relativity theory."

    Sigurd: "Where did I discuss the expansion of the universe. "

    All together: "THE AGE IS BASED ON EXPANSION WHICH IS PREDICTED BY GR SO THERE CANNOT BE A CONFLICT BETWEEN GR AND AGE"
    No the age is not based on the expansion but measuring the age is. Try to get your facts correct.
    Yawn! Its late. See you tomorrow little troll.
    You seem to be the one who is trolling here.

    Is the age of the universe in conflict with relativity?

    No.

    Why?

    Because the age of the universe is derived using relativity. It is derived by applying relativity to our observations of expansion. It is the theory that describes the expansion that allows us to derive the age of the universe.

    That theory is General Relativity, rather than Special Relativity, however.
     

  14. #214  
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    Quote Originally Posted by Markus Hanke View Post
    Quote Originally Posted by Dishmaster View Post
    I have been thinking in a similar direction. Maybe, time is not a fundamental quantity, but more something that is derived from other more basic entities, like entropy. One can calculate with time, but why shouldn't it be possible that there is another quantity that is actually more fundamental? In QM, we use momentum and length. And wouldn't it be more clever to describe the Universe in quantities of conservation? So, in this sense, yes, we may experience and even measure time, but maybe it is not the fundamental quantity we should be looking at when describing the "distance" between events.
    Have you considered what would happen to the laws of nature if we go from a (3+1) space-time to 3-space ?
    I am not debating spacetime. I am just wondering, if time is more something like a mathematical construct that is derived from more fundamental quantities. In this sense, time would exist as something you can count and calculate with, but it may not be the actual observable that is causing the changes.
     

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    Quote Originally Posted by SpeedFreek View Post
    Quote Originally Posted by sigurdV View Post
    Quote Originally Posted by Strange View Post
    Quote Originally Posted by sigurdV View Post
    Quote Originally Posted by SpeedFreek View Post
    How do you think the age of the universe was derived?

    From the expansion.
    And how does that apply to my argument?
    Do try and keep a logical sequence ideas going, it makes dialog so much easier.

    Sigurd: "When I heard that there was an age to our universe I immediately raised the question if that was in conflict with the theory of relativity."

    Strange: "No conflict because the expansion of the universe is described (and predicted) by relativity theory."

    Sigurd: "Where did I discuss the expansion of the universe. "

    All together: "THE AGE IS BASED ON EXPANSION WHICH IS PREDICTED BY GR SO THERE CANNOT BE A CONFLICT BETWEEN GR AND AGE"
    No the age is not based on the expansion but measuring the age is. Try to get your facts correct.
    Yawn! Its late. See you tomorrow little troll.
    You seem to be the one who is trolling here.

    Is the age of the universe in conflict with relativity?

    No.

    Why?

    Because the age of the universe is derived using relativity. It is derived by applying relativity to our observations of expansion. It is the theory that describes the expansion that allows us to derive the age of the universe.

    That theory is General Relativity, rather than Special Relativity, however.
    It seems as if you think I felt that an eventual conflict should be obvious and recognised immediately? That there should be something wrong in using the theory of relativity to calculate the age of the universe? No! I didnt expect things to be that simple. Would you really? Why did you assume that I thought so? And why didnt you ask me about it? Then I could have explained to you that such a thing would have occurred to somebody long before I knew about the measurement. So it could be ruled out from the start. Didnt you realize that?
     

  16. #216  
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    I think we must have crossed wires here.

    How could a prediction of a theory be in conflict with that theory?

    It might be the case that a theory predicts something that is in conflict with observation, but how could it be in conflict with the very theory that predicts it? Me no understando.
     

  17. #217  
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    Quote Originally Posted by SpeedFreek View Post
    I think we must have crossed wires here.

    How could a prediction of a theory be in conflict with that theory?

    It might be the case that a theory predicts something that is in conflict with observation, but how could it be in conflict with the very theory that predicts it? Me no understando.
    Suppose it is a theory of the predictive powers of theories and that it predicts that everyone of its own predictions fails... would you say it is not in conflict with itself?
     

  18. #218  
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    Quote Originally Posted by sigurdV View Post
    Quote Originally Posted by SpeedFreek View Post
    I think we must have crossed wires here.

    How could a prediction of a theory be in conflict with that theory?

    It might be the case that a theory predicts something that is in conflict with observation, but how could it be in conflict with the very theory that predicts it? Me no understando.
    Suppose it is a theory of the predictive powers of theories and that it predicts that everyone of its own predictions fails... would you say it is not in conflict with itself?
    ??! And I thought you claimed to support relativity.

    Stop being such a sophist. You are showing mastery in the art of obfuscation here.
     

  19. #219  
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    Quote Originally Posted by sigurdV View Post
    Suppose it is a theory of the predictive powers of theories and that it predicts that everyone of its own predictions fails... would you say it is not in conflict with itself?
    I'm sure that is terribly witty. But it is not very relevant to the question about physical theories.

    We use GR to measure the age of the universe (by looking at the history of expansion), so how can those measurements conflict with GR?
    Without wishing to overstate my case, everything in the observable universe definitely has its origins in Northamptonshire -- Alan Moore
     

  20. #220  
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    Anyway, the underlying point here is that the fact that GR makes a prediction for the age of the universe based on the cosmological parameters in the findings of the WMAP analysis of the cosmic microwave background, doesn't change the fact that time is relative, rather than absolute.

    By absolute, we mean the same everywhere.

    By relative, we mean people in different places will get different results.

    There is nothing in relativity to stop anyone from using the correct mathematics to transform their own measurements to another frame, in order to calculate what that other frame would calculate. But what relativity tells us is that one measurement is no more real than another. Each is equally valid.

    The laws of physics apply equally to all frames of reference. No experiment you make within the confines of your own frame of reference will tell you anything different. With no windows, there is no way to tell you are moving, unless you are accelerating (and we are all accelerating right now, by the way). When in uniform motion, the laws of physics cannot tell you if you are moving or not. You might look out of the window and see something else, or even the universe itself, moving relative to yourself. But that makes no difference to how time applies to yourself, it only makes a difference to how time behaves in the other frame, relative to yourself. It is up to you to interpret the situation as you will, but the laws of physics don't differentiate.

    So, even if you are moving at a relativistic speed in relation to the universe, and can see all the apparent relativistic effects out of the window that tell you that you are moving in relation to the universe, to the laws of physics the universe might as well all be moving in relation to you. Even as you accelerate, your own time ticks inexorably on at 1 second per second (or however we choose to arbitrary divide it up), basing its measurement of time on whatever method you choose - measurements of atoms, quartz crystals, light etc - anything that can be quantified using the laws of physics.

    Even if you calculate that, due to your accelerations, you are now heavily time-dilated in relation to everyone else in the universe, rather than the other way around, it makes no difference - you still age at 1 second per second in your own frame of reference. The Earth, the local universe, or even the rest frame of the CMB might be the obvious frame to relate time to, but time itself is no more absolute in that frame than it is in your own.

    What relativity tells us is that time is relative, rather than an absolute.
     

  21. #221  
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    It's always confusing to talk about looking out the window of a space ship at a star as you pass by. Why? Because Special Relativity isn't the only effect in play. There's also the star's own local gravity which it is experiencing and you are not experiencing (at least not as strongly). There's also non-relativistic Doppler Effect blue shifting the light if you are approaching and red shifting it if you are departing. The blue shifted image of an event will appear to move faster. The red shifted image of an event will appear to move slower.

    As to SR itself, it is often confusing when you are first learning the theory to understand that if two observers are both approaching one another at a relativistic speed (the distance is closing at a relativistic rate) then they both observe each other to be time dilated. That is very weird. One is naturally tempted to choose one of the observers as the "stationary" one, and reason that the "stationary" one is experiencing time at its normal rate, and the "moving" one is experiencing it at a slower rate. But that's not thinking relativistically. In relativity, neither one can be sure they're not the one that's moving.

    In relativity, it's quite possible that your space ship is stationary and all the stars you "pass" by, are actually passing you while you sit stationary.
    Some clocks are only right twice a day, but they are still right when they are right.
     

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    That sounds like the stasis drive.
     

  23. #223  
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    Quote Originally Posted by SpeedFreek View Post
    Quote Originally Posted by whizkid View Post

    The standard you choose for speed, distance-extension and change (time) are all based on space, which is real. everything else is in your mind.
    I do not understand what the problem is here - you sentence that I bolded makes absolutely no sense.
    How come, when a photon travels a certain distance in space, a caesium atom "vibrates" a certain number of times? How can that be ONLY to do with space? How can whatever it is that regulates that relationship be only in the mind?
    How come the Earth always takes a certain length of time to circumnavigate the Sun?
    What regulates all these physical process, such that they always have the same duration in any given frame of reference?
    Just space? Makes no sense to me.
    I'll try to show the sense of that sentence, SpeedFreek, and proobably you are the one who can understand and explain to your forum-mates.
    But it is necessary that you, for a moment, drop the prejudice that time exists and that what I say makes no sense, and forget about GR. Else, all I say is wrong (rant).
    Imagine you are the first scientist in the world, you are discovering physics, the world:

    I suppose you refer only to the words in red, but let's consider all aspects:

    I am sure you agree that space exists, is real: it is considered a property of matter, (which is the basic real concept: substance)
    Space is the extension of matter, its dimension , size, volume.
    Space is the only dimension, the dimension of matter, if you think anything else can have dimension, please state it and prove it
    Space has one dimension (diameter,volume) and three ortogonal axes , considering 3 "dimensions" is a first distortion of reality
    Space is called also the absence of matter where matter can move to: the empty space. (this poses serious questions which we'll skip here)
    You can measure empty space with a lump of matter, you measure matter (the occupied space) measuring the empty space around it.

    1) the standard for matter-space is space (cm.) , the distance between me and the door is the empty space between me and the door.

    So far all that exists is matter (energy) that moves from space to space at different rate (speed)
    The fact that matter moves gives origin to an abstract concept: MOTION.
    Motion is a mystery if you do not take if for granted (like time) if you analyse it profoundly you get in deep trouble (so we'll skip it)
    Motion is the distance between a body and itself (sic !)
    Bodies move at different speed, so you choose a standard to compare speeds
    I suppose you agree that the standard for speed is space V= S/T(=change) , you measure space, the distance between a body and itself

    2) the standard od motion-speed is space (cm.), or, rather, space divided by space
    (even though what you do in reality is to compare two motions, usually one motion and C, and every measure (like the constant α, is dimensioneless, 1cm= C/310^10)

    I suppose your trouble is only in the standard of change, let me know if you agree so far, it this makes sense to you, and then I'll clarify the rest. But please note: motion is change of position, to conceive motion you must be able to remember the past.

    Change is a concept of higher level (a hyperonym), as you can yet have change in the same position
    Last edited by whizkid; January 10th, 2013 at 04:06 AM.
     

  24. #224  
    Moderator Moderator Markus Hanke's Avatar
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    I think this is enough. It is impossible for you to admit of your mistakes, it is simply too embarassing for you.
    You feel the need to save your face. I will ignore you until you make sense. Good Bye.
    Alright then, I think you have made it rather obvious now that you are not here to learn and understand, but only to argue your own version of reality, which, unfortunately for you, bears little resemblance to actual physics.

    For everyone else, here is the actual physics again, in concise form :
    - length contraction and time dilation are relational laws between reference frames
    - there is no absolute frame of reference, hence no universal time
    - "the universe" is not a valid frame of reference, and neither is a photon
    - the age of the universe is a direct result of the Lambda-CDM model, which is in itself a solution of the Einstein field equations ( GR )
    - the age of the universe is based on an extrapolation by a comoving observer
    - different observers might measure different ages of the universe, depending on the entire history of the clock used. This is not a contradiction.
    - relativity is a self-consistent system, which can be proven mathematically. There are no contradictions within its axioms.
    - it is not possible for an observer to determine his state of motion without reference to a valid outside frame

    Quick References :
    Theory of relativity - Wikipedia, the free encyclopedia
    Spacetime - Wikipedia, the free encyclopedia
    Age of the universe - Wikipedia, the free encyclopedia

    In-Depth Textbooks :
    Spacetime Physics: Edwin F. Taylor, John Archibald Wheeler: 9780716723271: Amazon.com: Books
    Dubrovin, Novikov, Fomenko, Modern Geometry-Methods and Applications, Part I,II,III (Universitext)

    I invite all interested readers to review the explanations given by SpeedFreek, Strange and myself, and furthermore to review the references provided above.
    Last edited by Markus Hanke; January 10th, 2013 at 07:30 AM.
     

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    Quote Originally Posted by SpeedFreek View Post
    By absolute, we mean the same everywhere.
    By relative, we mean people in different places will get different results.
    What relativity tells us is that time is relative, rather than an absolute.
    Probably you do not realise that when you say that TIME is relative, you are acknowledging the exstistence of a supernatural Being : Mr TIME, far more absolute than absolute time, who can control every change in the world.

    In any moment there are billions of physical and chemical processes CHANGES (time) taking place everywhere.
    if you state that somewhere (on Earth or elsewhere ?) people will get different results, you are stating that ALL of those billion processes can be slowed or accelerated at the same time.

    I hope you are not referring to the Earth, where this is not recorded or possible. Maybe in distant regions of or outside the Universe?
    I thought that happened not in places but at speeds. But even If you mean at different speeds the problem does not change.

    Please tell me, if a ship is edging or orbiting the Earth at C
    TIME nearly stops inside? but, supposedly not only clocks, I suppose the engines stops and it falls down?
    And what about gravity?, does gravity stop inside the ship and then it does not fall? and what about the atoms in the ship, do the electrons stop revolving around the protons?

    Is this a bad example? Can you tell me what really happens according to GR?
    I explained my point of view in my previous post, can you explain yours?
    Last edited by whizkid; January 10th, 2013 at 07:10 AM.
     

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    Quote Originally Posted by whizkid View Post
    Please tell me, if a ship is orbiting the Earth at C TIME nearly stops inside? and I suppose the engines stops and its falls down?
    And what about gravity?, does gravity stop inside the ship and it does not fall? and what about the atoms in the ship, do the electrons stop revolving around the protons?
    This is just a rather pathetic argument from incredulity/ignorance. What is the point about making wild and meaningless statements about something you can't be bothered to make the smallest effort to understand? "Relativity must be wrong because I think it is silly."
    Without wishing to overstate my case, everything in the observable universe definitely has its origins in Northamptonshire -- Alan Moore
     

  27. #227  
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    Quote Originally Posted by whizkid View Post
    TIME nearly stops inside? but, supposedly not only clocks, I suppose the engines stops and it falls down?
    Surely you are having a laugh...?
    Are you serious ?
     

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    Why is this still in the mainstream physics section I wonder...clearly we are dealing with people who are not here to learn or understand.
     

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    Quote Originally Posted by Markus Hanke View Post
    Quote Originally Posted by whizkid View Post
    Can you please give your definition of time?
    A geometrical, uni-directional, temporal dimension
    .
    Are youu serious, Markus?
    is that a scientific definition?
    do you know that temporal (tempus-temporis) is the adjectival form of TIME
    are you defining time with time?, you objected to my use of "when" and use time a dozen of times in your definition!
    are you having a laugh ?

    You are a nice guy and rather competent, but just because you master GR, you think you know all the answers , and you are the only one in this forum that has nothing to learn.

    I suppose you are more influent than Strange and can have this thread removed, but after all it is right, because you do not even know that the first MUST of Science is to clearly define its terms, and, by the way, I do not mind stopping to post.

    If you cannot give an answer, the other is ignorant, stupid or unwilling to learn.

    Adrress the questions, the issues.!!! refute arguments, articulate an explanation!
    you can only give links or cut and paste from Einstein.!!

    Give me a definition that is not a joke!
     

  30. #230  
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    Quote Originally Posted by whizkid View Post
    Are youu serious, Markus?
    is that a scientific definition?
    Yes, it is. There are two types of geometric dimensions - spatial dimenions and temporal dimensions. The two differ by their metric signature, and by the fact that the latter is uni-directional. Mind you, all of this was already in my definition.

    you think you know all the answers , and you are the only one in this forum that has nothing to learn.
    Errr...I think you should have a look in my started threads.

    I suppose you are more influent than Strange
    Not at all, we are all on the same level. We are not moderators or administrators, just normal forum members.

    If you cannot give an answer, the other is ignorant, stupid or unwilling to learn.
    No, the ignorant ones are those who, after having been provided with an answer, refuse to acknowledge same.

    Adrress the questions, the issues.!!! refute arguments, articulate an explanation!
    you can only give links or cut and paste from Einstein.!!
    I have addresses all of your questions, and never once have I quoted anything from Einstein.

    Give me a definition that is not a joke!
    Feel free to drop the word "temporal" - the definition still stands then.
     

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    Quote Originally Posted by Markus Hanke View Post
    Feel free to drop the word "temporal" - the definition still stands then.
    Markus, do not try to be too smart:
    a geometric definition is still a definition and must obey the same rules as all the others.

    Please, if you are serious, give me a definition of time dropping all words that are related to time.
    You do it, because if I simply write them off, it is even more evident that is a mess (if not a joke).

    If you did not really cut-and-paste it from Einstein, reframe it into a meaningful sentence that explains what is time and how you prove that it exists. You haven't even tried, so far, only dogmatized.

    If you cannot, be honest and avow it. You must not be ashamed, nobody, not the greatest geniuses , could do it.

    After that we can continue a serious discussion, and you have a lot to learn.

    P.S. I hope you realize you CANNOT give a geometric definition of something, before you give THE definition of something
     

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    Quote Originally Posted by whizkid View Post
    P.S. I hope you realize you CANNOT give a geometric definition of something, before you give THE definition of something
    Which bit of the definition are you incapable of understanding? Is it the word "geometric" or "dimension" or "uni-directional"? You do know what geometry is, don't you? And you are aware it has moved on quite a bit since Euclid?

    It is hard to provide a definition to someone who doesn't appear to know the most basic mathematical concepts. Where do we need to start?

    You haven't even tried, so far, only dogmatized.
    You are the only dogmatic one around here.
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    Geo -metry : (the measurement of the Earth).
    a discipline concerning the properties of space (size,shape, position of figures or objects).

    One can give a geometric definition, description of something, only after one has defined that something as an object (or space) having those properties

    One cannot give a geometric description of anything else.
    do you know what is size,shape, dimension, figure,shape, Earth?
     

  34. #234  
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    Quote Originally Posted by whizkid View Post
    Geo -metry : (the measurement of the Earth).
    a discipline concerning the properties of space (size,shape, position of figures or objects).

    One can give a geometric definition, description of something, only after one has defined that something as an object (or space) having those properties

    One cannot give a geometric description of anything else.
    do you know what is size,shape, dimension, figure,shape, Earth?
    As I say, geometry, and mathematics generally, has moved on quite a bit in the last 3000 years. Maybe you need to catch up.
    Without wishing to overstate my case, everything in the observable universe definitely has its origins in Northamptonshire -- Alan Moore
     

  35. #235  
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    Quote Originally Posted by whizkid View Post

    P.S. I hope you realize you CANNOT give a geometric definition of something, before you give THE definition of something
    Well while I have a bit of quarrel with Markus/s last post, this is logical nonsense

    Some perfectly coherent "objects" can ONLY be described in terms of their geometry

    Suppose the common-variety circle. How would you describe it? Euclid gives us one way (the algebra in plane geometry), modern mathematicians say it is a 1-manifold, with intrinsic geometry. Is there another way to define the circle?

    I doubt this means much to you.

    PS by edit: Just had a thought - a rare thing for me! - You seem to be peddling an Existentialist agenda. Namely existence precedes essence;

    In fact, modern mathematics works in precisely the opposite direction. To emphasize this, take what one might call the "militant wing", that claims - or claimed - that if you cannot tell me how a mathematical object is to be constructed, then I am under obligation to believe in its existence .

    The adherents to this view were by no means fools - I cite Kronecker and Brouwer off the top of my head, both of whom made very serious contributions to mathematics. One tends to be a little more moderate these days, but the fact remains nonetheless, that the existence of a mathematical object is defined by its properties

    I am minded to lock this thread. Anyone any thoughts?
    Last edited by Guitarist; January 10th, 2013 at 11:21 AM.
     

  36. #236  
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    Quote Originally Posted by Guitarist View Post
    Well while I have a bit of quarrel with Markus/s last post
    Ha ha, no surprises here Guitarist, I find it quite impossible to live up to your high standards

    I am minded to lock this thread. Anyone any thoughts?
    By all means, proceed. This has been going around in circles for days now.
     

  37. #237  
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    Quote Originally Posted by whizkid View Post
    Please, if you are serious, give me a definition of time dropping all words that are related to time.
    Let's drop the word "temporal" then : A geometrical, uni-directional, dimension with metric signature opposite that of the three spatial dimensions.

    If you did not really cut-and-paste it from Einstein


    I didn't.

    reframe it into a meaningful sentence that explains what is time and how you prove that it exists.


    See above. As for the proof of existence, see earlier on this thread.

    After that we can continue a serious discussion


    There is never going to be a serious discussion with you about the subject, which is why it is time ( see what I've done here
    ) to lock this.
    Strange likes this.
     

  38. #238  
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    Quote Originally Posted by Guitarist View Post
    I am minded to lock this thread. Anyone any thoughts?
    Might as well. When we get amateur "philosophers" trying to prove physics wrong, it is obviously a waste of everyone's time.
    Without wishing to overstate my case, everything in the observable universe definitely has its origins in Northamptonshire -- Alan Moore
     

  39. #239  
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    The question as to whether or not time exists inevitably descends into discussions of what one means by "time" and what one means by "exists". The problem which this gives rise to was apparently noted in Confessions by St Augustine centuries ago - regarding what time is - "If no one asks me, I know; but if any Person should require me to tell him, I cannot."

    Space - time, or what philosophers refer to as "Block time" and what was referred to by McTaggert as the B-series are certainly useful ways of thinking about time. The notion of space-time appears to have been essential to the development of General Relativity, despite Einstein's original scepticism when he first came across the idea. However, there are things which it can't explain and these matters have often been referred to by physicists. Examples: - (1) towards the end of his book "The Emperor's New Mind" , Roger Penrose mentions some of his childhood meanderings - "Perhaps I am simply living the same ten minutes' experiences over and over again, each time with exactly the same perceptions", (2) "The distinction between past, present and future is only an illusion, even if a stubborn one." - Einstein, (3) Paul Davies referring to his own childhood in his book "About Time - Einstein's unfinished revolution" - "I lay awake at night pondering this. Why was I living now rather than at some other epoch in history?"

    These comments and queries about time are closely connected with what we mean by "the present", and there are some who think that an understanding of this will involve an understanding of consciousness - something we don't have. I don't see them as "philosophical" or "unscientific" questions, nor are they at all trivial as they bear directly on our perception of time. But space-time is of little use as an aid to their understanding.
     

  40. #240  
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    Quote Originally Posted by JonG View Post
    The question as to whether or not time exists inevitably descends into discussions of what one means by "time" and what one means by "exists".
    Quite. And as whizzkid isn't whizzy enough to tell us what he means by either of these (just that everyone else is wrong) this is going nowhere.

    As an engineer, I tend to find such discussions fairly pointless anyway. The definition used in physics works; it is useful. Why waste time on metaphysics and hair splitting? Can we improve healthcare or energy efficiency by arguing about definitions like that?
    Without wishing to overstate my case, everything in the observable universe definitely has its origins in Northamptonshire -- Alan Moore
     

  41. #241  
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    Quote Originally Posted by Strange View Post
    As an engineer, I tend to find such discussions fairly pointless anyway. The definition used in physics works; it is useful. Why waste time on metaphysics and hair splitting? Can we improve healthcare or energy efficiency by arguing about definitions like that?
    If one required posts on this board to improve energy efficiency or healthcare, I suspect that few posts would survive.

    The nature of time is a matter which has fascinated many people - certainly not just those of a philosophical frame of mind - for centuries. Many of these people have been reputable scientists such as those I mentioned above. One which I didn't mention but is very relevant - "Time must never be thought of as pre-existing in any sense; it is a manufactured quantity" - Hermann Bondi. Bondi was a physicist, albeit one of the steady state universe variety (but I don't think that's illegal , or is it?). If anyone isn't interested in the topic, they can just ignore the thread. But to deny those who are interested in physics and also interested in time the opportunity to discuss it is somewhat restrictive.
     

  42. #242  
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    I would ignore it if it was in the right place: Philosophy.
    Without wishing to overstate my case, everything in the observable universe definitely has its origins in Northamptonshire -- Alan Moore
     

  43. #243  
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    You should not strange,the thread is where it should be.time is not a notion of one school of thought. If it overlap into philosophy let it be.its not about the branch of thought that explains time but what the explanation is.
    "I am sorry for making this letter longer than usual.I actually lacked the time to make it shorter."###
     

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    Quote Originally Posted by SpeedFreek View Post
    Quote Originally Posted by sigurdV View Post
    Quote Originally Posted by SpeedFreek View Post
    I think we must have crossed wires here.

    How could a prediction of a theory be in conflict with that theory?

    It might be the case that a theory predicts something that is in conflict with observation, but how could it be in conflict with the very theory that predicts it? Me no understando.
    Suppose it is a theory of the predictive powers of theories and that it predicts that everyone of its own predictions fails... would you say it is not in conflict with itself?
    ??! And I thought you claimed to support relativity.

    Stop being such a sophist. You are showing mastery in the art of obfuscation here.
    YOU NO UNDERSTANDO?
    You ask in a way that clearly shows that you think that you are clever,
    and that your question has no good answer! You asked how a theory...
    without specifying any particular theory...
    could be in conflict with itself. And you obviously thought no theory can!
    Then I show you how! And are you happy about it? Do you react scientifically?

    Dont Ask Questions If You Dont Appreciate Answers!

    If there is anything "crosswired" in here then its within your brain
    May I remind you that Science is not a religion, and should not be treated religiously?
     

  45. #245  
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    Quote Originally Posted by whizkid View Post
    Quote Originally Posted by Markus Hanke View Post
    Quote Originally Posted by whizkid View Post
    Can you please give your definition of time?
    A geometrical, uni-directional, temporal dimension
    .
    Are you serious, Markus?
    is that a scientific definition?
    do you know that temporal (tempus-temporis) is the adjectival form of TIME
    are you defining time with time?, you objected to my use of "when" and use time a dozen of times in your definition!
    are you having a laugh ?

    Give me a definition that is not a joke!
    Here is Einsteins definition of simultaneity:

    The events a and b are simultaneous if and only if lightrays from a and b simultaneously arrive at the midpoint of the segment ab.

    Some so called "Scientists" that interprete "Science" religiously cannot see the circularity of the definition!
    Strange, for instance, has repeatedly insisted that the definition is NOT circular. Showing that he doesnt know what "circular" means.
    I bet they see nothing amiss in the following "definition":

    A "definition" is a sentence defining that which is to be defined.
     

  46. #246  
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    You clearly saying that einstein used is point which is his definition of simulaneity as a conclusion of what simultaneous events should appear like under this circumstance.
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  47. #247  
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    Quote Originally Posted by sigurdV View Post

    Here is Einsteins definition of simultaneity:

    The events a and b are simultaneous if and only if lightrays from a and b simultaneously arrive at the midpoint of the segment ab.

    Some so called "Scientists" that interprete "Science" religiously cannot see the circularity of the definition!
    Strange, for instance, has repeatedly insisted that the definition is NOT circular. Showing that he doesnt know what "circular" means.
    I bet they see nothing amiss in the following "definition":

    A "definition" is a sentence defining that which is to be defined.
    1. I did not talk about simultaneity, only time
    2. Einstein's definition of simultaneity is not circular in any way

    YOU NO UNDERSTANDO?
    You ask in a way that clearly shows that you think that you are clever,
    and that your question has no good answer! You asked how a theory...
    without specifying any particular theory...
    could be in conflict with itself. And you obviously thought no theory can!
    Then I show you how! And are you happy about it? Do you react scientifically?

    Dont Ask Questions If You Dont Appreciate Answers!

    If there is anything "crosswired" in here then its within your brain
    May I remind you that Science is not a religion, and should not be treated religiously?
    You are sounding like my six year old having a tantrum.
     

  48. #248  
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    Quote Originally Posted by merumario View Post
    You clearly saying that einstein used is point which is his definition of simulaneity as a conclusion of what simultaneous events should appear like under this circumstance.
    I only EXHIBITED Einsteins definition of simultaneity. It can easily be seen that the concept "simultaneously" is used to define "simultaneous" ... So the question is if there are TWO concepts of simultanity, one used to define the other... or if there is only ONE concept defining itself circularly. It seems neither solution is entirely satisfactory for all concerned parties. But I see no third alternative...do you?

    The religiously inclined will continue claiming theres no circularity involved in Einsteins definition but they will not be able to prove their claim. All they can do is to repeate the claim in the hope that the more times the claim is made the truer it gets. Ha ha!
    Einstein himself remarked something like: SO!? theres a hundred professors against me? One is enough if he is correct!

    From Wikipedia:Main article: Fallacies of definition

    Definitions should avoid circularity. To define a horse as 'a member of the species equus' would convey no information whatsoever. For this reason, Locking[specify] adds that a definition of a term must not comprise of terms which are synonymous with it. This would be a circular definition, a circulus in definiendo.

    To say that two events are simultaneous if they happen simultaneously... IS circular!

    The concept to be defined may NOT appear in the the defining part of the definition.

    That is the definition of a circular definition.

    Einstein was of course aware of this and he had a motivation that is accepted by Science.
    I will however not tell what it is... Trolls can look it up for themselves.
    Last edited by sigurdV; January 11th, 2013 at 01:52 AM.
     

  49. #249  
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    Quote Originally Posted by sigurdV View Post
    I only EXHIBITED Einsteins definition of simultaneity it can easily be seen that the concept "simultaneously" is used to define "simultaneous" ... So the question is if there are TWO concepts of simultanity, one used to define the other... or if there is only ONE concept defining itself circularly. It seems neither solution is entirely satisfactory for all concerned parties. But I see no third alternative...do you?
    Can you explain why you think that the definition is circular ? The midpoint is just that - a point. There is only one well defined clock reading at that one point. The two light rays either arrive at the same reading of that clock or they don't. You are reducing the problem of simultaneity of two separated clocks to a simple reading of a single clock. Where exactly is the circularity ?
     

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    Quote Originally Posted by sigurdV View Post
    To say that two events are simultaneous if they happen simultaneously... IS circular!
    He is not defining the word "simultaneous"; we all know what that means. If we don't we can look it up in a dictionary.

    He is defining what "simultaneous" means for two events separated in space. And, further, what "simultaneous" means when those two events are observed from different frames of reference.

    He does this based on something that is unambiguous: the simultaneous arrival of signals at a single point in space.

    It really isn't that complicated.
    Without wishing to overstate my case, everything in the observable universe definitely has its origins in Northamptonshire -- Alan Moore
     

  51. #251  
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    Quote Originally Posted by Markus Hanke View Post
    Quote Originally Posted by sigurdV View Post
    I only EXHIBITED Einsteins definition of simultaneity it can easily be seen that the concept "simultaneously" is used to define "simultaneous" ... So the question is if there are TWO concepts of simultanity, one used to define the other... or if there is only ONE concept defining itself circularly. It seems neither solution is entirely satisfactory for all concerned parties. But I see no third alternative...do you?
    Can you explain why you think that the definition is circular ? The midpoint is just that - a point. There is only one well defined clock reading at that one point. The two light rays either arrive at the same reading of that clock or they don't. You are reducing the problem of simultaneity of two separated clocks to a simple reading of a single clock. Where exactly is the circularity ?
    You seem to ask seriously so I will try to answer.

    You are now replacing "simultaneously" with "arriving at a point at the same time" This is perhaps ok! Lets not at the moment look deep into what is meant by "the same" suffice it to mention that its not yet demonstrated that we can successfully take away simultaneity altogether from the definiens. But, as I said, I accept for the moment your replacement ... the definition is no longer circular BUT instead there are now TWO concepts of simultaneity the "at the same time" concept used to define the physical concept of simultaneity. How do they relate to each other?

    Ordinarily its said that the physical concept REPLACES the older common concept but the moment that happens the definition gets circular. How do you prove that "by the same time" is not meant "by the same ABSOLUTE time"? Be that for now however it may...my point is this far that:

    EITHER there are TWO not identical concepts to the term simultanity or the definition is circular
    .

    Is this a satisfying situation you have been aware of?
     

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    Quote Originally Posted by sigurdV View Post
    BUT instead there are now TWO concepts of simultaneity the "at the same time" concept used to define the physical concept of simultaneity. How do they relate to each other?
    Why would there be two concepts of simultaneity ? At the midpoint there is only one clock; at any given time on the clock there is either no light ray, one light ray or two light rays present. Would you agree thus far ?
     

  53. #253  
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    Quote Originally Posted by Markus Hanke View Post
    Quote Originally Posted by sigurdV View Post
    BUT instead there are now TWO concepts of simultaneity the "at the same time" concept used to define the physical concept of simultaneity. How do they relate to each other?
    Why would there be two concepts of simultaneity ? At the midpoint there is only one clock; at any given time on the clock there is either no light ray, one light ray or two light rays present. Would you agree thus far ?
    Yes I agree, but by two concepts I mean first your clock concept then the concept defined by use of the clock concept
    .
    You should understand that they cannot be identical on pain of circularity. Its easy to keep them apart if you keep in mind that the first concept is "simultaneously" and the other is "simultaneous".
    Again: The difference between the concepts is that one is used to define the other!

    What worries me here is if it can be shown that the circulatity cant be avoided...What then?
    But Im not interested in investigating that line of thought for the moment. I assume it can be avoided somehow.
    So go on with your investigation:

    Is it clear in your mind what concept of simultaneity you use when you decide that the rays from a and b arrives simultaneously at the midpoint? No ray before or after the other? Lets call it something to distinguish it from the "physical" concept defined by the definition ...Any particular name coming to mind?

    Do you mind if Im mean enough to suggest "Absolute" simultanety? Isnt it the same as the old Newtonian concept?
     

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    Quote Originally Posted by sigurdV View Post

    To say that two events are simultaneous if they happen simultaneously... IS circular!
    Stop talking utter bollocks.

    He didnt say anything of the sort.

    What he said was two events can be considered to be simultaneous IF THE LIGHT FROM THOSE EVENTS reaches a place equidistant from those events at the same time. That's the same time in one place.

    So, if you are standing halfway between the events, and the light from those events reaches you at the same time, you know those events (which actually occurred in the past) happened at the same time.

    Which you would know, if you had bothered reading the long and well thought out explanation I posted in that thread you started about this, to which you haven't responded yet.

    The whole issue is based on how one determines, from one place, whether events that are are in two places are simultaneous or not. If the light from both events reaches one place, at the same time, and that place is equidistant from those events, then the answer is clear.

    ONLY A COMPLETE FOOL WOULD THINK THAT WAS A CIRCULAR ARGUMENT.

    You sir, are completely deluded. You argue arrogantly from a position of TOTAL ignorance.
    Last edited by SpeedFreek; January 11th, 2013 at 07:09 AM.
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  55. #255  
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    Quote Originally Posted by sigurdV View Post
    If there is anything "crosswired" in here then its within your brain
    At least I actually use my brain.
     

  56. #256  
    Brassica oleracea Strange's Avatar
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    I can only assume that Sigurd has chosen to remain wilfully ignorant on principle. It is like a child with his eyes shut, fingers in ears, shouting "LA LA LA - CAN'T HEAR YOU" and then complaining that he doesn't understand...

    Pathetic.
    Without wishing to overstate my case, everything in the observable universe definitely has its origins in Northamptonshire -- Alan Moore
     

  57. #257  
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    Quote Originally Posted by sigurdV View Post
    Is it clear in your mind what concept of simultaneity you use when you decide that the rays from a and b arrives simultaneously at the midpoint? No ray before or after the other? Lets call it something to distinguish it from the "physical" concept defined by the definition ...Any particular name coming to mind?
    Yes, the term is "simultaneously". Which, to anyone with a brain, would be easy to understand if we are talking about the light arriving at a single place - the midpoint. It is when there is separation between places that these definitions are required, which is THE WHOLE POINT of the relativity of simultaneity.

    Is this sinking in yet? Have you had a "lightbulb" moment yet? Are you still not getting this?
     

  58. #258  
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    Quote Originally Posted by sigurdV View Post
    You should understand that they cannot be identical on pain of circularity. Its easy to keep them apart if you keep in mind that the first concept is "simultaneously" and the other is "simultaneous".
    Again: [U]The difference between the concepts is that one is used to define the other!
    It is not circular. Simultaneous at one place is being used to define the meaning of simultaneous at two separated locations.
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  59. #259  
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    Quote Originally Posted by SpeedFreek View Post
    Quote Originally Posted by sigurdV View Post
    Is it clear in your mind what concept of simultaneity you use when you decide that the rays from a and b arrives simultaneously at the midpoint? No ray before or after the other? Lets call it something to distinguish it from the "physical" concept defined by the definition ...Any particular name coming to mind?
    Yes, the term is "simultaneously". Which, to anyone with a brain, would be easy to understand if we are talking about the light arriving at a single place - the midpoint. It is when there is separation between places that these definitions are required, which is THE WHOLE POINT of the relativity of simultaneity.

    Is this sinking in yet? Have you had a "lightbulb" moment yet? Are you still not getting this?
    Sorry pal but nothing you say is news!
    Why do you think Einstein bothered to state that light rays should arrive at the midpoints simultaneously?
    Dont you understand that the rays are separated until they SIMULTANEOUSLY meet in the point? And that they separate afterwards? If one of the rays arrive slightly earlier than the other then they are NOT simultaneous at the midpoint of ab. Are you taking Einsteins definition seriously or not?

    The problem intelligent people like you dont recognise is that this simultaneous arrival should not be by the same concept of simultaneity as in the defined concept because the definition is then circular.

    And when they at last understand that... then they try to immediately "IMPROVE" Einsteins definition! The Master probably had a bad day or something... He just overlooked a little detail, but this simple matter will be fixed in a minute or so. So fix it then!
     

  60. #260  
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    Quote Originally Posted by sigurdV View Post
    The problem intelligent people like you dont recognise is that this simultaneous arrival should not be by the same concept of simultaneity as in the defined concept because the definition is then circular.
    Blimey. You really are dumb as a bag of spanners.

    It is not the same concept. He is defining how to determine simultaneity for two locations which are physically separate.
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  61. #261  
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    Quote Originally Posted by sigurdV View Post
    You should understand that they cannot be identical on pain of circularity. Its easy to keep them apart if you keep in mind that the first concept is "simultaneously" and the other is "simultaneous".
    Again: The difference between the concepts is that one is used to define the other!
    sigurdV, what on earth are you talking about ?

    Is it clear in your mind what concept of simultaneity you use when you decide that the rays from a and b arrives simultaneously at the midpoint? No ray before or after the other?
    I did not use the concept of simultaneity for the midpoint ( which is taken to be point-like ! ). What I referred to was the numbers of light rays at the midpoint at any given point in time. If there exists a reading of the clock at which exactly two light rays arrive at the clock, the events which emitted those rays are simultaneous. If on the other hand a reading exists at which exactly one light ray arrives at the clock ( not more and not less than one ), then the events cannot be simultaneous. Before or after do not play into this.
     

  62. #262  
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    Quote Originally Posted by sigurdV View Post
    The problem intelligent people like you dont recognise is that this simultaneous arrival should not be by the same concept of simultaneity as in the defined concept because the definition is then circular.
    THE WHOLE ISSUE SURROUNDS EVENTS THAT ARE SEPARATED BY SPACE. HOW CAN WE TELL IF THOSE EVENTS ARE SIMULTANEOUS, IF THEY ARE SEPARATED BY SPACE?

    There is no problem with simultaneity if both the events are in the same place (such as the events of the light arriving in the same place). This is completely trivial to define.

    Either you are completely ignorant of the issue Einstein was actually addressing (the determination of simukltaneity for events that are separated by space - two distant events) and thus should not be so arrogant with your responses, OR, you are simply trolling us.

    I explained the whole thing in that thread you started. HAVE YOU READ IT YET? If you have any problems with the definition of simultaneity, why aren't you asking them in the thread you started, entitled "Definition of simultaneity", where I explained all this?
     

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    The Choir of Trolls sings again: The definition is not circular. The definition is not circular. Oh no! No no no!
    Then they concentrate a little and tries to find new pretty things to say abut sigurdV instead of trying to understand
    why Einstein did not use the words "to be at the same time in the midpoint"
    instead of "arrive simultaneously at the midpoint of ab".
    They paint a very amusing charicature of serious hard working Scientists!
     

  64. #264  
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    sigurdV, it is clear that you are not here to learn and understand, you are here only to proliferate your own misconceptions, or possibly you are just simply a troll looking to waste everyones time ( ). We have all tried to explain to you the physics over the last 250+ posts; but now I believe it is quite enough.

    I say lock this crap.
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  65. #265  
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    Sorry chaps, enough nonsense is more than enough nonsense.

    Thread closed
     

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