Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Question about einsteins theory of relativity

  1. Mar 12, 2010 #1
    I have a question about einsteins theory of relativity.

    he stated, that speed described by *constant* c (0.3Gm/h) is equal, no matter what observer you choose.

    imagine this scenario:
    observer A - a guy on earth, sitting in the lab chatting with B
    observer B - a guy on sace ship that that orbit our star system with v = 0.999c.
    person C - a guy wich assist a pilot or a scientist in lab.

    you are in room with A, watching B preparing to takeoff. They both synchronize clocks, its 15:00.
    B is leaving, lets forget abbout innertia that should kill him instantly. After 3 hours hes in designated speed, 0.999c.
    they start conversation:
    (lets forget about time required for radio transmission to reach partner and its doppler effect, B is traveling in circles just to make it easier, relativistics events are same for cicrle movement.)

    - A: Hey B, 'whats the time on your clock?'.
    - B: Its '17:11'
    - A: Oh realy, its 18:02!
    - B: wtf, i they told me in school time slow down when you travel at high speed.
    - A: so it did! its 17:11 for you, while its 18:02 for us!
    - B: wtf you cheat :( impossible.
    - A: hey, do you really think that c is constant?
    - B: sure, why?
    - A: well, fire that laser into our mirror, and tell us how fast it return to you, dont forget to adjust angle to your speed!
    - B: its 18:10, firing laser, im 1 light hour from it, so i shoud recive reply in 2 hours.
    2 hours later...
    - A: B, you should get this signal right about now!
    - B: wtf, only 19 minutes had passed!
    - A: nop, its 20:10!
    - B: ... your tellin me that this signal made to earth and back in 19 minutes?
    - A: return to base, you will pick up someone special.
    - B: ok





    now lets reverse roles.
    you are in a ship with B, while chatting with A, whos on earth.

    its 23:00, you both synchronise clocks.

    - A: do you have a passenger
    - B: right, im ready to go.
    - A: good luck this time, i will ask you same questions, physics doesnt change in few hours, so you shoud report back simmilar results.
    - B: im in my trajectory, speed 0.999c, exactly as last time. time is 02:02. WTF ive made it faster last time!
    - A: yeah something is wrong, ifs 01:49!
    - B: ok i will make this laser test now, you ready!
    - A: sure!
    - B: 01:50, firing laser
    2 hours later...
    - B: ive got this signal, exactly 2 hours passed this time!
    - A: hey only 19 minutes here! and we recived your beam after 8.5 minutes from your report! it traveled 1 light hour in 8.5 minutes! How it happend?
    - B: there is nothing wrong, you are traveling with v = 0.999c in relation to me.
    - A: yeah, but results were opposite when your passenger was on earth! Why physics treat him as the observer of the universe?!
    - B: i dont know, returning to base.



    now here is the question, accorgind to einsteins relativity, everything is relative, for example - c = constant.

    But where is this observer, to wich its relative? You cant 'its relative to all'.
    Because you and your friend might take a place of A and B and get exactly same results!
    Will physics will be relative to you, or your friend? They cant be to both!
    if they were, B would report exactly what A. And then time dilatation wouldbt be possible!
    Length contraction doesnt apply also, because speed is kind of displacement, and all according to guy C is shifted in a fabric of space. So it act as it were contracted, but this is another topic.


    My question is, is there a fundamental flaw in Einstains theory, or there is a single observer (perhaps part of a single human brain), that is responsible for mine and your own very existance, a GOD?

    And if it exist, do you realize the implications? It can manipulate all the universe at once! Just changing its form! Of course its to weak to blow a star just thinking so, but it can affect sub atomic vibrations by changing himself (change perception = change what exist. If your ultimate perception = change will be also ultimate). Universe according to relativity will 'adapt' in some ways. Time dilatation, mass change are ways it do so.
    If its the center of all, what you see, what i see, is just an interaction to presence of this being! If universe is expanding, its in a center of it (propably, here i only guess, im not sure). And if it is, this 'observer' can be detected by any inteligent being, just by examining space expansion in 2 points!
     
  2. jcsd
  3. Mar 12, 2010 #2
    Re: relativity = god found

    You can't assume that radio transmission is instantaneous. No information can travel faster than the speed of light.

    The physical laws will hold for both observers from their own observations however if they communicate their results they will realize that the observations will be different. This doesn't mean that special relativity fails. It just means that the all laws are the same as viewed by an observer from his/her reference frame.

    Special relativity doesn't really say anything about laws being the same in any reference frame as viewed from any other reference frame.

    Do you understand the difference?
     
  4. Mar 12, 2010 #3
    Re: relativity = god found

    ok then change scenario to more 'common' way.

    player B is flying for XX hours and returns. Then he compare clocks.
    if C was with him - B's clock will be ahead of A.
    if C was with A - B's clock will be behind A.



    get it now?


    and whos to say, wich one will be slowed down?

    You think ur an observer? Me also. i take ship 1, you stay on earth. Winner is the one with more time on his clock than oponent. Will you win this, or will i? Whos to decide?
     
  5. Mar 12, 2010 #4
    Re: relativity = god found

    I don't get what you're saying.



    Exactly! You're trying to compare people in two different reference frames you can't do this. The special relativity doesn't say anything about people in two different reference frames.

    If I do an experiment in my reference frame and you do the same experiment in a space ship and we both measure our own results we will get the same results.

    If you do an experiment in your reference frame and we both measure your experiment we will get different results but this is not what S.R. is saying.


    If you're talking about leaving earth then returning then you will win. But if this is the case we're not talking about special relativity anymore because you had to accelerate to do this action which is not supported by special relativity. If you want more information look at the twin paradox.
     
  6. Mar 12, 2010 #5

    Doc Al

    User Avatar

    Staff: Mentor

    Re: relativity = god found

    The observer who turns around--and thus accelerates--can be distinguished from the one who stays in the same inertial frame the whole time. This is the notorious 'twin paradox'. But everyone agrees that it is the traveling twin who experiences less proper time during the round trip flight.
     
  7. Mar 12, 2010 #6
    Re: relativity = god found

    I cant only if i want to measure universe from arbitrary point of view.
    But i can if i want to explain how does it work, and why.
    I think Einstein found the design of universe, at least basics of it. But did he asked himself a simple question:
    Am i real? Am i here? Do i exist?
    I guess if he did answer is YES!

    If you ask yourself those questions, you will most likely say 'yes'.
    No matter wich human you ask, all of them will say yes,im real!

    And now second issue, if you are real, then everything else is in your reference frame! You own the universe, because it is your frame, all is relative to you! you never move, all move relativly to you! c is always constant to you!
    They all agree. But it cant be right, there are no paralell reference frames!
    Divide all people into 2 groups, load 2 space ships and send them for a trip, then return.
    Team with slowed down clock loses.
    Do it untill untill 1 person remain. He will be real. If you take his frame of reference, you will always have c = const, and will always have fastest clock (gravity and special effects not counting).


    Are you real? Are you even CAPABLE of experiencing slowed frame of reference, and variable C? 'Real being' is not. If you go to ship A, and i go to ship B, 1 of us will experience slower frame. Of course all local experiments will be same, but its about comparing your reality, to mine. Wich is real, and wich is only a imitation.
     
  8. Mar 12, 2010 #7

    Doc Al

    User Avatar

    Staff: Mentor

    Re: relativity = god found

    You're not making much sense. All observers are 'real'.
     
  9. Mar 12, 2010 #8
    Re: relativity = god found

    oh really?
    then you agree, you will never lose this competition? You go to ship A, and start moving relativly to B, and your clock will be ALWAYS further in future than B's.
    B loses? Someone MUST as stated in relativity. You are either on B, or A. You cant stay on earth and watch them. If you do, you are out of equation, and they will have their clocks equal.

    Now im B, and i say '********, all frames are real, this topic suck'. And what, that assumption makes me win?
    You think you have your own reference point, i think the same, but we both cant win, you, or me is not real, and this experiment is just very simple explanation of reason of existance! There are more more complicated ways to prove some things, but i lack technology to check them.
     
  10. Mar 12, 2010 #9
    Re: relativity = god found

    You're moving into the realm of philosophy Einsteins laws wont tell you anything pertaining to existence, etc...

    In fact some no science will really give you answers in that respect. Personally I'm of the belief that science only serves practical purposes as good approximations that can be utilized.
     
  11. Mar 12, 2010 #10

    Matterwave

    User Avatar
    Science Advisor
    Gold Member

    Re: relativity = god found

    From what I am reading, you are simply having a hard time with the Twin paradox. Twin A, on Earth, says that Twin B's clock is moving slower, while Twin B, on the rocket, says that Twin A's clock is moving slower. Yet, you believe this can't be possible, correct? Both twins can't be right, one must be wrong.

    The idea behind this paradox is indeed very conceptually confusing. What you must realize, though, is that the twins can't really compare their clocks until they return to the same place (i.e. Twin B returns to Earth).

    The paradox is like this:
    While Twin B is on his journey, he thinks he is right (A's clock is moving slower) and A is wrong, and A thinks A is right (B's clock is moving slower) and B is wrong. Special relativity says that you can't say who's right or wrong if the two frames are inertial, and no frame jumping occurs.

    However, when B returns to Earth, they can compare clocks. In that case, B's clock will have ticked less. Thus we have a paradox.

    The resolution of the paradox is two-fold. First, twin B must have accelerated during his journey (after-all, he came back!), and as such, during his time of acceleration, special relativity doesn't apply. The second (related to the first point) is that twin B must have changed reference frames on his journey. One reference frame in which he is moving away from twin A and one reference frame in which he is moving towards twin A. Therefore, Twin A is the reliable source (since he neither accelerated nor changed reference frames) and it is, in the end, Twin A who is correct.
     
  12. Mar 12, 2010 #11

    Doc Al

    User Avatar

    Staff: Mentor

    Re: relativity = god found

    I don't know what you mean by "always" or "further in the future". Once the round trip is made and the two compare clocks (or ages), the one who stayed home in the inertial frame will be older. So?

    Both observers are quite real, but analyzing things from the accelerating frame is a bit more complicated. Realize that it's not a simple matter of comparing two inertial frames, where you can say that each sees the other's clock go slow. Nonetheless, both observers agree that relativity predicts the observed behavior of the clocks, regardless of whose frame you choose to analyze things from.

    Do a search on "twin paradox" and you'll find many threads explaining these things in excruciating detail.
     
  13. Mar 12, 2010 #12

    Mentz114

    User Avatar
    Gold Member

    Re: relativity = god found

    I'm sorry to nit-pick your explanation because you've made an effort to explain the 'paradox'. You've chosen a scenario where one twin remains inertial, and designated that twin as the 'correct' or 'reliable' one.

    But what happens if both twins go on journeys and return to earth ? Who is 'correct' or 'reliable' then ?

    The elapsed time on their clocks depends on the details of their journeys - on the proper interval of their world lines and nothing else.

    So there is a simple formula for calculating what their clocks will read. This has been stated many times now in threads about the 'twins'.

    [edit] posted simultaneously with the post above.
     
  14. Mar 12, 2010 #13

    JesseM

    User Avatar
    Science Advisor

    Re: relativity = god found

    emc22, do you understand that the time dilation law only applies in inertial frames? An inertial frame is one which moves at constant velocity (constant speed and direction) for all time, so an object at rest in this frame never feels any G-forces corresponding to acceleration (here we're talking about an SR context where gravity is ignored--think of ships in deep space for example). And if B turns around to return to A, then B must have accelerated when he turned around (he knew he accelerated since he felt G-forces), so he will have changed velocity in every inertial frame. If you actually do the calculations from the perspective of any inertial frame, including a frame where A was in motion and B was at rest for the first part of the journey before turning around, all frames will agree that B is the one who's younger when A and B finally reunite and compare clocks. I showed the details of how one might calculate the aging on such a trip from the perspective of two different frames (with both frames getting the same answer for the final ages) in post 36 of this thread if you're interested.
     
  15. Mar 12, 2010 #14
    Re: relativity = god found

    You dont get one critical thing.
    Universe is not a ball. You cant take it in hand, rotate it, look into diffrent places, and imagine yourself in one of them. You exist inside it, you are a part of this, you cant see yourself!
    You only see world around! You experience events aroud. Dont think in 3rd person about yourself, you dont have any point of reference there!
    Third person view might work, but its rather a simulation - a prediction what might happen. Yet you experience things in first person view, you must remember that anytime!
    I had troubles in understanding it myself, but come on, it was AGES ago and i was way more stupid then.


    I gave you a practical experiment. 2 ships, 1 'winner'. There is no philosophy there.
    Im not talking about possible implications, im not talking why you exist, i talk about predictable facts and a serious flaw in your understanding.

    it is pratcical. possibility of changing c, possibility of instant travel to other galaxy, its science.
    but fact that all of it is meaningless, no matter what you do its meaningless is philosophy.


    depends where am i. my point of reference = only real one. you should also come to this conclusion, you = real, and here where my experiments decide whos real and whos not.

    A's thought process is also defined by speed, dont forget it. example as above, if im with A - shes winner. If im with B - she is the winner.
     
  16. Mar 12, 2010 #15

    Dale

    Staff: Mentor

    Re: relativity = god found

    Why not?

    Your writing is really difficult to decipher, so I assume that english is not your first language, but from what I can piece together I think that you misunderstand the first postulate of relativity. The point of the relativity postulate is just that the coordinates you use to describe a physical situation are nothing more than labels, and different "natural" ways of labeling things will disagree about the labels but agree on the results. All reference frames will agree on the outcome of any given experiment, even if they disagree about how to most naturally label things.
     
  17. Mar 12, 2010 #16

    Mentz114

    User Avatar
    Gold Member

    Re: relativity = god found

    I can't wait to hear what it is ...
    oh, and there was me thinking the universe was a ball and I am actually someone else.
    Hard to believe the last bit but I'll take your word for it.
    The conclusions you draw from the experiment are wrong. This has been explained to you.
    No, it is not science. It's science fiction. Almost certainly instantaneous travel is impossible.

    That does not make sense. Every person has a point of view and every person is real.
    If you travelled with A then you'd have the same experience and aging as A, and similarly if you travelled with B, you'd age like B etc. You've said something that is true, and also acknowledged that A and B have their own viewpoints.

    All you've got to accept now is accept that there's no paradox, no winners or losers, both viewpoints are valid.

    The fact that A and B will see one anothers clocks running slowly does not affect the outcome when they meet and compare elapsed times.

    Finally I would ask you to stop being arrogant and saying 'don't forget ...' or 'what you're not getting is ...'. These matters have been argued about for a 100 years by people a lot smarter than you or me. Acting as if they're all wrong and you're right makes you look a prat.
     
  18. Mar 13, 2010 #17

    Matterwave

    User Avatar
    Science Advisor
    Gold Member

    Re: relativity = god found

    The twin paradox traditionally has one twin stay on Earth (inertial), and one twin go off into space. If both twins travel, then the result depends on the journey. In explaining the traditional twin paradox, did I do something wrong?
     
  19. Mar 13, 2010 #18

    Mentz114

    User Avatar
    Gold Member

    Re: relativity = god found

    Matterwave,

    there's lots of things in your first post that don't help. Stuff like 'changing frames', and 'it depends on which twin is inertial'. You just said
    But both twins are always travelling through spacetime, and the result always depends on both journeys. The clocks just show the proper time of those journeys.

    The important thing is the spacetime bit - not acceleration ( which I presume is what you mean by 'changing frame' ).

    Another thing worth pointing out is that the 'time dilation' effect depends only on instantaneous relative velocity and is a different thing altogether from the integrated worldline.

    The explanation you gave is commonly given, but in my opinion it sweeps the essential issues under the carpet. Please don't take it personally.
     
  20. Mar 13, 2010 #19

    Matterwave

    User Avatar
    Science Advisor
    Gold Member

    Re: relativity = god found

    Ok, well that's the explanation that I've always heard. If it's wrong, then sorry to bring it up. :)
     
  21. Mar 13, 2010 #20
    Re: relativity = god found

    I believe you're thinking of the example for Differential Aging (i.e. Planet of The Apes) and not The Twin Paradox. I made this mistake myself here until someone was kind enough to correct me.

    @All: Is it doing the OP any favours to discuss his theory in this fashion? When the boom is dropped on him (inevitably, thankfully) it will be after playing with him a little bit (mentz114). I enjoy that as much as the next person, and often more, but I am given to understand that this is an educational site. I think the point has come where either a more direct approach is used in the discussion, or the crackpot is finally put out of his misery.

    Again... Kruger-Dunning Effect. I think by letting him/her go on this way, we're at least not helping where possible and maybe exacerbating matters.

    EDIT: To be fair, that said I have no idea how to get through to people like him, with "all of the answers" and all of the ego, lacking ALL of the humility and self-reflection.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook