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Everything posted by michel123456

  1. Dear Staff I have exceeded my attachments quota and I have to delete some of the images & videos I have posted. The Forum does have an attachment managing section under "My Attachments" of my Profile but I cannot spot any "Delete" option. Help please. Thank you.
  2. I cannot post any attachment, I have overpassed my attachment quota. How can I delete some of them? Thx
  3. I have put the (..) in order to make this post shorter. I have read all your comments. I will proceed in 2 steps with diagrams as suggested by @joigus & @The victorious truther. Let's go back to something simpler: a ray of light from the Earth to planet X & back, a mirror is placed on planet X Oops the import image is disabled??? Ihave used all of the attachment space allowed, I will continue this post after the issue will be resolved.
  4. Thank you. I'll keep this answer in the drawer. ------------------------------------ Now take the return trip: A goes back to Earth.(the switch between A & B was made by another member, and i followed) When he arrives and look back at planet X, what does he observe? Hint, Planet X & A are both inertial.
  5. What kind of pipe? Metallic? What diameter (inside & outside)? Where does this pipe comes from (the roof?) & where does it go?
  6. But A is also at rest. He sees (observes, measures) the Earth length contracted & the distance to the Earth is also contracted. A & B must be considered on the same ground. The situation is symmetric, reversible, how to say. Motion is relative: there is no Earth at rest & A travelling. For A, the Earth is travelling.
  7. Not the traveling twin upon his return, no no. I am asking about the traveling twin when he passes by planet X. This traveling twin (A) is observing twin at rest (B) as aging less than him. Because he uses the laws of Relativity exactly in the same way. So B observes A aging less, and A observes B aging less. They are observing THE SAME THING.
  8. But What the trveler twin is observing? he is observing that the guy at rest is older. How is that possible?
  9. You got me. 1.I hope I have that much. 2. Again, Relativity is OK to me as long it is considered as a Theory that describes (between others) a phenomena comparable to perspective: a kind of effect caused by the different states of motion of different observers, a Theory that explains how one observer can relate his observation to another observer. Taking the example of length contraction, it seems evident (to all of us I hope) that once the traveler stops, the resting observer does not observe length contraction anymore, the phenomena has vanished. In fact, in his own FOR, the traveler was never contracted at all: length contraction is an observational effect that appears from the FOR of reference (at rest). Exactly as the forearm presented in perspective: it does not change length. Is this doubting of Relativity?
  10. That is highly confusing, I assumed the dices were equidistant. Thanks for the explanation. I was still thinking about this statement, when I agree too quickly it means I haven't think enough.☺️ The frequency equation gives results clocks ticking slower but also faster than normal. In Janus example, with 0.8c, the clock that goes away ticks at 0.3 rate, and the returning clock ticks at rate 3. As seen from the observer at rest, this clock ages faster. So, why do you say that time for the free falling trajectory is a maximum?
  11. As I wrote, for each answer I get, more questions raise: ( my error corrected) Quest1. Why is the distance d2 larger than the distance d1? Shouldn't it be contracted? Quest2. Why is the red distance smaller than the orange one? I am counting 4 intervals for the red one (4 squares) and 8 or more for the orange one. If the cube is moving at constant velocity, the 2 lines should be equal. And I have to admit that I had in mind picture B. I was wrong again as it seems. But I still don't know why: in this picture B everything looks fine. Good point. That's a good input for the "what is time" thread.
  12. That is the point, why is it not inconsistent? As you say, the image of planet X at 3 LH that the traveler A observes when bypassing B is different than the image of planet X at 1 LH as seen by resting observer B. It is not a small difference. 3 times farther means 9 times smaller. Nicely presented. Except that intuition would say that the guy who covered the long path through the corners would be older than the one going straight away, while the result of the twin paradox is the contrary. @Janus could you please continue your example & describe what traveler A observes when reaching planet X? Thank you.
  13. This is an issue I see all the time in people trying to grasp relativity. In the theory (with minimal ontological assumptions of Minkowski spacetime) while you have this effect of length contraction that is rather mathematically explicit even by theory or ontology what you would actually observe is something like. . . In fact I'm pretty sure there is even a further different classical perspective of the cube that you would expect which does differ from the visual image seen above that special relativity would, being approximately correct, in the end expect. That is worth a separate thread. Some Moderator will send me a warning & do the job (I hope) with a link here for those interested. A comment from Swansont about the same topic some posts above says: The laws of perspective (that try to represent our visual everyday experience) say that an object that gets away from you is seen as if its size was diminishing, and an object that gets close to you is seen as getting larger. Of course the object does not change size in "reality", it is simply an effect of optics, but as I read here, it is completely ignored in Relativity. The moving examples posted above by V.T. do not care about this perspective effect. From Wiki What is foreshortening: https://drawpaintacademy.com/foreshortening/ The analogy with length contraction is pure coincidence, I guess. Or not. Are the laws of physics a single thing that enties everything ( the way we see things on a daily basis), or are the laws of perspective totally independent of Relativity? (as it seems to be the case at first sight). And respectively, can Relativity ignore the fact that objects appear smaller as their distance from the observer increase? And not taking count of this effect when representing the distortion of objects that move at near to c velocity?
  14. So you seem to agree that A & B would see different things although getting the same light. If that does not hurt your feelings at the departure, why is it so mind blowing at the arrival at planet X?
  15. Let's take it from the start. At time zero A & B are at rest looking at planet X that is 1LH away. Out of magic, B steps instantly into a FOR that travels at 0.8c. What does B sees? Doesn't he sees planet X length contracted? And closer to him? Instantly? While observer A sees it normal as usual? Or am I wrong there too?
  16. I meant the Earth will look larger, because closer. And length contracted. 1 hour ago, the traveler was closer to the Earth, and the Earth was closer to the traveler.
  17. And 1 hour behind, the Earth was closer to him. So he is observing the earth larger (because of regular perspective). And because of length contraction, he is observing the Earth flattened.
  18. But if the traveler looks behind him just before stopping, he will see the earth as it was in the past 1 hour ago. At this time (1hour ago) the Earth was closer to him. Because he is in a state of motion he sees things differently than the observer at rest at the bar.* You know that you are right, and I know it. If you read my previous posts more carefully you may understand than I don't want to counter the mathematics of Relativity. I am against some interpretations of relativity. Like the "multiple reality" argument, or like the present discussion. * And yes I was wrong. I forgot that when the traveler stops he jumps into another FOR and he must see what other people are seeing from this FOR.
  19. There must be a delay. If I am wrong, then the delay is somewhere else. Go and find it. As observed from the Earth, the image of the traveler going away is delayed. So logically speaking, the image of the Earth that as seen by the traveler is delayed too. There is no reason why one observer would see a delay and the other not.
  20. As I wrote above: if he stopped, it is 60 minutes aka1 hour (because he is 1 HL away). If he makes the U-turn immediately it gets complicated because you have to count for the velocity after the U-turn. It is this instant that Janus describes when the traveler is going back but observer on the Earth haven't seen the U-turn yet. But we have not reached an agreement on what is happening. Basically I am the bad guy disagreeing with everybody.
  21. When the traveler makes the U-turn, he sees the Earth still getting away from him. He will see the Earth stop going away and begin the rush at him some minutes after he made the U-turn, because there is a delay. The image of the Earth takes some time to go to the traveler. See it otherwise: if the traveler stopped for a drink at destination, he would see the image of the Earth stop getting away from him after 1 hour. (approx 4 beers in Belgian units)
  22. Because what the traveler sees is the same (the mirror) of what the observer on earth sees. When the traveler goes out, as much the distance to the Earth increases, as much the delay increases too. And on the return trip, as much the distance reduces, so reduces the delay. The turning point will not be reached at the middle point (in time) of the travel. Although it will be the middle point in distance. If the clock makes the U-turn at the middle point in time, at the end of the travel the clock will miss the Earth by a distance corresponding to the delay (if I am correct, this is more a guess than an accurate calculation). Check with Janus example.
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