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    A Regarding a prior thread on BU vs Presentism

    OK, so Ibx seemed to understand my question. I thought the follow-on sentence amplified it enough, however I'll reword the OP below to make it clearer. Ibx, thanx for the response. That's the way I've always understood it as well, ie the Presentist interpretation requires a preferred frame...
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    A Regarding a prior thread on BU vs Presentism

    Very sorry Halc, but I really have no idea why you would post this in relation to my question. Brest regards, GrayGhost
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    A Regarding a prior thread on BU vs Presentism

    OK, so I was reading thru a prior thread UNLEARNING THE BLOCK UNIVERSE, initiated by user Lynch101, and which has already been locked by the forum. There were many good responses. It was stated that PRESENTISM and the BLOCK UNIVERSE are 2 philosophical interpretations of the very same LTs, and...
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    A Lorentz transformation

    By convention, the unprimed frame records the primed system moving at +v, and so the primed frame records the unprimed system moving at -v. As Erland said above, you can just substitute -v for v in the LTs, and you'll find that the inverse LTs are attained. Gamma is found to be the same for the...
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    B Development of Special Relativity

    I think that a derivation of the LTs, either as Einstein did in his 1905 paper, or by Algebra alone (as it's often taught today), is all that's needed. However for many, the Minkowski spacetime diagrams are also needed to reach the full meaning of SR, as a picture can paint a 1000 words. I can...
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    B Development of Special Relativity

    Mister T, Agreed. I thought the Mechanical Universe episodes wrt relativity theory were very good, particularly for the year in which it was made (so long ago). They did a very nice job on those, in presentation. Best regards, GrayGhost
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    B Development of Special Relativity

    NoahsArc, Just to add to the above ... algebra alone suffices, because the relationship between differing inertial frames is assumed to be linear, due to the observed properties of homogeniety attributed to space and time. That was stated by Einstein in his 1905 OEMB paper, near the beginning...
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    B Reference frame symmetry in Special Relativity

    OK Dale. You're right, I shall try to do better in that respect. Here's what I had for that ... Best Regards, GrayGhost
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    B Reference frame symmetry in Special Relativity

    x-vision, BTW, for your scenario the LTs apply, but only after some modification. The LTs were derived for spacetime systems that have a common origin. IOW x,y,z,t = x',y',z',t' = 0,0,0,0. Their spatial origins momentarily coincide at one point in time, when both their clocks read zero. In...
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    B Reference frame symmetry in Special Relativity

    x-vision, Wrt my prior post #28, your OP scenario's spacetime diagram redone with with proper convention ... Best regards, GrayGhost
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    B Reference frame symmetry in Special Relativity

    x-vision, While my prior spacetime diagram was correct in its depicted coordinates, it was technically incorrect from a standpoint of "proper convention" for spacetime diagrams. Proper convention, is to present the system which holds the velocity as positive (worldines slant from lower-left to...
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    B Reference frame symmetry in Special Relativity

    x-vision, I reposted the spacetime diagram after you looked at it. I noticed I had omitted the negative signs on the (star's) x' values depicted there. They are corrected now. Best regards, GrayGhost
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    B Reference frame symmetry in Special Relativity

    Here's a force-fitted spacetime diagram for x-vision's OP scenario, as he stated it. Please verify, thanx ... Best regards, GrayGhost
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    B Reference frame symmetry in Special Relativity

    Hi Dale. I see you guys were trying to make a single scenario that matched v-vision's OP, although I don't believe he had that in mind when he initially posted. It is a good idea though. I did draft the spacetime diagram here, however whereas you said "In both frames the other frame’s clock...
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    B Reference frame symmetry in Special Relativity

    x-vision, In your OP (original post), in the 1st half of your scenario description, you mentioned the star as stationary, and the rocket 10 ly distant moving inertially inbound toward the star at 0.9c. At that velocity, the gamma factor is indeed γ = 1/√(1-v²/c²) = 2.294. So when the rocket...
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    I Minus sign in Minkovsky´s metric

    DaTario, I'll refer you to a former post here which may help ... https://www.physicsforums.com/threads/distance-between-two-points-in-spacetime.491216/#post-3254542 Best Regards, GrayGhost
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    I Does the "space twin" benefit from length contraction?

    My post was redundant to LaymanB's post #7 ... https://www.physicsforums.com/threads/does-the-space-twin-benefit-from-length-contraction.933918/#post-5898964 ... so I deleted my post here. Sorry 'bout that. Best Regards, GrayGhost
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    I Demonstration of time dilation

    Regarding this matter... Consider gazillions of clocks (virtual or not) synchronized in their own frames, and let's say they are equally spaced wrt the axis-of-propagation for simplicity. Per a stationary observer ... moving clocks tick slower, period. Observers of both POVs are correct. Per...
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    B Relativity of simultaneity

    Andrew1955 had asked ... how did Einstein make the leap of faith that time must pass more slowly in a moving frame, based on his train thought-experiment alone? Before Maxwell, there was absolute time, absolute simultaneity, and a variable light speed. As such, the train passenger must agree...
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    B Relativity of simultaneity

    Hello Andrew. I've been looking through your thread here. The problem as I see it, is that you do not yet understand the theory, and so as is often the case, you challenge the validity of the relativistic effects. And until one understands the theory, one has no other choice but to lean toward...
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    I Einstein's definition of time

    Sorry, I have a type-O correction in my prior ... I wrote ... ", the received light image shows the clock arrived at the station at 7, by the clock on the wrist of he at the station." I should have written ... ", the received light image shows the train arrived at the station at 7, by the...
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    I Einstein's definition of time

    Aufbauwerk 2045, Also, in OEMB Section 1 when Einstein talks about an observer "in the neighborhood" of the clock, or the clock "in the neighborhood" of the event, he's only minimizing the light travel time (delay) from event to clock, and/or clock to observer('s eyes). An observer (A) at a...
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    I Einstein's definition of time

    Learning the Special theory (SR) from Einstein's 1905 paper (OEMB) is totally fine. There's nothing wrong with it. I consider it an excellent way to learn it. However afterwards, it is extremely beneficial to learn the geometric approach of Minkowski spacetime diagrams. The geometric...
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    I Why do people keep saying photons are timeless?

    Hello weezy, nice to make your acquaintance. The reason they do that, is because there is no other option to predict a speed c POV. The photon cannot be held in a state of rest, and thus has no inertial POV (even though it travels at a steady speed). We only know what material POVs...
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    Length contraction clarification

    I must agree. WIKI's page is misleading, if not mistaken IMO. A spacetime interval has a length s, and its square is not the spacetime interval itself. The "spacetime interval" is that which possesses the length of s, and "that" is the line element (or path) between the 2 reference events in...
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    Do you think Relativity theory can explain all the paradoxes?

    All, It is not my practice to not respond to the posts of others. I have been told by mentor that my interpretation of option 3, which envisions events shifting in (space)time, is not mainstream relativity, and should not be discussed in this forum. The reason, is because only 1 coordinate...
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    Do you think Relativity theory can explain all the paradoxes?

    Firstly, happy Turkey Day to all. On another matter, let's say one uses radar time to determine the velocity of the target, using τ1 = ½( τ0+ τ2). Would not the non-inertial POV (of relative relativistic rate) often record superluminal motions? Thank You, GrayGhost
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    Do you think Relativity theory can explain all the paradoxes?

    Dalespam, But multiple points in 1 spacetime system do not map to any single event, wrt option 3 ... The convention of option 3 must allow for events to relocate per the non-inertial POV (including backward in time), which is something that can never happen per always-inertial POVs. So...
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    Do you think Relativity theory can explain all the paradoxes?

    DaleSpam, I should have said the above this way ... The event marked by Jill's remote location "when Bob first initiates his proper acceleration", digresses backward in time per Jack's spacetime system during his rapid proper acceleration. Indeed, Jill is always in the present per...
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    Do you think Relativity theory can explain all the paradoxes?

    PeterDonis, Your summaries are very good here. Trojan666ru need only realize the difference between "as the remotely located Jill presently exists in Jack's spacetime system" versus "as per EM images of Jill received by Jack at Jack's own location". I could explain this via Minkowski...
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