Recent content by GrayGhost

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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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