We imagine a rocket lying on the x axis.
It is a small rocket which measures 5 meters.
The base is in position x1 = 3, and the head is in position x2 = 8.
An observer O 'then crosses O at this instant at 0.8c.
Where is x'1 and where is x'2 in R '?
Let's apply the TLs.
x '= (x-vTo) / sqrt (1-v² / c²)
The major mistake of ALL relativists consists in setting To = 0. However,
when O 'crosses O, the event that it will perceive (the rocket sends its
photon) has already occurred in R at To = -x / c
The best way to avoid this trap is to start directly from the same
formula, but using the form:
x '= γ [x + sqrt(x²+y²+z²).v/c]
We then have the real points x'1 and x'2.
We notice then that there is no, but then not at all, by change of frame
of reference, and in this precise and very real case (the universe is made
like that), of "contraction of the length of the rocket ", and that the
measurement of the length of this 5-meter rocket in R will strangle the
relativist who drinks his soup, when we give him the value of the"
contraction "in R '.

R.H.

--
"Mais ne nous y trompons pas. Il n'y a pas que de la violence
avec des armes. Il y a des situations de violence".
Abbé Pierre.
<http://news2.nemoweb.net/?DataID=xyfyVfDcvCxxW504G4htP_1Bsww@jntp>

Richard Hachel <r.hachel@tiscali.fr> wrote:
> We imagine a rocket lying on the x axis.
> It is a small rocket which measures 5 meters.
> The base is in position x1 = 3, and the head is in position x2 = 8.
> An observer O 'then crosses O at this instant at 0.8c.
> Where is x'1 and where is x'2 in R '?

To measure length of any object, this rocket included, the locations of the
endpoints have to be measured at the same time. Since this is done in
different locations, there needs to be assurance with clocks near those
locations, to insure that the measurements are at the same time.

This means that you CANNOT WAIT at the origin for a signal to arrive from
where the endpoints of the rocket are. Your whole premise, Richard, is that
there is on recording place, at the origin, where you have placed an
observer with one clock. This does not meet muster for invoking the
operational definition of length, and so unfortunately you have to abandon
this premise — it is useless (as I’ve told you before).

> Let's apply the TLs.
> x '= (x-vTo) / sqrt (1-v² / c²)
> The major mistake of ALL relativists consists in setting To = 0. However,
> when O 'crosses O, the event that it will perceive (the rocket sends its
> photon) has already occurred in R at To = -x / c
> The best way to avoid this trap is to start directly from the same
> formula, but using the form:
> x '= γ [x + sqrt(x²+y²+z²).v/c]
> We then have the real points x'1 and x'2.
> We notice then that there is no, but then not at all, by change of frame
> of reference, and in this precise and very real case (the universe is made
> like that), of "contraction of the length of the rocket ", and that the
> measurement of the length of this 5-meter rocket in R will strangle the
> relativist who drinks his soup, when we give him the value of the"
> contraction "in R '.
>
> R.H.
>
>
>
>

--
Odd Bodkin -- maker of fine toys, tools, tables

Le 03/01/2022 à 18:33, Odd Bodkin a écrit :
> Richard Hachel <r.hachel@tiscali.fr> wrote:
>> We imagine a rocket lying on the x axis.
>> It is a small rocket which measures 5 meters.
>> The base is in position x1 = 3, and the head is in position x2 = 8.
>> An observer O 'then crosses O at this instant at 0.8c.
>> Where is x'1 and where is x'2 in R'?
>
> To measure length of any object, this rocket included, the locations of the
> endpoints have to be measured at the same time.

Sure.

And?

I wrote : An observer O' then crosses O at this instant at 0.8c.

Where is x'1 and where is x'2 in R'?

R.H.

Richard Hachel <r.hachel@tiscali.fr> wrote:
> Le 03/01/2022 à 18:33, Odd Bodkin a écrit :
>> Richard Hachel <r.hachel@tiscali.fr> wrote:
>>> We imagine a rocket lying on the x axis.
>>> It is a small rocket which measures 5 meters.
>>> The base is in position x1 = 3, and the head is in position x2 = 8.
>>> An observer O 'then crosses O at this instant at 0.8c.
>>> Where is x'1 and where is x'2 in R'?
>>
>> To measure length of any object, this rocket included, the locations of the
>> endpoints have to be measured at the same time.
>
> Sure.
>
> And?
>
> I wrote : An observer O' then crosses O at this instant at 0.8c.

That’s the location of observers, one place at one time.
To *measure* the locations of the ends of the rocket, you need clocks near
the ends of the rocket. Neither of those are at the origin, because the
rocket isn’t there.

Simple question, Richard. You are standing alongside some train tracks. The
train is moving. Your job, according to your boss, is to measure the length
of this moving train. How would you go about that task?

>
> Where is x'1 and where is x'2 in R'?
>
>
> R.H.
>

--
Odd Bodkin -- maker of fine toys, tools, tables

On Monday, 3 January 2022 at 20:06:47 UTC+1, bodk...@gmail.com wrote:
> Richard Hachel <r.ha...@tiscali.fr> wrote:
> > Le 03/01/2022 à 18:33, Odd Bodkin a écrit :
> >> Richard Hachel <r.ha...@tiscali.fr> wrote:
> >>> We imagine a rocket lying on the x axis.
> >>> It is a small rocket which measures 5 meters.
> >>> The base is in position x1 = 3, and the head is in position x2 = 8.
> >>> An observer O 'then crosses O at this instant at 0.8c.
> >>> Where is x'1 and where is x'2 in R'?
> >>
> >> To measure length of any object, this rocket included, the locations of the
> >> endpoints have to be measured at the same time.
> >
> > Sure.
> >
> > And?
> >
> > I wrote : An observer O' then crosses O at this instant at 0.8c.
> That’s the location of observers, one place at one time.
> To *measure* the locations of the ends of the rocket, you need clocks near
> the ends of the rocket. Neither of those are at the origin, because the
> rocket isn’t there.

What a pity that clocks of the real world don't have much in
common with the delusions of poor idiot Giant Guru:(