# Watch problem

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### Richard Hachel

Nov 22, 2021, 5:25:07 PM (13 days ago) Nov 22
to
In relativity, you always have to be extremely precise in the words and
terms you use.
It is not always easy.
For example, when we say: "When the origins O and O 'coincide, the watches
are triggered".
As Inspector Columbo would say: "Yes, sir, I'm not contradicting, sir, we
trigger the watches. But WHAT watches?"
A smart kid will immediately throw himself to the ground, giggling.
And he will say: "But the watches of the two origins O and O ', it is
obvious".
And Columbo, because it is Columbo will respond. "No, sir, it can't be
those watches. It's obviously not the ones that we set off."
And against all, he is right.
It is necessarily not those that we trigger.
I love this guy.

R.H.

### robby

Nov 23, 2021, 2:15:03 AM (13 days ago) Nov 23
to
Le 22/11/2021 à 23:25, Richard Hachel a écrit :
> In relativity, you always have to be extremely precise in the words
> and terms you use.

ce groupe est francophone.

--
Fabrice

### Thomas 'PointedEars' Lahn

Nov 23, 2021, 2:18:33 AM (13 days ago) Nov 23
to
Richard Hachel wrote:

> In relativity, you always have to be extremely precise in the words and
> terms you use.

And you are not.

> It is not always easy.

It becomes easier when you study this so that you know what you are talking

> For example, when we say: "When the origins O and O 'coincide, the watches
> are triggered".
> As Inspector Columbo would say: "Yes, sir, I'm not contradicting, sir, we
> trigger the watches. But WHAT watches?"
> A smart kid will immediately throw himself to the ground, giggling.
> And he will say: "But the watches of the two origins O and O ', it is
> obvious".

Nonsense. These are origins of spaceTIME coordinate systems. It is the
same as saying: There are two watches which are in the same place and
*there* they show the same time.

> And Columbo, because it is Columbo will respond. "No, sir, it can't be
> those watches. It's obviously not the ones that we set off."

Nonsense.

> And against all, he is right.
> It is necessarily not those that we trigger.
> I love this guy.

But you still do not understand special relativity.

PointedEars
--
Q: What did the female magnet say to the male magnet?
A: From the back, I found you repulsive, but from the front
I find myself very attracted to you.
(from: WolframAlpha)

### Richard Hachel

Nov 23, 2021, 3:39:13 PM (12 days ago) Nov 23
to
C'est vrai, ce groupe est francophone. Mais en matière de relativité, ce
que je dis reste vrai.
Il est très important de bien définir les choses, et de bien comprendre
les choses.

Or, en matière de relativité, certaines notions sont mathématiques,
mais elles sont intellectuellement "abstraite", dans le sens où on ne
comprend pas clairement ce qu'on est en train de dire.

Prenons le virage de la fusée dans le "voyageur de Langevin" lorsque le
jumeau des étoiles fait demi-tour.

Y a-t-il beaucoup de relativistes qui parviennent à se représenter le
"dessin animé" de la chose en l'esprit?

C'est un peu la même chose lorsqu'on écrit les transformations de
Lorentz, et surtout les transformations telles que je les donne, moi.

Le problèmes est : "que représentent tes variables?".

Comprend-on clairement de quoi ça parle?

Ce n'est pas toujours facile.

Prenons la transformation que je donne : tout le monde la comprend-elle?
Sait-on de quoi ça cause et quelles sont les quantités représentées?

Je le répète, tout cela n'est pas simple.

<http://news2.nemoweb.net/jntp?ZTxOvLZ3sEYypyQk038GfR7Fn64@jntp/Data.Media:1>

R.H.