Re: That Minkowski time intervals cannot be current in both frames.

"alen" <alen1@xxxxxxxxxxxxxxx> wrote in message news:f5792e19-c038-4900-90eb-d8b021ccb878@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
On Aug 28, 3:17 am, PD <thedraperfam...@xxxxxxxxx> wrote:
On Aug 27, 10:56 am, alen <al...@xxxxxxxxxxxxxxx> wrote:

[...]
> > ... and only a group of about 10 people could count on their
> > two hands the total number of times the meaning of "event"
> > was explained.
> > You are good at this, so perhaps you could have a go?
> > Good luck - you'll need it :-)

> > Dirk Vdm

> It's no good, Dirk. You guys have spacetime to work
> with, I don't. I work only dynamically, without any
> spacetime supposition, so I can't use your picture
> of what an 'event' means. To do so, for me, would
> be to presuppose the answer while I am still asking
> the question. So I have to try to talk to you in terms
> of your 'events' without subscribing to what you mean
> by the term, which is pretty difficult, and perhaps
> hopeless. It is very hard, perhaps impossible, to
> get any of you to even temporarily suspend the
> spacetime concept and go back to the original
> dynamical scenario Einstein used.

> Alen

The trick, you see, is communication, which means using terms with a
shared meaning. Often, this means establishing ahead of time what the
words mean. And when discussing a subject that is now rather old (like
relativity), those terms have long-established meanings, and it
behooves the beginner to ask what those words mean, rather than to
enter the discussion using the same words but with a whole different
connotation.

PD

Well, what would you do if the meanings
already contain an acceptance of something
that might not be correct? If you use the terms,
just for the sake of discussion, you must
implicitly accept what is possibly not correct.

If, for example, (x,y,z,t) and (x',y',z',t') are to
be regarded as different coordinate descriptions
of one spacetime event, but I don't accept that
they certainly do so,

In terms of a change-of-reference transform, they are *defined* to be that ... you don't have a choise .. you cannot change that definition or you are no longer talking about a change-of-reference transform.

That is the whole *point* of such a transform .. to tell you what the coordinates of the SAME event will be when labeled in a different frame of reference

and consider whether they
might not actually be referring to two distinct
spacetime events.

In which case (x',y',z',t') is NOT the result you get from applying the transform for the event (x,y,z,t) .. instead there there are *another* set of coordinates (x'1,y'1,z'1,t'1) that DO correspond to the event labeled (x,y,z,t) .. and the transform is between THOSE coordinates.

You can't be talking rationally about transforms for a set of coordinates for a single event, and then say that its a different event.

So how can I discuss an event
without assuming what I question, i.e. that there
is only one event, apart from the consideration that
the term 'event' therefore might not even be the most
appropriate description anyway??

So .. how do you map the coordinates of a single event from one frame of reference to another? You do accept that if an event exists, it exists in all frames of reference, as all the frame of reference does is define where you put your axes when working out coordinates. Events don't appear and disappear because you changed frame of reference


.

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