> On Tuesday, May 14, 2013 9:37:47 PM UTC+10, Y wrote:
> > On Sunday, May 5, 2013 6:50:12 PM UTC+10, HG Wilson wrote:
>
> > > Even if that were true, it does not affect my paradox.
>
> > > Time intervals that are equal in one frame cannot be UNEQUAL in
>
> > > another.
>
> > Yes they can. That is like saying, all of the visible vertical edges of a cube in a perspective drawing *MUST BE* the same length in the picture plane, even though the actual height of cube would be invariant. You need to understand the difference.
>
> It is not the same. Perspective has to do with angles subtended by identical heights.
Perspective is a drawing convention that follows certain rules, such
as linear perspective. In nature we do not see things in perspective.
The rules of what we actually see in nature are far too complex to
model completely in a perspective drawing for any given person, so we
make approximations of what people actually see with perspectives.
Perspectives are models.
When we look at objects in nature of invariant size, we also see that
they have relative size. This depends on the positioning and
perception of the observer.
Of course, it is possible to take a measuring tape and to walk around
to several locations to confirm that the size the objects are indeed
invariant. Doing so, it is also possible to make assertions on the
'absolute' sizes of these objects. Supposedly, SR does not or should
not concern with this. SR concerns with measurement from varied, non
orthogonal positions 'views' of things from other reference frames. In
many regards, these reference frames are analogous to a picture
plane.
In a nutshell, SR concerns with how to make or interpret measurements
in a 'parabolic' rather than linear perspective. Therefore, If the SR
Theory entails or purports that absolute forms of reference and
measurement are not possible, then the SR theory is wrong. Both
absolute and relative forms of measurement are mutually accessible.
Infact, in perspective, measurement is less dependable. Try measuring
a cube in a perspective drawing and make empirical comments on it's
dimensions. As I have shown you, perspective is rife with deception
and paradox.
Here's your problem. You feel that unlike the edge, or shape of an
object, time cannot be measured in a way that is consistent with a
relative view. To you, 'time' does not intersect the picture plane. I
will show you, this is because of your ill conceived view of time.
"Your 'perspective' idea does not apply to time intervals."
You may be right. Why does time not intersect the picture plane in the
same way that other projections do ? In my opinion, the only way for
time (from frame A) to intersect another observers picture plane at
(frame B), is if there is a light projection from (frame A's) clock.
This is the easiest way to think about it.
You believe that an interval is something that cannot be shown on a
drawing. It can. In my picture plane, I can have a projection of the
other observer's clock. If I generate that view for any given instant,
given that we have synchronised clocks, my view of my clock would show
a different time than his. Light took more time to project and arrive
from his source than mine.
An artist sits down with a picture plane and renders a landscape in an
instant. In that landscape are two identical clocks wired
synchronously. One of them is 1 meter away, and the other is 1 km.
Will that instantanous rendering have the same time for both clocks ?
No.
Does this mean that an absolute time is not accessible ? No.
The clock from frame A can be used as a height line for frame B. Might
need a 3rd clock here...
-y