sci.physics.research

On 23 Feb., 14:00, jacques <...@> wrote:
> On 22 f=E9v, 02:09, Ilja Schmelzer <...@>
> wrote:
>
> > On 15 Feb., 21:47, jacques <...@> wrote:

> In my understanding, that makes a conceptual difference which may
> explain why at the end of the round trip the elapsed proper time of
> traveler and lab observer (integrated on their respective worldline)
> are different but not their size.

The analogon of the size is the current speed of the clock. It is
unchanged as well.

What would be an analogon of proper time? Imagine two Bell spaceships
which, during their round-trip, measure the tension of the string and
integrate. Then the result will differ from similar spaceships in
rest.

Even better. Assume that the spaceships are not exactly ideal Bell
spaceships. They use the same power program, but the string influences
in an infinitesimal way their acceleration, which, therefore, is no
longer identical. The "size" of the spaceship pair decreases, and for
greater string tension decreases faster. Then, after the round trip,
the "size" will be smaller for the travelling device.

Thus, no asymmetry between space and time. And, in above cases, length
contraction and time dilation are physical effects.