Re: The Nanometre Twin

Peri of Pera wrote:
On Oct 28, 11:35 am, Tom Roberts <tjroberts...@xxxxxxxxxxxxx> wrote:
Peri of Pera wrote:
Bertie is 1.8m tall and weighs 60kg. In 2110 when he is 30 years of
age, he leaves on a spaceship to destination xyz in our galaxy. On
board, Bertie is in suspended animation with his body positioned in
the direction of motion. The speed of the spaceship is of a magnitude
to affect time, length and mass by a factor of 10. The trip to xyz and
back lasts 100 earth clock years but on his return Bertie should be
only 40 years of age due to the time dilation he experienced in space.
He should be 18cm tall and have a mass of 600kg according to the
contraction and mass increase effects of special relativity.
No. You are confusing effects on INCREMENTAL MEASUREMENTS with
accumulated values.

SR states that there are 3 effects of motion - TD, LC and MI. They
either occur together or not at all.

Asuming TD="time dilation, LC="Length contraction", and MI="'relativistic mass' increase", then yes, all three are based on the same factor gamma, which is a function of the velocity of the object relative to the inertial frame in which measurements are made.


Whether they remain after v
changes is another question.

Right. I thought that was you question -- you seem to think that all three remain after v changes. That's simply wrong, as each is a function of v, and when v=0 then gamma=1 and these effects disappear.

Note, however, that TD is the INSTANTANEOUS rate of clock ticks, and if one counts ticks then the COUNT will remain after v changes. This COUNT is what we mean by "clapsed proper time" or "age". Neither LC nor MI has this property, because we don't "count ticks" for them, we simply measure them at a given time. IOW: when the traveling twin returns and comes to rest, TD, LI, and MI all disappear (i.e. the ratio is 1.0), but the total # of clock ticks can be different because TD was not 1.0 during the trip.


I used 'suspended animation' to have Bertie in a consistent attitude
during the trip. If he moves around, he would shrink in all directions
not just from head to toe. He would return in an unhuman form.

You're not reading what I wrote. The effects of LC DISAPPEAR when the twin returns. He will return in NORMAL form.


Tom Roberts
.

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