| Topic: |
Science > Physics |
| User: |
"Stephen Bint" |
| Date: |
29 Oct 2003 08:57:42 PM |
| Object: |
Time dilation - No Need to Do the Math |
I started a thread about the twin paradox and cross-posted it to three
newsgroups. I am grateful to those who discussed it, even though it got a
tiny bit personal at times :)
I was frustrated by the account of the twin paradox in the FAQ for
sci.physics (http://www.faqs.org/faqs/physics-faq/part4/), because it
resorts to saying that there is assymetry in the situation. One twin has
undergone an acceleration and it is that one which is younger.
That cannot be the case, because time dilation is supposed to explain why a
light beam, travelling from floor to ceiling of a moving spaceship will not
trace out its V-shaped path faster than c. Time must appear to be slowed
down or else the observer, looking through the window will see the beam
travel faster than c.
But if two people pass eachother on skateboards, watching eachother's
bouncing beams, they must both see time dilation in the other, or one of
them will see the beam going faster than c.
Claiming an assymetry based on the acceleration histories of the observer,
overlooks the fact that the time dilation must be real and identical in both
directions at all times or else someone will see the bouncing beam going
faster than c.
If only one skateboard rider is younger, what did this younger one see, the
other getting older? The beam going even faster than expected, much more
than c?
It baffles me, that intelligent people, capable of algebra, cannot see that
the assertion that time is slowed in a moving frame is a symmetrical
assertion, because frames move relative to eachother, symmetrically.
Besides which, the formula for time dilation is a function of the velocity
of the observed frame and makes no mention whatsoever of the acceleration of
either frame, before or while the calculation is made.
I was told again and again by several posters, "Do the math. Just plug the
numbers into the formulas and it all works out just fine." These were the
same people who want me to factor in acceleration, which is not mentioned in
the formula, because time dilation is purely a function of the relative
velocity, which is the same in both directions.
Plug the relative velocity of skateboarders A and B into the formula and
find out how much slower B's clock is, than A's. And how much slower A's is,
than B's. I don't need to "do the math" to see that this formula is telling
me two things which cannot both be true.
I suppose it depends on your definition of "working out fine".
Because I constructed my example with two moving twins, to force them to
face the symmetry, the defenders of relativity introduced a new twist:
acceleration causes time to speed up, cancelling out the age difference, in
both skateboarders. This is an new addition to relativity. Einstein never
said anything of the sort.
To say that acceleration makes time run faster, implies that if one of the
skateboarders is accelerating, the time contraction due to acceleration will
at least partially counteract the dilation caused by the velocity (predicted
by Einstein), allowing the other to see the bouncing beam move faster than
c.
Still, though frustrated, I thoroughly enjoyed the thread I started and I am
grateful to all of the people who had the patience to contribute. In return,
I can only assure you that I will continue to post under the name "Stephen
Bint", so as not to undermine your killfile strategies.
And may I say in conclusion, that trying to bring the sweet light of reason
to the proponents of relativity, is like trying to bring salvation to the
DAMNED.
Stephen Bint
.
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| User: "kenseto" |
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| Title: Re: Time dilation - No Need to Do the Math |
02 Nov 2003 08:41:07 AM |
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"Stephen Bint" <binty@iname.com> wrote in message
news:3fa07dad$0$118$65c69314@mercury.nildram.net...
Besides which, the formula for time dilation is a function of the velocity
of the observed frame and makes no mention whatsoever of the acceleration
of
either frame, before or while the calculation is made.
I was told again and again by several posters, "Do the math. Just plug the
numbers into the formulas and it all works out just fine." These were the
same people who want me to factor in acceleration, which is not mentioned
in
the formula, because time dilation is purely a function of the relative
velocity, which is the same in both directions.
Relative motion (velocity v in the time dilation equation) between A and B
is the vector difference of their absolute motions. Whoever has a higher
state of absolute motion his clock will run slower than the other clock.
This means that if A has a higher state of absolute motion then his clock
will run slower than B's clock and from B's point of view his clock will run
faster than A's clock. This concept destroys the SR concept of mutual time
dilation and illustrates the incompleteness of SR.
Ken Seto
Plug the relative velocity of skateboarders A and B into the formula and
find out how much slower B's clock is, than A's. And how much slower A's
is,
than B's. I don't need to "do the math" to see that this formula is
telling
me two things which cannot both be true.
I suppose it depends on your definition of "working out fine".
Because I constructed my example with two moving twins, to force them to
face the symmetry, the defenders of relativity introduced a new twist:
acceleration causes time to speed up, cancelling out the age difference,
in
both skateboarders. This is an new addition to relativity. Einstein never
said anything of the sort.
To say that acceleration makes time run faster, implies that if one of the
skateboarders is accelerating, the time contraction due to acceleration
will
at least partially counteract the dilation caused by the velocity
(predicted
by Einstein), allowing the other to see the bouncing beam move faster than
c.
Still, though frustrated, I thoroughly enjoyed the thread I started and I
am
grateful to all of the people who had the patience to contribute. In
return,
I can only assure you that I will continue to post under the name "Stephen
Bint", so as not to undermine your killfile strategies.
And may I say in conclusion, that trying to bring the sweet light of
reason
to the proponents of relativity, is like trying to bring salvation to the
DAMNED.
Stephen Bint
.
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| User: "stmx3" |
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| Title: Re: Time dilation - No Need to Do the Math |
03 Nov 2003 09:52:44 AM |
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kenseto wrote:
[snip]
Relative motion (velocity v in the time dilation equation) between A and B
is the vector difference of their absolute motions. Whoever has a higher
state of absolute motion his clock will run slower than the other clock.
This means that if A has a higher state of absolute motion then his clock
will run slower than B's clock and from B's point of view his clock will run
faster than A's clock. This concept destroys the SR concept of mutual time
dilation and illustrates the incompleteness of SR.
Ken Seto
What is absolute motion in light of relativity? How do you determine
A's "higher state" of absolute motion?
[snip]
.
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| User: "kenseto" |
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| Title: Re: Time dilation - No Need to Do the Math |
03 Nov 2003 12:36:13 PM |
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"stmx3" <stmx3NOSPAMM@NOSPAMM.netscape.net> wrote in message
news:3FA67A60.50009@NOSPAMM.netscape.net...
kenseto wrote:
[snip]
Relative motion (velocity v in the time dilation equation) between A and
B
is the vector difference of their absolute motions. Whoever has a higher
state of absolute motion his clock will run slower than the other clock.
This means that if A has a higher state of absolute motion then his
clock
will run slower than B's clock and from B's point of view his clock will
run
faster than A's clock. This concept destroys the SR concept of mutual
time
dilation and illustrates the incompleteness of SR.
Ken Seto
What is absolute motion in light of relativity? How do you determine
A's "higher state" of absolute motion?
As I said observed relative velocity between A and B is the vector
difference of their absolute motions.
To determine the state of absolute motion of any observer you need to do the
experiment outlined in the following link:
A paper entitled "Unification of Physics" is available at the following
link. It includes a new proposed experiment to detect absolute motion.
http://www.journaloftheoretics.com/Links/Papers/Seto.pdf
Ken Seto
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| User: "stmx3" |
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| Title: Re: Time dilation - No Need to Do the Math |
03 Nov 2003 01:15:14 PM |
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kenseto wrote:
"stmx3" <stmx3NOSPAMM@NOSPAMM.netscape.net> wrote in message
news:3FA67A60.50009@NOSPAMM.netscape.net...
kenseto wrote:
[snip]
Relative motion (velocity v in the time dilation equation) between A and
B
is the vector difference of their absolute motions. Whoever has a higher
state of absolute motion his clock will run slower than the other clock.
This means that if A has a higher state of absolute motion then his
clock
will run slower than B's clock and from B's point of view his clock will
run
faster than A's clock. This concept destroys the SR concept of mutual
time
dilation and illustrates the incompleteness of SR.
Ken Seto
What is absolute motion in light of relativity? How do you determine
A's "higher state" of absolute motion?
As I said observed relative velocity between A and B is the vector
difference of their absolute motions.
To determine the state of absolute motion of any observer you need to do the
experiment outlined in the following link:
A paper entitled "Unification of Physics" is available at the following
link. It includes a new proposed experiment to detect absolute motion.
http://www.journaloftheoretics.com/Links/Papers/Seto.pdf
Damn! That was a waste of time. No well defined first principles. I
was suckered in.
Ken Seto
.
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| User: "kenseto" |
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| Title: Re: Time dilation - No Need to Do the Math |
04 Nov 2003 07:23:48 AM |
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"stmx3" <stmx3NOSPAMM@NOSPAMM.netscape.net> wrote in message
news:3FA6A9D6.9010908@NOSPAMM.netscape.net...
kenseto wrote:
"stmx3" <stmx3NOSPAMM@NOSPAMM.netscape.net> wrote in message
news:3FA67A60.50009@NOSPAMM.netscape.net...
kenseto wrote:
[snip]
Relative motion (velocity v in the time dilation equation) between A
and
B
is the vector difference of their absolute motions. Whoever has a
higher
state of absolute motion his clock will run slower than the other
clock.
This means that if A has a higher state of absolute motion then his
clock
will run slower than B's clock and from B's point of view his clock
will
run
faster than A's clock. This concept destroys the SR concept of mutual
time
dilation and illustrates the incompleteness of SR.
Ken Seto
What is absolute motion in light of relativity? How do you determine
A's "higher state" of absolute motion?
As I said observed relative velocity between A and B is the vector
difference of their absolute motions.
To determine the state of absolute motion of any observer you need to do
the
experiment outlined in the following link:
A paper entitled "Unification of Physics" is available at the following
link. It includes a new proposed experiment to detect absolute motion.
http://www.journaloftheoretics.com/Links/Papers/Seto.pdf
Damn! That was a waste of time. No well defined first principles. I
was suckered in.
Idiot.
.
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| User: "Dirk Van de moortel" |
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| Title: Re: Time dilation - No Need to Do the Math |
03 Nov 2003 11:10:51 AM |
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"stmx3" <stmx3NOSPAMM@NOSPAMM.netscape.net> wrote in message news:3FA67A60.50009@NOSPAMM.netscape.net...
kenseto wrote:
[snip]
Relative motion (velocity v in the time dilation equation) between A and B
is the vector difference of their absolute motions. Whoever has a higher
state of absolute motion his clock will run slower than the other clock.
This means that if A has a higher state of absolute motion then his clock
will run slower than B's clock and from B's point of view his clock will run
faster than A's clock. This concept destroys the SR concept of mutual time
dilation and illustrates the incompleteness of SR.
Ken Seto
What is absolute motion in light of relativity? How do you determine
A's "higher state" of absolute motion?
Here's Ken's definition of Absolute Motion:
http://users.pandora.be/vdmoortel/dirk/Physics/Fumbles/UltAbs.html
No joke.
Dirk Vdm
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| User: "stmx3" |
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| Title: Re: Time dilation - No Need to Do the Math |
03 Nov 2003 12:59:50 PM |
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Dirk Van de moortel wrote:
"stmx3" <stmx3NOSPAMM@NOSPAMM.netscape.net> wrote in message news:3FA67A60.50009@NOSPAMM.netscape.net...
kenseto wrote:
[snip]
Relative motion (velocity v in the time dilation equation) between A and B
is the vector difference of their absolute motions. Whoever has a higher
state of absolute motion his clock will run slower than the other clock.
This means that if A has a higher state of absolute motion then his clock
will run slower than B's clock and from B's point of view his clock will run
faster than A's clock. This concept destroys the SR concept of mutual time
dilation and illustrates the incompleteness of SR.
Ken Seto
What is absolute motion in light of relativity? How do you determine
A's "higher state" of absolute motion?
Here's Ken's definition of Absolute Motion:
http://users.pandora.be/vdmoortel/dirk/Physics/Fumbles/UltAbs.html
No joke.
Dirk Vdm
Damn! Does anyone discuss real physics on this ng? Is there a
moderated ng where someone can help or get help on the basics (not the
more advanced sci.physics.research ng)?
.
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| User: "Gregory L. Hansen" |
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| Title: Re: Time dilation - No Need to Do the Math |
03 Nov 2003 03:17:53 PM |
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In article <3FA6A63A.2040207@NOSPAMM.netscape.net>,
stmx3 <stmx3NOSPAMM@NOSPAMM.netscape.net> wrote:
Dirk Van de moortel wrote:
"stmx3" <stmx3NOSPAMM@NOSPAMM.netscape.net> wrote in message
news:3FA67A60.50009@NOSPAMM.netscape.net...
kenseto wrote:
[snip]
Relative motion (velocity v in the time dilation equation) between A and B
is the vector difference of their absolute motions. Whoever has a higher
state of absolute motion his clock will run slower than the other clock.
This means that if A has a higher state of absolute motion then his clock
will run slower than B's clock and from B's point of view his clock will run
faster than A's clock. This concept destroys the SR concept of mutual time
dilation and illustrates the incompleteness of SR.
Ken Seto
What is absolute motion in light of relativity? How do you determine
A's "higher state" of absolute motion?
Here's Ken's definition of Absolute Motion:
http://users.pandora.be/vdmoortel/dirk/Physics/Fumbles/UltAbs.html
No joke.
Dirk Vdm
Damn! Does anyone discuss real physics on this ng? Is there a
moderated ng where someone can help or get help on the basics (not the
more advanced sci.physics.research ng)?
Short of sci.physics.research, you probably won't find much better than
here. People do discuss real physics on this newsgroup sometimes, it can
be easy to miss. It helps to learn some of the names around here. People
have asked who are the crackpots and who are the scientists before, and
that's a question I won't answer. First, because the scientists will call
the crackpots crackpots and the crackpots will call the scientists
crackpots. Second, because even those new to the newsgroup and to physics
seem able to sort them out on their own pretty quickly.
--
"Let us learn to dream, gentlemen, then perhaps we shall find the
truth... But let us beware of publishing our dreams before they have been
put to the proof by the waking understanding." -- Friedrich August Kekulé
.
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| User: "sal" |
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| Title: Re: Time dilation - No Need to Do the Math |
03 Nov 2003 01:30:42 PM |
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stmx3 wrote:
Damn! Does anyone discuss real physics on this ng? Is there a
moderated ng where someone can help or get help on the basics (not the
more advanced sci.physics.research ng)?
There are some extremely competent people who participate in this ng,
who seem happy to spend time giving helpful answers to serious
questions, sometimes accompanied by textbook recommendations.
The current thread is, unfortunately, not an example of a serious
question, as far as I can tell.
--
To email me directly, take out nospam and put back foobox.
.
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| User: "Big Bird" |
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| Title: Re: Time dilation - No Need to Do the Math |
30 Oct 2003 10:55:54 PM |
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"Stephen Bint" <binty@iname.com> wrote in message news:<3fa07dad$0$118$65c69314@mercury.nildram.net>...
It baffles me, that intelligent people, capable of algebra, cannot see that
the assertion that time is slowed in a moving frame is a symmetrical
assertion, because frames move relative to eachother, symmetrically.
The reason is that all these intelligent people capable of algebra
have themselves been where you are now: ignorant of special
relativity, only in posession of some snippets and chunks gleaned from
the pop-literature.
Every physics freshman or highschool student who first learns SR
encounters exactly the same conceptual problems that you are
encountering -- that's why the twin-"paradoxon" and the various other
well-known riddles around relativity are such clichees.
Those other people then decided to learn what SR actually says and how
one is actually supposed to understand these things. Contrary to what
you falsely assert in the subject-line, there is very much the need to
do the math.
Until you have computed for yourself what SR actually has to say about
a given situation, you CANNOT POSSIBLY proclaim that its statements
are in conflict with observation. Because you have no idea what its
statements ARE.
Besides which, the formula for time dilation is a function of the velocity
of the observed frame and makes no mention whatsoever of the acceleration of
either frame, before or while the calculation is made.
You will forever be puzzled by relativity, as long as you think in
terms of a "formula for time dilation". You might as well give up
right here and now and either join the kooks or shut up. If you want
to *understand* special relativity, then you'll have to bite the
bullet and sit down and figure out by yourself for yourself (with the
aid of a good book, one might hope) what kind of mathematical
statements follow from which postulates in what order under what
assumptions.
Only if you have some mathematical grasp of WHY the Loretz transforms
look the way they do (and you have probably never actually seen the
form they take when they're used by actual physicists) can you
appreciate what might happen if you tweak this piece here or poke into
that end there.
You CANNOT understand SR if you think it is a bunch of formulas. Each
of the mathematical entities you may have encountered MEANS something.
And all your problems stem from a lack of grasp of that *meaning*.
.
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| User: "Paul Cardinale" |
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| Title: Re: Time dilation - No Need to Do the Math |
30 Oct 2003 08:57:58 AM |
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"Stephen Bint" <binty@iname.com> wrote in message news:<3fa07dad$0$118$65c69314@mercury.nildram.net>...
[crap snipped]
I see that you are both a jackass and an idiot.
You believe that because you are too stupid/lazy/arogant to learn the
math, that all you need to do is wave your arms and try to apply your
own ignorant comic-book misconception of relativity. You are a
clueless ineducable blubbering baffoon.
Paul Cardinale
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| User: "Stephen Bint" |
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| Title: Re: Time dilation - No Need to Do the Math |
30 Oct 2003 10:55:31 AM |
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"Paul Cardinale" <pcardinale@volcanomail.com> wrote in message
news:64050551.0310300657.2f5a033d@posting.google.com...
"Stephen Bint" <binty@iname.com> wrote in message
news:<3fa07dad$0$118$65c69314@mercury.nildram.net>...
[crap snipped]
I see that you are both a jackass and an idiot.
You believe that because you are too stupid/lazy/arogant to learn the
math, that all you need to do is wave your arms and try to apply your
own ignorant comic-book misconception of relativity. You are a
clueless ineducable blubbering baffoon.
Paul Cardinale
You can only resort to personal attacks. What you cannot do is face the
issue, which I keep bringing up for you to ignore. You call me names, you
bleat "do the math" and you run like a cur from the question at hand.
This is the question I have asked Jon Bell. You won't be able to answer it
and I suspect you won't even understand it:
Two skateboards glide past eachother at speed.
On each skateboard is an observer and a device which sends a light pulse
from a source which is 1m above the base, vertically down to a mirror on the
base, which reflects it directly vertically back to the source. To one of
the observers (either one) the light pulse on the other board traces a
V-shaped path, which is longer than the vertical one. If there is no time
dilation, the observer will see the pulse travel a greater distance in the
same time, and therefore, see it travelling faster than c.
Time dilation slows the event on the other skateboard, the exact amount
necessary to make the light pulse travel this longer path at exactly c. The
length of the V-shaped path and consequently, the time dilation required, is
purely a function of the relative velocity of the two skateboards.
Furthermore, the path that A sees the pulse trace on B's skateboard is
exactly the same length as the path seen by B, taken by the light pulse on
A's skateboard.
So the time dilation must be identical in both directions, regardless of how
they acheived their relative velocity.
So what if your travelling twin was passing earth and viewing such an
experiment there. Either he will see time slowed down there, or he will see
the light pulse travelling faster than c there. Is that not the case?
So there it is. Don't worry if you can't see the point or understand the
question. Just call me few names and bleat "Do the math!" over and over and
everyone will think you are mature and intelligent.
Stephen
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| User: "Paul Cardinale" |
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| Title: Re: Time dilation - No Need to Do the Math |
30 Oct 2003 09:05:14 PM |
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"Stephen Bint" <binty@iname.com> wrote in message news:<3fa1420b$0$113$65c69314@mercury.nildram.net>...
"Paul Cardinale" <pcardinale@volcanomail.com> wrote in message
news:64050551.0310300657.2f5a033d@posting.google.com...
"Stephen Bint" <binty@iname.com> wrote in message
news:<3fa07dad$0$118$65c69314@mercury.nildram.net>...
[crap snipped]
I see that you are both a jackass and an idiot.
You believe that because you are too stupid/lazy/arogant to learn the
math, that all you need to do is wave your arms and try to apply your
own ignorant comic-book misconception of relativity. You are a
clueless ineducable blubbering baffoon.
Paul Cardinale
You can only resort to personal attacks. What you cannot do is face the
issue, which I keep bringing up for you to ignore. You call me names,
You deserved every bit of it by making asinine assertions about a
theory without bothering to learn the theory. Moreoverm your premise
that you needn't bother to calculate what a theory predicts in order
to claim that it's predictions are false goes beyond idiotic.
you
bleat "do the math" and you run like a cur from the question at hand.
This is the question I have asked Jon Bell. You won't be able to answer it
and I suspect you won't even understand it:
"Ah. Arogance and stupidity all in one package. How efficient of
you."
Two skateboards glide past eachother at speed.
On each skateboard is an observer and a device which sends a light pulse
from a source which is 1m above the base, vertically down to a mirror on the
base, which reflects it directly vertically back to the source. To one of
the observers (either one) the light pulse on the other board traces a
V-shaped path, which is longer than the vertical one. If there is no time
dilation, the observer will see the pulse travel a greater distance in the
same time, and therefore, see it travelling faster than c.
Time dilation slows the event on the other skateboard, the exact amount
necessary to make the light pulse travel this longer path at exactly c. The
length of the V-shaped path and consequently, the time dilation required, is
purely a function of the relative velocity of the two skateboards.
Furthermore, the path that A sees the pulse trace on B's skateboard is
exactly the same length as the path seen by B, taken by the light pulse on
A's skateboard.
So the time dilation must be identical in both directions, regardless of how
they acheived their relative velocity.
So what if your travelling twin was passing earth and viewing such an
experiment there. Either he will see time slowed down there, or he will see
the light pulse travelling faster than c there. Is that not the case?
Each twin will observe the other's clock to be running slow.
Note however that the formula for time dilation, by itself, is
insufficient for resolving the twin paradox.
Paul Cardinale
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| User: "Stephen Bint" |
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| Title: Re: Time dilation - No Need to Do the Math |
31 Oct 2003 08:28:00 PM |
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"Paul Cardinale" <pcardinale@volcanomail.com> wrote in message
news:64050551.0310301905.49591179@posting.google.com...
"Stephen Bint" <binty@iname.com> wrote in message
news:<3fa1420b$0$113$65c69314@mercury.nildram.net>...
So what if your travelling twin was passing earth and viewing such an
experiment there. Either he will see time slowed down there, or he will
see
the light pulse travelling faster than c there. Is that not the case?
Each twin will observe the other's clock to be running slow.
So, will they both be younger than eachother, afterwards? They have
experienced the same degree of time dilation, have they not?
Note however that the formula for time dilation, by itself, is
insufficient for resolving the twin paradox.
Paul Cardinale
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| User: "Paul Cardinale" |
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| Title: Re: Time dilation - No Need to Do the Math |
03 Nov 2003 09:40:42 AM |
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"Stephen Bint" <binty@iname.com> wrote in message news:<3fa319b2$0$105$65c69314@mercury.nildram.net>...
"Paul Cardinale" <pcardinale@volcanomail.com> wrote in message
news:64050551.0310301905.49591179@posting.google.com...
"Stephen Bint" <binty@iname.com> wrote in message
news:<3fa1420b$0$113$65c69314@mercury.nildram.net>...
So what if your travelling twin was passing earth and viewing such an
experiment there. Either he will see time slowed down there, or he will
see
the light pulse travelling faster than c there. Is that not the case?
Each twin will observe the other's clock to be running slow.
So, will they both be younger than eachother, afterwards?
No, of course not. In the usual scenerio, the travelling twin
observes the Earth-bound clock to advance rapidly as he turns around.
This more than offsets the slowing due to relative motion that he
observes of his twin's clock on Earth.
They have
experienced the same degree of time dilation, have they not?
They have both observed the same amount of time dilation in the
other's time;
however the travelling twin observed an additional effect of his
twin's time rapidly advancing as he turned around.
Paul Cardinale
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| User: "Stephen Bint" |
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| Title: Re: Time dilation - No Need to Do the Math |
03 Nov 2003 06:45:54 PM |
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"Paul Cardinale" <pcardinale@volcanomail.com> wrote in message
news:64050551.0311030740.60d5fa30@posting.google.com...
"Stephen Bint" <binty@iname.com> wrote in message
news:<3fa319b2$0$105$65c69314@mercury.nildram.net>...
"Paul Cardinale" <pcardinale@volcanomail.com> wrote in message
news:64050551.0310301905.49591179@posting.google.com...
"Stephen Bint" <binty@iname.com> wrote in message
news:<3fa1420b$0$113$65c69314@mercury.nildram.net>...
So what if your travelling twin was passing earth and viewing such
an
experiment there. Either he will see time slowed down there, or he
will
see
the light pulse travelling faster than c there. Is that not the
case?
Each twin will observe the other's clock to be running slow.
So, will they both be younger than eachother, afterwards?
No, of course not. In the usual scenerio, the travelling twin
observes the Earth-bound clock to advance rapidly as he turns around.
This more than offsets the slowing due to relative motion that he
observes of his twin's clock on Earth.
They have
experienced the same degree of time dilation, have they not?
They have both observed the same amount of time dilation in the
other's time;
however the travelling twin observed an additional effect of his
twin's time rapidly advancing as he turned around.
Paul Cardinale
Paul,
I can no longer see inconsistency in your position. I am still not prepared
to say that I believe in time dilation, or that it is definitely not
paradoxical, but your position does not contradict itself as I first
thought.
Stephen
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| User: "Jeff Root" |
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| Title: Re: Time dilation - No Need to Do the Math |
03 Nov 2003 01:00:10 PM |
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Paul Cardinale replied to Stephen Bint:
In the usual scenerio, the travelling twin observes the
Earth-bound clock to advance rapidly as he turns around.
I'm no expert on relativity, but that statement appears to be
incorrect. It is at least misleading.
The acceleration isn't what causes the rapid advancement, it
is the new velocity, which is in the opposite direction from
the old velocity relative to the other twin. If the change
in velocity takes a long time, which it must if the twin in
the spacecraft is not to be squished, then there will be a
significant amount of advancement seen in the stay-at-home's
clock during the acceleration. But if it happens very quickly,
the time of the turnaround simply marks a rapid change in the
observed rate of advancement of the stay-at-home's clock. In
either case, the rate of advancement increases from the start
of the turnaround acceleration to the end.
-- Jeff, in Minneapolis
..
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| User: "Stephen Bint" |
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| Title: Re: Time dilation - No Need to Do the Math |
03 Nov 2003 06:46:06 PM |
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"Jeff Root" <jeff5@freemars.org> wrote in message
news:964c68dd.0311031100.68127400@posting.google.com...
Paul Cardinale replied to Stephen Bint:
In the usual scenerio, the travelling twin observes the
Earth-bound clock to advance rapidly as he turns around.
I'm no expert on relativity, but that statement appears to be
incorrect. It is at least misleading.
The acceleration isn't what causes the rapid advancement, it
is the new velocity, which is in the opposite direction from
the old velocity relative to the other twin. If the change
in velocity takes a long time, which it must if the twin in
the spacecraft is not to be squished, then there will be a
significant amount of advancement seen in the stay-at-home's
clock during the acceleration. But if it happens very quickly,
the time of the turnaround simply marks a rapid change in the
observed rate of advancement of the stay-at-home's clock. In
either case, the rate of advancement increases from the start
of the turnaround acceleration to the end.
-- Jeff, in Minneapolis
.
I disagree. Time dilation is direction-independent. Unfortunately most
treaments of it use examples of twins moving away and back, so that red and
blue shift effects on timing signals are huge compared to the time dilation
effects, which muddies the waters.
Stephen
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| User: "Bilge" |
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| Title: Re: Time dilation - No Need to Do the Math |
03 Nov 2003 07:25:38 PM |
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Stephen Bint:
"Jeff Root" <jeff5@freemars.org> wrote in message
news:964c68dd.0311031100.68127400@posting.google.com...
Paul Cardinale replied to Stephen Bint:
In the usual scenerio, the travelling twin observes the
Earth-bound clock to advance rapidly as he turns around.
I'm no expert on relativity, but that statement appears to be
incorrect. It is at least misleading.
The acceleration isn't what causes the rapid advancement, it
is the new velocity, which is in the opposite direction from
the old velocity relative to the other twin. If the change
in velocity takes a long time, which it must if the twin in
the spacecraft is not to be squished, then there will be a
significant amount of advancement seen in the stay-at-home's
clock during the acceleration. But if it happens very quickly,
the time of the turnaround simply marks a rapid change in the
observed rate of advancement of the stay-at-home's clock. In
either case, the rate of advancement increases from the start
of the turnaround acceleration to the end.
-- Jeff, in Minneapolis
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I disagree. Time dilation is direction-independent.
No, it isn't. The velocity only enters as v^2 which is a positive
number.
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| User: "Paul Cardinale" |
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| Title: Re: Time dilation - No Need to Do the Math |
03 Nov 2003 05:54:33 PM |
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(Jeff Root) wrote in message news:<964c68dd.0311031100.68127400@posting.google.com>...
Paul Cardinale replied to Stephen Bint:
In the usual scenerio, the travelling twin observes the
Earth-bound clock to advance rapidly as he turns around.
I'm no expert on relativity, but that statement appears to be
incorrect.
You are mistaken. It is correct.
It is at least misleading.
Not at all.
The acceleration isn't what causes the rapid advancement, it
is the new velocity,
In case you hadn't noticed, the acceleration IS the change to a new velocity.
which is in the opposite direction from
the old velocity relative to the other twin. If the change
in velocity takes a long time, which it must if the twin in
the spacecraft is not to be squished, then there will be a
significant amount of advancement seen in the stay-at-home's
clock during the acceleration.
Sure.
But if it happens very quickly,
the time of the turnaround simply marks a rapid change in the
observed rate of advancement of the stay-at-home's clock.
Right.
In
either case, the rate of advancement increases from the start
of the turnaround acceleration to the end.
Which is in complete agreement with what I wrote.
Paul Cardinale
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| User: "Jeff Root" |
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| Title: Re: Time dilation - No Need to Do the Math |
04 Nov 2003 09:47:41 AM |
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Paul Cardinale replied to Jeff Root:
Paul Cardinale replied to Stephen Bint:
In the usual scenerio, the travelling twin observes the
Earth-bound clock to advance rapidly as he turns around.
I'm no expert on relativity, but that statement appears to be
incorrect.
You are mistaken. It is correct.
It is at least misleading.
Not at all.
So you are saying that the travelling twin observes the
Earth-bound clock to advance rapidly as he turns around,
and then stop advancing rapidly when the turn is completed
and he is coasting back to Earth. The rate of advancement
observed during the turnaround is greater than at any other
time. Correct?
The acceleration isn't what causes the rapid advancement, it
is the new velocity,
In case you hadn't noticed, the acceleration IS the change to a
new velocity.
Yes, the acceleration is the change to a new velocity. But the
acceleration is not the new velocity. My understanding is that
it is the velocity which causes the effect, not the change to
that velocity.
which is in the opposite direction from
the old velocity relative to the other twin. If the change
in velocity takes a long time, which it must if the twin in
the spacecraft is not to be squished, then there will be a
significant amount of advancement seen in the stay-at-home's
clock during the acceleration.
Sure.
But if it happens very quickly,
the time of the turnaround simply marks a rapid change in the
observed rate of advancement of the stay-at-home's clock.
Right.
In either case, the rate of advancement increases from the
start of the turnaround acceleration to the end.
Which is in complete agreement with what I wrote.
What you wrote previously clearly implied that the observed
rate of advancement is proportional to the acceleration during
the turnaround. I don't believe you meant that.
-- Jeff, in Minneapolis
..
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| User: "Paul Cardinale" |
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| Title: Re: Time dilation - No Need to Do the Math |
05 Nov 2003 08:39:14 AM |
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(Jeff Root) wrote in message news:<964c68dd.0311040747.74ed6140@posting.google.com>...
Paul Cardinale replied to Jeff Root:
Paul Cardinale replied to Stephen Bint:
In the usual scenerio, the travelling twin observes the
Earth-bound clock to advance rapidly as he turns around.
I'm no expert on relativity, but that statement appears to be
incorrect.
You are mistaken. It is correct.
It is at least misleading.
Not at all.
So you are saying that the travelling twin observes the
Earth-bound clock to advance rapidly as he turns around,
and then stop advancing rapidly when the turn is completed
and he is coasting back to Earth. The rate of advancement
observed during the turnaround is greater than at any other
time. Correct?
Correct.
The acceleration isn't what causes the rapid advancement, it
is the new velocity,
In case you hadn't noticed, the acceleration IS the change to a
new velocity.
Yes, the acceleration is the change to a new velocity. But the
acceleration is not the new velocity. My understanding is that
it is the velocity which causes the effect, not the change to
that velocity.
Depends what you mean by "the effect". Time dilation is a function of
velocity.
But the rapid advancement observed at the turnaround occurs because of
the turnaround, which of course goes hand-in-hand with the
acceleration.
which is in the opposite direction from
the old velocity relative to the other twin. If the change
in velocity takes a long time, which it must if the twin in
the spacecraft is not to be squished, then there will be a
significant amount of advancement seen in the stay-at-home's
clock during the acceleration.
Sure.
But if it happens very quickly,
the time of the turnaround simply marks a rapid change in the
observed rate of advancement of the stay-at-home's clock.
Right.
In either case, the rate of advancement increases from the
start of the turnaround acceleration to the end.
Which is in complete agreement with what I wrote.
What you wrote previously clearly implied that the observed
rate of advancement is proportional to the acceleration during
the turnaround. I don't believe you meant that.
To find the relationship between the observed rate of advancement and
acceleration, differentiate the LT with respect to t and solve for t'.
Paul Cardinale
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| User: "Jon Bell" |
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| Title: Re: Time dilation - No Need to Do the Math |
05 Nov 2003 09:55:42 AM |
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In article <64050551.0311050639.1b3799e0@posting.google.com>,
Paul Cardinale <pcardinale@volcanomail.com> wrote:
jeff5@freemars.org (Jeff Root) wrote in message
news:<964c68dd.0311040747.74ed6140@posting.google.com>...
So you are saying that the travelling twin observes the
Earth-bound clock to advance rapidly as he turns around,
and then stop advancing rapidly when the turn is completed
and he is coasting back to Earth. The rate of advancement
observed during the turnaround is greater than at any other
time. Correct?
Correct.
Provided of course that you interpret the word "observe" carefully, and
come up with a suitable procedure for performing that observation. See
the posting I just made in another thread, which describes such a
procedure.
--
Jon Bell <jtbellap8@presby.edu> Presbyterian College
Dept. of Physics and Computer Science Clinton, South Carolina USA
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| User: "Gregory L. Hansen" |
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| Title: Re: Time dilation - No Need to Do the Math |
03 Nov 2003 03:10:13 PM |
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In article <964c68dd.0311031100.68127400@posting.google.com>,
Jeff Root <jeff5@freemars.org> wrote:
Paul Cardinale replied to Stephen Bint:
In the usual scenerio, the travelling twin observes the
Earth-bound clock to advance rapidly as he turns around.
I'm no expert on relativity, but that statement appears to be
incorrect. It is at least misleading.
The acceleration isn't what causes the rapid advancement, it
is the new velocity, which is in the opposite direction from
the old velocity relative to the other twin. If the change
in velocity takes a long time, which it must if the twin in
the spacecraft is not to be squished, then there will be a
significant amount of advancement seen in the stay-at-home's
clock during the acceleration. But if it happens very quickly,
the time of the turnaround simply marks a rapid change in the
observed rate of advancement of the stay-at-home's clock. In
either case, the rate of advancement increases from the start
of the turnaround acceleration to the end.
It's a comment on the subject line, anyway. Try "Time Dilation - You
Gotta Do The Math". The experiment can be analyzed from the Earth frame
by assuming instantaneous acceleration. That's fine because an
Earth-frame analysis ignores the point of view of the traveller. But when
you hop onto the spaceship with the travelling twin, a lot happens during
that acceleration and you need to calculate it explicitly to see how the
traveller relates to pre-acceleration and post-acceleration Earth time.
See, e.g., Muller, "The Twin Paradox in Special Relativity", AJP 40, 966
(1972). From the abstract, "If we account for the effects of acceleration
by keeping track of the instantaneous Lorentz frame of the accelerating
twin, both calculations agree."
Or Perrin, "Twin paradox: A complete treatment from the point of view of
each twin", Am J Phys 47, 317 (1979).
--
"Let us learn to dream, gentlemen, then perhaps we shall find the
truth... But let us beware of publishing our dreams before they have been
put to the proof by the waking understanding." -- Friedrich August Kekulé
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| User: "Dan Bloomquist" |
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| Title: Re: Time dilation - No Need to Do the Math |
01 Nov 2003 10:55:27 AM |
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Stephen Bint wrote:
"Paul Cardinale" <pcardinale@volcanomail.com> wrote in message
Each twin will observe the other's clock to be running slow.
So, will they both be younger than eachother, afterwards? They have
experienced the same degree of time dilation, have they not?
You just took the word 'observe' and turned it into 'be'. The twins
don't 'experience' time dilation. There is no time dilation _in_ the
observer's frame. The 'laws' of physics are identical for both twins in
their own frames.
As this thread seems to go in circles, I'll guess your next question is,
'How can they observe each other getting younger but they are not?'
Because you are assuming some master clock that says how old they are
without relevance to the distance between them. SR is a space-time
theory, it is not an absolute time theory. As long as you drag stuff
into the theory that isn't part of the theory you are not addressing the
theory.
Best, Dan.
--
http://lakeweb.net
http://ReserveAnalyst.com
dbAtLakewebDotCom
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| User: "Stephen Bint" |
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| Title: Re: Time dilation - No Need to Do the Math |
01 Nov 2003 01:07:59 PM |
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"Dan Bloomquist" <lakeweb@citlink.net> wrote in message
news:3FA3E579.8060607@citlink.net...
Stephen Bint wrote:
"Paul Cardinale" <pcardinale@volcanomail.com> wrote in message
Each twin will observe the other's clock to be running slow.
So, will they both be younger than eachother, afterwards? They have
experienced the same degree of time dilation, have they not?
You just took the word 'observe' and turned it into 'be'. The twins
don't 'experience' time dilation. There is no time dilation _in_ the
observer's frame. The 'laws' of physics are identical for both twins in
their own frames.
As this thread seems to go in circles, I'll guess your next question is,
'How can they observe each other getting younger but they are not?'
Because you are assuming some master clock that says how old they are
without relevance to the distance between them. SR is a space-time
theory, it is not an absolute time theory. As long as you drag stuff
into the theory that isn't part of the theory you are not addressing the
theory.
Best, Dan.
--
http://lakeweb.net
http://ReserveAnalyst.com
dbAtLakewebDotCom
Dan,
Am I to blame for the thread going in circles? The FAQ for this newsgroup
and many posters who have berated me for my ignorance/stupidity/whatever,
have said that time dilation slows aging. When that becomes embarassing,
they switch to saying it doesn't. I go in circles, chasing them.
Stephen
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| User: "Dan Bloomquist" |
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| Title: Re: Time dilation - No Need to Do the Math |
01 Nov 2003 01:50:30 PM |
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Stephen Bint wrote:
"Dan Bloomquist" <lakeweb@citlink.net> wrote in message
news:3FA3E579.8060607@citlink.net...
Stephen Bint wrote:
"Paul Cardinale" <pcardinale@volcanomail.com> wrote in message
Each twin will observe the other's clock to be running slow.
So, will they both be younger than eachother, afterwards? They have
experienced the same degree of time dilation, have they not?
You just took the word 'observe' and turned it into 'be'. The twins
don't 'experience' time dilation. There is no time dilation _in_ the
observer's frame. The 'laws' of physics are identical for both twins in
their own frames.
As this thread seems to go in circles, I'll guess your next question is,
'How can they observe each other getting younger but they are not?'
Because you are assuming some master clock that says how old they are
without relevance to the distance between them. SR is a space-time
theory, it is not an absolute time theory. As long as you drag stuff
into the theory that isn't part of the theory you are not addressing the
theory.
Best, Dan.
--
http://lakeweb.net
http://ReserveAnalyst.com
dbAtLakewebDotCom
Dan,
Am I to blame for the thread going in circles? The FAQ for this newsgroup
and many posters who have berated me for my ignorance/stupidity/whatever,
have said that time dilation slows aging. When that becomes embarassing,
they switch to saying it doesn't. I go in circles, chasing them.
Here it is, apples:
dilation slows aging for _one_(A) twin _relative_ to the other twin(B)
_if_ one twin(A) travels in multiple frames of reference. Time dilation
did not occur in either frame on it's own. The twins traveled in
different spacetimes _and_ returned to the same frame.
Oranges:
You said, 'So, will they both be younger than eachother, afterwards?'
I haven't seen anyone use the term 'afterwards' in the context of
inertial frames. I haven't seen anyone say 'they will _be_ younger than
each other.'
You said, 'They have experienced the same degree of time dilation.' SR
didn't say this, you did. I pointed out that you took the word 'observe'
and turned it into 'be'. You are still claiming a circle without
addressing the contraction you are creating.
Now, you can not point out a contradiction unless you say SR says
something it doesn't, it is that simple. You are inventing
contradictions in your mind and to support those contradiction you are
misrepresenting the theory.
Best, Dan.
--
http://lakeweb.net
http://ReserveAnalyst.com
dbAtLakewebDotCom
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| User: "Stephen Bint" |
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| Title: Re: Time dilation - No Need to Do the Math |
01 Nov 2003 07:28:23 PM |
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"Dan Bloomquist" <lakeweb@citlink.net> wrote in message
news:3FA40E80.4050900@citlink.net...
Stephen Bint wrote:
"Dan Bloomquist" <lakeweb@citlink.net> wrote in message
news:3FA3E579.8060607@citlink.net...
Stephen Bint wrote:
"Paul Cardinale" <pcardinale@volcanomail.com> wrote in message
Each twin will observe the other's clock to be running slow.
So, will they both be younger than eachother, afterwards? They have
experienced the same degree of time dilation, have they not?
You just took the word 'observe' and turned it into 'be'. The twins
don't 'experience' time dilation. There is no time dilation _in_ the
observer's frame. The 'laws' of physics are identical for both twins in
their own frames.
As this thread seems to go in circles, I'll guess your next question is,
'How can they observe each other getting younger but they are not?'
Because you are assuming some master clock that says how old they are
without relevance to the distance between them. SR is a space-time
theory, it is not an absolute time theory. As long as you drag stuff
into the theory that isn't part of the theory you are not addressing the
theory.
Best, Dan.
--
http://lakeweb.net
http://ReserveAnalyst.com
dbAtLakewebDotCom
Dan,
Am I to blame for the thread going in circles? The FAQ for this
newsgroup
and many posters who have berated me for my
ignorance/stupidity/whatever,
have said that time dilation slows aging. When that becomes embarassing,
they switch to saying it doesn't. I go in circles, chasing them.
Here it is, apples:
dilation slows aging for _one_(A) twin _relative_ to the other twin(B)
_if_ one twin(A) travels in multiple frames of reference. Time dilation
did not occur in either frame on it's own. The twins traveled in
different spacetimes _and_ returned to the same frame.
Oranges:
You said, 'So, will they both be younger than eachother, afterwards?'
I haven't seen anyone use the term 'afterwards' in the context of
inertial frames. I haven't seen anyone say 'they will _be_ younger than
each other.'
You said, 'They have experienced the same degree of time dilation.' SR
didn't say this, you did. I pointed out that you took the word 'observe'
and turned it into 'be'. You are still claiming a circle without
addressing the contraction you are creating.
Now, you can not point out a contradiction unless you say SR says
something it doesn't, it is that simple. You are inventing
contradictions in your mind and to support those contradiction you are
misrepresenting the theory.
Best, Dan.
Dan,
You say that I cannot point out a contradiction. The FAQ says that a twin
flies away from earth and back again and has aged less. It says the reason
they haven't both aged less is because the has undergone several
accelerations.
The contradiction is this. If time dilation occurs, it happens both ways.
The effects of relative velocity must work two ways, because relative
velocity is a two-way relationship.
Because when earth looks at the travelling twin they must not see the light
in his cabin go faster than c, the twin must be dilated wrt earth.
Because when the travelling twin looks at the earth the twin must not see
the light on earth go faster than c, so the earth must be dilated, wrt twin.
The contradiction is, that time dilation occurs for both parties, but only
causes aging in one party.
It suggests that time dilation causes aging, sometimes.
Stephen
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| User: "Dan Bloomquist" |
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| Title: Re: Time dilation - No Need to Do the Math |
01 Nov 2003 09:09:23 PM |
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Stephen Bint wrote:
Dan,
You say that I cannot point out a contradiction. The FAQ says that a twin
flies away from earth and back again and has aged less. It says the reason
they haven't both aged less is because the has undergone several
accelerations.
In case you missed the page:
http://www.phys.unsw.edu.au/~jw/twin.html
The contradiction is this. If time dilation occurs, it happens both ways.
The effects of relative velocity must work two ways, because relative
velocity is a two-way relationship.
Only if the frames _stay_ inertial.
Because when earth looks at the travelling twin they must not see the light
in his cabin go faster than c, the twin must be dilated wrt earth.
Not sure why the 'must' baggage, but yes.
Because when the travelling twin looks at the earth the twin must not see
the light on earth go faster than c, so the earth must be dilated, wrt twin.
yes.
The contradiction is, that time dilation occurs for both parties, but only
causes aging in one party.
Point out the contradiction in the link, explicitly. Quit pretending
twin B did _not_ change frames.
It suggests that time dilation causes aging, sometimes.
There is no suggestion, there is no paradox. The math has been tested
against almost 100 years of observations. The math is explicit, there is
no 'sometimes'.
You are claiming a contradiction yet you can not point it out. You are
saying it doesn't make sense to you therefore it is wrong. And what it
amounts to is to say nature doesn't suit your your senses so nature is
wrong. Well, here is the real clue, nature could care less what you
think. Science is about building models around observations. SR is
observationally consistent. Consider the particle in an accelerator,
(among other experiments), as twin B.
But, if you'd like, continue to say the model is wrong without pointing
to the observation that backs your claim. And don't use the observation
you invent in your mind.
And, if you are sincere about getting this, it is about 'spacetime',
'spacetime', 'spacetime'.
T^2 = t^2 - s^2
There really is no more to it. Quite eloquent, IMHO.
Stephen
Best, Dan.
--
http://lakeweb.net
http://ReserveAnalyst.com
dbAtLakewebDotCom
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| User: "Stephen Bint" |
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| Title: Re: Time dilation - No Need to Do the Math |
01 Nov 2003 11:07:45 PM |
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"Dan Bloomquist" <lakeweb@citlink.net> wrote in message
news:3FA4755C.60702@citlink.net...
Stephen Bint wrote:
Dan,
You say that I cannot point out a contradiction. The FAQ says that a
twin
flies away from earth and back again and has aged less. It says the
reason
they haven't both aged less is because the has undergone several
accelerations.
In case you missed the page:
http://www.phys.unsw.edu.au/~jw/twin.html
The contradiction is this. If time dilation occurs, it happens both
ways.
The effects of relative velocity must work two ways, because relative
velocity is a two-way relationship.
Only if the frames _stay_ inertial.
Because when earth looks at the travelling twin they must not see the
light
in his cabin go faster than c, the twin must be dilated wrt earth.
Not sure why the 'must' baggage, but yes.
Because when the travelling twin looks at the earth the twin must not
see
the light on earth go faster than c, so the earth must be dilated, wrt
twin.
yes.
The contradiction is, that time dilation occurs for both parties, but
only
causes aging in one party.
Point out the contradiction in the link, explicitly. Quit pretending
twin B did _not_ change frames.
It suggests that time dilation causes aging, sometimes.
There is no suggestion, there is no paradox. The math has been tested
against almost 100 years of observations. The math is explicit, there is
no 'sometimes'.
You are claiming a contradiction yet you can not point it out. You are
saying it doesn't make sense to you therefore it is wrong. And what it
amounts to is to say nature doesn't suit your your senses so nature is
wrong. Well, here is the real clue, nature could care less what you
think. Science is about building models around observations. SR is
observationally consistent. Consider the particle in an accelerator,
(among other experiments), as twin B.
But, if you'd like, continue to say the model is wrong without pointing
to the observation that backs your claim. And don't use the observation
you invent in your mind.
And, if you are sincere about getting this, it is about 'spacetime',
'spacetime', 'spacetime'.
T^2 = t^2 - s^2
There really is no more to it. Quite eloquent, IMHO.
Dan,
You were right to direct me back to the link and I found that I had
misunderstood it. The contradiction is that it says explicitly that Jane
observes Joe's clock going more slowly on both legs of the journey, then the
analysis and diagram show her receiving his anniversary signals more than
once a year on the return journey.
First it says:
"On the outward leg Jane observes Joe's clock to run slowly, and she
observes that it ticks slowly on the return run. So will Jane conclude that
Joe will have aged less?"
Then it says:
"In the second of these inertial frames, she receives a lot of anniversary
messages from Joe. If she pretended that she had been in this frame when Joe
sent them (the dashed line extrapolation of her returning world line, i.e.
if she had been travelling towards Earth at constant v for six of her
years), she would conclude that Joe had been sending them for eight of his
years."
In other words, Jane observes, on Joe's clock, eight years of Joe history in
six years. She watches the clock go slowly on both legs of the journey,
slower than hers, yet she sees eight anniversaries tick past in six of her
years.
On the diagram, she is receiving anniversary messages more than once a year,
so she must surely be seeing his clock go more quickly than her own on the
way back.
Why is that not a contradiction of "she observes that it ticks slowly on the
return run"?
Stephen
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