The SRians Said: Time is What the Clock Measures

"kenseto" wrote in message
...

"George Dishman" wrote in message
...

"kenseto" wrote in message
...

"jem" wrote in message
news:iHpce.314$qV3.159@lakeread04...
Tom Roberts wrote:

jem wrote:


Bottom line: In SR and GR the elapsed proper times shown by the
clocks
in a twin scenario will differ.

i.e. the tick counts on their clocks differ.

But one cannot infer from this that the
clocks themselves "ticked at different rates".

Right. In fact it must be assumed that the tick rates are the same in
order to infer that the difference in tick counts represents a
difference in elapsed time.

That is correct.

I disagree. The clocks tick at different rates can represent the
difference
in elapsed time.

That is also correct.

Ken, it isn't that one is right and the other is
wrong, it is two different ways of looking at the
same phenomenon.

No these two ways are different. When you said that a clock ticks at the
same rate in different frames that mean that a clock second represents the
same amount of universal time (absolute time) in different frames.

No, see my other post. I mean equal amounts of
proper time, not universal time.

When I
said that a clock ticks at different rates in different frames that mean
that a clock second represents a different amount of universal time
(absolute time) in different frames (different state of absolute motion).

My difinition explains why the speed of light is a constant math ratio in
all frames as follows:
Light path length of rod (299,792,458m)/the absolute time content for a
clock second comoving with the rod.

Yes, that is the Lorentz Aether explanation, it
gives the same results as SR but assumes universal
time and that the rod shrinks by as much as the
clock slows due to physical interactions with the
aether.

In SR/GR, clocks always
tick at their usual rates,

and there's the assumption.

Right....that's a nonsenical assumption. It assumes that each tick have
the
same absolute duration in all frames of reference.

That is wrong, the assumption is that each clock
produces the same number of ticks in the same
amount of time as measured in the clock's rest
frame. It isn't really an assumption, that is how
clocks are built.

Here you assumed that a tick represents the same amount of TIME (absolute
time) in different frames. So it is an assumption after all. :-)

No, that is still wrong, you added "(absolute time)"
when in fact I was talking about "clock time" as I
think you call it.

Correct...that's what I was getting at.

What you are missing is that "jem" is using
"universal" to mean a "universal calibration
method", not units of "universal time".

You are missing something here. There is no such thing as universal
calibration.

Right, but there can be a universal METHOD of
calibration.

Even if you have a mean of calibrating the distant clock with
your clock they will go out of synch immediately. Why? Because clocks are
running at different rates in different frames.

That is essentially correct, though again it
is slightly ambiguous. Each clock produces the
same number of ticks in one second of its own
"clock time" but that means it produces fewer
ticks in one second of the other clock's
"clock time".

George

kenseto wrote:

"jem" wrote in message news:iHpce.314$qV3.159@lakeread04...

Tom Roberts wrote:


jem wrote:


Bottom line: In SR and GR the elapsed proper times shown by the clocks
in a twin scenario will differ.

i.e. the tick counts on their clocks differ.

But one cannot infer from this that the

clocks themselves "ticked at different rates".

Right. In fact it must be assumed that the tick rates are the same in
order to infer that the difference in tick counts represents a
difference in elapsed time.


I disagree. The clocks tick at different rates can represent the difference
in elapsed time.

If two clocks tick at different rates then a difference in their tick
counts will be due to both the difference in their elapsed times and the
difference in their tick rates, ehich represents more than just a
difference in elapsed time.


In SR/GR, clocks always

tick at their usual rates,

and there's the assumption.


Right....that's a nonsenical assumption. It assumes that each tick have the
same absolute duration in all frames of reference.

I thimk you're too hung up on the word "absolute". The fact that time
*intervals* have the same duration for every (ideal) clock implies
nothing about the amount of time each clock experiences betweeen two
events (except that the time difference will equal the difference in
tick counts).


but the elapsed proper time between two

points in spacetime depends on the path taken between them -- this is
_geometry_, not any sort of change in "tick rates".

Right, so Relativity assumes all (ideal) clocks always tick at the same
rate, which implies that the measured "time content" in each tick is a
constant (i.e. "universal"). This is what I thought Seto was getting at
with his question.


Correct...that's what I was getting at.

Ken Seto

kenseto wrote:
"jem" wrote in message news:fwpce.313$qV3.89@lakeread04...

kenseto wrote:


"jem" wrote in message
news:NVqbe.33167$d43.27684@lakeread03...


kenseto wrote:


"jem" wrote in message
news:GFPae.32562$d43.23992@lakeread03...



kenseto wrote:




"jem" wrote in message
news:IGOae.32553$d43.18173@lakeread03...




Clock time is not invariant. Absolute time (or universal time or

duration)

is invariant.



that isn't what I meant (or thought you meant) by
"universal time". As you indicated originally, "time" is the
measurement of a clock, and since SR assumes that clocks (ideal ones)
are identical and are unaffected by motion,


This SR assumption is bogus. Even ideal clocks are running at different
rates at different states of moiton.



it logically follows that
the time intervals on those clocks are equivalent regardless of the
overall state of motion. It's in this sense that the time intervals are
"universal".


There is no clock that can measure the same interval of universal time

with

the same clock reading. SR was invented to determine the clock reading

in

the observed frame for an interval of universal time in the observer's
frame...BTW, I use universal time and absolute time interchangeably.



However, SR assumes all clocks are identical and are unaffected by
motion, so in this sense one second has the same duration in all
reference frames.


This is indeed a bogus assumption. It is designed to avoid the

implication


of absolute time.

Well, the assumption isn't bogus, since "essentially ideal" clocks have
been constructed. However, the existence of ideal clocks doesn't
necessarily "avoid the implications of absolute time".



Moving clocks simply accumulate fewer seconds than
stationary clocks. This desription is probably the better of the two.


But this description contradicts what you said earlier: that a clock

second


is an interval of universal time (absolute time or duration).

Definitely not. If two collocated and synchronized ideal clocks are
moved apart and later reunited, the only way to interpret a difference
in their readings as one clock having experienced less time than the
other, is to assume that the calibrated time intervals (i.e. the
"temporal content" of each interval) on both clocks are identical.


No...both clocks experienced the same amount of absolute time. The

different

clock readings contains the same amount of absolute time. Why? Because a
clock time interval does not represent the same amount of absolute time

in

different frames (different state of absolute motion).

The question you asked at the start of the thread had to do with the SR
interpretation of time, and that's what I addressed. SR doesn't utilize
absolute time (i.e. invariant time) so that term isn't applicable to SR.
However, SR does assume that time intervals (e.g. clock seconds) are the
same for all observers regardless of their motion, and that in a sense
can be described as a "universal time".


OK that's was my point. But this SR description of time intervals
contradicts what Alan Lightman said in his book: he said that a clock second
in the observer's frame correspond to less than a clock second in the
observed frame.

I explained previously the sense in which his statement is correct
(observers *measure* the elapsed times of moving and stationary clocks
to be different). That the situation can also be explained in a way
that appears contradictory illustrates one of the drawbacks of using
everyday language to describe the content of mathematical models.


For a detail

explanation of this please read my Improved Relativity Theory (IRT) in

the

following link (Pages 2-4)
http://www.geocities.com/kn_seto/NPApaper.pdf

If you want IRT to gain some credibility, all you need to do is show how
you reproduced the Pioneer trajectories with it.


I don't have the data that call for by the IRT equations to do the
calculations..

So how can you claim that IRT resolves the discrepancies that arise
under GRT?


In the meantime maybe
you could explain a couple of things that aren't clear to me.

What's the difference between "physical length" and "light path length"?


If a rod is in a state of absolute motion the physical length would be
shorter than the light path length. Why? Because light will need to travel
an extra length to catch up to the other end of the rod during its flight to
cover the length of the rod.
My proposed experiments in the same above link are designed to show this
effect of absolute motion.

What I get from that description is that "light path length of a rod" is
the distance a light pulse would travel from the trailing end to the
leading end of a uniformly moving rod, where the distance and speed
measurements are carried out in the absolute reference frame. Is that
right?


What's meant by "the time interval for the simultaneity to occur will be
different in different frames"?


The assumption here is that the two frames are in different states of
absolute motion. In Einstein's train gedanken: the train is in a higher
state of absolute motion than the track. That means that the track observer
will see the lightning strikes to be simultaneous at a time L/c. However,
the light path length in the train is gamma*L. Therefore the train observer
will see the strikes to be simultaneous at gamma*L/c.

I can't think of any sense in which "time interval for simultaneity to
occur" is meaningful. Are you perhaps referring to the time lag between
the lightning strikes and the light flashes reaching the onservers? If
so, note that if the light flashes reach either one of the observers
simultaneously, they certainly won't reach the other observer
simultaneously.

"jem" wrote in message news:XJ3de.615$sy6.240@lakeread04...
kenseto wrote:

"jem" wrote in message
news:iHpce.314$qV3.159@lakeread04...

Tom Roberts wrote:


jem wrote:


Bottom line: In SR and GR the elapsed proper times shown by the clocks
in a twin scenario will differ.

i.e. the tick counts on their clocks differ.

But one cannot infer from this that the

clocks themselves "ticked at different rates".

Right. In fact it must be assumed that the tick rates are the same in
order to infer that the difference in tick counts represents a
difference in elapsed time.


I disagree. The clocks tick at different rates can represent the
difference
in elapsed time.

If two clocks tick at different rates then a difference in their tick
counts will be due to both the difference in their elapsed times and the
difference in their tick rates, ehich represents more than just a
difference in elapsed time.

The problem here is that you used tick counts as elapsed time. So the
difference in their tick counts is the same as the difference in elapsed
time.


In SR/GR, clocks always

tick at their usual rates,

and there's the assumption.


Right....that's a nonsenical assumption. It assumes that each tick have
the
same absolute duration in all frames of reference.

I thimk you're too hung up on the word "absolute".

But absolute time (universal time) is the only time that exists. Clock
time...a clock second... will represent a different amount of absolute time
in different frames.

The fact that time
*intervals* have the same duration for every (ideal) clock

This would mean that your (ideal) clock is an universal clock....no such
clock exists. Definition for a universal clock: A clock that records the
same rate passage of absolute time in different frames (different state of
absolute motion). Also a universal clock will experience no time
dilation....there is no slowing of a universal clock due to motion of any
kind.

implies
nothing about the amount of time each clock experiences betweeen two
events (except that the time difference will equal the difference in
tick counts).

Here you use tick count to represent the passage of absolute time in
different frames.

Ken Seto

Tom Roberts wrote:
jem wrote:

Tom Roberts wrote:

The value displayed on a particular clock _must_ be invariant,
because the value it displays cannot possibly depend upon how one
looks at the clock.


That's certainly true, but it would be true even if everyone's clocks
ticked at different rates when collocated,


In that case they aren't good clocks. When we discuss clocks we
implicitly require them to be calibrated to the same unit of time (i.e.
so they _do_ tick at the same rate when collocated and comoving).


Right, so Relativity assumes all (ideal) clocks always tick at the
same rate,


See above. This is essentially what we mean by "clock". But we can only
compare them accurately when they are collocated and comoving.

Yes, but without the assumption that the tick rates are unaffected by
motion, it's wouldn't be possible to infer that differences in tick
counts represent differences in elapsed times (e.g. LET assumes that
mtion has a specific affect on the tick rates, and from that infers
there's no difference in elapsed (absolute) times).

George Dishman wrote:

"kenseto" wrote in message
...

"jem" wrote in message news:iHpce.314$qV3.159@lakeread04...

Tom Roberts wrote:


jem wrote:

Bottom line: In SR and GR the elapsed proper times shown by the clocks
in a twin scenario will differ.

i.e. the tick counts on their clocks differ.

But one cannot infer from this that the

clocks themselves "ticked at different rates".

Right. In fact it must be assumed that the tick rates are the same in
order to infer that the difference in tick counts represents a
difference in elapsed time.


That is correct.


I disagree. The clocks tick at different rates can represent the
difference
in elapsed time.


That is also correct.

Ken, it isn't that one is right and the other is
wrong, it is two different ways of looking at the
same phenomenon.


In SR/GR, clocks always

tick at their usual rates,

and there's the assumption.

Right....that's a nonsenical assumption. It assumes that each tick have
the
same absolute duration in all frames of reference.


That is wrong, the assumption is that each clock
produces the same number of ticks in the same
amount of time as measured in the clock's rest
frame. It isn't really an assumption, that is how
clocks are built.


but the elapsed proper time between two

points in spacetime depends on the path taken between them -- this is
_geometry_, not any sort of change in "tick rates".

Right, so Relativity assumes all (ideal) clocks always tick at the same
rate, which implies that the measured "time content" in each tick is a
constant (i.e. "universal"). This is what I thought Seto was getting at
with his question.

Correct...that's what I was getting at.


What you are missing is that "jem" is using
"universal" to mean a "universal calibration
method", not units of "universal time".

No, "George", I meant what I said. The fact that Relativity asserts
that differences in elapsed time *are* differences in the tick counts of
(ideal) clocks, logically implies that every interval between the ticks
of every such clock contains a universal quantity of time.

"jem" wrote in message news:Z94de.616$sy6.335@lakeread04...
kenseto wrote:
"jem" wrote in message news:fwpce.313$qV3.89@lakeread04...

kenseto wrote:


"jem" wrote in message
news:NVqbe.33167$d43.27684@lakeread03...


kenseto wrote:


"jem" wrote in message
news:GFPae.32562$d43.23992@lakeread03...



kenseto wrote:




"jem" wrote in message
news:IGOae.32553$d43.18173@lakeread03...




Clock time is not invariant. Absolute time (or universal time or

duration)

is invariant.



that isn't what I meant (or thought you meant) by
"universal time". As you indicated originally, "time" is the
measurement of a clock, and since SR assumes that clocks (ideal ones)
are identical and are unaffected by motion,


This SR assumption is bogus. Even ideal clocks are running at different
rates at different states of moiton.



it logically follows that
the time intervals on those clocks are equivalent regardless of the
overall state of motion. It's in this sense that the time intervals
are
"universal".


There is no clock that can measure the same interval of universal time

with

the same clock reading. SR was invented to determine the clock reading

in

the observed frame for an interval of universal time in the observer's
frame...BTW, I use universal time and absolute time interchangeably.



However, SR assumes all clocks are identical and are unaffected by
motion, so in this sense one second has the same duration in all
reference frames.


This is indeed a bogus assumption. It is designed to avoid the

implication


of absolute time.

Well, the assumption isn't bogus, since "essentially ideal" clocks
have
been constructed. However, the existence of ideal clocks doesn't
necessarily "avoid the implications of absolute time".



Moving clocks simply accumulate fewer seconds than
stationary clocks. This desription is probably the better of the
two.


But this description contradicts what you said earlier: that a clock

second


is an interval of universal time (absolute time or duration).

Definitely not. If two collocated and synchronized ideal clocks are
moved apart and later reunited, the only way to interpret a difference
in their readings as one clock having experienced less time than the
other, is to assume that the calibrated time intervals (i.e. the
"temporal content" of each interval) on both clocks are identical.


No...both clocks experienced the same amount of absolute time. The

different

clock readings contains the same amount of absolute time. Why? Because
a
clock time interval does not represent the same amount of absolute time

in

different frames (different state of absolute motion).

The question you asked at the start of the thread had to do with the SR
interpretation of time, and that's what I addressed. SR doesn't utilize
absolute time (i.e. invariant time) so that term isn't applicable to SR.
However, SR does assume that time intervals (e.g. clock seconds) are the
same for all observers regardless of their motion, and that in a sense
can be described as a "universal time".


OK that's was my point. But this SR description of time intervals
contradicts what Alan Lightman said in his book: he said that a clock
second
in the observer's frame correspond to less than a clock second in the
observed frame.

I explained previously the sense in which his statement is correct
(observers *measure* the elapsed times of moving and stationary clocks
to be different). That the situation can also be explained in a way
that appears contradictory illustrates one of the drawbacks of using
everyday language to describe the content of mathematical models.


For a detail

explanation of this please read my Improved Relativity Theory (IRT) in

the

following link (Pages 2-4)
http://www.geocities.com/kn_seto/NPApaper.pdf

If you want IRT to gain some credibility, all you need to do is show how
you reproduced the Pioneer trajectories with it.


I don't have the data that call for by the IRT equations to do the
calculations..

So how can you claim that IRT resolves the discrepancies that arise
under GRT?

Those claims are based on the theoretical predictions of Model Mechanics.
The problem of GRT are resolved by the ad hoc additions of dark matter and
dark energy. Model Mechanics (IRT) includes these entities in its basic
descriptions of the universe.


In the meantime maybe
you could explain a couple of things that aren't clear to me.

What's the difference between "physical length" and "light path length"?


If a rod is in a state of absolute motion the physical length would be
shorter than the light path length. Why? Because light will need to
travel
an extra length to catch up to the other end of the rod during its
flight to
cover the length of the rod.
My proposed experiments in the same above link are designed to show this
effect of absolute motion.

What I get from that description is that "light path length of a rod" is
the distance a light pulse would travel from the trailing end to the
leading end of a uniformly moving rod,

Yes.

where the distance and speed
measurements are carried out in the absolute reference frame. Is that
right?

No...the distance measurement is carried out in the observer's frame. The
method is using the light-second to do the measurement. Using light-second
to measure distance automatically measures the light path length of a rod.
Why? Because the absolute time content for an observer's clcok second is a
direct consequence of the state of absolute motion of the clock co-moving
with the rod. BTW this is the reason why the speed of light is measured to
be a constant math ratio in all frames as follows:
Light path length of rod (299,792,458m)/thew absolute time content for a
clock second co-moving with the rod.


What's meant by "the time interval for the simultaneity to occur will be
different in different frames"?


The assumption here is that the two frames are in different states of
absolute motion. In Einstein's train gedanken: the train is in a higher
state of absolute motion than the track. That means that the track
observer
will see the lightning strikes to be simultaneous at a time L/c.
However,
the light path length in the train is gamma*L. Therefore the train
observer
will see the strikes to be simultaneous at gamma*L/c.

I can't think of any sense in which "time interval for simultaneity to
occur" is meaningful.

Why not? If the light path in the train is longer than in the track then
light will take a longer time (absolute time) to reach the observer in the
middle and thus simultaneity in the train will take a longer time to occur.

Are you perhaps referring to the time lag between
the lightning strikes and the light flashes reaching the onservers?

No...the lightning strikes are simultaneous in the track and in the train.
In the track the simultaneity occur at an earlier time because the light
path length in the track is shorter than in the train.

Ken Seto

If
so, note that if the light flashes reach either one of the observers
simultaneously, they certainly won't reach the other observer
simultaneously.

kenseto wrote:

"jem" wrote in message news:XJ3de.615$sy6.240@lakeread04...

kenseto wrote:


"jem" wrote in message

news:iHpce.314$qV3.159@lakeread04...

Tom Roberts wrote:



jem wrote:


Bottom line: In SR and GR the elapsed proper times shown by the clocks
in a twin scenario will differ.

i.e. the tick counts on their clocks differ.

But one cannot infer from this that the


clocks themselves "ticked at different rates".

Right. In fact it must be assumed that the tick rates are the same in
order to infer that the difference in tick counts represents a
difference in elapsed time.


I disagree. The clocks tick at different rates can represent the

difference

in elapsed time.

If two clocks tick at different rates then a difference in their tick
counts will be due to both the difference in their elapsed times and the
difference in their tick rates, ehich represents more than just a
difference in elapsed time.


The problem here is that you used tick counts as elapsed time.

It's not a problem - it's what's done in Relativity.

So the
difference in their tick counts is the same as the difference in elapsed
time.

Right.

In SR/GR, clocks always


tick at their usual rates,

and there's the assumption.


Right....that's a nonsenical assumption. It assumes that each tick have

the

same absolute duration in all frames of reference.

I thimk you're too hung up on the word "absolute".


But absolute time (universal time) is the only time that exists. Clock
time...a clock second... will represent a different amount of absolute time
in different frames.

That's the interpretation in IRT and LET, but not in Relativity which
doesn't model an absolute time.


The fact that time
*intervals* have the same duration for every (ideal) clock


This would mean that your (ideal) clock is an universal clock....no such
clock exists. Definition for a universal clock: A clock that records the
same rate passage of absolute time in different frames (different state of
absolute motion). Also a universal clock will experience no time
dilation....there is no slowing of a universal clock due to motion of any
kind.

I've described clock behavior in the contest of Relativity, and as I
keep telling you "absolute time" isn't a feature of Relativity (i.e. the
definition you gave of a universal clock isn't meaningful).

Consider the odometer analogy TR mentioned. Does the rate at which the
odometer moves change as a result of the motion of the vehicle? No, but
two cars with synchronized odometers can leave and return to a single
location and show different odometer readings. This is the sense in
which time dilation affects clocks.

implies
nothing about the amount of time each clock experiences betweeen two
events (except that the time difference will equal the difference in
tick counts).


Here you use tick count to represent the passage of absolute time in
different frames.

Passage of time, yes. Passage of absolute time, no.

"jem" wrote in message news:rn4de.618$sy6.438@lakeread04...
George Dishman wrote:

"kenseto" wrote in message
...

"jem" wrote in message news:iHpce.314$qV3.159@lakeread04...

Tom Roberts wrote:
snip
but the elapsed proper time between two
points in spacetime depends on the path taken between them -- this is
_geometry_, not any sort of change in "tick rates".

Right, so Relativity assumes all (ideal) clocks always tick at the same
rate, which implies that the measured "time content" in each tick is a
constant (i.e. "universal"). This is what I thought Seto was getting at
with his question.

Correct...that's what I was getting at.


What you are missing is that "jem" is using
"universal" to mean a "universal calibration
method", not units of "universal time".

No, "George", I meant what I said.

No need for quotes, that's my real name.

The fact that Relativity asserts that differences in elapsed time *are*
differences in the tick counts of (ideal) clocks, logically implies that
every interval between the ticks of every such clock contains a universal
quantity of time.

OK, then I misread your first version
and I apologise for that.

If I follow, you are saying each second
measured by an ideal clock contains the
same amount of (proper) time regardless
of its motion, hence that amount is in
a sense "universal" which is perfectly
correct. I could be wrong but I think
from some of Ken's other comments that
he was saying that the definition
implied each second as measured by a
clock contained the same amount of
universal (or absolute) time which is
quite different.

George

"jem" wrote in message news:Sh4de.617$sy6.117@lakeread04...
Tom Roberts wrote:
jem wrote:
snip
Right, so Relativity assumes all (ideal) clocks always tick at the same
rate,

See above. This is essentially what we mean by "clock". But we can only
compare them accurately when they are collocated and comoving.

Yes, but without the assumption that the tick rates are unaffected by
motion, it's wouldn't be possible to infer that differences in tick counts
represent differences in elapsed times (e.g. LET assumes that mtion has a
specific affect on the tick rates, and from that infers there's no
difference in elapsed (absolute) times).

Isn't it the other way round? LET assumes time is
universal and is therefore forced by experiment to
conclude that clock rates vary with speed. In other
words the formulae for length contraction, time
dilation and mass increase are empirical in LET
but derived from the geometry in SR.

George