Apparently there is no connection between the gravitational Shapiro
delay in signal propagation times and the motion of the Solar system in
our galaxy. But what is apparent may not be real. Let us examine this
issue in detail. Let A be a transmitter of radar or Laser signal and B
be a transponder or reflector such that the distance AB=D and the line
AB passes close to the Sun. If Tr is the round-trip signal propagation
time then as per Irwin Shapiro, Tr is greater than 2D/c and the
difference Tr-2D/c could be of the order of 200 micro-seconds or so.

D
A..........................B
*

Let me first illustrate the main principle by which the common velocity
V of two objects A and B separated by distance D=AB in a Celestial
Reference Frame (where V is assumed to be along AB) can be determined
just by measuring the total uplink and downlink or round-trip signal
propagation time Tr. [We may consider A to be an Earth Station, B a
Pioneer type spacecraft]

~ D
t1 A1.........................B1 ~
t2 A2.........................B2

~
t2 A2.........................B2
~
t3 A3.........................B3

At some instant of time t1 let the position of objects A and B be A1
and B1 (as shown) such that D=A1B1. Let us assume that at t1 a signal
pulse is transmitted from A1 towards B1. By the time this signal pulse
reaches the location B1, B is no longer there and has moved forward. At
another instant of time t2 let the position of objects A and B be A2
and B2 (as shown) such that D=A2B2. Let us assume that the signal pulse
reaches B2 at time t2.

Then the uplink signal propagation time Tu is,
Tu = t2-t1
B1B2 = V*(t2-t1) = V*Tu
and D + B1B2 = D + V*Tu = c*Tu ...(1)
Or Tu = D/(c-V) ...(2)

Let us now assume that at t2 a signal pulse is transmitted back from
the spacecraft transponder at B2 towards A2. At still another instant
of time t3 let the position of objects A and B be A3 and B3 (as shown)
such that D=A3B3. At time t3 this signal pulse reaches the location A3
(where A has just reached). Then,

Td = t3-t2
A2A3 = V*(t3-t2) = V*Td
and D - A2A3 = D - V*Td = c*Td ...(3)
Or Td = D/(c+V) ...(4)

Therefore from (2) and (4) we get,

Tr = Tu + Td = D/(c-V) + D/(c+V)
=(2D/c)/[1-(V/c)^2] ... (5)
yielding V = c.(Tu-Td)/Tr ... (6)
Or V = c.sqrt[(Tr-2D/c)/Tr] ... (7)
That shows how we can determine the common velocity V of two objects A
and B in a celestial reference frame.

Of course for a known value of the common velocity V of A and B, we can
compute the time delay (Tr-2D/c) as,

From relation (5) we get,
Tr =(2D/c).[1+(V/c)^2] ... (8)
Or (Tr-2D/c)= (2D/c).(V/c)^2 ... (9)

Now let us consider the motion of the solar system as a whole within
our galaxy. In the galactic reference frame, Sun is known to be moving
with a speed of about 220 km/s. It is quite reasonable to assume that
the direction AB under consideration may be randomly oriented to the
velocity vector of the Sun in the galactic frame. Hence for
illustration purpose, we may assume the common velocity V of A and B to
be of the order of 100 km/s in the galactic reference frame. Further,
taking the Earth-Venus distance AB=D to be of the order of about 250
million km, we can compute the expected time delay (Tr-2D/c) from
equation (9) as,

(Tr-2D/c)=[2*(2.5*10^11)/(3*10^8)]*[10^5/(3*10^8)]^2
= 185 micro seconds
This time delay will have a maxima when 2D/c is maximum, which in the
Earth-Venus case will be maximum when the Earth, Sun and Venus are in
line.

However, this time delay is currently being interpreted as
gravitational time delay. Isn't it high time that we start considering
the physical effects of our motion (as illustrated above) in the
Galactic or Universal reference frame more seriously?

http://www.geocities.com/gurcharn_sa...rsal_frame.pdf

GSS

"GSS" writes:


Apparently there is no connection between the gravitational Shapiro
delay in signal propagation times and the motion of the Solar system in
our galaxy. But what is apparent may not be real. Let us examine this
.... abbreviated ...
Of course for a known value of the common velocity V of A and B, we can
compute the time delay (Tr-2D/c) as,

From relation (5) we get,
Tr =(2D/c).[1+(V/c)^2] ... (8)
Or (Tr-2D/c)= (2D/c).(V/c)^2 ... (9)

Now let us consider the motion of the solar system as a whole within
our galaxy. In the galactic reference frame, Sun is known to be moving
with a speed of about 220 km/s. It is quite reasonable to assume that
the direction AB under consideration may be randomly oriented to the
velocity vector of the Sun in the galactic frame. Hence for
illustration purpose, we may assume the common velocity V of A and B to
be of the order of 100 km/s in the galactic reference frame. Further,
taking the Earth-Venus distance AB=D to be of the order of about 250
million km, we can compute the expected time delay (Tr-2D/c) from
equation (9) as,

(Tr-2D/c)=[2*(2.5*10^11)/(3*10^8)]*[10^5/(3*10^8)]^2
= 185 micro seconds
This time delay will have a maxima when 2D/c is maximum, which in the
Earth-Venus case will be maximum when the Earth, Sun and Venus are in
line.

However, this time delay is currently being interpreted as
gravitational time delay. Isn't it high time that we start considering
the physical effects of our motion (as illustrated above) in the
Galactic or Universal reference frame more seriously?

First, you are performing your calculations as seen by an observer at
rest with the galaxy. Such an observer does not exist in reality.
You should transform into the frame where A and B are at rest. This
is of course appropriate because we -- the observers -- are comoving
with the solar system, plus or minus a few tens of km/s. [ For
example, we don't look up in the sky and see the sun rushing away at
220 km/s. ] In that comoving frame, V is zero, so your "effect"
disappears.

Second, your "effect" would vary as the cosine of the angle between
the line of sight and the galactic rotation stream. That is in fact
*not* what is seen from the Shapiro delay. The Shapiro effect has a
very specific, and very different, behavior which depends on rather
more complicate function of the angle (involving a logarithm). For
example,
http://en.wikipedia.org/wiki/Shapiro_effect
Thus, your "effect" would nevery be confused with the Shapiro delay
effect.

Finally, you could treat the light travel time question in the
"galactic" frame, but because you are getting differences of order
(V/c)^2, you must take relativity into account when transforming to
what a solar system observer would measure. The "galactic" observer
is moving at velocity -V with respect to the solar system, so there
would be Lorentz factors of order (1-(V/c)^2), which would ultimately
cancel out your effect when doing the transformations properly (each
leg must be done separately).

So no, it's not high time that we start considering your "effect" as
an explanation for the Shapiro delay.

CM

"Craig Markwardt" wrote in message ...
| Finally, you could treat the light travel time question in the
| "galactic" frame, but because you are getting differences of order
| (V/c)^2, you must take relativity into account

Hey ****head!

On Tue, 02 Jan 2007 20:01:13 GMT, Tom Roberts wrote:

"the basic equations of SR are only APPROXIMATELY valid."

and he should know, he wrote a lot in the FAQ's.

The basic equations of NM are what the basic equations
of SR approximate to.

"Sorcerer" writes:

"Craig Markwardt" wrote in message ...
| Finally, you could treat the light travel time question in the
| "galactic" frame, but because you are getting differences of order
| (V/c)^2, you must take relativity into account

Hey ****head!

Your irrelevant invective is noted.

On Tue, 02 Jan 2007 20:01:13 GMT, Tom Roberts wrote:

"the basic equations of SR are only APPROXIMATELY valid."

and he should know, he wrote a lot in the FAQ's.

I totally agree with this quotation alleged to be from Tom Roberts.
One must know the domain of applicability of any equations before
applying them. SR by itself fails at the quantum scale and also fails
in the presence of significant gravitational fields or other
non-inertial situations.

However, since the toy model of "GSS" is expressed in a purely
inertial frame, and does not involve gravitational fields or quantum
scales, SR is exactly applicable. Thus your comment is irrelevant.

The basic equations of NM are what the basic equations
of SR approximate to.

That is incorrect. SR has terms of order ~(v/c)^2 which classical
Newtonian mechanics does not, and those terms are vital to the theory.

CM

"Craig Markwardt" wrote in message ...
|
| "Sorcerer" writes:
|
| "Craig Markwardt" wrote in message ...
| | Finally, you could treat the light travel time question in the
| | "galactic" frame, but because you are getting differences of order
| | (V/c)^2, you must take relativity into account
|
| Hey ****head!
|
| Your irrelevant invective is noted.

Well good, fill your notebook up, ****head, I've got plenty more.

|
| On Tue, 02 Jan 2007 20:01:13 GMT, Tom Roberts wrote:
|
| "the basic equations of SR are only APPROXIMATELY valid."
|
| and he should know, he wrote a lot in the FAQ's.
|
| I totally agree with this quotation alleged to be from Tom Roberts.

So do I. As to "alleged", Google has the record.



| One must know the domain of applicability of any equations before
| applying them.

Domains of applicability:

Newtonian Mechanics: the real universe.
SR: paper universe.

| SR by itself fails at the quantum scale and also fails
| in the presence of significant gravitational fields or other
| non-inertial situations.


Ok, so it's a failure, as you allege. shrug

| However, since the toy model of "GSS" is expressed in a purely
| inertial frame, and does not involve gravitational fields or quantum
| scales, SR is exactly applicable. Thus your comment is irrelevant.

The alleged "inertial frame" is irrelevant, thus your comment is
irrelevant, ****-for-brains.
(Add the invective to your notebook.)

Stick your head up your arse to this.
"If we assume that the result proved for a polygonal line is also valid for a continuously curved line, we arrive at this result: If one of two synchronous clocks at A is moved in a closed curve with constant velocity until it returns to A, the journey lasting t seconds, then by the clock which has remained at rest the travelled clock on its arrival at A will be 1/2 tv^2/c^2 second slow. Thence we conclude that a balance-clock at the equator must go more slowly, by a very small amount, than a precisely similar clock situated at one of the poles under otherwise identical conditions." -- Albert ****wit Einstein.

Ref: http://www.fourmilab.ch/etexts/einstein/specrel/www/

So much for your inertial frame irrelevancy, you ****in' cretin.

(Add the invective to your notebook.)

| The basic equations of NM are what the basic equations
| of SR approximate to.
|
| That is incorrect. SR has terms of order ~(v/c)^2 which classical
| Newtonian mechanics does not, and those terms are vital to the theory.
|
It very much is correct. The alleged theory is irrelevant, ****head.
(Add the invective to your notebook.)

Do not place an atomic clock anywhere near McMurdo Sound,
it might prove your tin god was a ****ing raving lunatic,
whereas your brain is merely inertial.
(Add the invective to your notebook.)

Craig Markwardt wrote:
"GSS" writes:

Apparently there is no connection between the gravitational Shapiro
delay in signal propagation times and the motion of the Solar system in
our galaxy. But what is apparent may not be real. Let us examine this
... abbreviated ...
Of course for a known value of the common velocity V of A and B, we can
compute the time delay (Tr-2D/c) as,

From relation (5) we get,
Tr =(2D/c).[1+(V/c)^2] ... (8)
Or (Tr-2D/c)= (2D/c).(V/c)^2 ... (9)

Now let us consider the motion of the solar system as a whole within
our galaxy. In the galactic reference frame, Sun is known to be moving
with a speed of about 220 km/s. It is quite reasonable to assume that
the direction AB under consideration may be randomly oriented to the
velocity vector of the Sun in the galactic frame. Hence for
illustration purpose, we may assume the common velocity V of A and B to
be of the order of 100 km/s in the galactic reference frame. Further,
taking the Earth-Venus distance AB=D to be of the order of about 250
million km, we can compute the expected time delay (Tr-2D/c) from
equation (9) as,

(Tr-2D/c)=[2*(2.5*10^11)/(3*10^8)]*[10^5/(3*10^8)]^2
= 185 micro seconds
This time delay will have a maxima when 2D/c is maximum, which in the
Earth-Venus case will be maximum when the Earth, Sun and Venus are in
line.

However, this time delay is currently being interpreted as
gravitational time delay. Isn't it high time that we start considering
the physical effects of our motion (as illustrated above) in the
Galactic or Universal reference frame more seriously?

First, you are performing your calculations as seen by an observer at
rest with the galaxy. Such an observer does not exist in reality.
You should transform into the frame where A and B are at rest. This
is of course appropriate because we -- the observers -- are comoving
with the solar system, plus or minus a few tens of km/s. [ For
example, we don't look up in the sky and see the sun rushing away at
220 km/s. ] In that comoving frame, V is zero, so your "effect"
disappears.

Dear Craig, here we are discussing the "effect" of galactic motion of
the Solar system and not *my "effect"* or *your "effect"*.

In the very beginning I had made it clear (snipped by you for brevity),
"Let me first illustrate the main principle by which the common
velocity V of two objects A and B separated by distance D=AB in a
Celestial Reference Frame (where V is assumed to be along AB) can be
determined just by measuring the total uplink and downlink or
round-trip signal propagation time Tr. [We may consider A to be an
Earth Station, B a Pioneer type spacecraft]"

The 'Celestial Reference Frame' considered above could be the
Barycentric Celestial Reference Frame (BCRF) in which the positions of
all spacecraft are invariably referred. At certain point of time, the
object A (DSN type Earth station) and the object B (Pioneer type
spacecraft) could both be moving with a common velocity of about 30
km/s along AB in BCRF. The round-trip signal propagation time Tr could
be measured with a precision atomic clock located in the ground
station. Here all the *observers* are co-located at the ground station
and hence at rest wrt the object A and *not* wrt the BCRF. In fact we
can make a general statement here that all space missions are always
referred to the BCRF and *none* of the observers is ever at rest in
BCRF. Therefore, all round-trip signal propagation time measurements
made with precision atomic clocks *at rest* in the ground station are
always *valid* irrespective of the fact the ground station is in motion
wrt the Celestial Reference Frame considered.

Let us bear in mind that SR is not an *authority* but just a *model*.
You may try to *justify* it through logical arguments, whereas I shall
try to *invalidate* it.

Quoting from arXiv:gr-qc/0208046 v1
Independent Confirmation of the Pioneer 10 Anomalous Acceleration

"The epoch of transmission from the Earth is t1, the epoch of
interaction of the signal with the Pioneer 10 spacecraft is t2, and the
epoch of reception back at the Earth is t3.

The 3-vectors r1, r2, and r3 represent the positions of the
corresponding antenna at the corresponding epoch, and v1, v2, and v3
represent the velocities. The vector difference, r12, is defined as r2
- r1. These vector quantities are measured in the solar system
barycenter frame. The original station times in the ATDF records are
referred to Coordinated Universal Time (UTC)."

Thus even in your own papers you have never insisted that the DSN
atomic clocks *must* be at rest in BCRF.


Second, your "effect" would vary as the cosine of the angle between
the line of sight and the galactic rotation stream. That is in fact
*not* what is seen from the Shapiro delay. The Shapiro effect has a
very specific, and very different, behavior which depends on rather
more complicate function of the angle (involving a logarithm). For
example,
http://en.wikipedia.org/wiki/Shapiro_effect
Thus, your "effect" would never be confused with the Shapiro delay
effect.

Yes, the time delay (Tr-2D/c) will vary as the cosine of the angle
between the line AB and the velocity vector of the Solar system motion
in the Galactic reference frame. To demonstrate that, the line AB will
have to be oriented in *all* possible directions in the space. But that
has never been done in practice because firstly it was never considered
necessary and secondly there are enormous problems associated with such
measurements. Because this time delay was pre-conceived as a
'gravitational' delay, this has always been measured only around
superior conjunction of two planets where the variation of 2D/c factor
on the RHS of equation (9) becomes a dominant factor (apart from the
refraction effects).

In fact when the line AB is significantly away from the superior
conjunction, the distance D itself is 'evaluated' by equating Tr with
2D/c and this Tr is assumed as 'normal'. Thereafter as the line AB
passes through the superior conjunction, the *excess* of Tr is noted
and taken as 'Shapiro delay'. Quoting from one of the study reports on
Shapiro time delay measurements with Mariner spacecraft,
"As the line of sight between Earth and Mars drew closer and closer to
the sun, a measurable excess time delay began to occur. When the line
of sight came nearest to the Sun (called superior conjunction), the
maximum excess time delay occurred -- about 200 microseconds as
predicted by Shapiro's equations."

The major problem associated with the measurement of such time delays
(Tr-2D/c) with planetary objects (like earth and Venus) is the
variation of D during the signal propagation times of a few hundred
seconds when the accuracy in D required for measuring a few microsecond
time delay must be of the order of a few meters.


Finally, you could treat the light travel time question in the
"galactic" frame, but because you are getting differences of order
(V/c)^2, you must take relativity into account when transforming to
what a solar system observer would measure. The "galactic" observer
is moving at velocity -V with respect to the solar system, so there
would be Lorentz factors of order (1-(V/c)^2), which would ultimately
cancel out your effect when doing the transformations properly (each
leg must be done separately).

As explained above and also pointed out by 'Sorcerer' this is just
"bull****" of SR. No observer is ever required to be at rest in the
Celestial Frame considered for reference of positions of objects.

So no, it's not high time that we start considering your "effect" as
an explanation for the Shapiro delay.

CM

Let me refer you to one of the old technical notes which shows that the
scientific community is already conscious of some effects of the Solar
system Galactic motion. I am only impressing upon the necessity of
seriously examining the effect of this motion on observed phenomenon of
signal propagation time delays which so far have been modeled as
gravitational Shapiro time delays.

GSS

-------------------------------------------------------------
Comparison of "Old" and "New" Concepts: Reference Systems
by Jean Kovalevsky
http://www.iers.org/documents/public...9/tn29_031.pdf
.....
5 Further Remarks
1. The motion of the barycenter of the solar system is not linear in
its orbit about the center of the Galaxy. There is therefore a
Coriolis-like acceleration, which gives rise to a galactic geodesic
precession. It is not included in the definition of the ICRS. This
means that one should either distinguish between a natural barycentric
system from the BCRS, or to apply, in the dynamical representations of
the motion of planets in the BCRS, the corresponding acceleration. ....

Craig Markwardt wrote:
"GSS" writes:


Apparently there is no connection between the gravitational Shapiro
delay in signal propagation times and the motion of the Solar system in
our galaxy. But what is apparent may not be real. Let us examine this
... abbreviated ...
Of course for a known value of the common velocity V of A and B, we can
compute the time delay (Tr-2D/c) as,

From relation (5) we get,
Tr =(2D/c).[1+(V/c)^2] ... (8)
Or (Tr-2D/c)= (2D/c).(V/c)^2 ... (9)

Now let us consider the motion of the solar system as a whole within
our galaxy. In the galactic reference frame, Sun is known to be moving
with a speed of about 220 km/s. It is quite reasonable to assume that
the direction AB under consideration may be randomly oriented to the
velocity vector of the Sun in the galactic frame. Hence for
illustration purpose, we may assume the common velocity V of A and B to
be of the order of 100 km/s in the galactic reference frame. Further,
taking the Earth-Venus distance AB=D to be of the order of about 250
million km, we can compute the expected time delay (Tr-2D/c) from
equation (9) as,

(Tr-2D/c)=[2*(2.5*10^11)/(3*10^8)]*[10^5/(3*10^8)]^2
= 185 micro seconds
This time delay will have a maxima when 2D/c is maximum, which in the
Earth-Venus case will be maximum when the Earth, Sun and Venus are in
line.

However, this time delay is currently being interpreted as
gravitational time delay. Isn't it high time that we start considering
the physical effects of our motion (as illustrated above) in the
Galactic or Universal reference frame more seriously?

First, you are performing your calculations as seen by an observer at
rest with the galaxy. Such an observer does not exist in reality.
You should transform into the frame where A and B are at rest. This
is of course appropriate because we -- the observers -- are comoving
with the solar system, plus or minus a few tens of km/s. [ For
example, we don't look up in the sky and see the sun rushing away at
220 km/s. ] In that comoving frame, V is zero, so your "effect"
disappears.

Second, your "effect" would vary as the cosine of the angle between
the line of sight and the galactic rotation stream. That is in fact
*not* what is seen from the Shapiro delay. The Shapiro effect has a
very specific, and very different, behavior which depends on rather
more complicate function of the angle (involving a logarithm). For
example,
http://en.wikipedia.org/wiki/Shapiro_effect
Thus, your "effect" would nevery be confused with the Shapiro delay
effect.

Finally, you could treat the light travel time question in the
"galactic" frame, but because you are getting differences of order
(V/c)^2, you must take relativity into account when transforming to
what a solar system observer would measure. The "galactic" observer
is moving at velocity -V with respect to the solar system, so there
would be Lorentz factors of order (1-(V/c)^2), which would ultimately
cancel out your effect when doing the transformations properly (each
leg must be done separately).

So no, it's not high time that we start considering your "effect" as
an explanation for the Shapiro delay.

CM

You are trying to talk sense into a troll, he brings the same ****
around every 3 months, with a comet precision.

On Jan 1, 1:14 am, "GSS" wrote:
Apparently there is no connection between the gravitational Shapiro
delay in signal propagation times and the motion of the Solar system in
our galaxy. [...]

What you have proposed was already discovered in 1887. The
Michelson-Morley experiment did show just that --- with a null result.
Since then, FizGerald and Lorentz had already proposed a length
contraction or distance reduction to explain the null result. The
distance between the transponder and the receiver as observed by either
is actually less than the actual distance as observed by the galactic
reference. Time is also dilated.

However, the Shapiro experiment needs to establish an extremely
accurate distance measurement between the transponder and the receiver
right at the moments of the experiment. Such accuracy in such a large
distance is very questionable.

"GSS" writes:

Craig Markwardt wrote:
"GSS" writes:

Apparently there is no connection between the gravitational Shapiro
delay in signal propagation times and the motion of the Solar system in
our galaxy. But what is apparent may not be real. Let us examine this
... abbreviated ...
Of course for a known value of the common velocity V of A and B, we can
compute the time delay (Tr-2D/c) as,

From relation (5) we get,
Tr =(2D/c).[1+(V/c)^2] ... (8)
Or (Tr-2D/c)= (2D/c).(V/c)^2 ... (9)

Now let us consider the motion of the solar system as a whole within
our galaxy. In the galactic reference frame, Sun is known to be moving
with a speed of about 220 km/s. It is quite reasonable to assume that
the direction AB under consideration may be randomly oriented to the
velocity vector of the Sun in the galactic frame. Hence for
illustration purpose, we may assume the common velocity V of A and B to
be of the order of 100 km/s in the galactic reference frame. Further,
taking the Earth-Venus distance AB=D to be of the order of about 250
million km, we can compute the expected time delay (Tr-2D/c) from
equation (9) as,

(Tr-2D/c)=[2*(2.5*10^11)/(3*10^8)]*[10^5/(3*10^8)]^2
= 185 micro seconds
This time delay will have a maxima when 2D/c is maximum, which in the
Earth-Venus case will be maximum when the Earth, Sun and Venus are in
line.

However, this time delay is currently being interpreted as
gravitational time delay. Isn't it high time that we start considering
the physical effects of our motion (as illustrated above) in the
Galactic or Universal reference frame more seriously?

First, you are performing your calculations as seen by an observer at
rest with the galaxy. Such an observer does not exist in reality.
You should transform into the frame where A and B are at rest. This
is of course appropriate because we -- the observers -- are comoving
with the solar system, plus or minus a few tens of km/s. [ For
example, we don't look up in the sky and see the sun rushing away at
220 km/s. ] In that comoving frame, V is zero, so your "effect"
disappears.

Dear Craig, here we are discussing the "effect" of galactic motion of
the Solar system and not *my "effect"* or *your "effect"*.

In the very beginning I had made it clear (snipped by you for brevity),
"Let me first illustrate the main principle by which the common
velocity V of two objects A and B separated by distance D=AB in a
Celestial Reference Frame (where V is assumed to be along AB) can be
determined just by measuring the total uplink and downlink or
round-trip signal propagation time Tr. [We may consider A to be an
Earth Station, B a Pioneer type spacecraft]"

The 'Celestial Reference Frame' considered above could be the
Barycentric Celestial Reference Frame (BCRF) in which the positions of
all spacecraft are invariably referred. ...

However, your actual toy model was *not* the solar system reference
frame. In fact, the implication of your toy model was that "if *only*
scientists would account for the common galactic motion (i.e. V ~ 200
km/s) then the need for the Shapiro effect would/could go away." That
implication is erroneous.

... At certain point of time, the
object A (DSN type Earth station) and the object B (Pioneer type
spacecraft) could both be moving with a common velocity of about 30
km/s along AB in BCRF. The round-trip signal propagation time Tr could
be measured with a precision atomic clock located in the ground
station. Here all the *observers* are co-located at the ground station
and hence at rest wrt the object A and *not* wrt the BCRF. In fact we
can make a general statement here that all space missions are always
referred to the BCRF and *none* of the observers is ever at rest in
BCRF. Therefore, all round-trip signal propagation time measurements
made with precision atomic clocks *at rest* in the ground station are
always *valid* irrespective of the fact the ground station is in motion
wrt the Celestial Reference Frame considered.

And of course all proper space ranging/tracking analysis accounts for
the round trip light travel time, including the motions of both the
remote bodies and the earth station(s) during the trip, so your
"effect" would not be relevant. Your original toy model posited a
*common* motion of V ~ 200 km/s. That is not the case for any
spacecraft tracking experiment that you are just now bringing up.
*Now* that you discuss 30 km/s instead of 200 km/s, let's see what
your equation (9) predicts[*] .... about 16 usec. Suddenly it
becomes a lot less interesting in comparison to the actual Shapiro
delay.
[*] not that I agree that your equation (9) is correct or relevant..

Let us bear in mind that SR is not an *authority* but just a *model*.
You may try to *justify* it through logical arguments, whereas I shall
try to *invalidate* it.

Nothing I said above dealt with special relativity, so your comment is
irrelevant. Even in classical Newtonian physics, your claimed effect
is frame dependent. In the frame where your original two bodies are
at rest, the residual in your equation (9) becomes zero.


Quoting from arXiv:gr-qc/0208046 v1
Independent Confirmation of the Pioneer 10 Anomalous Acceleration

"The epoch of transmission from the Earth is t1, the epoch of
interaction of the signal with the Pioneer 10 spacecraft is t2, and the
epoch of reception back at the Earth is t3.

The 3-vectors r1, r2, and r3 represent the positions of the
corresponding antenna at the corresponding epoch, and v1, v2, and v3
represent the velocities. The vector difference, r12, is defined as r2
- r1. These vector quantities are measured in the solar system
barycenter frame. The original station times in the ATDF records are
referred to Coordinated Universal Time (UTC)."

Thus even in your own papers you have never insisted that the DSN
atomic clocks *must* be at rest in BCRF.

That is true. However it was *you* that set up completely separate
problem of the effect of common motion in the galaxy (V ~ 200 km/s).

In the paper that you refer to -- and indeed all proper spacecraft
tracking analysis -- the correct coordinate transformations between
frames are done, and an accounting of the round trip light travel time
including body motions during the signal travel time are accounted
for. Thus, the very thing that you were bemoaning was not occurring
(scientists treating motion of the bodies during signal signal
transmission), is in fact occurring!


Second, your "effect" would vary as the cosine of the angle between
the line of sight and the galactic rotation stream. That is in fact
*not* what is seen from the Shapiro delay. The Shapiro effect has a
very specific, and very different, behavior which depends on rather
more complicate function of the angle (involving a logarithm). For
example,
http://en.wikipedia.org/wiki/Shapiro_effect
Thus, your "effect" would never be confused with the Shapiro delay
effect.

Yes, the time delay (Tr-2D/c) will vary as the cosine of the angle
between the line AB and the velocity vector of the Solar system motion
in the Galactic reference frame. To demonstrate that, the line AB will
have to be oriented in *all* possible directions in the space. ...

That is an erroneous statement. It is not necessary to sample *all
possible* directions to distinguish between your "effect" (cosine
dependence) and the Shapiro effect (with logarithms, etc). The
Shapiro effect is very greatly enhanced along lines of sight that pass
close to the sun, while your "effect" is not.

... But that
has never been done in practice because firstly it was never considered
necessary and secondly there are enormous problems associated with such
measurements. Because this time delay was pre-conceived as a
'gravitational' delay, this has always been measured only around
superior conjunction of two planets where the variation of 2D/c factor
on the RHS of equation (9) becomes a dominant factor (apart from the
refraction effects).

That is also incorrect. Many spacecraft have been sent on many
trajectories throughout the solar system, both in the plane and out of
the plane (examples: Voyagers, Pioneers, Ulysses, Galileo). When also
adding to the mix planetary (and asteroid) ranging, it is of course
absurd to argue that they all have superior conjunction along exactly
the same line in celestial coordinates. They do not. In fact, the
observed Shapiro delay strongly depends on the Earth-Sun-Body angle,
irrespective of the solar system motion vector through the galaxy.



In fact when the line AB is significantly away from the superior
conjunction, the distance D itself is 'evaluated' by equating Tr with
2D/c and this Tr is assumed as 'normal'. Thereafter as the line AB
passes through the superior conjunction, the *excess* of Tr is noted
and taken as 'Shapiro delay'. Quoting from one of the study reports on
Shapiro time delay measurements with Mariner spacecraft,
"As the line of sight between Earth and Mars drew closer and closer to
the sun, a measurable excess time delay began to occur. When the line
of sight came nearest to the Sun (called superior conjunction), the
maximum excess time delay occurred -- about 200 microseconds as
predicted by Shapiro's equations."

Ignoring the above comments, which are already fatal to your supposed
effect, let's consider a body which is several different positions
relative to the sun (let's say 1, 5, 10 and 20 degrees, on either side
of the sun). The corresponding Shapiro delay is (using
4GM/c^3*ln(1-cos(th))),

Angle [deg] -20 -10 -5 -1 +1 +5 +10 +20
Shapiro [us] 55 82 110 173 173 110 82 55

with a "cusp" at conjunction.

Now let's compare that to the "cosine effect". Since that is
dependent on the earth-sun-galactic motion angle, let's consider two
cases, one where the earth-sun line is parallel to the galactic
motion, and one where it is perpendicular. To be generous, let's pick
speeds of 30 km/s and distances of 2 AU, although since the equation
is not exactly sensical, the values are a bit arbitrary. In reality,
at conjunction, most motion will be perpendicular to the line of
sight, so your "effect" would be even smaller. Your equation (9),
after accounting for the cosine effect, yields,

Angle [deg] -20 -10 -5 -1 +1 +5 +10 +20
Parallel [us] 18.79 19.69 19.92 19.99 19.99 19.92 19.69 18.79
Perp. [us] -6.84 -3.47 -1.74 -0.35 +0.35 +1.74 +3.47 +6.84

with no "cusp" in either case.

In short, your "effect" is far too small, produces far too little
variation at conjunction, and is of the wrong functional form, to be
mistaken for a Shapiro-like delay. Thus your claimed "effect" is
falsified.

The major problem associated with the measurement of such time delays
(Tr-2D/c) with planetary objects (like earth and Venus) is the
variation of D during the signal propagation times of a few hundred
seconds when the accuracy in D required for measuring a few microsecond
time delay must be of the order of a few meters.

(a) What makes you think that the variations in D during signal travel
time are not accounted for in the analysis? They are.
(b) One microsecond accuracy corresponds to approx c(dt) = 300 meters
not a "few meters." What makes you think that ranging techniques are
not accurate to the ~km level? They can be.
Thus, your claimed "major problems" are negligible.


Finally, you could treat the light travel time question in the
"galactic" frame, but because you are getting differences of order
(V/c)^2, you must take relativity into account when transforming to
what a solar system observer would measure. The "galactic" observer
is moving at velocity -V with respect to the solar system, so there
would be Lorentz factors of order (1-(V/c)^2), which would ultimately
cancel out your effect when doing the transformations properly (each
leg must be done separately).

As explained above and also pointed out by 'Sorcerer' this is just
"bull****" of SR. No observer is ever required to be at rest in the
Celestial Frame considered for reference of positions of objects.

So who measures the uplink transmission and downlink reception epochs
that go into your equations?

So no, it's not high time that we start considering your "effect" as
an explanation for the Shapiro delay.

CM

Let me refer you to one of the old technical notes which shows that the
scientific community is already conscious of some effects of the Solar
system Galactic motion. ...

Your reference is notable only in that it discusses the implications
of the coordinate system tied to stars orbiting the galaxy is not
precisely inertial. Your "effect" had nothing to do with non-inertial
frames.


... I am only impressing upon the necessity of
seriously examining the effect of this motion on observed phenomenon of
signal propagation time delays which so far have been modeled as
gravitational Shapiro time delays.


However, as noted above, the "effect" you examined could never be
mistaken for a Shapiro-like delay, and therefore it is irrelevant.
Furthermore, your implication that your "effect" is relevant within
the solar system frame is also incorrect, because the analysis of
ranging/tracking data *does* account for body motion during the signal
propagation time, while you erroneously supposed that it did not.

CM



GSS

-------------------------------------------------------------
Comparison of "Old" and "New" Concepts: Reference Systems
by Jean Kovalevsky
http://www.iers.org/documents/public...9/tn29_031.pdf
....
5 Further Remarks
1. The motion of the barycenter of the solar system is not linear in
its orbit about the center of the Galaxy. There is therefore a
Coriolis-like acceleration, which gives rise to a galactic geodesic
precession. It is not included in the definition of the ICRS. This
means that one should either distinguish between a natural barycentric
system from the BCRS, or to apply, in the dynamical representations of
the motion of planets in the BCRS, the corresponding acceleration. ....


--
--------------------------------------------------------------------------
Craig B. Markwardt, Ph.D. EMAIL:
Astrophysics, IDL, Finance, Derivatives | Remove "net" for better response
--------------------------------------------------------------------------

Craig Markwardt wrote:
"GSS" writes:

Craig Markwardt wrote:
"GSS" writes:

Apparently there is no connection between the gravitational Shapiro
delay in signal propagation times and the motion of the Solar system in
our galaxy. But what is apparent may not be real. Let us examine this
... abbreviated ...
Of course for a known value of the common velocity V of A and B, we can
compute the time delay (Tr-2D/c) as,

From relation (5) we get,
Tr =(2D/c).[1+(V/c)^2] ... (8)
Or (Tr-2D/c)= (2D/c).(V/c)^2 ... (9)

Now let us consider the motion of the solar system as a whole within
our galaxy. In the galactic reference frame, Sun is known to be moving
with a speed of about 220 km/s. It is quite reasonable to assume that
the direction AB under consideration may be randomly oriented to the
velocity vector of the Sun in the galactic frame. Hence for
illustration purpose, we may assume the common velocity V of A and B to
be of the order of 100 km/s in the galactic reference frame. Further,
taking the Earth-Venus distance AB=D to be of the order of about 250
million km, we can compute the expected time delay (Tr-2D/c) from
equation (9) as,

(Tr-2D/c)=[2*(2.5*10^11)/(3*10^8)]*[10^5/(3*10^8)]^2
= 185 micro seconds
This time delay will have a maxima when 2D/c is maximum, which in the
Earth-Venus case will be maximum when the Earth, Sun and Venus are in
line.

However, this time delay is currently being interpreted as
gravitational time delay. Isn't it high time that we start considering
the physical effects of our motion (as illustrated above) in the
Galactic or Universal reference frame more seriously?

First, you are performing your calculations as seen by an observer at
rest with the galaxy. Such an observer does not exist in reality.
You should transform into the frame where A and B are at rest. This
is of course appropriate because we -- the observers -- are comoving
with the solar system, plus or minus a few tens of km/s. [ For
example, we don't look up in the sky and see the sun rushing away at
220 km/s. ] In that comoving frame, V is zero, so your "effect"
disappears.

Dear Craig, here we are discussing the "effect" of galactic motion of
the Solar system and not *my "effect"* or *your "effect"*.

In the very beginning I had made it clear (snipped by you for brevity),
"Let me first illustrate the main principle by which the common
velocity V of two objects A and B separated by distance D=AB in a
Celestial Reference Frame (where V is assumed to be along AB) can be
determined just by measuring the total uplink and downlink or
round-trip signal propagation time Tr. [We may consider A to be an
Earth Station, B a Pioneer type spacecraft]"

The 'Celestial Reference Frame' considered above could be the
Barycentric Celestial Reference Frame (BCRF) in which the positions of
all spacecraft are invariably referred. ...

However, your actual toy model was *not* the solar system reference
frame. In fact, the implication of your toy model was that "if *only*
scientists would account for the common galactic motion (i.e. V ~ 200
km/s) then the need for the Shapiro effect would/could go away." That
implication is erroneous.

... At certain point of time, the
object A (DSN type Earth station) and the object B (Pioneer type
spacecraft) could both be moving with a common velocity of about 30
km/s along AB in BCRF. The round-trip signal propagation time Tr could
be measured with a precision atomic clock located in the ground
station. Here all the *observers* are co-located at the ground station
and hence at rest wrt the object A and *not* wrt the BCRF. In fact we
can make a general statement here that all space missions are always
referred to the BCRF and *none* of the observers is ever at rest in
BCRF. Therefore, all round-trip signal propagation time measurements
made with precision atomic clocks *at rest* in the ground station are
always *valid* irrespective of the fact the ground station is in motion
wrt the Celestial Reference Frame considered.

And of course all proper space ranging/tracking analysis accounts for
the round trip light travel time, including the motions of both the
remote bodies and the earth station(s) during the trip, so your
"effect" would not be relevant. Your original toy model posited a
*common* motion of V ~ 200 km/s. That is not the case for any
spacecraft tracking experiment that you are just now bringing up.
*Now* that you discuss 30 km/s instead of 200 km/s, let's see what
your equation (9) predicts[*] .... about 16 usec. Suddenly it
becomes a lot less interesting in comparison to the actual Shapiro
delay.

[*] not that I agree that your equation (9) is correct or relevant..

Let us bear in mind that SR is not an *authority* but just a *model*.
You may try to *justify* it through logical arguments, whereas I shall
try to *invalidate* it.

Nothing I said above dealt with special relativity, so your comment is
irrelevant. Even in classical Newtonian physics, your claimed effect
is frame dependent. In the frame where your original two bodies are
at rest, the residual in your equation (9) becomes zero.


Quoting from arXiv:gr-qc/0208046 v1
Independent Confirmation of the Pioneer 10 Anomalous Acceleration

"The epoch of transmission from the Earth is t1, the epoch of
interaction of the signal with the Pioneer 10 spacecraft is t2, and the
epoch of reception back at the Earth is t3.

The 3-vectors r1, r2, and r3 represent the positions of the
corresponding antenna at the corresponding epoch, and v1, v2, and v3
represent the velocities. The vector difference, r12, is defined as r2
- r1. These vector quantities are measured in the solar system
barycenter frame. The original station times in the ATDF records are
referred to Coordinated Universal Time (UTC)."

Thus even in your own papers you have never insisted that the DSN
atomic clocks *must* be at rest in BCRF.

That is true. However it was *you* that set up completely separate
problem of the effect of common motion in the galaxy (V ~ 200 km/s).

In the paper that you refer to -- and indeed all proper spacecraft
tracking analysis -- the correct coordinate transformations between
frames are done, and an accounting of the round trip light travel time
including body motions during the signal travel time are accounted
for. Thus, the very thing that you were bemoaning was not occurring
(scientists treating motion of the bodies during signal signal
transmission), is in fact occurring!


Second, your "effect" would vary as the cosine of the angle between
the line of sight and the galactic rotation stream. That is in fact
*not* what is seen from the Shapiro delay. The Shapiro effect has a
very specific, and very different, behavior which depends on rather
more complicate function of the angle (involving a logarithm). For
example,
http://en.wikipedia.org/wiki/Shapiro_effect
Thus, your "effect" would never be confused with the Shapiro delay
effect.

Yes, the time delay (Tr-2D/c) will vary as the cosine of the angle
between the line AB and the velocity vector of the Solar system motion
in the Galactic reference frame. To demonstrate that, the line AB will
have to be oriented in *all* possible directions in the space. ...

That is an erroneous statement. It is not necessary to sample *all
possible* directions to distinguish between your "effect" (cosine
dependence) and the Shapiro effect (with logarithms, etc). The
Shapiro effect is very greatly enhanced along lines of sight that pass
close to the sun, while your "effect" is not.

... But that
has never been done in practice because firstly it was never considered
necessary and secondly there are enormous problems associated with such
measurements. Because this time delay was pre-conceived as a
'gravitational' delay, this has always been measured only around
superior conjunction of two planets where the variation of 2D/c factor
on the RHS of equation (9) becomes a dominant factor (apart from the
refraction effects).

That is also incorrect. Many spacecraft have been sent on many
trajectories throughout the solar system, both in the plane and out of
the plane (examples: Voyagers, Pioneers, Ulysses, Galileo). When also
adding to the mix planetary (and asteroid) ranging, it is of course
absurd to argue that they all have superior conjunction along exactly
the same line in celestial coordinates. They do not. In fact, the
observed Shapiro delay strongly depends on the Earth-Sun-Body angle,
irrespective of the solar system motion vector through the galaxy.



In fact when the line AB is significantly away from the superior
conjunction, the distance D itself is 'evaluated' by equating Tr with
2D/c and this Tr is assumed as 'normal'. Thereafter as the line AB
passes through the superior conjunction, the *excess* of Tr is noted
and taken as 'Shapiro delay'. Quoting from one of the study reports on
Shapiro time delay measurements with Mariner spacecraft,
"As the line of sight between Earth and Mars drew closer and closer to
the sun, a measurable excess time delay began to occur. When the line
of sight came nearest to the Sun (called superior conjunction), the
maximum excess time delay occurred -- about 200 microseconds as
predicted by Shapiro's equations."

Ignoring the above comments, which are already fatal to your supposed
effect, let's consider a body which is several different positions
relative to the sun (let's say 1, 5, 10 and 20 degrees, on either side
of the sun). The corresponding Shapiro delay is (using
4GM/c^3*ln(1-cos(th))),

Angle [deg] -20 -10 -5 -1 +1 +5 +10 +20
Shapiro [us] 55 82 110 173 173 110 82 55

with a "cusp" at conjunction.

Now let's compare that to the "cosine effect". Since that is
dependent on the earth-sun-galactic motion angle, let's consider two
cases, one where the earth-sun line is parallel to the galactic
motion, and one where it is perpendicular. To be generous, let's pick
speeds of 30 km/s and distances of 2 AU, although since the equation
is not exactly sensical, the values are a bit arbitrary. In reality,
at conjunction, most motion will be perpendicular to the line of
sight, so your "effect" would be even smaller. Your equation (9),
after accounting for the cosine effect, yields,

Angle [deg] -20 -10 -5 -1 +1 +5 +10 +20
Parallel [us] 18.79 19.69 19.92 19.99 19.99 19.92 19.69 18.79
Perp. [us] -6.84 -3.47 -1.74 -0.35 +0.35 +1.74 +3.47 +6.84

with no "cusp" in either case.

In short, your "effect" is far too small, produces far too little
variation at conjunction, and is of the wrong functional form, to be
mistaken for a Shapiro-like delay. Thus your claimed "effect" is
falsified.

The major problem associated with the measurement of such time delays
(Tr-2D/c) with planetary objects (like earth and Venus) is the
variation of D during the signal propagation times of a few hundred
seconds when the accuracy in D required for measuring a few microsecond
time delay must be of the order of a few meters.

(a) What makes you think that the variations in D during signal travel
time are not accounted for in the analysis? They are.
(b) One microsecond accuracy corresponds to approx c(dt) = 300 meters
not a "few meters." What makes you think that ranging techniques are
not accurate to the ~km level? They can be.
Thus, your claimed "major problems" are negligible.


Finally, you could treat the light travel time question in the
"galactic" frame, but because you are getting differences of order
(V/c)^2, you must take relativity into account when transforming to
what a solar system observer would measure. The "galactic" observer
is moving at velocity -V with respect to the solar system, so there
would be Lorentz factors of order (1-(V/c)^2), which would ultimately
cancel out your effect when doing the transformations properly (each
leg must be done separately).

As explained above and also pointed out by 'Sorcerer' this is just
"bull****" of SR. No observer is ever required to be at rest in the
Celestial Frame considered for reference of positions of objects.

So who measures the uplink transmission and downlink reception epochs
that go into your equations?

So no, it's not high time that we start considering your "effect" as
an explanation for the Shapiro delay.

CM

Let me refer you to one of the old technical notes which shows that the
scientific community is already conscious of some effects of the Solar
system Galactic motion. ...

Your reference is notable only in that it discusses the implications
of the coordinate system tied to stars orbiting the galaxy is not
precisely inertial. Your "effect" had nothing to do with non-inertial
frames.


... I am only impressing upon the necessity of
seriously examining the effect of this motion on observed phenomenon of
signal propagation time delays which so far have been modeled as
gravitational Shapiro time delays.


However, as noted above, the "effect" you examined could never be
mistaken for a Shapiro-like delay, and therefore it is irrelevant.
Furthermore, your implication that your "effect" is relevant within
the solar system frame is also incorrect, because the analysis of
ranging/tracking data *does* account for body motion during the signal
propagation time, while you erroneously supposed that it did not.

CM



GSS

-------------------------------------------------------------
Comparison of "Old" and "New" Concepts: Reference Systems
by Jean Kovalevsky
http://www.iers.org/documents/public...9/tn29_031.pdf
....
5 Further Remarks
1. The motion of the barycenter of the solar system is not linear in
its orbit about the center of the Galaxy. There is therefore a
Coriolis-like acceleration, which gives rise to a galactic geodesic
precession. It is not included in the definition of the ICRS. This
means that one should either distinguish between a natural barycentric
system from the BCRS, or to apply, in the dynamical representations of
the motion of planets in the BCRS, the corresponding acceleration. ....


--
--------------------------------------------------------------------------
Craig B. Markwardt, Ph.D. EMAIL:
Astrophysics, IDL, Finance, Derivatives | Remove "net" for better response
--------------------------------------------------------------------------

Uh, oh excellent presentation!
Please be aware that you are wasting your talent and breath on a well
known antirelativistic troll with an agenda. :-)