On Mar 7, 8:13*pm, "Androcles" wrote:
wrote in message

...
On Mar 6, 9:02 pm, pmb wrote:





On Feb 26, 2:18 am, wrote:

On Feb 25, 10:03 pm, pmb wrote:

On Feb 25, 2:24 pm, "Paul B. Andersen"

wrote:
Juan R. González-Álvarez skrev:

Tom Roberts wrote on Mon, 25 Feb 2008 15:47:04 +0000:

The best model we have for the propagation of light near a
massive

no.

object like the sun is GR, in which the curvature of spacetime is
the
important aspect in determining the path light follows. And it
agrees
with measurements to part-per-million accuracy over an enormous
range.

Theories without spacetime curvature also agree with that.

Could you name one of those theories, please?

Personally I know of no such theories. However spacetime curvature is
not neccesary for light deflection in a gravitational field. So long
is there is a gravitational field present, i.e. non-vanishing
connection coefficients, then a particle can be deflected. A uniform
g-
field is a perfect example. The spacetime curvature associated with a
uniform gravitational field is zero and yet a beam of light will be
deflected. Geometrically speaking the deflection is described as the
observer corresponding to a frame of reference for which a geodesic
represents a non-straight line in space, i.e. one changes from
Minkowski coordinates to "curvilinear" coordinates. Spacetime
curvature is only neccesary when geodesic deviation is expected.

Pete- Hide quoted text -

- Show quoted text -

HiPete

I remember Kip Thorne commenting, in his non-mathematical book on the
history of gravitational physics, that he occasionally liked to use
teleparallel gravity to evaluate gravitational wave phenomena.
Teleparallelism is a GR equivalent.

http://en.wikipedia.org/wiki/Teleparallelism

Bruce- Hide quoted text -

- Show quoted text -

Hi Bruce

Thanks. I've heard of that but have not had the time to learn about
it. Other subjects have taken a higher priority lately. Thanks for
reminding me of it. Do you know much about this subject? How is
Schitz's "Gravity from the ground up?" going? Have you finished
reading it? If so how did you like it?

Best wishes

| Hi Pete

| The limit of my GR knowledge is founded in the metric equations which
| I learned to use when I worked through Edwin's book.

The limit of your knowledge is learning how to push the "radians" button
on your hand "help" calculator, ****head.- Hide quoted text -

Dip****, I have enough sense to realize that the proof for a
theoretical model is the empirical confirmation of the predictions the
model makes wrt natural phenomena. Unlike you and the set of whining
dumb****s that frequent this site crying foul because the way the
universe works doesn't fit their goofy worldview. You're right at the
top of this set of nitwits. You're a mouthy punk, Androcles, who
should find something meaningful to do with the rest of your life. I
can easily fix my mathematical mistake. Your problems are clearly much
greater and probably beyond your ability to fix.





- Show quoted text -

wrote in message
...
On Mar 7, 8:13 pm, "Androcles" wrote:
wrote in message

...
On Mar 6, 9:02 pm, pmb wrote:





On Feb 26, 2:18 am, wrote:

On Feb 25, 10:03 pm, pmb wrote:

On Feb 25, 2:24 pm, "Paul B. Andersen"

wrote:
Juan R. González-Álvarez skrev:

Tom Roberts wrote on Mon, 25 Feb 2008 15:47:04 +0000:

The best model we have for the propagation of light near a
massive

no.

object like the sun is GR, in which the curvature of spacetime
is
the
important aspect in determining the path light follows. And it
agrees
with measurements to part-per-million accuracy over an enormous
range.

Theories without spacetime curvature also agree with that.

Could you name one of those theories, please?

Personally I know of no such theories. However spacetime curvature
is
not neccesary for light deflection in a gravitational field. So long
is there is a gravitational field present, i.e. non-vanishing
connection coefficients, then a particle can be deflected. A uniform
g-
field is a perfect example. The spacetime curvature associated with
a
uniform gravitational field is zero and yet a beam of light will be
deflected. Geometrically speaking the deflection is described as the
observer corresponding to a frame of reference for which a geodesic
represents a non-straight line in space, i.e. one changes from
Minkowski coordinates to "curvilinear" coordinates. Spacetime
curvature is only neccesary when geodesic deviation is expected.

Pete- Hide quoted text -

- Show quoted text -

HiPete

I remember Kip Thorne commenting, in his non-mathematical book on the
history of gravitational physics, that he occasionally liked to use
teleparallel gravity to evaluate gravitational wave phenomena.
Teleparallelism is a GR equivalent.

http://en.wikipedia.org/wiki/Teleparallelism

Bruce- Hide quoted text -

- Show quoted text -

Hi Bruce

Thanks. I've heard of that but have not had the time to learn about
it. Other subjects have taken a higher priority lately. Thanks for
reminding me of it. Do you know much about this subject? How is
Schitz's "Gravity from the ground up?" going? Have you finished
reading it? If so how did you like it?

Best wishes

| Hi Pete

| The limit of my GR knowledge is founded in the metric equations which
| I learned to use when I worked through Edwin's book.

The limit of your knowledge is learning how to push the "radians" button
on your hand "help" calculator, ****head.- Hide quoted text -

| Dip****, I have enough sense to realize that the proof for a
| theoretical model is the empirical confirmation of the predictions the
| model makes wrt natural phenomena. Unlike you and the set of whining
| dumb****s that frequent this site crying foul because the way the
| universe works doesn't fit their goofy worldview. You're right at the
| top of this set of nitwits. You're a mouthy punk, Androcles, who
| should find something meaningful to do with the rest of your life. I
| can easily fix my mathematical mistake.

Go on then, fix this:
http://en.wikipedia.org/wiki/Gravita..._time_dilation

" While an observer on the Earth measure 1,000,000 years,
an observer on the Moon (if we ignore the mass of the Moon)
would measure 1000000.0006797 years.
That is approximately 6 hours more than the observer on the Earth." --
ASS-istant professor Paul B. Andersen.

You are an arrogant, stupid and ignorant arsehole, vane peacocks,
without a clue how to measure time astronomically; and so was the
cretin Einstein. An observer on the Moon would look at the day-night
terminator on the Earth to determine the ****in' time and there
is no way he'd see it crossing New York when it was noon.
You are part of the set of whining dumb****s that frequent this site
crying foul because the way the universe works doesn't fit your goofy
worldview.
No only is the limit of your knowledge learning how to push the
"radians" button on your hand "help" calculator, ****head, but you
don't even know how to tell the ****in' time, you dumb *******.

On Mar 7, 7:26*pm, wrote:
On Mar 6, wrote:





On Feb 26, 2:18*am, wrote:

On Feb 25, wrote:

On Feb 25, 2:24*pm, "Paul B. Andersen"

wrote:
Juan R. González-Álvarez skrev:

Tom Roberts wrote on Mon, 25 Feb 2008 15:47:04 +0000:

The best model we have for the propagation of light near a massive

no.

object like the sun is GR, in which the curvature of spacetime is the
important aspect in determining the path light follows. And it agrees
with measurements to part-per-million accuracy over an enormous range.

Theories without spacetime curvature also agree with that.

Could you name one of those theories, please?

Personally I know of no such theories. However spacetime curvature is
not neccesary for light deflection in a gravitational field. So long
is there is a gravitational field present, i.e. non-vanishing
connection coefficients, then a particle can be deflected. A uniform g-
field is a perfect example. The spacetime curvature associated with a
uniform gravitational field is zero and yet a beam of light will be
deflected. Geometrically speaking the deflection is described as the
observer corresponding to a frame of reference for which a geodesic
represents a non-straight line in space, i.e. one changes from
Minkowski coordinates to "curvilinear" coordinates. Spacetime
curvature is only neccesary when geodesic deviation is expected.

Pete- Hide quoted text -

- Show quoted text -

HiPete

I remember Kip Thorne commenting, in his non-mathematical book on the
history of gravitational physics, that he occasionally liked to use
teleparallel gravity to evaluate gravitational wave phenomena.
Teleparallelism is a GR equivalent.

http://en.wikipedia.org/wiki/Teleparallelism

Bruce- Hide quoted text -

- Show quoted text -

Hi Bruce

Thanks. I've heard of that but have not had the time to learn about
it. Other subjects have taken a higher priority lately. Thanks for
reminding me of it. Do you know much about this subject? How is
Schitz's "Gravity from the ground up?" going? Have you finished
reading it? If so how did you like it?

Best wishes

Hi Pete

The limit of my GR knowledge is founded in the metric equations which
I learned to use when I worked through Edwin's book. I havn't finished
'Gravity from the ground up' because I've temporarily lost the drive
to further my knowledge of gravitational physics. Hopefully I'll get
it back. This thread begins with the pronouncement to 'forget about
curved spacetime' because the path of light, in a gravitational field,
is a function of 'light has mass'. Apparently the originator of the
thread has a problem understanding the purpose of scientific
theoretical models. Which is to accurately make predictios wrt natural
phenomena that can be empirically confirmed. What's important is
accuracy within a domain of applicability and usefulness for doing
scientific analysis. I think that jives with what Thorne was saying
when he sometimes prefers to use the teleparalel equivalent to GR for
analyzing gravitational wave phenomena. That's how I see it.

Best wishes

Bruce

Nice to hear from you Bruce. What has grabbed your attention in
physics lately if not gr?

Best wishes

Pete

On Mar 7, 1:22*am, wrote:
On Mar 4, 3:40*am, "Y.Porat" wrote:





On Mar 4, 2:53*am, wrote:

Apologies if this is a duplicate -- I'm having some news problems.

In sci.physics Koobee Wublee wrote:

On Feb 25, 7:47 am, Tom Roberts wrote:
The best model we have for the propagation of light near a massive
object like the sun is GR, in which the curvature of spacetime is the
important aspect in determining the path light follows. And it agrees
with measurements to part-per-million accuracy over an enormous range.
First, derive a set of geodesic equations a massed particle traveling
at high speed near the sun. *Then, gradually reducing the mass to zero
and increasing the speed to c, do you see a discontinuity at mass = 0
and speed = c?

This is definitely a worthwhile exercise. *I recommend that you do it.

On Mar 7, 7:07*am, The Ghost In The Machine
wrote:
In sci.physics.relativity,

*wrote
on Thu, 6 Mar 2008 16:53:22 -0800 (PST)
:





On Mar 6, 9:19*am, "Androcles" wrote:
"PD" wrote in message

....
On Mar 6, 9:38 am, The Ghost In The Machine

wrote:
In sci.physics.relativity, Eric Gisse

wrote
on Thu, 6 Mar 2008 06:50:41 -0800 (PST)
:

On Mar 5, 9:55 pm, Koobee Wublee wrote:
On Mar 4, 6:03 pm, wrote:

I suggest that you try for a graceful retreat.

Well, I found a mistake in the boundary condition. As you have
suggested, I will execute a graceful retreat this time. In doing so,
my instinct might still be correct about any high-speed particle
having a discontinuity as its speed goes to the speed of light.

My god your arrogance is astounding. DO THE COMPUTATION.

What math would you have him do? ;-) There is indeed a
discontinuity in the SR energy equation

E = m c^2 / sqrt(1-v^2/c^2)

Going through infinity to become imaginary energy sounds like
a pretty big discontinuity to me....

| There's no going *through* infinity. There is an *approach* to
| infinity. A function that has an infinite asymptote is not
| discontinuous.

y = tan(x) for x = 0 to pi has no discontinuity at pi/2?
Why yes, yes it does.

*Graph it nitwit.

tan pi = .054886...
tan pi/2 = .027422...
tan pi/100 = .0005483...
tan pi/1000 = .00005483...

The mathematical convention is to use radians, not degrees,
as Androcles has already pointed out. *Pi/2 = 90 degrees.
Pi = 180 degrees.

Most calculators more sophisticated than a "four-banger"
have a radian mode. *Also, one can approximate tan pi to
arbitrary precision by using the formulae:

sin(x) = x - x^3/3! + x^5/5! - x^7/7! ...
cos(x) = 1 - x^2/2! + x^4/4! - x^6/6! ...

(where n! = n.(n-1).(n-2)...(3).(2).(1))

and then dividing tan(x) = sin(x)/cos(x).

In these formulae x is expressed in radians.

The function tan(x) has a singularity at pi/2 + n*pi for any integer n.



****ing idiot!
HAHAHAHAHAHA!- Hide quoted text -

- Show quoted text -

--
#191,
fortune: not found

--
Posted via a free Usenet account fromhttp://www.teranews.com- Hide quoted text -

- Show quoted text -

----------------
in order to turn degrees to Radians
you have to
divide the degrees by 180 and multiply by Pi

x degrees = x times Pi /180 (radians )
(and vice versa )
(secondary school .....)

ATB
Y.Porat
-------------------------------

The speed of light varies depending on the strength of the
gravitational field. Einstein said that. You might want to check out:

arXiv:gr-qc/0704.3485

and the references therein.

"Tom" wrote in message
...
| The speed of light varies depending on the strength of the
| gravitational field. Einstein said that. You might want to check out:
|
| arXiv:gr-qc/0704.3485
|
| and the references therein.

Oh well, if Einstein said it then it must be so.
Einstein said the "time" required by light to travel from A to B equals
the "time" it requires to travel from B to A, like this,
http://www.androcles01.pwp.blueyonde...rt/tAB=tBA.gif
so 12 = 4, right?

Tom wrote:
The speed of light varies depending on the strength of the
gravitational field. Einstein said that.

He said that in 1911, early on the then-unfinished journey to General
Relativity. GR itself does not really have this property -- the _LOCAL_
speed of light is everywhere c. When measured over non-local paths the
speed of light can vary, but there is no definite dependence on
"strength of the gravitational field", it's rather that one must compute
an integral over the path to obtain the theoretical value for such a
speed measurement.

Yes, as one prolific idiot around here is fixated on,
in the APPROXIMATION of weak fields and restriction to
paths at fixed gravitational potential, for Newtonian
coordinates one can express the non-local COORDINATE
speed of light in terms of the gravitational potential.
In 1911 Einstein did not understand all the caveats
mentioned here, but certainly did by 1915; this idiot
still does not understand them.


You might want to check out:
arXiv:gr-qc/0704.3485
and the references therein.

Arxiv.org gives "bad identifier".


Tom Roberts

Dear Tom Roberts:

"Tom Roberts" wrote in message
et...
Tom wrote:

You might want to check out:
arXiv:gr-qc/0704.3485
and the references therein.

Arxiv.org gives "bad identifier".

http://arxiv.org/abs/0704.3485
.... "A Simple Optical Analysis of Gravitational Lensing"
by Xing-Hao Ye, Qiang Lin

David A. Smith

On Mar 11, 5:27*am, Tom Roberts wrote in
sci.physics:
Tom wrote:
The speed of light varies depending on the strength of the
gravitational field. Einstein said that.

He said that in 1911, early on the then-unfinished journey to General
Relativity. GR itself does not really have this property -- the _LOCAL_
speed of light is everywhere c. When measured over non-local paths the
speed of light can vary, but there is no definite dependence on
"strength of the gravitational field", it's rather that one must compute
an integral over the path to obtain the theoretical value for such a
speed measurement.

* * * * Yes, as one prolific idiot around here is fixated on,
* * * * in the APPROXIMATION of weak fields and restriction to
* * * * paths at fixed gravitational potential, for Newtonian
* * * * coordinates one can express the non-local COORDINATE
* * * * speed of light in terms of the gravitational potential.
* * * * In 1911 Einstein did not understand all the caveats
* * * * mentioned here, but certainly did by 1915; this idiot
* * * * still does not understand them.

The year is 1920 Roberts Roberts and Divine Albert still believes that
the speed of light "varies with position" in a gravitational field, as
Superior Brother Steve Carlip explains to you:

http://math.ucr.edu/home/baez/physic...of_light..html
Superior Brother Steve Carlip: "Einstein went on to discover a more
general theory of relativity which explained gravity in terms of
curved spacetime, and he talked about the speed of light changing in
this new theory. In the 1920 book "Relativity: the special and
general theory" he wrote: ". . . according to the general theory of
relativity, the law of the constancy of the velocity of light in
vacuo, which constitutes one of the two fundamental assumptions in the
special theory of relativity [. . .] cannot claim any unlimited
validity. A curvature of rays of light can only take place when the
velocity of propagation of light varies with position." Since
Einstein talks of velocity (a vector quantity: speed with direction)
rather than speed alone, it is not clear that he meant the speed will
change, but the reference to special relativity suggests that he did
mean so. THIS INTERPRETATION IS PERFECTLY VALID AND MAKES GOOD
PHYSICAL SENSE, but a more modern interpretation is that the speed of
light is constant in general relativity."

In a sense, Superior Brother Steve Carlip is less dishonest (or more
naive) than you Roberts Roberts.

Pentcho Valev