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Some questions on GR from a layman



 
 
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  #1  
Old March 7th 11, 06:44 AM posted to sci.physics.relativity,sci.physics,sci.math,sci.astro
Koobee Wublee
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Default Some questions on GR from a layman

On Mar 6, 4:49 pm, Daryl McCullough wrote:
GunFred says...


My first question is how good is this image to illustrate the essence
of GR? I think something is wrong or at least over simplified. In my
view, if space [or spacetime] is warped or bent, any object would
follow the same trajectory, no matter what speed it has.


That is correct. Locally, the object will follow the same
trajectory. However, as it is observed by others, the geodesics will
follow a constraint. This constraint should be identified. Before
GR, it was either the path with the least accumulated amount of time
such as Fermat’s principle that gives rise to Snell’s law or the path
with the shortest local distance. After GR, the geodesics was modeled
after the path with the least accumulated spacetime. This model got
to be the dumbest one since light always propagate with an accumulated
spacetime of zero. shrug

The other thing is that you are not correct that curved space
means that objects take the same trajectory, regardless of velocity.
Think about the surface of the Earth.


That is pure nonsense. The surface of the earth is still represented
by flat space as given by the longitude, latitude, and altitude.
shrug

My second question is why a gravity field is explained by assuming
space is warped, and why an electrical field is not explained that
way?


Curved space was first conceptualized by Gauss. However, it was his
student Riemann who came up with a mathematical model to described
curved space. Riemann went on to try to find a connection between
curved space and gravitation. He failed. Space can be curved or
warped as much as it wants to, but as long as there is no time
dilation or a curvature in the temporal dimension, there is no
gravitation. It was until the concept of time and space that
gravitation can be modeled as the curvature in spacetime. shrug

In contrast, electric fields do not affect all matter in the
same way; neutral matter is not affected by gravity,


Wrong. As long as an object has positive mass, it is affected by
gravity even if it is neutral. shrug Giving you the benefit of the
doubt, you probably meant the electric field.

positively
charged matter is affected in the opposite way from negatively
charged matter. So there is no way to eliminate the effect of
electric fields by viewing spacetime as warped.

Now, that's not completely true. There actually is a theory,
called "Kaluza Klein Theory"...


That was merely an unsupported speculation. shrug There remains no
unification between gravity and electromagnetism. shrug

My third question is about a seeming inconsistency between GR and SR.
I would like to stress the word "seeming" because I am confident that
it is just because I don't understand either GR or SR well. As stated
before, GR provided the insight that a free falling body in a
gravitation field is in fact just inert in a warped space. It is not
being accelerated. It would be accelerated if it was not in free fall,
but standing on a structure that prevented it from falling, just like
anything standing on earth and experiencing gravity force is
equivalent to being accelerated. Now, if a body in free fall in a
gravitation field is just like being inert, there is a nice example of
the twin paradox. Consider twins, both in orbit around a heavy body,
in the same plane but in opposite directions. Both are in orbit and
therefore free falling and therefore inert in warped space. They meet
each other after having traversed every half orbit. On one encounter
they synchronized their clocks. On the next encounter they should have
inconsistent clocks according to SR (assuming I understand SR and GR
correct, which is likely not the case, but I am eager to receive some
clarifying education in this matter).


That is correct. The twin’s paradox brings out the stupidity in SR.
After all, the Lorentz transform, in which SR is an interpretation of,
is not supported by any experiments --- not even the MMX. You see.
The MMX requires all observations to be referenced back to the
absolute frame of reference. If one can show mathematically, that the
absolute frame of reference will vanish, then the mathematical model
would be valid. Larmor was the first to come up with the version that
leads to the Lorentz transform. In Larmor’s transform, all
observations have to be referenced back to the absolute frame of
reference. With the way the transform as presented where all
observers are traveling in parallel to each other against the absolute
frame of reference, one can easily find the absolute frame of
reference vanish. Poincare did just that. So, Larmor’s transform
which does not satisfy the principle of relativity became the Lorentz
transform which now satisfies the principle of relativity. The
problem is that in general, the absolute frame of reference does not
vanish in Larmor’s transform. shrug

It's only *locally* true that freefall in GR is like inertial
motion in SR. What "locally" means is: in a small region of spacetime.

[...]

Special Relativity can be used (approximately) within one of the
little regions, but cannot be used to describe the relationship
between distant regions.


Nonsense. The issue is about the twin’s paradox. shrug

My fourth question is about time in gravitation fields. I understood
GR says that time is walking slower in gravity fields.


No, not in general. There are infinite solutions to the field
equations (GR). Not all of them exhibits gravitational time
dilation. However, any solutions that degenerate into Newtonian law
of gravity does manifest gravitational time dilation. There are many
hypotheses that call out for gravitational time dilation. So, the
Schwarzschild metric as one of the infinite solutions to GR is not
unique in doing that. shrug

No, that's not completely correct. It's not that time runs slower
in one region than in another, it's that there can be multiple
paths that take different amounts of time to travel, even though
they connect the same two points. If you are traveling from New
York City to Chicago, there might be a path that is 750 miles long,
according to the mileage markers, and another path that is 850
miles long. It's not that the mileage markers are farther apart
on one of the paths than the other, it's just that different
paths have different lengths.


It is amazing how one can find so much foliage (bull****) from a
simple concept of gravitational time dilation. shrug

The elapsed time on a clock is like the "length" of a path
through spacetime.


This is just wrong. Spacetime is

** ds^2 = c^2 dt^2 – dx^2 – dy^2 – dz^2

Where

** ds^2 = length of spacetime squared
** dt^2 = time segment squared
** dx^2 + dy^2 + dz^2 = spatial length squared

Time is not spacetime, space is not spacetime, and time is not space.
Daryl is very intoxicated in voodoo mathematics. shrug

My fifth question is about absolute time and instantaneous information
transfer (required by absolute time).


Absolute time or absolute simultaneity does not say information can be
instantaneously transferred. shrug

Under absolute simultaneity, all observers do agree that all events
happen chronologically in order. Under relative simultaneity, the
chronological order of events is not guaranteed to be observed so
between two observers. The interferometers of the MMX very much ruled
out relative simultaneity since the interference pattern can be
observed coherently experiments after experiments. shrug
  #2  
Old March 7th 11, 08:45 AM posted to sci.physics.relativity,sci.physics,sci.math,sci.astro
Eric Gisse
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Posts: 1,465
Default Some questions on GR from a layman

On Mar 6, 9:44*pm, Koobee Wublee wrote:
[...]

The other thing is that you are not correct that curved space
means that objects take the same trajectory, regardless of velocity.
Think about the surface of the Earth.


That is pure nonsense. *The surface of the earth is still represented
by flat space as given by the longitude, latitude, and altitude.
shrug


The wublee thinks the Earth's surface is flat.

And shrugged 13 times in one post.

[...]
  #3  
Old March 7th 11, 09:22 AM posted to sci.physics.relativity,sci.physics,sci.math,sci.astro
Koobee Wublee
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Posts: 815
Default Some questions on GR from a layman

On Mar 6, 11:45 pm, Eric Gisse wrote:
On Mar 6, 9:44 pm, Koobee Wublee wrote:


That is pure nonsense. The surface of the earth is still represented
by flat space as given by the longitude, latitude, and altitude.
shrug


The wublee thinks the Earth's surface is flat.


The college dropout thinks the surface of a sphere represents curved
space, and a simple geometric analysis will prove the college dropout
and Daryl wrong. The surface of a sphere by no means is curved
space. Einstein Dingleberries tend to worship the nonsense in which
only Einstein Dingleberries can understand themselves. shrug

And shrugged 13 times in one post.


You will find two more in this post. shrug
  #4  
Old March 7th 11, 10:36 AM posted to sci.physics.relativity,sci.physics,sci.math,sci.astro
hanson
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Posts: 2,934
Default Some questions on GR from a layman

.... ahahahaha... AHHAHAHA.... AHAHAHA....

"Koobee Wublee" wrote:
Eric Gisse wrote:
Koobee Wublee wrote:
Daryl McCullough wrote:


Daryl McCullough wrote:
curved space means that objects take the same
trajectory, regardless of velocity.
Think about the surface of the Earth.


KW wrote:
That is pure nonsense. The surface of the earth is still represented
by flat space as given by the longitude, latitude, and altitude.
shrug


Eric Gisse wrote:
The wublee thinks the Earth's surface is flat.


KW wrote:
The college dropout Gissethinks the surface of a sphere represents curved
space, and a simple geometric analysis will prove the college dropout
and Daryl wrong. The surface of a sphere by no means is curved
space. Einstein Dingleberries tend to worship the nonsense in which
only Einstein Dingleberries can understand themselves. shrug

[alt: Einstein Cling-ons tend to worship Einstein's Dingleberries.]
[ Z: http://www.urbandictionary.com/ : Cling on & cling-ons]

Eric Gisse, the shrug-counter, wrote:
And shrugged 13 times in one post.


KW wrote:
You will find two more in this post. shrug

hanson wrote:
.... AHAHAHAHA.. You are too kind, Wubli... AHAHAHA...

Let's see. Gisse's CV:
-- ~ 9 years of college: NO BSc.
-- Fired from his 1st job after 60 days.
-- Dreamt of flying to the stars with Uncle rect-Al Schwartz.
All that with... No BSc, no job, no space flight... ahahaha...

Naturally, Gisse's loud mouthing on the UseNet appears
to be a compensation for his abject failures...
Poor ******* really, that Gisse. I feel kinda sorry for him...
because to boot, Y. Porat has posted that Eric is morbidly
obese and repulsively ugly looking... ... Somewhere, Eric,
the poor sod, had grabbed and clung onto the wrong end
of the rubber ruler which had too many Einstein Dingleberries
on it...
Thanks for the laughs, though, guy...ahahahanson

  #5  
Old March 7th 11, 12:54 PM posted to sci.physics.relativity,sci.physics,sci.math,sci.astro
Eric Gisse
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Posts: 1,465
Default Some questions on GR from a layman

On Mar 7, 12:22*am, Koobee Wublee wrote:
On Mar 6, 11:45 pm, Eric Gisse wrote:

On Mar 6, 9:44 pm, Koobee Wublee wrote:
That is pure nonsense. *The surface of the earth is still represented
by flat space as given by the longitude, latitude, and altitude.
shrug


The wublee thinks the Earth's surface is flat.


The college dropout thinks the surface of a sphere represents curved
space, and a simple geometric analysis will prove the college dropout
and Daryl wrong. *The surface of a sphere by no means is curved
space. *Einstein Dingleberries tend to worship the nonsense in which
only Einstein Dingleberries can understand themselves. *shrug

And shrugged 13 times in one post.


You will find two more in this post. *shrug


When presented with the silliness of his idea, the wublee ****s a wall
of insults and re-asserts that the surface of a sphere is flat.

  #6  
Old March 7th 11, 12:55 PM posted to sci.physics.relativity,sci.physics,sci.math,sci.astro
Eric Gisse
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Posts: 1,465
Default Some questions on GR from a layman

On Mar 7, 1:36*am, "hanson" wrote:
[snip another wall of barely coherent insults]

I see you agree that the surface of a sphere is flat.
  #7  
Old March 7th 11, 05:10 PM posted to sci.physics.relativity,sci.physics,sci.math,sci.astro
PD
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Posts: 1,572
Default Some questions on GR from a layman

On Mar 7, 2:22*am, Koobee Wublee wrote:
On Mar 6, 11:45 pm, Eric Gisse wrote:

On Mar 6, 9:44 pm, Koobee Wublee wrote:
That is pure nonsense. *The surface of the earth is still represented
by flat space as given by the longitude, latitude, and altitude.
shrug


The wublee thinks the Earth's surface is flat.


The college dropout thinks the surface of a sphere represents curved
space, and a simple geometric analysis will prove the college dropout
and Daryl wrong. *The surface of a sphere by no means is curved
space.


Of course it is. A surface is a 2D space. (Perhaps KW is flummoxed by
the idea of a space that has anything other than 3 dimensions.) And it
is curved, which can be demonstrated any number of ways, including
measuring the sum of the interior angles of a 3-sided polygon in that
surface.

*Einstein Dingleberries tend to worship the nonsense in which
only Einstein Dingleberries can understand themselves. *shrug

And shrugged 13 times in one post.


You will find two more in this post. *shrug


  #8  
Old March 7th 11, 09:33 PM posted to sci.physics.relativity,sci.physics,sci.math,sci.astro
Daryl McCullough
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Posts: 196
Default Some questions on GR from a layman

Koobee Wublee says...

On Mar 6, 4:49 pm, Daryl McCullough wrote:
GunFred says...


My first question is how good is this image to illustrate the essence
of GR? I think something is wrong or at least over simplified. In my
view, if space [or spacetime] is warped or bent, any object would
follow the same trajectory, no matter what speed it has.


That is correct.


No, it is not correct. You really have no idea what you are
talking about. A geodesic through a curved space is determined
by *two* quantities: (1) a starting point, and (2) a starting
velocity vector. The path certainly does depend on the velocity.

This is made explicit in the equation for the geodesic:

(d/ds)^2 x^u = -Gamma^u_vw (d/ds)x^v (d/ds)x^w

The path explicitly depends on the velocity (those d/ds x^v terms
on the right-hand side).

It's one thing to not be interested in these topics. Fine.
But don't pretend to understand a topic that you have no
interest in and know nothing about.

--
Daryl McCullough
Ithaca, NY

  #9  
Old March 7th 11, 09:40 PM posted to sci.physics.relativity,sci.physics,sci.math,sci.astro
Daryl McCullough
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Posts: 196
Default Some questions on GR from a layman

Koobee Wublee says...

On Mar 6, 4:49 pm, Daryl McCullough wrote:


The other thing is that you are not correct that curved space
means that objects take the same trajectory, regardless of velocity.
Think about the surface of the Earth.


That is pure nonsense. The surface of the earth is still represented
by flat space as given by the longitude, latitude, and altitude.


The *surface* of the Earth is a 2-dimensional curved surface. That means
that a point on the Earth is characterized by two numbers: the latitude
and the longitude. Altitude for a point on the surface of the Earth is
not an independent coordinate, since the altitude is a *function* of
latitude and longitude.

The surface of the Earth is a 2-D curved surface, embedded in a
3-dimensional flat (for most purposes) space.

You wade into topics that you have no understanding of. It's
very bizarre.

The most striking difference between a curved space and a flat space
is that in flat space, geodesics that start off parallel remain parallel.
In flat space, the geodesics are the straight-line paths.

On the surface of the Earth, the geodesics are the "great circle
routes". The equator and the lines of longitude are examples of
geodesics. Geodesics that start off parallel do not remain parallel.
This can easily be seen by taking the line of 0 degrees longitude,
and the line of 5 degrees longitude. At the equator, these geodesics
are parallel. But if you follow them all the way to the North Pole,
they are no longer parallel.

--
Daryl McCullough
Ithaca, NY

  #10  
Old March 7th 11, 09:41 PM posted to sci.physics.relativity,sci.physics,sci.math,sci.astro
hanson
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Posts: 2,934
Default Some questions on GR from a layman

Polemic "Eric Gisse" at alt.morons, wrote:
"hanson" wrote:
[snip another wall of barely coherent insults]

I see you agree that the surface of a sphere is flat.

hanson wrote:
ahahahaha... a 2D surface is by definition flat,
if not then it acquires a 3rd dimension also by def.
What is it that you don't understand about that?

IOW, like KW said:
"The surface of a sphere by no means is curved"...

Curved space only exists in the mind of Einstein
Dingleberries when they worship Albert's rectum
and awe: "That must be it. Looks just like that
space-time rubber trampoline which Albert's
cling-ons are talking about"

Now, let us return and see whether you still
have some intellectual balls, or whether your
beytsyim fell off already and gummed up
your mentation:

----------------
"Eric Gisse" wrote:
"hanson" wrote:
"Eric Gisse" wrote:

Eric wrote:
snip bantering with Porat
I've always liked to think the electron is a
topological defect in space, but I can't
reconcile that theory with the proton which
is an actual assemblage of parts which
has the opposite charge.

hanson wrote:
First things first. Forget the proton part
for now. The natural world is grainy &
discrete, with its obviously very large to
vanishingly small matter elements.
So, the question arises "why does the
current, real, universe have a lower cutoff
graininess that matches the size of the
electron's rest mass?... Did you answer
that ton you own satisfaction?

Eric weaseled and wrote:
Your muddled thinking and writing style hurts my mind.

hanson wrote:
ahaha... Anyways, what is the reasons in your
pain ridden mind why the electron mass should
be the basic defect in your topological space?

It has been known now for 200+ years that
the converters from 1D space to mass is
G/c^2 = r/m, or for 70 years that H^2/G = rho
(m-density) in the "outer limits", where you like
to muse & fantasize at.

So what is so new in your take Eric?

Put the cofactors like 2,3,4..., Pi and [a], the
fine structure constant, into any of the
r^(1 to 3) / m converters and you'll get
to what you want.

When you have found the numerical match,
interpret & discuss your equation, pontificate
and brag about it... instead of you cranking
Porat, who has a far deeper insight into his
physics then you have now into your own...

Eric, show that you have some intellectual
balls, .... ahahaha... ahahanson





 




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