Do all agree that space can really curve, expand, contract,
etc.??

Anyone got any problem with that concept??

If everyone agrees. Then what are the main arguments of
Anti-Relativists such as EL, Traveller, etc.

I'm a bit confused. What part of Relativity do you not
agree and what part do you agree. Is space being curvable,
expandable being one you all agree??

Relativistic Cosmology has so many empirical data from
gravitional lensing to black holes. At least space
being curvable, expandable is almost infallible, agree??

That means Time Dilation and other stuff are where you
don't agree with. Right??

Please elaborate and fill me in. Thanks.

Cos_mo

"Cos_mo" wrote in message oups.com...

Do all agree that space can really curve, expand, contract,
etc.??

It can even disappear!

Anyone got any problem with that concept??

It usually does disappear!

Sue...


If everyone agrees. Then what are the main arguments of
Anti-Relativists such as EL, Traveller, etc.

I'm a bit confused. What part of Relativity do you not
agree and what part do you agree. Is space being curvable,
expandable being one you all agree??

No... the calculating space called fourspace or spacetime
is curveable.


Relativistic Cosmology has so many empirical data from
gravitional lensing to black holes. At least space
being curvable, expandable is almost infallible, agree??

Show your transformations from fourspace to 3D and
somebody might get agreeable.


That means Time Dilation and other stuff are where you
don't agree with. Right??

Here is your "time dilation"
But, is this the most general solution?
Suppose that we define the advanced time...
http://farside.ph.utexas.edu/teachin...es/node46.html

AFAIK there isn't much dispute that it exist.
My radio works.


Please elaborate and fill me in. Thanks.
Gladly
http://arxiv.org/abs/physics/0204034

Regards,
Sue...


Cos_mo

Hi, Cos_mo,


Do all agree that space can really curve, expand, contract,
etc.??


I have just searched Google using the term 'curved', and come up with
'curved brush stroke' and 'curved mirror'. In General Relativity (GR),
the word is not used in either of these senses.

Modern physics often deals with conditions which are somewhat removed
from our ordinary everyday experience. We have confidence in its
theories because they are usable, and give answers which are consistent
with the results of experiments (although it is almost certain that
something even better will come along one day). In order to talk about
these theories we have to use words, and many of them have ordinary
everyday meanings, which can lead to some confusion.

The sense of the word 'curvature' as used in GR was first introduced by
Gauss, and is connected to the everyday meanings of the word, but is
*not* an everyday meaning of the word. The Gaussian sense is a
metaphorical extension of the concept of curvature. Are you familiar
with the use of metaphor in e.g. poetry? GR is very poetic.

Even the people who are unhappy with the word 'curvature' must accept
that conditions vary from point to point. There are gases, liquids and
solids. Near a magnet, little bits of iron experience a force which is
not transmitted by any of solid, liquid or gas. Near a rubbed comb,
little bits of paper experience a force which is similar but not the
same. Near a large lump of matter, there is a third sort of force.

The force exerted generally by matter on matter is called gravity, and
the current best theory is due to Einstein. Due to its historical
development it is associated with the geometry of curved space as
developed by Riemann and others. However AFAICS, the name 'metric
tensor' in GR could just as easily be replaced by 'gravitational field
tensor'. This would remove the link with curvature, expansion,
contraction, etc. and remove a potential stumbling block of relativity
theory. However it's not a very big stumbling block, and a person who
is not willing to think outside the box and to consider that everyday
words can perhaps be used with metaphorically extended meanings is not
going to get very far in any case.


Anyone got any problem with that concept??


There are lots of people who have problems with the concepts of GR, but
then, there are lots of people who have problems. There are many more
people who believe in witches and demons than who understand GR.
Generally speaking, it is best not to seek answers to scientific
questions by democratic vote.


If everyone agrees. Then what are the main arguments of
Anti-Relativists such as EL, Traveller, etc. I'm a bit confused.


They are also confused, and their arguments do not hold water. You can
find similar uninformed certainty propping up the bar in almost any
hostelry.


What part of Relativity do you not
agree and what part do you agree. Is space being curvable,
expandable being one you all agree??
Relativistic Cosmology has so many empirical data from
gravitional lensing to black holes. At least space
being curvable, expandable is almost infallible, agree??


Why do you want agreement? I would be more impressed if you asked for
understanding.


That means Time Dilation and other stuff are where you
don't agree with. Right??

Wrong.

Cheers,

Zigoteau.

space cannot cure
cannot contarct cannot expand!!

the only thing space can do is
host particles !!
is there something simpler than that !! (:-)!!!!!

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

Y.Porat wrote:
space cannot cure

Of course space cannot cure. If it can, we don't
need doctors.

cannot contarct cannot expand!!

No, space can't cause cataract. We know it can't cure,
but it can't cause diseases either.

the only thing space can do is
host particles !!

Yes, you got it right here. Space can host particles
like viruses. That's the way it can cause illnesses.

Do you understand what I'm saying? If not. I'll explain
deeper. Say. Are you a witch doctor?

Cos_mo

is there something simpler than that !! (:-)!!!!!

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

Zigoteau wrote:
Hi, Cos_mo,


Do all agree that space can really curve, expand, contract,
etc.??


I have just searched Google using the term 'curved', and come up with
'curved brush stroke' and 'curved mirror'. In General Relativity (GR),
the word is not used in either of these senses.

Modern physics often deals with conditions which are somewhat removed
from our ordinary everyday experience. We have confidence in its
theories because they are usable, and give answers which are consistent
with the results of experiments (although it is almost certain that
something even better will come along one day). In order to talk about
these theories we have to use words, and many of them have ordinary
everyday meanings, which can lead to some confusion.

The sense of the word 'curvature' as used in GR was first introduced by
Gauss, and is connected to the everyday meanings of the word, but is
*not* an everyday meaning of the word. The Gaussian sense is a
metaphorical extension of the concept of curvature. Are you familiar
with the use of metaphor in e.g. poetry? GR is very poetic.

Even the people who are unhappy with the word 'curvature' must accept
that conditions vary from point to point. There are gases, liquids and
solids. Near a magnet, little bits of iron experience a force which is
not transmitted by any of solid, liquid or gas. Near a rubbed comb,
little bits of paper experience a force which is similar but not the
same. Near a large lump of matter, there is a third sort of force.

The force exerted generally by matter on matter is called gravity, and
the current best theory is due to Einstein. Due to its historical
development it is associated with the geometry of curved space as
developed by Riemann and others. However AFAICS, the name 'metric
tensor' in GR could just as easily be replaced by 'gravitational field
tensor'. This would remove the link with curvature, expansion,
contraction, etc. and remove a potential stumbling block of relativity
theory. However it's not a very big stumbling block, and a person who
is not willing to think outside the box and to consider that everyday
words can perhaps be used with metaphorically extended meanings is not
going to get very far in any case.


But according to cosmology, the universe is expanding, there
is something in the vacuum called dark energy or cosmological
constant or quistessence that is making space expand.

Uhm... I'm talking about the expansion as it relates to physical
space. In General relativity. It is the abstract 4D space/time
geometry that is curving and causing gravity.

So I guess there are two kinds of space shape shifting. One
a physical one, the other a curving of the 4D Einstein
Spacetime which is not physical.


Cos_mo




Anyone got any problem with that concept??


There are lots of people who have problems with the concepts of GR, but
then, there are lots of people who have problems. There are many more
people who believe in witches and demons than who understand GR.
Generally speaking, it is best not to seek answers to scientific
questions by democratic vote.


If everyone agrees. Then what are the main arguments of
Anti-Relativists such as EL, Traveller, etc. I'm a bit confused.


They are also confused, and their arguments do not hold water. You can
find similar uninformed certainty propping up the bar in almost any
hostelry.


What part of Relativity do you not
agree and what part do you agree. Is space being curvable,
expandable being one you all agree??
Relativistic Cosmology has so many empirical data from
gravitional lensing to black holes. At least space
being curvable, expandable is almost infallible, agree??


Why do you want agreement? I would be more impressed if you asked for
understanding.


That means Time Dilation and other stuff are where you
don't agree with. Right??

Wrong.

Cheers,

Zigoteau.

Here's an interesting link about the early philosophy of relativity

http://plato.stanford.edu/entries/genrel-early/

In classical mechanics, the geometry was euclidean. After Maxwell
equations the geometry became non-euclidean.

Hi, Cos_mo.


But according to cosmology, the universe is expanding, there
is something in the vacuum called dark energy or cosmological
constant or quistessence that is making space expand.


You may be aware that human beings have as yet never been further away
from the earth than the moon. Dark energy, the cosmological constant,
the expansion of the universe, are all concepts relevant to deep space
much further away than the Andromeda galaxy, and they are also signs
that perhaps not everything in the theory is correct. You can believe
it all if you want to. Why not? It's a harmless bit of fun, pushes a
lot of people's buttons, and doesn't make a blind bit of difference to
everyday life. However a scientist at the cutting edge must keep in
mind the experimental evidence on which all these theories are based,
and be ready to revise them when new evidence comes to hand.


Uhm... I'm talking about the expansion as it relates to physical
space. In General relativity. It is the abstract 4D space/time
geometry that is curving and causing gravity.


Let's get things clear. There is no doubt at all about apples falling
downwards, hitting famous scientists on the head. There is no doubt
that the moon endlessly orbits the earth. We have a theory which
explains these facts, and it involves a metaphorical extension to the
concept of curvature. However the fall of the apple caused the theory,
the theory did not cause the fall. The theory *describes* the fall. A
simpler theory, which also describes the fall, and which is still very
much in use, does not involve curvature.


So I guess there are two kinds of space shape shifting. One
a physical one, the other a curving of the 4D Einstein
Spacetime which is not physical.


I'm sorry, but this does not mean very much. It indicates that you are
a long way from understanding the currently best theory of gravity. Do
you know what the metric tensor is, and how it is connected to the
special theory of relativity? Then, can you write down the field
equations of GR? Sort those two questions out, and then try asking
about curvature again.

Cheers,

Zigoteau.

Zigoteau wrote:
Hi, Cos_mo.


But according to cosmology, the universe is expanding, there
is something in the vacuum called dark energy or cosmological
constant or quistessence that is making space expand.


You may be aware that human beings have as yet never been further away
from the earth than the moon. Dark energy, the cosmological constant,
the expansion of the universe, are all concepts relevant to deep space
much further away than the Andromeda galaxy, and they are also signs
that perhaps not everything in the theory is correct. You can believe
it all if you want to. Why not? It's a harmless bit of fun, pushes a
lot of people's buttons, and doesn't make a blind bit of difference to
everyday life. However a scientist at the cutting edge must keep in
mind the experimental evidence on which all these theories are based,
and be ready to revise them when new evidence comes to hand.


Uhm... I'm talking about the expansion as it relates to physical
space. In General relativity. It is the abstract 4D space/time
geometry that is curving and causing gravity.


Let's get things clear. There is no doubt at all about apples falling
downwards, hitting famous scientists on the head. There is no doubt
that the moon endlessly orbits the earth. We have a theory which
explains these facts, and it involves a metaphorical extension to the
concept of curvature. However the fall of the apple caused the theory,
the theory did not cause the fall. The theory *describes* the fall. A
simpler theory, which also describes the fall, and which is still very
much in use, does not involve curvature.


So I guess there are two kinds of space shape shifting. One
a physical one, the other a curving of the 4D Einstein
Spacetime which is not physical.


I'm sorry, but this does not mean very much. It indicates that you are
a long way from understanding the currently best theory of gravity. Do
you know what the metric tensor is, and how it is connected to the
special theory of relativity? Then, can you write down the field
equations of GR? Sort those two questions out, and then try asking
about curvature again.

Cheers,

Zigoteau.


Pop-sci books are written for Layman to get a rough idea.
Of course mastering the equations is great. It is in getting
the rough idea or conceptual basis for Layman that is the goal
of books such as by Brian Greene.

All I'm saying is... for example. In Big Bang when a singularity
is inflated to the entire size of the universe. What happened
to the Minkowski geometry. I mean, as physical space is expanding,
what happens to the Einstein 4D spacetime geometry. What
are their relationship. Hope other kinder folks can assist.
Just want the rough conceptual sense. Later of course I can
go to the details such as solving metric tensors but for
just want to have a general idea now. You can't expect a
layman to spend 2 years enrolling in general relativity
classes and solving the equations just to understand it in a
conceptual sense. I'm not arguing that equations are not
necessary.

If you can't still understand what I'm saying. Well....
Hmm... how do I get it across, let's see. Supposed your son
asks you what is going on in the Minkowski 4d spacetime
geometry when the physical space is expanding from a
singularity. How would you answer it.

Hmm... maybe you still can't understand my point. Hope
others who got my idea can convey the rough concepts
which I'll study in gross mathematical details if I have
the time. Hope you got my point.

Cos_mo

Hi, Cos_mo,


Well....
Hmm... how do I get it across, let's see. Suppose your son
asks you what is going on in the Minkowski 4d spacetime
geometry when the physical space is expanding from a
singularity. How would you answer it.


Been there, done that. He was "interested" in the gee-whiz aspects of
relativity but was not interested in doing the hard work to get to
grips with the math, and is now a technician, not a scientist. On the
bright side, that's better than a used-car salesman, or a drug-pusher,
or a soldier of fortune.

I see the point of knowing all the big words and understanding nothing.
It's called blinding with science, and there's a lot of it about, and I
think it stinks.

Cheers,

Zigoteau.