"Baugh" wrote in message
...
Harry wrote:
"Baugh" wrote in message
...
Students get confused by "which
twin is really older" or "which measuring rod is really shorter" in
those classic paradoxes because they think "time dilates" and "lengths
contract". It is relativity in a language of absolutes.

That's unavoidable: whatever one chooses as model, there has be
something
absolute related to absolute effects such as the one twin who really
ends up
older -- be it Space or Spacetime.


I don't agree that it is necessarily unavoidable. But difficult to
avoid presenting the theory without an underlying model. Our language
and cognative processes are heavily biased toward models.
That's why so much confusion gets posted as 'common sense'.
That is why these "Einstein was stupid" posters seem oblivious
to patient arguments. They haven't undergone the dicipline required
to update their mental language. The just cannot "see" the ideas.
It takes a long time and hard work to upgrade our mental language.

Its ten (thousand?) times harder to be the first which is why, though I
can in hindsight be critical of Einstein, I hold him in the highest
respect.

It would take systematic integration of "new" concepts into the common
language, the language in which people think and communicate, before
the newer physics becomes intuitively obvious 'common sense'.

In his time Newton's laws defied 'common sense'. Everyone knew that
objects moved until their 'inertia was exausted' and then they dropped.

I'm not sure such an integration can occur until/unless the competing
doctrine of religious absolutes wanes. (That is it competes for
influence in the evolution of our language.)

I am sure that Minkowski's "geometric model" of Einstein's GR has
confused physicists into investigating such nonsense as string and
M-theory based quantum gravitation. They take the ontological reality
of space-time way too seriously. I would argue that space-time is
a conceptual construct, specifically the (partial) parametrization of
the group acting on physical objects.

But this is not "Minkowski's fault" non-Euclidean geometry was very new
at that time and the delusion that geometry is physical had been around
for millenia. I cringe when I see papers titled "quantum geometry",
"quantum space-time" and mathematical constructs labeled "quantum
groups". But that's the current fad and until I or someone sucessfully
produces an actual quantum *theory* incorporating Einstein's equivalence
principle instead of "quantized" models, the journals will abound with
"quantized" mathematical abstractions.

Regards,
James Baugh

My current research is based on this point of view.

I largely agree on that -- success with your research!
Regards,
Harald

"Dr ***" wrote in message
...

"Harry" wrote in message
...

"Baugh" wrote in message
...
SNIP
Students get confused by "which
twin is really older" or "which measuring rod is really shorter" in
those classic paradoxes because they think "time dilates" and "lengths
contract". It is relativity in a language of absolutes.

That's unavoidable: whatever one chooses as model, there has be something
absolute related to absolute effects such as the one twin who really ends
up
older -- be it Space or Spacetime.

Regards,
Harald

Dr *** wrote:
That is very true and perhaps the observer pov could be designated as the
absolute/reference so as to avoid this confusing and only slightly
productive multi vector debate that can be irreconcilable.

Sorry but I didn't read your recent discussions, I have no clue what you
mean with "multi vector debate".

Harald

"Bill Hobba" wrote in message
...

"Baugh" wrote in message
...
Bill Hobba wrote:
[...]
In the end you can call it 4-mass, 4-momentum, or 4-energy; depending
on
which units you prefer. In which case E (= Pc) = Mc^2 is a 4-vector
identity giving the unit conversions.


Hmmmmm. That I am not so sure about. Energy is a scalar (in modern
times
defined as the conserved Noether charge related to time symmetry) -
which is
another reason it is best not to introduce the concept of
traverse/relativistic mass.

Not quite right. Energy-momentum is the vector conserved Noether charge
related to the time-space translational symmetry.

Yes.

Different observers
will see different Energies so it is not a Lorentz scalar.

Yep.

Now anything can be a "scalar" if you reduce the group enough
but in the end the Noether charges are covariant to the respective
generators.

Yep.


This puts energy-momentum and relativistic angular
momentum on the same footing as components of the ten-vector
Noether charge covariant with the ten-vector of the adjoint
representation of the Poincare group.

We separate out the energy-momentum because we can separate
out the translations as a normal subgroup. If you work
in deSitter space-time this is no longer the case.
Poincare becomes SO(4,1) and everything looks like components of an
"angular momentum" in 5-dim.

From my limited understanding of such matters I agree.


Such a mass depends on the direction of the
applied force - while energy does not. So if we wish to use E=MC^2
then
we must stick to invariant mass.

The original doesn't show up in my newsreader. Not so if you referred to
dynamic mass m=gamma*M -- I hope you don't think that gamma depends on the
direction of the force! Moreover E= mc^2 is only valid for invariant mass in
the special case that v=0. For v=/=0 one should use dynamic mass or write
explicitly gamma*M in the energy equation.

Hm? Not that I am aware of. The "relativistic mass" is the
"relativistic energy" [ is the relativistic momentum's time component].
(Et,Ex,Ey,Ez) = c^2(Mt,Mx,My,Mz) [ = c(Pt,Px,Py,Pz) ]

Mt = "traverse/relativistic mass"

Relativistic mass is a defined quantity which does not have properties we
normally associate with mass - ie if it is used in F=MA then it is only
valid for forces in the direction of motion (as you note below).

Right -- as long as you limit yourself to classical intuition.
Dynamic mass is in relativity by definition incompatible with F=ma just as
F=ma is incompatible with rocket science!
F = dp/dt = F = ma + v dm/dt
When you don't overlook that, things get a lot clearer (at least it did so
for me!).

Best regards,
Harald.

Dr *** wrote:
"Harry" wrote in message
...
[...]
For me "science" includes metaphysics, and that's where "SRT" as principle
theory is a subset of both the "LET" model as well as the more popular
"Spacetime" model.


Metaphysics is a branch of philosophy. Science is an dicipline within a
separate branch of philosophy. Including metaphysics in science is
like including "mammal" within an "crow". Science at it foundation does
not depend on metaphysics, it is class of epistomological dicipline.

Scientists on the other hand often get caught up in metaphysical
questions just as they also get caught up in funding questions and
religious debates. Scientists are people who "also do science".
But I see no room for metaphysics in science. Some science in your
metaphysics may be useful or it may not... depends on what metaphysics
you've chosen.

But metaphysical debates which do not change one aspect of what you can
observe in the laboratory/observatory do not have any business
being labeled "scientific".

Again science is an *epistimological* dicipline.

Regards,
James Baugh
p.s. Be sure to indent and mark or quote included text when you reply.

"Baugh" wrote in message
news
Dr *** wrote:
"Harry" wrote in message
...
[...]
For me "science" includes metaphysics, and that's where "SRT" as
principle
theory is a subset of both the "LET" model as well as the more popular
"Spacetime" model.

Not "Dr" wrote that but I did. "Dr" messes up the quote structure when he
replies.

Metaphysics is a branch of philosophy. Science is an dicipline within a
separate branch of philosophy. Including metaphysics in science is
like including "mammal" within an "crow". Science at it foundation does
not depend on metaphysics, it is class of epistomological dicipline.

Your definition of science differs from that of the dictionaries that I
consulted such as for example American Heritage and it appears to be
inconsistent with natural philosophy which I think was the precessor of
physics and metaphysics.
Where do you base your definition on?

Scientists on the other hand often get caught up in metaphysical
questions just as they also get caught up in funding questions and
religious debates. Scientists are people who "also do science".
But I see no room for metaphysics in science. Some science in your
metaphysics may be useful or it may not... depends on what metaphysics
you've chosen.

But metaphysical debates which do not change one aspect of what you can
observe in the laboratory/observatory do not have any business
being labeled "scientific".

Again science is an *epistimological* dicipline.

I agree that *physics* is an epistimological dicipline. Science seems to be
badly defined.

Best regards,
Harald

Harry wrote:
"Baugh" wrote in message
news

[...]
For me "science" includes metaphysics, and that's where "SRT" as

principle

theory is a subset of both the "LET" model as well as the more popular
"Spacetime" model.


Not "Dr" wrote that but I did. "Dr" messes up the quote structure when he
replies.

Pardon me for not catching that.


Metaphysics is a branch of philosophy. Science is an dicipline within a
separate branch of philosophy. Including metaphysics in science is
like including "mammal" within an "crow". Science at it foundation does
not depend on metaphysics, it is class of epistomological dicipline.


Your definition of science differs from that of the dictionaries that I
consulted such as for example American Heritage and it appears to be
inconsistent with natural philosophy which I think was the precessor of
physics and metaphysics.
Where do you base your definition on?


Scientists on the other hand often get caught up in metaphysical
questions just as they also get caught up in funding questions and
religious debates. Scientists are people who "also do science".
But I see no room for metaphysics in science. Some science in your
metaphysics may be useful or it may not... depends on what metaphysics
you've chosen.

But metaphysical debates which do not change one aspect of what you can
observe in the laboratory/observatory do not have any business
being labeled "scientific".

Again science is an *epistimological* dicipline.


I agree that *physics* is an epistimological dicipline. Science seems to be
badly defined.

Yes, the language evolves. Here's a good one (one I agree with mostly)
I found on the web:

"Science is a process for evaluating empirical knowledge (the scientific
method), a global community of scholars, and the organized body of
knowledge gained by this process and carried by this community (and
others). Natural sciences study nature; social sciences study human
beings and society." -en.wikipedia.org/wiki/Science -

I'd cut out the "community of scholars" part. That is unnecessary,
one man alone on an island may exibit science. There's a hidden
implication that concensus matters.

Regards,
James Baugh

"Baugh" wrote in message
...
Harry wrote:
"Baugh" wrote in message
news

[...]
For me "science" includes metaphysics, and that's where "SRT" as
principle
theory is a subset of both the "LET" model as well as the more popular
"Spacetime" model.

Metaphysics is a branch of philosophy. Science is an dicipline within a
separate branch of philosophy. Including metaphysics in science is
like including "mammal" within an "crow". Science at it foundation does
not depend on metaphysics, it is class of epistomological dicipline.


Your definition of science differs from that of the dictionaries that I
consulted such as for example American Heritage and it appears to be
inconsistent with natural philosophy which I think was the precessor of
physics and metaphysics.
Where do you base your definition on?
SNIP
I agree that *physics* is an epistimological dicipline. Science seems to
be
badly defined.

Yes, the language evolves. Here's a good one (one I agree with mostly)
I found on the web:

"Science is a process for evaluating empirical knowledge (the scientific
method), a global community of scholars, and the organized body of
knowledge gained by this process and carried by this community (and
others). Natural sciences study nature; social sciences study human
beings and society." -en.wikipedia.org/wiki/Science -

I'd cut out the "community of scholars" part. That is unnecessary,
one man alone on an island may exibit science. There's a hidden
implication that concensus matters.

Fine -- in fact, I didn't reflect long enough about epistemological: even
that is too broad for physics.
As soon as we evaluate empirical knowledge and make claims about its meaning
based on our personal ideas of nature, we come in the realm of metaphysics.
You may claim that "length contraction" and "time dilation" consist of bad
language in Spacetime physics, which is based on the (metaphysical) model of
a really existing space-time. But it is good language with Einstein's
relative (personal) reality model as well as with Lorentz' stationary ether
model, and it's also good language when one just wants to describe what one
predicts as measurement results -- many physicists such as Feynman used
those expressions for that purpose.

BTW, I could not find your posting about theories vs models, it seems to
have got stuck in a part of Google that is out of my reach and it also
didn't reach my Newsgroup mailbox!

Cheers,
Harald

"Baugh" wrote
Sent: Friday, May 13, 2005 2:01 PM

| Harry wrote:
| "Baugh" wrote in message
| ...

| For me "science" includes metaphysics, and that's where "SRT" as
principle
| theory is a subset of both the "LET" model as well as the more
popular
| "Spacetime" model.
|
| Metaphysics is a branch of philosophy. Science is an discipline
within a
| separate branch of philosophy. Including metaphysics in science is
| like including "mammal" within an "crow". Science at it foundation
does
| not depend on metaphysics, it is class of epistemological discipline.
|
|
| Your definition of science differs from that of the dictionaries that I
| consulted such as for example American Heritage and it appears to be
| inconsistent with natural philosophy which I think was the precessor of
| physics and metaphysics.
| Where do you base your definition on?
|
| SNIP
|
| I agree that *physics* is an epistemological discipline. Science seems
to
| be badly defined.

| Yes, the language evolves. Here's a good one (one I agree with mostly)
| I found on the web:
|
| "Science is a process for evaluating empirical knowledge (the scientific
| method), a global community of scholars, and the organized body of
| knowledge gained by this process and carried by this community (and
| others). Natural sciences study nature; social sciences study human
| beings and society." -en.wikipedia.org/wiki/Science -
|
| I'd cut out the "community of scholars" part. That is unnecessary,
| one man alone on an island may exibit science. There's a hidden
| implication that concensus matters.
|
|
| Fine -- in fact, I didn't reflect long enough about epistemological:
even
| that is too broad for physics.
| As soon as we evaluate empirical knowledge and make claims about its
meaning
| based on our personal ideas of nature, we come in the realm of
metaphysics.
|
| Yes, that is if we choose to think in metaphysical terms. (I think we
| must with regard to the devices we use to observe a specific phenomenon
| but not necessarily with regard to that specific phenomenon. In this
| sense I feel we are extending our 'selves' to include our tools.
| Eg. "I saw it with my eyes", "I saw that with my particle detector".
|
| You may claim that "length contraction" and "time dilation" consist of
bad
| language in Spacetime physics, which is based on the (metaphysical)
model of
| a really existing space-time. But it is good language with Einstein's
| relative (personal) reality model as well as with Lorentz' stationary
ether
| model, and it's also good language when one just wants to describe what
one
| predicts as measurement results -- many physicists such as Feynman used
| those expressions for that purpose.
|
| My claim is based on my opinion that there is more value in distancing
| ourselves from metaphysical language in understanding relativity.
| I may be projecting what was of value *to me* onto others. But I've
| found this to be pretty reliable. I learned that in cooking. Cook
| to my own tastes and usually most everyone else finds it tasty too.

Sure, I hope to have put your attention to the fact that you unwittingly
referred to a specific model of SRT and not to SRT itself.
BTW I stressed that "time dilation" is a fact of observation.

| I find the metaphysical language inhibits understanding. Specifically
| length doesn't 'contract' it 'rotates' as a component of a larger
| structure of measurements.

To the contrary, if measurements could be accurate enough what one would
*measure* is *contraction* of the *length* of objects and not "rotation" of
the object in space. Your "rotation" belongs to your preferred model!

| Length is not a property of the object but rather a relationship between
it and others.

Only in the Space-time model, not in Einstein's personal reality model nor
in Lorentz' stationary ether model.

| Boosts change that relationship via a rotation with regard to an
indefinite metric.

Only in your preferred metaphysics is that more than a mathematical
relationship!

Best regards,
Harald

"Harry" wrote in message
...
|
| "Baugh" wrote in message
| news | Dr *** wrote:
| "Harry" wrote in message
| ...
| [...]
| For me "science" includes metaphysics, and that's where "SRT" as
| principle
| theory is a subset of both the "LET" model as well as the more popular
| "Spacetime" model.
|
| Not "Dr" wrote that but I did. "Dr" messes up the quote structure when he
| replies.

Sorry about that Harald and others I just found that the indenting caused
returns after a few replies that made text less readable but if its causing
problems I will include | ok ? and not reply so much {:-)
--
Dr *** time/length/energy
http://home.freeuk.com/paulps/
Some updates the turnips are coming
up nicely. Ooh ah.{:-)

"Harry" wrote in message
...
snip
| Dynamic mass is in relativity by definition incompatible with F=ma just as
| F=ma is incompatible with rocket science!
| F = dp/dt = F = ma + v dm/dt

| When you don't overlook that, things get a lot clearer (at least it did so
| for me!).
|
| Best regards,
| Harald.

Would you mind clarifying your assuagements Harald.
Specifically p and m
--
Dr *** time/length/energy
http://home.freeuk.com/paulps/
Some updates the turnips are coming
up nicely. Ooh ah.{:-)