Newsgroup sci.physics 206699

Jo Helsen wrote:
> 
> the great and intrepid bashford@psnw.com (Crash) wrote:
> 
> >... "Our economy isn't growing fast enough!"  - Our politicians.
> 
> >* Sustained economic growth is impossible because it is tied to
> >* physical consumption (wealth).  Why impossible??  5% annual growth
> >* in the consumption of 2 grams of any substance will become a "hole"
> >* with a mass of 800 trillion planet earths in only 2,000 years.
> >* Thus long term economic growth is impossible.  This is but one
> >* of many fallacies in ALL orthodox economic foundations. - G. Hardin
> 
> That's what I have been wondering all about so many times. And now it turns out
> that some smart bloke thought about the same.
> It can't be anything else but true, and I wonder where this gets us with our
> consumption economy...
This appears to be a real dilemma. However, after pondering it for a minute, I 
would like to offer up a couple of points.
Firstly, a large portion of our economy is based on the consumption of energy. If 
we can implement cheap, "renewable" resources - i.e. solar, fusion, wind, etc. - 
in a somewhat efficient way, then we'll be a step up on the game, IMHO.
Secondly, if/when we finally expand and begin to colonize the solar system, our 
"non-renewable" resources would increase exponentially.
I'm sure there are many salient points remaining, but these are the ones that 
immediately struck me.
 - Mark -

goldbach wrote:
> Mike Wooding  wrote in article <3279340B.167E@wse.com>...
> > Crash wrote:
> > > I'm not sure you understand the mathematics of exponential growth.
> > > Consumption of non-renewable natural resources is growing
> > > exponentially. This consumption is NOT linked to population growth.
> > > Any economist will tell you that Man's natural thirst for wealth is
> > > unquenchable.
> >
> >  I'm not sure what's meant by consumption? Nothing is consumed so
> >  much as it's transformed from one arrangement to another. Excepting
> >  entropy, all such transformations are reversible - at least in
> >  principle. So, isn't entropy the only non-renewable resource? And
> 
> In open systems the 2nd Law and entropy are reversible. For example,
> living things  seem to nicely order things from less orderly outside stuff.
> It is not all down hill everywhere.
> Larry
> 
> >  it's destined to increase until the 2nd Law is ruled un-universal?
 Assume the Universe is a closed system. :-)
-- 
 mikew@wse.com (Mike Wooding)

Russell Turpin:
> What is ideal about ideals or tense about tensors?  
You've got me on ideals.  Tensors, however, were first introduced 
to describe stress in a solid body -- through the so-called stress 
and strain tensors.  Literally, it appears that the connection is 
to the word "tension".
-------------------------------------------------------------------
Jeff Candy                        The University of Texas at Austin
Institute for Fusion Studies      Austin, Texas
-------------------------------------------------------------------

Bjorn Olievier wrote:
> 1.  On the ceiling of a gymnasium there's a pulley.  A long, thick
> rope is hanging over it and both ends teach the ground.  On each side
> a boy hangs some metres above the floor.  The system is in rest.
> A/  One boy starts climbing to get higher than the other.  Will it
> work?  Explain.
Mmm tricky :)
This is a badly posed problem actually.  The reason is that statically,
the situation is in an indifferent equilibrium.  You can give a tiny
kick to one of the boys and the system will set in a uniform motion,
one boy rising and the other one descending (until one of them hits 
the floor or the other one gets its fingers crushed in the pulley at
the top :)  This motion will be damped due to friction at the pulley.
If one boy IS climbing at a uniform speed onto the rope, the static
forces are exactly the same as if he wasn't climbing.  HOWEVER, during
that short interval where he changes from hanging to climbing, he
is ACCELERATING, hence on top of his weight, he pulls a force equal
to a.M (M = mass of the boy, a = acceleration of the boy upward).
So he's setting the thing in motion because the forces do not balance
during this time.  Of course, on an ideal system (no friction), this
force would start accelerating the system in such a way that both
of the boys stay at eachother's height (because the force that is
necessary to accelerate the first boy is exactly equal to the force
needed to accelerate the other one at the same rate).
But we cannot have an ideal system, because then even the tiniest
difference in weight would make the heaviest boy fall down.  So 
SOME friction is needed.  Now imagine that one boy starts climbing
soooo slowly that his acceleration force isn't sufficient to overcome
this friction.... well, then it is caught by the pulley, and the rope
won't move.  Hence, with a bit of friction, it is possible to climb
VERY carefully without the other one also going up.
As the limiting case of the solutions with a little bit of friction,
in the limit of NO friction, is different from the solution at NO
friction (discontinuity), this is a badly posed problem.
> B/  They both start climbing, but one can climb better than the other.
> Wat will happen now?
Same as above, just consider the difference in acceleration.
> 
> 2.  The same device is used as in the previous problem.  Now on one
> side there's a monkey of 3,5 kg.  On the ohter side there's a cluster
> of bananas, also 3,5 kg.  The monkey starts climbing, hoping to reach
> the bananas.  Where will he get them?
He will always get them, as by climbing he shortens the piece of rope
between him and the bananas.  So, or they both accelate upwards (ideal
case) or he climbs up to the pulley, and then pulls the rope through the
pulley and gets the bananas... HOWEVER, from the moment he eats 
one of the bananas, he'll crash ! :)
cheers,
Patrick.

Christopher R Volpe  wrote [in part]:
>Brian Jones wrote:
>> 
>> It's not that simple. There are quite definite and real physical
>> results of such clocks that directly reflect the absoluteness behind
>> the definition. For example, given any two events, each observer will
>> find a different time between them.  This tells us that their clocks
>> all read differently at these same two events.  And yet the events
>> themselves obviously can have only a single time between them.
>Asserting that there can be only one time interval between two events is
>like claiming that there can be only one x interval between two points
>on a plane.
>> 
>(I think I've made the point clear.)
>--
>Chris Volpe
Slightly wrong analogy, Volpe.  In my case, it's the distance between
the two points in the plane, NOT their x-y-components.  But since you
cannot seem to grasp this, let's go on to the other little example,
which so far you have managed to ignore.
An observer has two x-axis clocks that have not yet been started.   He
passes a light source.  This source is energized midway of the clocks.
Since the rear clock movesTOWARD the light, and the front clock moves 
AWAY FROM it, the clocks will not be started at (absolutely) the same
time.
Given that the clocks cannot have the SAME reading at (absolutely) the
same time, what will their readings be at (absolutely) the same time? 
Fill in the blanks:
_________________                                  _________________
Rear Clock Reading                                 Right Clock Reading
NOTE: You cannot put zero in both places.
     §§ ßJ §§
bjon @ ix. netcom. com

In a previous article, +@+.+ (G*rd*n) wrote:
->I skipped over most of that discussion, which seemed to me
->to be an attempt to disqualify moggin from speaking about
->physics -- another math test.  Did I miss something?  Anyway:
[snip]
->matts2@ix.netcom.com (Matt Silberstein):
->| If you objection is with "understand" then that seems a very different
->| discussion. I don't see how "understanding" is different for science
->| as opposed to arts, humanities, sports, etc. It might me, but I would
->| like to see the arguments.
-> 
->It's no doubt as ill-defined for those as it is for the
->sciences.  And the practice of constructing arcana in
->these fields to keep out the unsanctified is an practice
->of great antiquity.  It's unfortunate to see it spreading
->into the sciences.
???
I ain't mathematical -- not exactly innumerate, but somewhat
dyscalculic.  I have been reading a *history* of the development
of 20thc physics -- quantum elctrodynamics, relativity, unification
and the like -- in the hopes of approaching some nonmathematical
picture of what modern physics is talking about.
This has been partially successful -- I now know more than I did.
It has also been unsuccessful.  The authors, Crease and [ow, forgot],
are not themselves physicists or mathematicians, but are intelligent
and lucid, and had the privilege of having the likes of Glashow,
Salam, Dyson, Feynman and many more patiently explain things to them.
There are several places where they just had to throw up their
hands and say, in effect if not literally, "trust me on this."
One (small) example:  several folx realized that leptons and hadrons
could be beautifully and elegantly described with a "group" (this
word having a specific mathematical usage), one of many catalogued
by a man named Cartan; specifically, the "SU(2)xU(1)" group.
It's clear that this *means* something to the particle physicists
involved -- they were really *excited* over this relationship.
SU(2)xU(1) means absolutely *nothing* to me, however.  I'm not
entirely certain I've even typed it right.
They don't know me.  They weren't/aren't trying to keep me out
of any temple.  They were not, at the time, the *least*bit*concerned*
with whether Joe Blow would know what they were talking about at
all, and it's paranoia on Joe's part to think that they were (or a 
childish desire to think himself worthy of such attention).  The
*fact* is, these guys, these physicists, see a relationship that
I will never ever know -- until I learn the math that describes it!
Till then, *my* only "model" for the population of leptons & hadrons
is a box of assorted chocolates -- a rather indiscriminate, and more
to the point *undescribable*, mix.
If I bother to learn a little more math, group theory in particular, 
I will be able to see the PATTERN that they see.  And my powers of
description will have expanded vastly over what they are now.
(Speaking of patterns, what's next in the series
1, 4, 7, 9, 11, 12, 14, 16, 19, 20, 23, 24, 27, ... ? ;-] )
The only thing keeping out "the unsanctified" is their own personal
belief that "math is too hard."  Followed, I think, by the intel-
lectual equivalent of "I'm too lazy to walk fast, so *you* should 
slow down and not go faster than me."
I don't worship the mathematically-educated; I could be one if I 
wanted.  If I *don't* so want; if *I* prefer to spend *my* attention
in other directions, why on earth should I suspect them of trying
to "keep me out" of what interests them???
---mellyrn, really quite gruntled, despite
----------------------------------------------------------------
speaking only for myself

Richard A. Schumacher wrote:
> 
> >What I cannot understand until today is how he is involve with a Nuclear &
> >Particle Group if he didn't understand the most simple question.
> 
> Could it be that you, leberal arts student having taken no
> physics courses, don't understand the situation? No, of
> course not. Silly me.
Oh come on.  It is clear that the neutrino doesn't exist.
I recently bought a Hilstatron (that's a portable neutrino
detector) - cuz they were available at a reduced price at
Snakeoil Inc Store, and on a very bright day, with the sun high
in the sky, I switched it on... and it detected no neutrinos.
So it's clear that they don't exist, right ? 
Moreover, I've been at the CERN beamline where these neutrinos
are supposed to come along... and even with the lights off,
nothing was seen.  So it's an INDEPENDENT CHECK that neutrinos
don't exist.  Or am I missing something ?
                                :-)
cheers,
Patrick.

OX-11 wrote:
> 
> therre is an even more interesting fossil -- in the upper rio grands
> valley of new mexico, there is the imprint of a bare human female footprint
> in a sandstone outcropping that is around 10 -60 million years old. The
> girl was walking and tripped. seh overcorrected by extending her foot and
> made the imprint in the once soft mud of the riverbank.  It left a deep
> impression clearly visible. You can even see the potho;e she stepped
> into, and the splash marks extending out from it.....
This post is an old creationism example that humans lived at the same 
time as dinosaurs.  To actually see the prints, you realize that any 
being could have made them, two footed or four footed.  But to say that 
it was a girl that made them, is a new one on me.  I am extremely 
interested to find out the sex of an individual just by their foot 
prints.  From what I understand, if you had available to you all the 
bones of the human body, the only one that would tell you the sex, would 
be the pelvis.  There seems to be some missing info in your post to let 
us know how the sex of the individual was determined in the footprints.
Jim Akerlund

-*---------
In article <3280BDF8.E30@rmb.co.za>, Hardy Hulley   wrote:
> ... Firstly, when an existing word is appropriated for use as
> a specialised technical term, the meaning ascribed to it is
> (almost always) both consistent with its existing meaning, and 
> related to same. ...
Like strange, charm, top and bottom?  
> ... Examples of this are countless: "complete", "valid", "consistent"
> (within logic), "compact", "continuous" (within analysis, topology
> and elsewhere), ...
These would be good examples if they didn't so often confuse
people who think the ordinary meaning of the term gives them some
insight into the technical meaning.  Consider Godel's
incompleteness theorem as the quintessential example.  And even
so, Hulley has picked terms that favor his claim.  What is ideal
about ideals or tense about tensors?  
Yes, people prefer to reuse existing terminology, when it is handy,
but I think Hulley overstates the case here, and regardless, that
it is not that important to his thrust.  Much more to the point is
what follows:
> Secondly, in good technical writing, the tendency is to make
> terminological usage explicit. Within mathematics this takes the 
> form of "DEFINITION *.*: A topological space is said to be
> *compact* if...".  ...
It is long, long, LONG past time for the lit critters to define
what they think Derrida meant by "constant" in his remark.  If
they are defending it in a technical sense, that should have been
one of their *first* moves.  (There *is* some technical
terminology floating around in these discussions, borrowed mostly
from early linguists, but it is far from clear to me that that is
what we are seeing here.)
Russell
-- 
 The difference between life and a movie script is that the script has 
 to make sense.         -- Humphrey Bogart

In article <55q2lh$ceg@sjx-ixn5.ix.netcom.com>,
	bjon@ix.netcom.com (Brian D. Jones) writes:
> Of course an absolute time exists,
Please answer the question.  Why must "absolute time" exist?
-- 
Steve Emmerson        steve@unidata.ucar.edu        ...!ncar!unidata!steve

briank@ibm.net (Brian Kennelly) wrote [in part]:

See my Throop reply.
     §§ ßJ §§
bjon @ ix. netcom. com

Alan \"Uncle Al\" Schwartz (uncleal0@ix.netcom.com) wrote:
: Baseball cap, pipe cap, fool's cap, lens cap, nurse's cap, dental cap, 
: spending cap, kneecap, caps as opposed to lowercase, bottle cap.
Ok, OK, very funny...!  What I am looking for, of course, is a capacitor
that is designed specifically to discharge quickly through a flashlamp.
Any of you jokers have one that you'd like to sell us?  Thanks!
pat

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Date: Tue, 5 Nov 1996 12:45:06 -0800 (PST)
From: "Lawrence B. Crowell" 
To: roland cook 
cc: Barron Burrow , nixon@geneseo.edu, tmoody@sju.edu,
        jeff@aiai.ed.ac.uk, norwoodr@etsuarts.east-tenn-st.edu,
        acampbell@cix.compulink.co.uk, srh@ccit.arizona.edu, md2738@mclink.it,
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        mikebarker@delphi.com, heuvel@muc.de, matpitka@rock.helsinki.fi,
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        rwarner@kentlaw.edu, wordenr@logica.com, hswift@swcp.com,
        chalmers@paradox.ucsc.edu, sarfatti@well.com, onesong@ix.netcom.com,
        hilken@maths.ox.ac.uk, pdavies@physics.adelaide.edu.au,
        JPL.Verhey@inter.nl.net, bdj10@cam.ac.uk, MaitEdey@aol.com,
        hensm@essex.ac.uk, vignes@monaco.mc, lcrowell@unm.edu
Subject: Re: The hard problem and QUANTUM GRAVITY.
In-Reply-To: 
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On Mon, 4 Nov 1996, roland cook wrote:
> 
> On Mon, 4 Nov 1996, Lawrence B. Crowell wrote:
> 
> > ...  There are approaches to general
> > relativity where the curving of light rays in spacetime is treated as an
> > optical problem.  In effect one can model a gravity field as a region of
> > spacen with a variable index of refraction of a medium.  The American 
> > Journal of Physics sometimes has some articles on this.  
> 
> I am aware that the comparison has been made -- it's not original with me. 
> However, I have done optical ray-tracing, and written programs for this
> purpose. 
> > 
> > The weakness in this approach is that it is difficult to model the motion
> > of nonzero mass particles in spacetime.  
> 
> The difficulty appears to be due to the theory, rather than to the
> modeling. Since there is no theory to account for density of space
> (although one can assert "curvature" which is quite a bit weirder)
> one can hardly model a non-theory.
> 
The optical approach is really a sort of approximation to the general
theory of relativity.
> One aspect of an increasing (electromagnetic?) density of space in the
> vicinity of mass (an extension of Van der Waals forces) is that it would
> account for acceleration -- which is not accounted for by the curvature of
> spacetime. 
>
The idea of general relativity is that a mass in curved spacetime
experiences no gravity.  The experience of an observer on a very small
reference frame, small with respect to the curvatures, freely
falling toward a gravitating mass measures nothing at all different from 
an observer at rest in flat spacetime sufficiently far removed from any 
gravitating mass.  It is when a rocket motor is turned on and the
observer is pushed away from free fall, or equivalently the observer in
flat spacetime suffers an acceleration, is there any meaning to
acceleration.  Indeed the reason you feel wieght is not so much due to
gravity as it is the material forces of the earth and floor underneath you
that are causing you to be diverted away from free fall.
However if you and your friend are on two different reference frames then
you will find that you are changing position relative to your friend.  You
geodesic is deviating away from hers.  This occurance is the source of
tidal accelerations, and these do have a meaning in general relativity.
Geodesic deviations and the evaluation of a vector as it is moved around a
closed loop in spacetime are measures of the spacetime curvature.
This is different from a gauge field such as the electromagnetic field.
Here there is a sort of internal space at every point, or epsilon
neighborhood, of spacetime.  In this internal space one is free to set a
global gauge condition, or equivalently you arbitrarily set a direction in
this internal space.  Yet if it turns out that in traversing from one
point to another there is an induced change in this internal direction
then a gauge field is present.  With the case of electromagnetism this
internal space is a circle in a complex plane.  Indeed one can see why
there are positive and negative charges since the only two real valued
positions on this circle are {1, -1}, which are the weights of the U(1)
Lie algebra of the complex valued circle.  For other gauge fields the
internal space is a geometry described by some higher dimensional Lie
algebra
L. Crowell
--------------48605E65138A--

In article <01bbcbfb$47a5d220$63b72399@default>, "twitch"  writes:
>
>
>...
>> Matti Meron includes:
>> 
>>      It was understood (by the physicists) that there is
>no
>>      absolute reference frame and no absolute rest in
>Newtonian
>>      physics.  Check F = ma again, in case you've any
>doubts.
>> 
>Leave us not forget, that Newton never said F=ma!  He
>talked in terms of momentum.
>
Yep.  But I'm trying to use a form that the nonphysicists are more 
familiar with.  Some generality is given up as a result, but at least 
the confusion level stays manageable (hopefully).
Mati Meron			| "When you argue with a fool,
meron@cars.uchicago.edu		|  chances are he is doing just the same"

I think the request was a serious one before some folks answered, he probably 
needs the cap pretty bad, and laser suppliers for scientific equipment are 
EXTREMELY high priced. Can anyone help him? 
Christopher R Volpe (volpe@ash.crd.ge.com) wrote:
: James P. Meyer wrote:
: > 
: > On Tue, 5 Nov 1996, Steve Work wrote:
: > 
: > > As long as all of them are sent to me at absolute zero, I will send you
: > > $3500 in the currency of the nation of my choice.  But remember, even
: > > liquid helium won't be cold enough.
: > 
: >         I'm sure you've seen the statement on the paper wrapper of a
: > band-aid, "Sterility guaranteed unless opened."  My caps were sent
: > wrapped with a statement, "Absolute zero guaranteed unless opened."
: > 
: >         And, just on the off chance you decide to weasle out of our deal
: > by quoting Einstein's E=MC^2, and claiming that the caps store energy
: > proportional to their mass even at absolute zero, the caps are also
: > guaranteed to be massless until their wrappers are opened.
: > 
: >         When can I expect to get my money?
: The envelope will arrive in a few days. It will be guaranteed to contain
: money unless opened.
: --
: Chris Volpe			Phone: (518) 387-7766 
: GE Corporate R&D;		Fax:   (518) 387-6560
: PO Box 8 			Email: volpecr@crd.ge.com
: Schenectady, NY 12301		Web:   http://www.crd.ge.com/~volpecr
: .
--
Bill 

Johnny Chien-Min Yu (caesar@copland.udel.edu) wrote:
: >>  The mind (machine) control system is the national security system of 
: >>  Taiwan from late of 1970s and should be the same in US or lots free 
: >>  countries.
: >....we have it in Australia too....we call it television.
: >
: >shel
: TV is most effectively broadcast system, therefore. it usually be used as
: a social educated tool in many countries.
: However, the above situation is different with the activities of mind 
: control operators.  That's because the acceptance of an idea is
: determined by the audience of TV.  Should the audience deem the arguments
: creditable, then they will hear it and investigate.  Therefore, the
: decision lays with audience.
: In the case of real mind control, the acceptance of idea lies with 
: the operators.  They can use ELF and other electronics means to 
: input the emotion or idea to audience (forcely change other's
: behaviors).  
: Therefore, the audience are being mind controllled, and the decision
: is made for them.  THIS IS WHAT MIND CONTROL REALLY IS.  The use of 
: mind game tactics and other scientifc technologies to manipulate other
: people's emotions, behaviors, and thoughts IS THE REAL MIND CONTROL! 
This is what schizophrenia really is.  Seriously, get some help.
--
+----------------------------------------------------------------------+
|    Paul D. Shocklee - physics grad student - Princeton University    |
+----------------------------------------------------------------------+
| Some oxygen molecules help fires burn while others help make water,  |
|        so sometimes it's brother against brother.                    |
+----------------------------------------------------------------------+

In article ,
Stephen.Baynes@soton.sc.philips.com wrote:
> 
> If I recall correctly the babylonean system was actually represented as
> pairs of base 6 and base 10 digits so perhaps one could get away with 196 =
> 6*6 + 10*6 + 10*10 entries (I will have to think about that number).
> 
My info shows base 10 for the least significant digit, 
followed by at least two layers of base 6 
resulting in a minimum of 360 entries for a multiplication table
-- 
Peter Kerr                        bodger
School of Music                   chandler
University of Auckland NZ         neo-Luddite

> > >or how many bushels in a hogshead.
> > 
> > None; the bushel is a measure of dry capacity and the  hogshead is a
> > measure of liquid capacity.
> 
> Surely volume is volume, regardless of wet or dry.  That's one more
> thing wrong with the American (formerly imperial) system of
> measurements.
> 
Nope, a bushel was originally a basket for measuring grain,
you wouldn't get many happy clients measuring ale by the bushel...
-- 
Peter Kerr                        bodger
School of Music                   chandler
University of Auckland NZ         neo-Luddite

Hello all Physics buffs!
	I was wondering if someone could explain to me in terms of physics why a
turbocharger draws less power from an engine than a supercharger does.  The
turbo is driven by exhaust gasses, where a supercharger is driven by a belt
directly off the engine.  Does it have something to do with exhaust gas
temperature difference across the turbo?
Thanks,
Jake

On Thu, 31 Oct 1996, Stephen La Joie wrote:
> What if indeed! 
> 
> I noted that my ol' Chemistry textbook says that glass flows like a liquid, 
> and it was written by a Cal Tech Prof, and now New Scientist 
> backs him up. Maybe it's not a myth. Maybe the only myth here is being
> spread by the "glass is solid" folk. 
Ok, dude, cite the book then, so we can all see.  Also, be clear to
distinguish that he's not talking about molten glass, please.
============================================================================
"Nationalism is an infantile disease. It is the measles of mankind."
-- Albert Einstein	Jeffrey L. Nelson http://mole.uvm.edu/~jlnelson
============================================================================

> >In the metric world, the designer just selects the dimension in mm such
> >that they are nicely divisable, if this is a design requirement. You
> >select some module size with many factors and try to make all other
> >dimensions multiples of this module size.
> 
> In metric units this is the 0.60 meter module.  In English, it is the
> yard.  I think the yard is simpler.
Yup, because our "metric" building industry still uses 2ft and 4ft
sheets of material which measure 610 & 1220mm. 600 & 1200 sheets 
are available but must still be specified separately. 
Yet 8inch bricks are actually 190mm to allow for the mortar...
-- 
Peter Kerr                        bodger
School of Music                   chandler
University of Auckland NZ         neo-Luddite

mellyrn@enh.nist.gov:
|> One (small) example:  several folx realized that leptons and hadrons
|> could be beautifully and elegantly described with a "group" (this
|> word having a specific mathematical usage), one of many catalogued
|> by a man named Cartan; specifically, the "SU(2)xU(1)" group.
-> U(n) is the unitary group.  It can be represented 
   as an n x n matrix U: 
                  U = exp(iH)
where H is an n x n Hermitian matrix.  Thus, U(1) is the continuous 
group with elements {exp(ia)}, with a real.  
   U(2) can be represented as a four-parameter, 2 x 2 matrix.
   U(n)                             n^2       , n x n
-> SU(n) is the "special" unitary group: those elements of U(n) 
   with determinant one.
   The only element of SU(1) is {1}.
   SU(2) can be represented as a three-parameter, 2 x 2 matrix.
   SU(n)                          n^2 - 1       , n x n
-------------------------------------------------------------------
Jeff Candy                        The University of Texas at Austin
Institute for Fusion Studies      Austin, Texas
-------------------------------------------------------------------

briank@ibm.net (Brian Kennelly) wrote [in part]:
>How do you measure or define this absolute speed?  Your argument has now
>stepped outside SR, and your conclusions cannot be used to criticize SR, only
>to try to offer an alternative.  If you stay within the assumptions of SR, 
>then you cannot carry through your argument.
It exists whether or not  I can "define" or "measure" it.  If two
clocks are started by a light source located midway of the clocks, and
the observer is moving with respect to the light source, the clocks
cannot be started at the same (absolute) time.   They will not be
absolutely synchronized (as are Newton's clocks -- on paper).  They
will differ absolutely.  And there are only (3) things involved:[1]
the observer's absolute speed V, [2] the distance between the two
clocks (which can be in terms of a measured value), and [3] light's
actual (or absolute) speed.  No outside observers are there.
In this case, the clocks are started by the light signals, and the
clocks will differ by exactly DV/c², where D is the observer-measured
distance between the two clocks, V is the observer's absolute speed,
and c is light's absolute speed.
     §§ ßJ §§
bjon @ ix. netcom. com

In article <55q2sg$fvl@panix2.panix.com>, +@+.+ (G*rd*n) writes:
>+@+.+ (G*rd*n) writes:
>| >In contemplating a system where extended bodies appeared to
>| >act like point masses, one might make up a theory as if
>| >extended bodies acted like point masses, and see if it
>| >worked -- especially if one had a previous theory (Kepler)
>| >which pointed that way.
>
>meron@cars3.uchicago.edu:
>| I don't see that much "understanding" involved in saying "things are 
>| the way they are".  Agreed, sometimes that's the only option you've 
>| left.  But if you apply it across the board, to everything ...
>
>That's not what I was trying to describe.  Suppose Newton
>finds that if he treats planetary bodies as point masses,
>his theories about their motion work.  This would be a
>considerable advance in the art of theory fabrication of
>his times, even without being able to show why extended
>bodies can be treated as point masses.  If he can now go on
>to explain this treatment mathematically, so much the
>better; but it wasn't necessary to the validity of the
>theory using point masses, which worked whether some of its
>features could be explained or not.
>
I agree.  And it is not uncommon in physics to use things because they 
seem to work, long before there is any justification available.  But 
the point mass issue (which, for some obscure reason, my collegues 
keep bringing up) isn't very interesting anyway.  You can, 
intuitively, see that when your distance from an extended mass is much 
larger then the size of this mass, it should be at least a good 
approximation to treat the mass as a point.  So lets get something 
that is far from intuitive.
The "common understanding" of planetary motion is that "planets 
proceed along regular orbits due to the atractive force of gravity".  
This creates the implication that attractive force gives rise to 
regular orbits.  Nothing could be further from the truth.  As I wrote 
elsewhere, for almost any possible attractive force you'll get 
irregular orbits which don't close on themself.  There are couple 
unique forces which give you closed orbits and the inverse squared 
distance force is one of them.  Now, this is not something that can be 
glimpsed through intuition.  Some math is needed.
Another thing.  If there is an attractive force, why don't the planets 
fall on the Sun.  You'll say "their velocity keeps them in orbit".  
Which is true but, again, won't work for any force.  And again, there 
is something more than intuition needed to see it.
So, the so called "intuitive understanding" amounts to not much more 
then statement of the facts:  Planets follow elliptical orbits.  Good, 
Kepler already showed so.  And adding the incantetion "... due to the 
force of gravity" isn't turning it into more understanding.  To my 
mind, you begin to understand a system when you can not only describe 
it but ask yourself "what if" questions and answer them.  Sorta "if I 
change such and such in the system, what'll be the result".  To use a 
computer analogy (no dirty C code, promise, I don't like C) the levels 
of understanding required to describe a computer, use it, and modify 
it are quite different.
>meron@cars3.uchicago.edu:
>| The complaints about "academic procedures of domination" are by now an 
>| old and rather tiresome whine.  When you make statements relevant to 
>| some field of activity (whether academic or not) it is quite 
>| reasonable for people in this field to question your knowledge.  I 
>| certainly wouldn't expect a different treatment when venturing to 
>| other fields.
>
>I wasn't whining about it, I was declining to play the
>game, and I thought I might as well say what game it was I
>was declining to play, since there are several games going
>on.  My knowledge of Calculus is irrelevant to this
>discussion, because (1) I am not posing as an authority,
>and (2) the discussion is not about Calculus.  
That's not exactly true.  This discussion is (or at least was, at some 
point) among other issues about "How much math and what math is needed 
to discuss physics?"  Calculus comes up naturally.  Moreover, when you 
came with the statement "but I learned calculus .." (completely 
unnecesserily, given that you don't want it to be a discussion about 
calculus) it was rather obvious that some of the responses will relate 
to it.
>An attempt to introduce a math test was, then, a rhetorical ploy
>derived from the power structure of an academic environment
>whose purpose was to win advantage rather than advance an
>argument.  Do you really want to disagree with that?  
Yes, definitely.
>meron@cars3.uchicago.edu:
>| Indeed, no.  But you claim to possess an "intuitive understanding" of 
>| Newtonian mechanics, specifically you claimed previously to possess 
>| intuitive understanding of cellestial mechanics.  When you make such 
>| claim somebody may ask "OK, what is it that you understand?"
>
>Very simple things; I can visualize a body moving in an
>ellipse about another body, for example, and moving more
>rapidly when near the other body then when far from it.
Why an ellipse?
Mati Meron			| "When you argue with a fool,
meron@cars.uchicago.edu		|  chances are he is doing just the same"

In a previous article, meron@cars3.uchicago.edu wrote:
->In article <55q2sg$fvl@panix2.panix.com>, +@+.+ (G*rd*n) writes:
->>meron@cars3.uchicago.edu:
->>| Indeed, no.  But you claim to possess an "intuitive understanding" of 
->>| Newtonian mechanics, specifically you claimed previously to possess 
->>| intuitive understanding of cellestial mechanics.  When you make such 
->>| claim somebody may ask "OK, what is it that you understand?"
->>
->>Very simple things; I can visualize a body moving in an
->>ellipse about another body, for example, and moving more
->>rapidly when near the other body then when far from it.
-> 
->Why an ellipse?
BANG!!
Right between the eyes!  O, well-shot, Mati!
---mellyrn, grinning hugely
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speaking only for myself

What "big jets" are we talking about?