HDTenEightyP/NetNews huggingface dataset:
From: lip@s1.gov (Loren I. Petrich)
Subject: Re: Report on Philosophies of Physicists
Organization: LLNL
Date: Tue, 1 Sep 1992 05:27:58 GMT


	I'v read Fritjof Capra's _The Tao of Physics_, and I must say
I'm not too impressed with it. It seems to me that he takes a metaphor
too far.

	In it, he invoked the "bootstrap" models of hadrons and their
interactions that were popular in the late 1960's. The hope of some of
the modelers, at least, is that one could deduce from the analyticity
of the S-matrix (that of input particles -> output particles; the
analyticity part means that it is well-behaved in a certain way) what
the possible S-matrices are. From there, one then goes on to see if
any one of the matches what one actually observes. The bootstrap model
was used especially to try to crack the tough nut of hadronic
interactions. In effect, all the hadrons were co-equal elementary
particles, and one would try to find out which "hadron universes" were
possible by considering the possible S-matrices for them.

	However, a competing idea appeared that turned out more
successful. In the late 1960's, there were some electron-proton deep
inelastic scattering experments that started to reveal evidence of
internal structure. Hadrons were apparently behaving as if they had
some internal constituents that could be loosened from one another by
giving them big impulses (such as virtual photons from oncoming
electrons). Eventually, these "partons" were shown to be equivalent to
the quarks postulated from low-energy (in elementary-particle terms)
studies. A theory was formulated, called QCD, for the interactions of
quarks with new elementary particles called "gluons". It has proven
very successful, as far as it has been possible to test it. At the
energies of the less energetic hadrons, like the nucleons and the
pions, it has been very difficult to make predictions of particle
masses and interaction strengths; one has to resort to finite
space-time lattices, and small ones at that (10 or so in each of the
four dimensions), to allow computations to be done in manageable
amounts of computer time. Be that as it may, it appears that hadronic
interactions are an epiphenomenon of quark and gluon interactions,
just as chemical reactions are an epiphenomenon of atomic electron,
electric-field, and nucleus interactions. As one nuclear physicist
complained, "They've turned us all into chemists!"

	FC's response? He accepts the deep inelastic scattering
results, but he still maintains that his bootstrap model somehow
reflects fundamental features, instead of being a chemistry-type
epiphenomenon. Or at least so it seems to me as I read his later work.

	So I guess there goes _The Tao of Physics_.

Newsgroups: sci.physics,sci.skeptic,alt.folklore.science
From: crb7q@kelvin.seas.Virginia.EDU (Cameron Randale Bass)
Subject: Re: The dangers in microwaved food...
Organization: University of Virginia
Distribution: na
Date: Wed, 26 Aug 1992 02:21:34 GMT

In article <1992Aug25.224720.24397@lmpsbbs.comm.mot.com> bhv@areaplg2.corp.mot.com (Bronis Vidugiris) writes:
>In article <25737@dog.ee.lbl.gov> sichase@csa3.lbl.gov writes:
>)In article <1992Aug25.165415.21655@lmpsbbs.comm.mot.com>, bhv@areaplg2.corp.mot.com (Bronis Vidugiris) writes...
>)> 
>)>As far as I know there is no evidence that microwave radiation has any
>)>effect on the body other than heating - if it is continuous.  There was
>)
>)The experts seem to be concerned about nerve damage.  If you are near 
>)a microwave oven with a leaky shield, then before you heat sensors
>)detect a problem it is possible that internal damage can be done to your
>)extremities.
>
>I don't recall anything like that.  I recall now that there was a problem
>with cataracts at *really* high levels, but I believe that was still believed
>to be due to the heating effects.

    I do not know of any such effect either, except for the fact that
    arms and legs and eyeballs have marvelous dimensions for developing hot
    spots under 2.45 GHz irradiation (especially eyeballs).  Babies
    heads have this same property, though most adults have heads
    that are too large to build up any substantial hot spots except
    in their eyes (c.f. Taflove and Brodwin, IEEE Microwave Theory and
    Techniques MTT-23:888 (1975)).

    Of course, the input power would have to be substantial in order to have
    any significant heat generation.

    Just another reason to keep kids and hammers away from your microwave...

                                    dale bass



-- 
C. R. Bass                                           crb7q@virginia.edu
Department of Mechanical and Aerospace Engineering
University of Virginia
Charlottesville, Virginia                            (804) 924-7926
From: andrew@rentec.com (Andrew Mullhaupt)
Newsgroups: sci.physics
Subject: Re: Satellite spying
Date: 26 Aug 92 16:13:40 GMT
Organization: Renaissance Technologies Corp., Setauket, NY.

In article <17clkqINNmqa@agate.berkeley.edu> ted@physics.Berkeley.EDU (Emory F. Bunn) writes:

>I'm way out of the subjects I know anything about, so any enlightenment
>from people who really know the story would be very welcome.

And very unlikely.

But some of the questions I would raise is whether the diffraction limit
calculations from the back of the envelope can't be evaded by using separated
frequencies, especially carefully chosen infrared, and possibly near UV.

We should assume, given the large cost of putting stuff into space, that the
spooks have done as much as possible to do ground based postprocessing to
enhance resolution. Also assume that they do a _ton_ of non-optical processing
called "analysis" and "interpretation".


Later,
Andrew Mullhaupt

P. S. I remember publically available statements that "National Technical
Means" included optics which could resolve the seams on a baseball at
50,000 ft. This turns out to be 4.2x10^-7 radians, which we can take to be
an upper bound.
Newsgroups: sci.physics,sci.skeptic,alt.folklore.science
From: bhv@areaplg2.corp.mot.com (Bronis Vidugiris)
Subject: Re: The dangers in microwaved food...
Organization: Motorola, CCR&D, CORP, Schaumburg, IL
Distribution: na
Date: Tue, 25 Aug 1992 22:47:20 GMT

In article <25737@dog.ee.lbl.gov> sichase@csa3.lbl.gov writes:
)In article <1992Aug25.165415.21655@lmpsbbs.comm.mot.com>, bhv@areaplg2.corp.mot.com (Bronis Vidugiris) writes...
)> 
)>As far as I know there is no evidence that microwave radiation has any
)>effect on the body other than heating - if it is continuous.  There was
)
)The experts seem to be concerned about nerve damage.  If you are near 
)a microwave oven with a leaky shield, then before you heat sensors
)detect a problem it is possible that internal damage can be done to your
)extremities.

I don't recall anything like that.  I recall now that there was a problem
with cataracts at *really* high levels, but I believe that was still believed
to be due to the heating effects.

This is from my memory of what our resident company-funded staff scientist
who investigated these sort of issues said.  (We got a lecture on the topic
one day.)

There is the issue, though, that even though  heating effects cause the
damage, one might not be aware of the microwave heating the same way one
would be aware of heat in a hot room - the body's sensors are not really
designed to detect internal heat, they are designed to detect external heat.

There's also the issue of the localization of the heat.  Short wavelengths
present more of a problem for possible 'hot spots' than longer ones.
Newsgroups: sci.physics
From: crb7q@kelvin.seas.Virginia.EDU (Cameron Randale Bass)
Subject: Re: Axiom of Physics
Organization: University of Virginia
Date: Sat, 29 Aug 1992 16:52:42 GMT

In article <1217@kepler1.rentec.com> andrew@rentec.com (Andrew Mullhaupt) writes:
>In article <1992Aug26.174922.6115@pellns.alleg.edu> frisinv@alleg.edu writes:
>>A friend and I have a small disagreement about the existance of an axiom  
>>of physics. She claims that all assumptions in physics are made from  
>>empirical evidence and therefore there are no axioms in physics. I  
>>maintain that the conservation of mass/energy is an axiom. Here is my  
>>argument: an axiom must be based on evidence. Euclid didn't just say  
>>parallel lines don't intersect, he saw evidence that they didn't and then  
>>stated the postulate. We have seen that energy and mass seem to be  
>>conserved. There is very strong evidence that they are conserved but (to  
>>my limited knowlege) there is no proof that they are conserved in all  
>>cases. Thererfore, conservation of mass/energy is an axiom of physics. Can  
>>anyone think of other axioms of physics?
>
>Quantum mechanics is often phrased in terms of axioms, but even the most
>ardent proponent of the quantum theory would have to admit that the axiom is
>part of the theory. The experimental connection to reality is _very_ impressive
>for quantum mechanics, but in some sense, to the extent that science is
>falsifiable, it cannot be axiomatic like say, associativity in mathematics.
>Whether you can have non-falsifiable statements in science is a function of
>which philosophy of science you subscribe to. If every scientifically
>meaningful statement is supposed to be falsifiable, then there are no axioms.

     Why?  I don't see how an axiomatic basis prevents falsifiability.
     Presumably your axiom has some physical validity, or it doesn't.
     However, I am not sure why the existence of physical falsifiability
     would necessarily disqualify a statement from being an axiom.
     Also, presumably the theory derivable (not necessarily actually derived)
     from an axiomatic basis (physically-based or not) is falsifiable.

                                   dale bass


-- 
C. R. Bass                                           crb7q@virginia.edu
Department of Mechanical and Aerospace Engineering
University of Virginia
Charlottesville, Virginia                            (804) 924-7926
From: mcirvin@husc8.harvard.edu (Mcirvin)
Newsgroups: sci.physics
Subject: Re: Axiom of Physics
Date: 26 Aug 92 23:58:28 GMT
Distribution: na

crb7q@kelvin.seas.Virginia.EDU (Cameron Randale Bass) writes:

>In article <25781@dog.ee.lbl.gov> sichase@csa3.lbl.gov writes:
>>
>>Eventually, one hopes that all axioms undergo direct experimental test,
>>verifying the fundmental assumptions of the theory by direct confrontation
>>with reality.  At that point, I suppose they loose their status as axioms
>>and become experimental facts.

>    I am not sure that the differentiation between an 'axiom' and
>    an 'experimental fact' (say the fact that we have never seen anything
>    have true speed greater than c for example) is very fruitful.

I think it is fruitful, but not quite in the sense Scott is using.
Axioms live in theories, whereas experimental facts live in the real
world, or our measurements thereof.  The constancy of c is usually
taken as an axiom of relativity; certainly Einstein treated it that
way.  But it's also an experimental fact, in the sense that there is
a lot of evidence for it.  If it were proven beyond all doubt by some
sort of experimental omniscience, that wouldn't change its status
as an axiom of relativity.  One could still construct a completely
different theory with a different set of axioms, though it would
be wrong as a description of reality.

To speak of "axioms of physics" is to create the wrong impression
that physics has one unified, unchanging theoretical edifice.  Axioms
of specific theories, on the other hand, surely exist, though which
theoretical facts are the axioms often depends on whom you talk to.
 
-- 
Matt McIrvin, Cambridge, Massachusetts, USA
From: johan@blade.stack.urc.tue.nl (Johan Wevers)
Newsgroups: sci.physics
Subject: Re: Gravity and SR
Keywords: gravity, relativity
Date: 2 Sep 92 11:06:24 GMT
Organization: MCGV Stack, Eindhoven University of Technology, the Netherlands.

ted@physics.Berkeley.EDU (Emory F. Bunn) writes:

>>Why is it that mass and gravitational fields curve spacetime?
>>Why not charge and electric field?

The energy density of the EM field also curves spacetime. In the case of
electrical charges in space, the energy-momentum tensor is expanded with
terms containing the EM field tensor.

> You couldn't form an 
>analogous theory for electromagnetism, since the paths of different
>sorts of particles in an electromagnetic field are different.

Not entirely true. The Kaluza-Klein theory is an extension of GR which
also includes the EM field. It uses 5 dimensions, the 5th however is so
strongly curved that we wouldn't notice it. (The same idea as in
superstring theory).

>-Ted

******************************************************************** 
* J.C.A. Wevers                *         u\  _\       /e+        2 * 
* johan@blade.stack.urc.tue.nl *     1 |   \ u \  X  /         |   * 
******************************** P = - |    >   >---<     + ...|   * 
*     The only nature of       *     N |   /   /     \         |   * 
*     reality is physics       *         u/   /d     u\            *
********************************************************************
Newsgroups: sci.physics
From: tony@nexus.yorku.ca (Anthony Wallis)
Subject: Re: Information Theory and Quantum Mechanics
Organization: York University
Date: Wed, 26 Aug 1992 20:56:30 GMT

Dave Griffiths (prim!dave@germany.eu.net) wonders :
> According to July's Scientific American, some theorists are trying to apply
> information theory to QM, where "the basis of reality may be the answer
> to a yes-or-no question".  ..

Ah, the latest "it-from-bit" craze.
Parallels the materialist's "qualia-from-cerebralia" and the Strong
AI proponent's "mental-from-buggerall".
What you get when you push reductionism to the ultimate limit.  Instead
of the 19th century's infinitely-hard-little-billiard-balls paradigm,
substitute the 20th century's everything-is-computational.  Well, it
may bother us when QM tells us the answer to most yes-or-no questions
is "maybe", but that's no great surprise to graduates from the School
of Hard Knocks, University of Life.

Should be "it-from-fuzzy-bit".  But then we're back to continuous
variables, eh ?  Perhaps the "basis of reality" is capricious demons
after all.

--
tony@nexus.yorku.ca = Tony Wallis, York University, Toronto, Canada
From: ddavis@casbah.acns.nwu.edu (Donald Davis)
Subject: Re: Magnetic Resonance and T1
Organization: Centre for the study of Non-Equilibrium Phenomena
Date: Mon, 31 Aug 1992 08:43:40 GMT

In article <la2v9pINNd7r@phad.hsc.usc.edu> ghenzie@phad.hsc.usc.edu (Gregory M. Henzie) writes:
>
>
>Well, my last post got screwed up so here I go again.
>
>Why does T1 for a substance typically increase with increasing magnetic

	Greg:

	Here's the quick and dirty explanation...  Nuclear magnetic relaxation
proceeds via transition of individuals spins between spin states in order to
reestablish the equilbrium (Boltzmann) distributions  The amount of energy that
the spins must exchange with their surroundings "the lattice" to make the 
transition (i.e. the splitting between the spin states) corresponds to a
frequency of electromagnetic radiation (E = hw).  The pathway by which spin
flips occur is via the interaction of the spin with a fluctuation in its local
magnetic field at the proper frequency; a photon is exchanged and a spin flip 
occurs.

	How long this equibration of spin population takes depends on the
intensity of local field fluctuations at the proper frequency.  These field
fluctuations arise from translational and rotational molecular motions and
T1 is in fact inversely related to the intensity (strictly the spectral
density) of molecular motion at the frequency whose energy corresponds to the
difference between 2 spin states.

	But why the increasing dependence of T1 on field strength?  At a
higher field strength, one is reliant upon higher frequency motions to provide
the pathway for relaxation, and where this increasing dependence is observed,
the intrinsic motions are either slower than or comparable to the frequency of
the spin transition.  For more information, without a lot of operators and
Hamiltionians to weigh you down, see "Nuts and Bolts NMR" by Fukushima and
Roeder, Addison Wesley, 1981.  Happy Resonating!

	-- Donald C. Davis
	Graduate Student, Department of Chemical Engineering, Northwestern U.
	Bringing Magnetic Resonace To Bear On Amorphous Polymers Since 1989!

	PS: T1 is not always an increasing function of field strength!  For
example, at high temperatures, organic small molecules in solution will
exhibit field-independent T1's.  For spins whose relaxation is governed by the
so-called chemical shift anisotropy mechanism, T1 is actually a *decreasing*
function of field strength at low and intermediate temperatures.
From: mcirvin@husc8.harvard.edu (Mcirvin)
Newsgroups: sci.physics
Subject: Re: Misner et al.
Date: 1 Sep 92 04:23:40 GMT
Article-I.D.: husc8.mcirvin.715321420
 <mcirvin.715055017@husc8> <1992Aug31.222201.23107@galois.mit.edu>

jbaez@riesz.mit.edu (John C. Baez) writes:

>As Segal has said of the University of Chicago, "It's not very good -
>it's only the best there is."  This may no longer be true of MTW; I like
>Wald quite a bit.  But when it came out I think it was true.  

I was a bit hard on MTW; I was being deliberately provocative.  My
frustrations are mostly with the prose style, particularly when dealing
with things that ought to be explained in complete sentences.  I do
like the detailed explanations of points that are usually large barriers
to understanding, and it's heartening to see such an imaginative approach
used in a standard textbook. 

Certainly it's preferable to Weinberg's book, which is what I actually
used to learn GR.  Weinberg gives you everything you need to do
calculations, if you're really fond of indices.
 
-- 
Matt McIrvin, Cambridge, Massachusetts, USA 
Newsgroups: sci.physics,sci.chem
From: mroussel@alchemy.chem.utoronto.ca (Marc Roussel)
Subject: Re: Entropy of the Universe, (was Re: Genesis - fact or fiction)
Organization: Department of Chemistry, University of Toronto
Distribution: na
Date: Sun, 23 Aug 1992 17:56:50 GMT

In article <1992Aug23.122027.17019@cs.rochester.edu> dietz@cs.rochester.edu
(Paul Dietz) writes:
>There have been recent experiments in which simple molecules catalyse
>their own formation from rather complex initial reactants, perhaps
>with a few mutations possible.  These experiments are cute, but
>irrelevant to biogensis: the molecules are not plausible prebiological
>molecules, nor is the amount of information they can carry
>significant.

     I think you're missing the point of such experiments.  No one is
claiming that these experiments represent realistic prebiotic
evolutionary mechanisms.  Rather, these reactions are simple models
which we can hope to understand.  This sort of chemical modeling is done
all the time when the real process we are interested in is too difficult
for us to study immediately.  The other example which springs to mind
is so-called model or artificial enzymes, usually made from
organometallic complexes; no one claims that these are exactly like
biological enzymes, but the models yield some insight into the function
of real enzymes and tell us what to look for in biochemical systems.
Similarly, the simple self-replicators tell us what to look for in more
realistic prebiotic evolution mechanisms.
     As I wrote in an earlier posting, the question of prebiotic
evolution is still wide open.  We hold many clues, but not much more.
There is however no reason to believe that anything miraculous happened
to get life started on this planet.

				Marc R. Roussel
                                mroussel@alchemy.chem.utoronto.ca
From: johan@blade.stack.urc.tue.nl (Johan Wevers)
Newsgroups: sci.physics
Subject: Re: Report on Philosophies of Physicists
Date: 3 Sep 92 13:49:30 GMT

barry@arnold.math.ucla.edu (Barry Merriman) writes:

>The above is all at the most metaphorical level. Is there any situation
>in the experience of the Eastern philosophers in which boolean logic 
>was strictly violated? (I.e. a situation precise enough to be
>cast into predicate logic, in which the logical operators did
>not work properly). I think not. Therefore we conclude they were
>either very interested in non-logical modes of thought, or they
>incorrectly understood what boolean logic was (quite likely).
>
>What this has to do with QM is not clear to me.

In QM, you often can't answer a question with `true' or `false'.
In the case of the double slit experiment, you know that the electron
has a chance of 1/2 to pass each slit, but you can't tell through which
slit it went.

Some people invented quantum logic: a 3 valued logic. But I think this
is also not good enough: if the electron would have a probability of
90% of going through one slit, and 10% of going through the other, I
think a 3-valued logic, which answers the truth walue of the question
`did the electron pass slit 1' with 1/2, is not good. I would suggest
to introduce a continue logic, where this truth values would be
0.9 and 0.1. The boolean logic is a limit case in which only the values
1 and 0 can occur.

Note that this is not the same concept as `fuzzy logic'.

******************************************************************** 
* J.C.A. Wevers                *         u\  _\       /e+        2 * 
* johan@blade.stack.urc.tue.nl *     1 |   \ u \  X  /         |   * 
******************************** P = - |    >   >---<     + ...|   * 
*     The only nature of       *     N |   /   /     \         |   * 
*     reality is physics       *         u/   /d     u\            *
********************************************************************
Xref: sparky sci.physics:13761 sci.skeptic:15320 alt.folklore.science:3183
From: sichase@csa3.lbl.gov (SCOTT I CHASE)
Newsgroups: sci.physics
Subject: Re: FTL Microwave Signal
Date: 26 Aug 92 19:39:21 GMT
Organization: Lawrence Berkeley Laboratory - Berkeley, CA, USA
Distribution: na
Reply-To: sichase@csa3.lbl.gov
NNTP-Posting-Host: 128.3.254.198
News-Software: VAX/VMS VNEWS 1.3-4   

In article <1992Aug26.021649.4507@augean.eleceng.adelaide.edu.AU>, dabbott@augean.eleceng.adelaide.edu.AU (Derek Abbott) writes...
> 
>None of the critics asked the obvious question which is: how do the
>authors propose to transfer any useful information on a single leading
>wavefront?? Surely you can only transfer one bit of data at FTL, which isn't
>too useful.

I think that the point is that if even one bit of information is transmittable
FTL, then we will all go off in search of the correct reformulation of
mechanics.  If we then find such a theory, we presumably would *then*
know how to exploit the effect in a serious way.

-Scott
--------------------
Scott I. Chase			"The question seems to be of such a character
SICHASE@CSA2.LBL.GOV		that if I should come to life after my death
				and some mathematician were to tell me that it
				had been definitely settled, I think I would
				immediately drop dead again."      - Vandiver
Newsgroups: sci.physics