HDTenEightyP/NetNews huggingface dataset:
From: holmes@opal.idbsu.edu (Randall Holmes)
Subject: Re: Report on Philosophies of Physicists
Organization: Boise State University Math Dept.
Date: Tue, 15 Sep 1992 18:38:14 GMT

In article <1992Sep14.191207.21572@guinness.idbsu.edu> holmes@opal.idbsu.edu (Randall Holmes) writes:
>In article <1992Sep13.174721.23818@CSD-NewsHost.Stanford.EDU> pratt@Sunburn.Stanford.EDU (Vaughan R. Pratt) writes:
>>In article <TORKEL.92Sep13095337@bast.sics.se> torkel@sics.se (Torkel Franzen) writes:
>>>In article <1992Sep13.050206.18067@CSD-NewsHost.Stanford.EDU> pratt@Sunburn.
>>>Stanford.EDU (Vaughan R. Pratt) writes:
>>>
[...]
>>To make this yet more concrete, Harvey Friedman (and there may be
>>others I don't know about) has for a long time been investigating the
>>mathematical content of not-#, to see whether it is equivalent to a
>>nice statement (which would make # similarly nice since the class of
>>nice statements, whatever that is, is presumably closed under
>>negation).  He says that thus far he hasn't found anything really
>>convincing for ZFC, though he has nice stuff off to the side, at ZC+V=L
>>(Zermelo with Choice and Constructibility but without Fraenkel's
>>Replacement).
>>
>>This seemingly quixotic quest is put in perspective by the celebrated
>>Paris-Harrington result, that the infinite Ramsey theorem is
>>independent of Peano Arithmetic.  This was proved by showing that it
>>was equivalent to (a slight strengthening of) not-# for PA, the
>>consistency of Peano Arithmetic.  The corresponding situation for ZFC
>>is that, while various nice propositions are known to be independent of
>>(i.e. undecided in) ZFC, none of these proofs to date have been via the
>>route that succeeded for Paris-Harrington in PA.  If a nice restatement
>>of not-# exists then one immediately obtains that this nice statement
>>is independent of ZFC, *via the independence of inconsistency* a la
>>Paris-Harrington.
>
>This is flat wrong.  # is false in the standard model of arithmetic
>(in ZFC, if you like); the Paris-Harrington Theorem is true there.
>Thus the PH theorem cannot be a strengthening of #.

Sorry -- lost a negation there!  This is fine.  Of course, PH _can_ be
(and is, if I recall correctly) a strengthening of not-# (Con(PA)).

[...]
>>-- 
>>======================================================| God found the positive
>>Vaughan Pratt   pratt@cs.Stanford.EDU   415-494-2545  | integers, zero was
>>======================================================| there when He arrived.
>
>
>-- 
>The opinions expressed		|     --Sincerely,
>above are not the "official"	|     M. Randall Holmes
>opinions of any person		|     Math. Dept., Boise State Univ.
>or institution.			|     holmes@opal.idbsu.edu


-- 
The opinions expressed		|     --Sincerely,
above are not the "official"	|     M. Randall Holmes
opinions of any person		|     Math. Dept., Boise State Univ.
or institution.			|     holmes@opal.idbsu.edu
Newsgroups: sci.physics,sci.math
From: pratt@Sunburn.Stanford.EDU (Vaughan R. Pratt)
Subject: Re: Uncertainty Principle [T.Bollinger => LONG]
Organization: Computer Science Department,  Stanford University.
Distribution: na
Date: Tue, 8 Sep 1992 06:52:13 GMT

In article <1992Sep5.071519.16554@asl.dl.nec.com> terry@aslws01.asl.dl.nec.com (Terry Bollinger) writes:
>In Dr. Penrose's discussion, the wavefunction that describes a particle
>has the appearance of a corkscrew in both of these spaces.

That's not quite what he says.  A corkscrew in one space is a spike
(delta function) in the other.  The point is that the corkscrew can be
in either space; the spike is then in the other space.  A spike in
position space represents a precisely located and hence highly
energetic (because of uncertain momentum) particle, while a spike in
momentum space represents a spatially very diffuse particle with a
precisely known momentum.

Now it is tempting to think that as the corkscrew is "shortened", let's
say by having its magnitude fall off at a Gaussian rate either side of
center, the matching spike stretches out into a corkscrew.  But this is
not what happens.  Instead the spike stretches out into a *planar*
Gaussian (actually closer to a sinc(x) = sin(x)/x curve), the plane
being that containing the time axis and the original spike.  (The
spike, and hence this plane, rotates about the time axis as the phase
of the original corkscrew is changed.)

This is not to say it is impossible to create a pair of functions both
of which have some helical character.  However I don't know of any way
such a pair would arise having intrinsic physical significance.
-- 
======================================================| God found the positive
Vaughan Pratt   pratt@cs.Stanford.EDU   415-494-2545  | integers, zero was
======================================================| there when He arrived.
Newsgroups: sci.physics
From: lbianchi@sol.yorku.ca ((Luigi M. Bianchi))
Subject: Ignorance
Organization: York University
Date: Thu, 10 Sep 1992 02:27:48 GMT

-- 


	Luigi Bianchi

Newsgroups: sci.physics
From: wayne@uva386.schools.virginia.edu (Tony Wayne)
Subject: Kite Physics Needed
Organization: Virginia's Public Education Network (Charlottesville)
Date: Wed, 16 Sep 92 02:34:22 GMT

I'm looking for some
good sources that can describe some of the physics in kite
flying.  A lot of what I know comes from remedial introductions
with a _little- math and a _few_ concepts sprinkled with
applying some physics.  I'm looking for more
so I can possible write a Kite CAD & flight simulator.  Any
suggestions?
-Tony
Newsgroups: sci.physics,rec.pets.cats
From: hank@netcom.com (Hank Roberts)
Subject: Re: Radioactive Cat: How Dangerous is She?
Date: Wed, 09 Sep 92 23:19:00 GMT
Organization: Netcom - Online Communication Services  (408 241-9760 guest) 
Distribution: na

sichase@csa2.lbl.gov (SCOTT I CHASE) writes:

>That's funny.  I had a radium dial watch about 12 years ago.  One day I was
...

>-Scott

The risk of going out in the car is way higher.  There's a cloud chamber at
San Francisco's Exploratorium that's very instructive; it's several square
feet of surface with a glass plate over it, and under the plate you can
see tracks (hundreds each moment, maybe many hundreds) of natural background
radiation. My dad's old radium-dial watch is in a box somewhere on a shelf,
along with at least one chunk of uranium-bearing ore from my old rock
collection; by the time the radioactive cat was down to those levels
I wouldn't worry much about her.

Remember the statistics prove that thin air and higher background
radiation make you young, stylish, and able to ski (grin).

How's the cat doing, by the way?
Newsgroups: sci.physics
From: dwr2560@zeus.tamu.edu (RING, DAVID WAYNE)
Subject: Hole theory (was: Re: Why do protons outnumber antiprotons?)
News-Software: VAX/VMS VNEWS 1.41    
Organization: Texas A&M University, Academic Computing Services
Date: Sat, 5 Sep 1992 00:58:00 GMT

mcirvin@husc8.harvard.edu (Mcirvin) writes...
>The correct formulation, using field theory, still has conserved
>quantities, like energy and (here, at least) lepton numbers; the
>electron antineutrino accounts for conservation of electron number
>when the electron is produced.  What you described, though, involves
>the machinery of a completely filled sea of negative energy electrons,
>and describes pair production as the elevation of a negative-energy
>electron to a positive-energy state, leaving a "hole."  That can't
>account for beta decay, since the thing that's produced along with
>the new electron is not a positron but an antineutrino.  A theory
>in which the creation and destruction of particles depends on this
>kind of particle-hole creation leaves no room for differences in
>the kinds of holes left behind by a particular particle.

Nonsense. The W pulls a neutrino out of the 'neutrino sea' and rotates
it into an electron. Certainly in the original hole theory the electron
didn't need to stay in the state exactly opposite the hole did it? 

Dave Ring
dwr2560@zeus.tamu.edu





Newsgroups: sci.physics,rec.pets.cats
From: danforth@riacs.edu (Douglas G. Danforth)
Subject: Re: How do we know individual photons exist?
Organization: RIACS, NASA Ames Research Center
Date: Tue, 15 Sep 92 19:16:30 GMT


The problem with "subphotons" as you discribe them is time.  It takes
time to acquire your little beasties.  As I recall, one of the arguments
against a classical interpretation of the photoelectric effect that
the instant the impinging light strikes the metal surface electrons
are observed to be ejected.  Classically, the energy is a function of
the amplitude of the wave which takes time to transfer.

- dgd

Newsgroups: sci.physics,sci.math
From: bhoughto@sedona.intel.com (Blair P. Houghton)
Subject: Re: Rotating Bucket of Water in a Gravitation Field...Part #2
Organization: Intel Corp., Chandler, Arizona
Date: Sat, 5 Sep 1992 19:09:53 GMT

In article <1992Sep4.121616.2819@sei.cmu.edu> firth@sei.cmu.edu (Robert Firth) writes:
>passage in his 'Science of Mechanics', Mach commented: "rotate the Heaven
>of fixed stars, and see what happens to the water in the bucket".

Nothing happens to it, if space itself is an inertial frame.

				--Blair
				  "Haha.  Three-degree
				   background.  Very funny."
Newsgroups: sci.physics
From: mxr@neptune.dsc.com (Max "Jellied Griddle Suicide" Rible)
Subject: Re: Where do physics graduates look for work?
Organization: Digital Sound Corporation
Date: Fri, 11 Sep 1992 00:15:28 GMT

abbasi@star.enet.dec.com  writes:
>Ok, you worked hard to get your physics degree, now what do you do?
>where do you look for work? when I mean work, I mean physics/science
>related, not flipping burgers.

>are there actually physics/science work out there?

Every person I know personally who has a PhD in physics (any branch)
is either working in academia or the computer industry.  I'm finishing
my BS in physics next June and intend to join the computer industry
full-time; I've been working in it off and on since I was 16.  The
grad students in the computer graphics lab I was working in when I was
a teenager didn't think much of the way I'd walked right into real
work without ever having to suffer in food service for years... :-)
/-------------v---------------------------------------------------------------\
| Max Rible   | "Uh oh, sounds like the machine is demonically possessed      |
| mxr@dsc.com | again.  Better than no messages at all, though!" - Sam & Max  |
\-------------^---------------------------------------------------------------/
-- 
Newsgroups: sci.physics
From: jewing@netcom.com (James Ewing)
Subject: James Doyne Farmer's email address
Date: Wed, 09 Sep 92 06:14:16 GMT
Organization: Netcom - Online Communication Services  (408 241-9760 guest) 

If anyone knows James Doyne Farmer's email address please email jewing@netcom.netcom.com.  He was involved in chaos theory research at UC Santa Cruz in the mid 1980's.
Newsgroups: sci.physics,sci.math
From: jbaez@riesz.mit.edu (John C. Baez)
Subject: Re: Computability of the universe
Organization: MIT Department of Mathematics, Cambridge, MA
Date: Fri, 11 Sep 92 18:17:36 GMT

In my opinion this fairly pervasive notion that you can only
"really" measure lengths that are rational numbers is an outdated
remnant of one of the Greeks' less bright moments.  For example:

Say we all measured distances with a circular roller that was one foot
in diameter.  (I think they do something like this sometimes.)  We
measure distances by rolling this thing along and counting the number
of revolutions.  Okay, now we are measuring things in units of pi feet.
If our driveway looks to be 40 revolutions long, our best guess is
that it's 40pi feet long.

Say we all measured distances by taking a meter square and cutting it
along the diagonal, and holding the diagonal up against what we are
trying to measure.  Now we are measuring things in units of the square
root of two feet.  If we have a book that's as tall as the diagonal of
the square, our best guess is that it's the square root of two feet long.

To make it even clearer how silly this all is, let's simply take an
ordinary ruler and DEFINE an inch to be equal to e "Napier's inches". 
Okay, now if we measure something and it looks to be as long as the
distance between two marks, we say it's e Napier's inches long.

I suspect that this may provoke some arguments from the "rationalists"
among us.  Seeing what the Pythagoreans did to that guy who proved the
existence of irrationals, maybe I should take out some more life
insurance.  But I insist that if you think about it, irrational
numbers are just as "real" in the physical world - and just as UNREAL
- as rational numbers.

You may complain that we never really know that something is EXACTLY
pi feet long.  Well, tough, we never really know that something is
EXACTLY one foot long.  "How about the standard imperial foot, at the
bottom of King James' leg?  That is by DEFINITION exactly one foot
long."  Well, for one, it's constantly changing length.  For two,
using it to measure anything ELSE will always be subject to
inaccuracies.  For three, we could just as well say that the imperial
foot is exactly the cube root of seven "zorches" long.  And for four,
there is no way to measure anything to be EXACTLY 1239827/47 imperial
feet long, any more than there is to measure anything to be EXACTLY pi
imperial feet long.  Rationals are nice in many ways, but the idea
that measurements of lengths always give rational numbers is just
plain silly.



Newsgroups: sci.physics,alt.sex
From: buick@belay (Patrick D. Buick)
Subject: Re: Subject?
Organization: Belay Enterprises Inc. Calgary, Alberta, Canada
Distribution: na
Date: Sun, 6 Sep 1992 16:20:14 GMT

In article <Btx5K3.Gw8@cs.dal.ca> franklin@ug.cs.dal.ca (Steve Franklin) writes:
>In <1579@dsinet> heinzl@hpw2 (Heinz Lottermoser) writes:
>
>>Do any of you even know what "terminal velocity" is???  The higher you are
>>does NOT mean the faster you fall unless you are in a friction free 
>>environment, or the coef. of friction is so low that it does not overcome
>>the acceleration.  
>
>   Well, I think that you are under a false presime here my friend. Although
>you will not be in a friction free environment, you are in a friction
>lessened environment. Any ol' physicist can tell you that the density 
>of the atmosphere decreases on average (devoid of any abrupt atmospheric
>changes like thunderclouds, hurricanes, etc) as you go higher up. Therefore,
>the coefficient of friction that a fallin body would encounter is LESS
>at higher regions of the atmosphere. Since terminal velocity will mainly
>depend on the surface area of the falling body, the shape of the falling
>body, and the coefficient of friction (viscosity/air resistance) the falling
>body encounters, it is clear why at higher regions, the individual
>will certainly move more quickly (assuming the same shape is held).
>
>steve
>
>>Sorry, just can't stand bad physics...
>
>   hypocrite!
>
>>The Howler...
>   yes, I probably would too
>-- 
>aasdSteveFranklin-Subliminal Psychology Major.ks;dlasBlueJaysRULEkasdfeahsdbfl
>sd;lfaswoq[eBuyMeAQuadra!!!mbnZMXCNdfsba;KdSPAMiuroqiyetIBMSuxiweuryth'ewr;mxn
>qpuepriuPartyOneqtuj;,n.,xnc,kjasFlameMeNot!;lkj;lkgkjd;askElvisLivesjhfquweru
>zx.cfranklin@ug.cs.dal.ca,sk;t;lrut[Superboy@ac.dal.cav.zx,Physics!eq3rwkh;oHA

Gads, if you had followed the original post.. what he meant was that if we 
dropped you from 1500 feet instead of 800 feet that you wouldn't hit the
ground any faster... all things being equal...  sheesh.. get off the podium..
:-)  [Sure.. try to confuse the issue... ]

Obfuscation: the best method of ensuring that your boss never knows just how
much you know or have done...!

Patrick
-- 
==========================================================
Patrick D. Buick EMT, EET | Internet: buick%belay.uucp@uunet.uu.net
Belay Enterprises Inc.    | Internet: buickp@cuug.ab.ca
Calgary, Alberta, Canada  | UUCP:..keyword!calgary!pixel!belay!buick
Newsgroups: sci.physics,sci.astro
From: ryba@ll.mit.edu (Marty Ryba)
Subject: Re: VLBI (was: My son would like to know about photons...)
Originator: ryba@ll.mit.edu (Marty Ryba)
Keywords: photon,size
Reply-To: ryba@ll.mit.edu (Marty Ryba)
Organization: Group 101, MIT Lincoln Lab.
Date: Thu, 10 Sep 92 12:52:35 GMT


In article <8SEP199214444432@zeus.tamu.edu>, dwr2560@zeus.tamu.edu (RING, DAVID WAYNE) writes:
|> mcirvin@husc8.harvard.edu (Mcirvin) writes...
|> >>Hmmm. When I was an undergrad I worked in the Caltech VLBI Processing unit.
|> >>We plugged around 8 hours of data taken from radio telescopes around the
|> >>world into the computer. The data was stored on VCR tapes. Since we were
|> >>measuring interference, I always wondered how the phase information could
|> >>be stored on a VCR tape. I would have thought each photon would go into
|> >>one antenna or the other. Any astrophysicists out there?
|> >
|> >[deletia]
|> >The processes that create strong classical electromagnetic waves are
|> >exactly those that produce something very close to a coherent 
|> >state of photons, since a coherent state is the closest thing to
|> >a classical EM wave that really exists.  Oscillating currents in
|> >a transmitting antenna, for instance, will produce nearly
|> >coherent photons, and so, presumably, would the oscillating
|> >currents involved in whatever astrophysical phenomena are being
|> >imaged.
|> 
|> I think I understand this explanation, except that I don't see why separate
|> photons should be correlated since in cases of interest the measured
|> radiation is thermal.
|> 
|> Dave Ring
|> dwr2560@zeus.tamu.edu

   Thermal or nonthermal is no matter - a collection of accelerating charges -
a classical time-varying current - will radiate a whole mess of photons
*coherently* creating a spherical plane wave *at a given frequency*.  Thermal
noise means that the phases of each frequency are uncorrelated, and the
amplitudes follow some statistical distribution.  Since
photons essentially do not interact w/ each other (high energy loops
neglected), linear superposition works and we can treat any aggregate signal
as a collection of such spherical outgoing waves.  At very large distances
we can treat these waves as plane waves.  Thus, each VLBI station receives
a bunch of correlated photons and converts that into a voltage recorded on
the tape.

   Hope I've made it clearer.  It's difficult to think in both classical and
quantum terms simultaneously.  Most phenomena fall toward one extreme or the
other, so we tend to neglect the less useful explanation.  It doesn't make
the unused explanation any less valid.

-- 
Dr. Marty Ryba             |	Generation X:
Group 101 - Radars 'R Us   |
MIT Lincoln Laboratory     |  Too young to be cynical,
ryba@ll.mit.edu            |		too old to be optimistic.
From: mcirvin@husc8.harvard.edu (Mcirvin)
Newsgroups: sci.physics
Subject: Re: Did electric/magnetic symmetry "break"?
Date: 10 Sep 92 02:07:42 GMT
Article-I.D.: husc8.mcirvin.716090862

terry@aslws01.asl.dl.nec.com (Terry Bollinger) writes:

>And by the way, I keep quoting this 68.5 figure, but still haven't looked
>it up -- this IS the same as the proposed charge of a monopole in particle
>physics, isn't it?

Yes.  Or, actually, (137.036)n/2, where n is an integer.  If you
want to use the monopole to explain charge quantization,
n should be +-1.  If you just want the monopole to be consistent
with known stuff, n can be any integer; you can have larger multiples
of the basic monopole unit. 

Dirac's argument that gives rise to the formula is quite ingenious,
and it illuminates the subject of why symmetry between electric and
magnetic charges would be difficult to fit into QED as currently
formulated.  The argument itself requires nothing more than the correct
coupling to electromagnetism in nonrelativistic quantum mechanics.
Sakurai's _Modern Quantum Mechanics_ and Jackson's
_Classical Electrodynamics_ both give good treatments of the subject;
Sakurai also describes the related Aharonov-Bohm effect, an illustration
of why it's the potential, not the field, that is of primary importance
in QM.
-- 
Matt McIrvin, Cambridge, Massachusetts, USA 
Newsgroups: sci.physics,sci.math
From: pratt@Sunburn.Stanford.EDU (Vaughan R. Pratt)
Subject: Re: Applied inconsistency
Organization: Computer Science Department,  Stanford University.
Date: Sun, 13 Sep 1992 23:18:58 GMT

In article <88808@netnews.upenn.edu> weemba@sagi.wistar.upenn.edu (Matthew P Wiener) writes:
>Do the
>physicists abandon ship?  Of course not.  They let the mathematicians
>figure it out, and will continue to assume RH.  In essence their TOE
>is modeled inside Large_Fragment(PA)+RH

Whoa, that's a remarkably strong claim.  George Mackey's understanding
of physics seems to involve Borel sets, is he completely alone in
that?  Anyway, if you want to understand Mackey you need to know about
Borel sets.  Now these can boot you way way up above PA, even above
ZC+V=L (Zermelo plus Choice plus Every-Set-is-Constructible).  Here's
one instance.

It is a theorem that a symmetric Borel relation (one whose graph is a
Borel set in the plane) on the interval [0,1] either contains or is
disjoint from some Borel function on [0,1].  (We're doing ordinary
mathematics here, i.e. this is a theorem of ZFC.)

While I have no idea where this particular theorem would come up in
physics, I've seen quite enough facts I couldn't grasp appealed to in
physics that I would not turn a hair if this fact that I can easily
grasp entered into some physics argument.

BUT this theorem is independent of ZC+V=L, i.e. it can't be proved
without using the Axiom of Replacement.  This puts it *way* out of
reach of any "Large_Fragment(PA)" and I would not expect RH to help
here.

The belief that somehow physics will never need to venture anywhere
near where mathematicians have been venturing has no rational basis.
There is no law saying physicists can't use any mathematics they can
understand (though they should pass one against their using the other
kind).

-- 
======================================================| God found the positive
Vaughan Pratt   pratt@cs.Stanford.EDU   415-494-2545  | integers, zero was
======================================================| there when He arrived.
Newsgroups: sci.physics
From: sawyer@utahep.uta.edu (Lee Sawyer)
Subject: Re: WHAT IS LIFE? A BOOK BY SCHRODINGER!!!
News-Software: VAX/VMS VNEWS 1.41    
Organization: University of Texas at Arlington High Energy Physics Group
Date: Tue, 8 Sep 1992 02:17:00 GMT

In article <1992Sep5.154913.42807@kuhub.cc.ukans.edu>, christos@kuhub.cc.ukans.edu writes...
[a question on finding Schrodinger's _What is Life ?_]

  This will sound snide, but the best way to find a book is to go to the library.
A good college or university library should have a copy of this. (I've read it -
a slim volume that talks about negative entropy in thermodynamic systems with 
a constant source and sink of energy; e.g. the earth.) If you cannot find it 
there, they  will certainly have Books In Print, which will tell if the book 
is in print, and if so by whom.



       ================
         Lee Sawyer

         Dept of Physics
         Univ. of Texas
               at Arlington
From: Nir.Oren@f42.n7101.z5.fidonet.org (Nir Oren)
Newsgroups: sci.physics
Subject: size of universe
Date: Thu, 10 Sep 92 19:39:00 GMT
Organization: FidoNet node 5:7101/42 - Lakeside BBS, Roodepoort

In one respect, is the universe not finite:
If the universe is 15,000,000,000 years old, then it can only have a 
radius of 15,000,000,000 light years, after all, nothing can travel 
faster then c. This also means, that even when and if the universe 
starts colapsing, it will still continue to expand, till the light 
reaches the universes "event horizon".
Is this true?
Chow
Nir
--  
INTERNET: Nir.Oren@f42.n7101.z5.fidonet.org
via:  THE CATALYST BBS in Port Elizabeth, South Africa.
       (catpe.alt.za)   +27-41-34-1122 HST or +27-41-34-2859, V32bis & HST.