HDTenEightyP/NetNews huggingface dataset:
From: matt@physics2.berkeley.edu (Matt Austern)
Newsgroups: sci.physics
Subject: Re: RFD: sci.physics.research moderated
Date: 17 Dec 92 22:54:35
Organization: Lawrence Berkeley Laboratory (Theoretical Physics Group)
	<1992Dec18.051840.28801@nuscc.nus.sg>
Reply-To: matt@physics.berkeley.edu
NNTP-Posting-Host: physics2.berkeley.edu
In-reply-to: matmcinn@nuscc.nus.sg's message of Fri, 18 Dec 1992 05:18:40 GMT

In article <1992Dec18.051840.28801@nuscc.nus.sg> matmcinn@nuscc.nus.sg (Brett McInnes) writes:

> I'm not so sure about this. Physicists working on fundamental questions do
> philosophy all the time, whether they like it or not. As for discussions
> degenerating into "I'm right, you're wrong." : is there any other kind of
> discussion here?							   

The way I look at it, whether or not some particular
philosophically-oriented article belongs on sci.physics.research can
be decided in the same way as for an article on any other kind of
subject: is it germane to a serious discussion about physics?

Sometimes, the answer will be yes.  I was at a talk this morning on
quantum cosmology; this field is one that I personally am somewhat
skeptical about, but there's no denying that it is an active area of
research by physicists, including some very good physicists.  Any work
in this area will inevitably involve some thought about the
philosophical underpinnings of quantum mechanics.

As always, though, it is possible for a discussion to drift far enough
that it is no longer really related to physics.  It will be the
moderator's responsibility, when that happens, to redirect the
discussion to a more appropriate group.  It will also be the
moderator's responsibility to cut off a discussion if it becomes
nothing more than a shouting match.


--
Matthew Austern                   Just keep yelling until you attract a
(510) 644-2618                    crowd, then a constituency, a movement, a
austern@lbl.bitnet                faction, an army!  If you don't have any
matt@physics.berkeley.edu         solutions, become a part of the problem!
Newsgroups: sci.physics
From: jbaez@riesz.mit.edu (John C. Baez)
Subject: Re: Can space-time intersect itself?
Organization: MIT Department of Mathematics, Cambridge, MA
Date: Sun, 13 Dec 92 21:57:43 GMT

In article <398@moene.indiv.nluug.nl> toon@moene.indiv.nluug.nl (Toon Moene) writes:
>In article <1992Dec2.232639.13222@galois.mit.edu> jbaez@riesz.mit.edu  
>(John C. Baez) writes:
>> In article <1992Dec2.014924.8076@netcom.com> raicu@netcom.com (Eugen  
>Raicu) writes:
>> >In principle, can there be any mass distribution that would result in a
>> >space-time which intersects itself? 
>> 
>> Not as far as I can tell, if I understand the question.  The point is
>> that spacetime is not embedded in some higher-dimensional space so it
>> can't "bump into itself".  This is precisely why it's nice to have an
>> intrinsic definition of manifolds, by the way!
>
>Now that's interesting - I'm sure I remember from my Differential Geometry  
>course that ANY manifold can be embedded in Rn. A five minutes worth of  
>flapping through the pages of my DG book* tells me that I have to modify  
>this to: ANY manifold that has a COUNTABLE base (so-called seperable  
>manifold).

Of course decent manifolds *can* be embedded in R^n - it's a nice
theorem that's often useful - but there is no canonical way of doing so,
and there is no reason to think that our actual spacetime is in fact so
embedded.   

>> Of course there are mathematically possible spacetime geometries with
>> "wormholes," that is, "handles."  This might be the closest thing to
>> what you are wondering about.  
>
>Yep, but do they represent physical space-time structures ?

Nobody knows but there have been millions of papers by distinguished
physicists exploring the possibility and its possible consequences.

"Wait a minute!" you cry.  "How come they're exploring the possible
consequences of wormholes but not the possible consequences of spacetime
being embedded in a higher-dimensional R^n?"  This is primarily a matter
of esthetics.  The prevailing view is that the former idea is pretty and
the latter one is ugly.  I could try to explain the reasons for this
view, but we just had a long discussion of embedded vs. intrinsic
approaches to differential geometry, so I won't.
Newsgroups: sci.physics
From: kpearce@magnus.acs.ohio-state.edu (BULLDAWG)
Subject: Re: Why is the sky blue?
Organization: The Ohio State University
Distribution: na
Date: Tue, 15 Dec 1992 20:25:50 GMT

In article <1992Dec15.135457.13692@linus.mitre.org> m14494@mwvm.mitre.org (Mike White) writes:
>> In that case the classical Rayleigh theory ...
>> ... x = 2 pi a / lambda...
>> ...spectrum of the sun convolved with a fourth-power law...
>> Rayleigh scattering...
>
>All this talk about scattering etc. just misses the point.  We all
>understand *how* the sky is blue, but the question is *why*?
>The mechanism that makes it blue is clear, but why does that
>mechanism exist instead of one that makes it, say, green?  Yes,
>yes, I know: "physics describes, it does not explain".  I've always
>found that answer to be a cop-out (as we used to say back in the
>60s).  I think "why" is an excellent question.
>

Because that is how God created the Universe and these are the rules that
he gave us.  }:)

Newsgroups: sci.physics
From: abian@iastate.edu (Alexander Abian)
Subject: Re: TIME HAS INERTIA - ABIAN  replies to Beatty
Organization: Iowa State University, Ames IA
Date: Thu, 17 Dec 1992 04:29:07 GMT

In <1gnodnINNkbs@chnews.intel.com> tbeatty@sedona.intel.com (Tim Beatty~) writes:

Dear Mr. Beatty                      12-16-92

You write:

>Dear Abian,

>In regards to your (A3):  I find it difficult to believe that objects like
>planets and rocks have "feelings" and understand "security".  Your (A3) is
>nothing more than what first year philosophy students ponder every day.  What
>motivates people.  The fact that you have concluded that it is selfishness means
>that you haven't taken any first year philosophy classes.  This approach to
>explaining behavior is usually dismissed because it fails to explain all
>behavior.  Read a first year philosophy book.

   I reply,

  Your  putting me down reaction   confirms strongly  my PRINCIPLE (A3),
 
"People do everything and resort to any means to gain a feeling of security"

 Your mockery, your supercilious attitude, your "Read a first year philo-
sophy " instead of saying  read "a kindergarten introductory course
in philosophy"  are all proving my (A3).  You did not want to debase
me more because that  made you feel secure !

    Yes, some  stones have more feeling than some people - moreover,
stones as well as plants constatntly act according to my (A3).  It takes
some insightful eye and mind to detect it.
    
   Read my previous postings and learn them by heart and repeat (A1)
to (A4) several times per day..  They will open your eyes and mind  and 
you will see the reasons and motivations of actions of everything including 
stones , planets and plants.

  EWith love               Alexander Abian

-- 
   The tendency of maintaining the status-quo, Reaction to provocation and
                The tendency of maintaining again a status-quo.  
    TIME HAS INERTIA  and some energy is lost to move Time forward  
  E = mcc  (Einstein)    must be replaced by    E = m(0) exp(-At) (Abian)
Newsgroups: sci.physics
From: hl5a@holmes.acc.Virginia.EDU (Winston Lin)
Subject: DMP
Organization: University of Virginia
Date: Wed, 16 Dec 1992 10:58:09 GMT


Hello there,
	In a problem (EMF class) with wedge shaped capacitor 
(instead of parallel), one is required to find the dominant mode of 
propagation.  Fringing effect is neglected, and the plates are assumed
to have perfect conductivity.

	Can anyone explain what 'dominant mode of propagtion' refers
to in the context?

	Any explanation is much appreciated...

		thanx

  (***-_-_-_-_-_-_-_-_-_-_--_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-***)
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    *       -- -- --       I    n  n    sss      tttt    o  o    n  n      * 
     *      --    --       I   nn  n  sssss       tt     oooo   nn  n     * 
      * - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -*  
     *       Hung-wen Lin	         2100 JPA APT.#7                *
    *       (804) 295-1094                Charlottesville, VA 22903        *
   *       e-mail: hl5a@virginia.edu                                        *
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Newsgroups: sci.physics
From: matmcinn@nuscc.nus.sg (Brett McInnes)
Subject: Re: Metals in liquid Nitrogen !!
Organization: National University of Singapore
X-Newsreader: Tin 1.1 PL4
Date: Sat, 12 Dec 1992 01:59:36 GMT

ps. Pennies are not made of copper. They are mostly zinc.
Newsgroups: sci.physics,rec.arts.startrek.tech
From: dabbott@augean.eleceng.adelaide.edu.AU (Derek Abbott)
Subject: How does Scotty beam up? (WAS Re: Superman... (WAS Re: Batman...))
Organization: Electrical and Electronic Eng., University of Adelaide
Date: Fri, 11 Dec 1992 06:56:16 GMT


Now that we have explained how that Batman light works and that Superman
propels himself with neutrinos, can somebody kindly explain how Scotty's
transporter works?

Has anybody calculated the energy & bandwidth it would theoretically take to
teleport a human body by a distance of 1 metre in 30 seconds?
Newsgroups: sci.physics
From: jbaez@riesz.mit.edu (John C. Baez)
Subject: Re: Why Wave Functions aren't Physical (Was: Re: QM non-causal?)
Organization: MIT Department of Mathematics, Cambridge, MA
Date: Tue, 15 Dec 92 06:38:57 GMT

>In article <1992Dec13.204233.10835@galois.mit.edu> jbaez@riesz.mit.edu (John C. Baez)
>totally misses the point in favor of a spelling flame:

On Usenet there is no such thing as "the" point, only my, your, his, and
her points.  I wasn't attempting to respond to your point.  I was
responding to Giles' points concerning applications of probability
theory to quantum mechanics.   

>If two events A and B are in isolated systems, isolated from the rest of
>the universe and each other, they will not be correlated. 

Since I don't know what "isolated from the rest of the universe" means,
I don't know what this means.  But it reminds me of an interesting fact.
In quantum field theory, say (to be simple) of a scalar field phi, in
the vacuum state the fields phi(x) and phi(y) at spacelike separated
points are not independent random variables but are correlated.  In
fact, the vacuum state can be shown to violate Bell's inequality:

Bell's inequality and quantum field theory II: Bell's inequalities are
maximally violated in the vacuum, Stephen Summers and Reinhard Werner,
J. Math. Phys..   (Sorry, I just have a preprint, so no more info.)

[A technical point: phi(x) should really be smeared with a test function
to obtain a random variable.]

I leave it to others to decide what "causes" this correlation.  

>I should further add that I have been a bit suspicious of Baez's definition
>of causality ever since I've noted he has had no problems with tachyons
>being non-causal while also believing in SR.

First of all, it's not "my" definition
of causality, it's a completely standard one; check out the references I
gave, e.g. p. 597 of Bogoliubov Logunov and Todorov's "Intro. to
Axiomatic QFT."   Second of all, the problem with the free tachyon field is not
that it's non-causal according to this definition (it's causal), the
problem is that it violates energy positivity.  That is, the Hamiltonian
is unbounded below.  "SR" is not a well-defined set of axioms, but it is
frequently taken to include Poincare-invariance, causality AND energy
positivity (and maybe other stuff too); all of these are independent
notions.  Thirdly, SR is not something I "believe in" -- general
relativity already shows that special relativity has its limitations --
it's just a model which appears to do quite well in a certain range of
circumstances.  


Newsgroups: sci.physics,sci.math
From: draper@sscvx1.ssc.gov
Subject: Re: TIME HAS INERTIA
Organization: Superconducting Super Collider Laboratory
Date: Fri, 11 Dec 1992 22:23:15 GMT

Being a fairly recent transplant to Texas, I was of course shocked at the size
of cockroaches down here.
But if a cockroach wanders out onto the sidewalk here and someone stomps on it
convincingly, it rarely needs restomping. And I have NEVER seen people lining
up to stomp on the same poor cockroach.

Paul Draper
University of Texas at Arlington
Mythink, not UTAthink, not SSCthink, not GOVthink.

Well, SOMEONE is bound to ask, "My tax dollars are paying for WHAT??"
From: ynecgan@cid.aes.doe.CA (Greg Neill)
Newsgroups: sci.physics
Subject: Re: Annual Unintentional sci.physics Humor Award
Date: 14 Dec 92 19:45:34 GMT
Organization: Environment Canada (CID), Dorval, QC

In article <1992Dec14.180553.5449@novell.com> dseeman@novell.com (Daniel Seeman) writes:
>In article <Bz4w2D.GJE@news.cso.uiuc.edu> dnash@uxa.cso.uiuc.edu (Dave Nash) writes:

>>Ah!  It becomes clear now.  Abian is a Borg.  (Molecules are irrelevant! 
>>Physics is futile!)
>>
>Funny!  That is just what I was thinking too!..."We WILL assimilate you..."
>
>dks.

Strange, I thought him to be more like Davros, the creater of the
Darleks on Dr. Who....  "RESISTANCE IS USLESS!!! YOU WILL OBEY!!  YOU
WILL OBEY!!!  EXTERMINATE! EXTERMINATE! EXTERMINATE!


-- 
------------------------------------------------------------------------------
Greg Neill,               | "Interfere!?! Of course we should interfere!
HNSX Supercomputers  Inc. |  Always do what you're best at, that's what
ynecgan@cid.aes.doe.ca    |  I always say."  - Dr. Who
Newsgroups: sci.physics
From: d91andiv@IDA.LiU.SE (Anders Ivner)
Subject: Re: Special relativity is SOOO irritating!
Organization: CIS Dept, University of Linkoping, Sweden
	<92Dec16.141330edt.547@neuron.ai.toronto.edu>
Distribution: sci
Date: Wed, 16 Dec 1992 22:59:05 GMT

In article <92Dec16.141330edt.547@neuron.ai.toronto.edu> radford@cs.toronto.edu (Radford Neal) writes:

   In article <D91ANDIV.92Dec15234743@astmatix.IDA.LiU.SE> d91andiv@IDA.LiU.SE (Anders Ivner) writes:

   >Consider a staff, one meter long. Now, given the speed v it 'shrinks'
   >to half a meter. We then have a wall, and an easily controllable
   >hatch placed .75 meters from the wall. The staff passes through the 
   >hatch, and we close the hatch behind it (BEFORE it hits the wall!)
   >The staff hits the wall, without being deformed (somewhat unrealistic!),
   >and since its speed now changes to 0 it is now fully 1 meters long.
   >What the **** happens????

   I'll take a crack at this... No guarantees, amateur physics only here :-)

   The actual dynamics of the staff hitting the wall is presumably not of
   interest (who knows what would really happen :-). Let's assume instead
   that the staff is equiped with a rocket motor, which it uses to
   rapidly deccelerate just before it would have hit the wall. In fact, I
   presume that we also don't want to worry about how rapidly the force
   from the rocket motor propagates through the staff, so lets assume that
   the staff is equiped with *many* rocket motors, distributed along its
   length, which all fire simultaneously, in the rest frame of the the staff.
   It's then not necessary for the rod to be enourmously rigid.

   The answer to the problem then seems to me to be pretty simple. In the
   rest frame of the wall, these rocket motors *do not* fire simultaneously.
   The ones toward the tail of the staff fire first. The observer at rest
   with the wall is then hardly surprised that the staff gets stretched out
   to a full meter. In fact, if my space-time diagrams don't lie, this
   happens before the tail passes through the hatch, so we never get to
   close it at all.

There is one problem with this theory:
(First, let's say that the staff has a sensor in the front, that starts
the rocket motors when the staff is, say .05 meters from the wall).
What if we, when we notice that the staff begins to decellerate, remove the
wall? (which, in our frame of reference occurs _before_ the front of the
staff reaches .05 meters from the wall). It would then have no reason
to decellerate... (sounds like one of those time-travelling paradoxes to
me)

      Radford Neal

Anders
From: cbettis@unlinfo.unl.edu (clifford bettis)
Newsgroups: sci.physics
Subject: Re: Materials for simple static electricity expts.
Date: 16 Dec 92 16:29:48 GMT
Article-I.D.: crcnis1.1gnlhsINNps8
Distribution: world
Organization: University of Nebraska--Lincoln
NNTP-Posting-Host: unlinfo.unl.edu

jweiss@paintbrush.cgd.ucar.edu (Jeffrey Weiss) writes:

>In my physics classes I recall we used cat fur, bakelite rods, and
>pith balls to do simple static electricity experiments.  Does anyone
>have any suggestions for common household substitutes?  I've found
>that rubbing plastic silverware with a wool blanket charges the
>plasticware, which I can then use to charge other plasticware.  I thus
>can create many charged spoons and forks but they all have same-sign
>charges.  Any hints on getting oppositely charged objects?
>--
>Jeff
>jweiss@ncar.ucar.edu
PVC pipe or anything made of PVC plastic will be charged negatively 
when rubbed with a paper towel. Acrylic plastic will be charged 
positively. Examples of both kinds of plastic are not too hard to find
around the average house. I use these materials in my classes because 
the plastics are cheap, don't break when you drop them and work no 
matter what the weather; paper towels are handy and if one gets 
contaminated by sweat or whatever, just get another. For really 
spectacular results make an electrophorus out of either of the 
plastics. The only disadvantage to them is that, if you use them as 
charged rods, they don't transfer charge by contact too well since 
they are such good insulators.
Cliff Bettis
Newsgroups: sci.physics
From: palmer@sfu.ca (Leigh Palmer)
Subject: Re: Another antigravity device
Organization: Simon Fraser University
Date: Tue, 15 Dec 1992 19:47:24 GMT

In article <1992Dec15.013620.24161@galois.mit.edu> jbaez@riesz.mit.edu (John C.
Baez) poses a question about a rigid body in Earth's gravitational field. He
claims that the object can be distorted by that field by an amount which will
produce an elastic potential energy gradient opposite to and stronger than the
gravitational potential energy gradient at the surface. That this can be done
is, of course, not in question; it can't. What I can't see is why it would
appear that it can be. GR aside, the distortion of a rigid body in a
gravitational force field is not proportional to the strength of the field; it
is, rather, proportional to the gradient of the (force) field. The tidal force
produces the distortion which makes manifest the elastic energy. 

Aha! I think I see the puzzle now: implicitly the distortion is proportional to
the force (Hookes' law intuition) and the elastic potential energy is
proportional to the square of the distortion, and hence to the square of the
force! Is that it, John? If so, I think I have solved it above. The distortion
will only be proportional to the force if a constraint force acts in addition
to gravity. Any "antigravity" action would not serve to levitate the object
sufficiently to lift it from the constraining floor on which it rests.

Leigh

Nah, I've got to find a better sig!
Newsgroups: sci.physics
From: matmcinn@nuscc.nus.sg (Brett McInnes)
Subject: Re: TIME HAS INERTIA.  (A3) ANSWERS THE FUNDAMENTAL QUESTIONS
Organization: National University of Singapore
X-Newsreader: Tin 1.1 PL4
Date: Mon, 14 Dec 1992 05:04:32 GMT

abian@iastate.edu (Alexander Abian) writes:
:  
:    
:    Abian, you are insane, your Principle (A3) is a useless incoherent
:    babble, meaningless garbage, beta-sigma, balderdash, nonsense, non-
:    scientific hallucination and alienation of mind.                    
Newsgroups: sci.physics,alt.sci.physics.new-theories
From: sarfatti@well.sf.ca.us (Jack Sarfatti)
Subject: re: Hal Puthoff's zero-point engine 1
Organization: Whole Earth 'Lectronic Link
Date: Mon, 21 Dec 1992 07:05:31 GMT


Hal Puthoff's work on extracting useful energy from the quantum vacuum
using the Casimir force looks very interesting.
Puthoff writes:
".. the Casimir force, ... closely-spaced metal plates being pushed
together ... is due to radiation pressure from the background
electromagnetic zero-point energy which has become unbalanced ..(by).. the
plates.  This attractive force is proportional to 1/D4... and becomes quite
strong at (D) ... on the order of 1000 Angstroms ...

An alternative candidate .. to obtaining energy from vacuum fluctuations
might lie in ... cold, dense, ... plasma in which charge condensation
occurs on the basis of a Casimir pinch effect ..."

My "precognition" tells me that eventually we will build Star Ships powered
by zero point energy. We will be able to amplify tranversable time-machine
wormholes out of the vacuum for our ships to fly through and we will be
able to communicate in "subspace" faster-than-light on the quantum
connection in a globally causally consistent forever expanding universe.
Indeed, if UFOs are real, some of them are such ships from our future.
Ref. Martin Gardner, Science Good Bad and Bogus "Magic and Paraphysics"
MONDO 2000 latest issue p.104
Newsgroups: sci.physics
From: palmer@sfu.ca (Leigh Palmer)
Subject: Re: Metals in liquid Nitrogen !!
Organization: Simon Fraser University
Date: Fri, 11 Dec 1992 22:13:53 GMT

Charles Dodgson and Josef Goebbels both noted (the former only good-naturedly)
that if one reiterates a falsehood sufficiently often it will become true. I
guess there is one chemist around who believes that applies to scientific
fallacy as well.

Leigh Palmer
Newsgroups: sci.physics
From: daryl@oracorp.com (Daryl McCullough)
Subject: Re: QM non-causal?
Organization: ORA Corporation
Date: Sat, 12 Dec 1992 22:05:17 GMT

larsj@kih.no@kih (larsj.johansen) writes:

>>Quantum mechanics predicts that, in the EPR
>>experiment, if one experimenter measures spin-up for his particle,
>>then the other experimenter will measure spin-down with probability
>>cos^2(theta/2). Where does the assumption of collapse come in?
>>It is definitely not necessary for experimenter A to assume that the
>>measurement performed by experimenter B collapses the wave function
>>in order to derive this probability.
>
>Well, there is a collapse in the sense that the wave function CHANGES 
>INSTANTLY (in fact, in the whole universe!) because of the first 
>measurement. Namely, the wavefunction |psi> collapses to one of the 
>eigenstates
>
>	|psi> = |+>|+> + |->|->  ----->    |psi> = |+>|+>

I disagree. There is no reason for experimenter A to assume that B's
measurement has this effect. Experimenter A can treat B as any other
quantum system.

>This sort of collapse will of course also take place in a classical 
>probabilistic theory.

That is not true, either. In classical probability theory, we each
have our own, subjective notions of probability. A measurement
performed by you does not affect *my* personal probability
distributions.

>Lets say that your neigbour throws a coin, and 
>depending on the result he travels either to Australia or stays home. 
>Your probability density of his position will then have peaks in 
>Australia and in your neighbours house. If you go over to his house, the 
>probability density will COLLAPSE. The collapse, however, does not imply 
>any nonlocal effects.

In this case, the "collapse" occurs when I go into his house. It does
not occur when my neighbor throws the dice (or when he looks at the
dice). That was my point, that in the EPR experiment, there is no need
to assume that the other experimenter's measurements collapse *my*
wave function.

>In the same vein, COLLAPSE in the QM-wavefunction does not AUTOMATICALLY 
>imply nonlocal effects.

It depends on whether the wave function is a physical quantity, or
a subjective quantity.

Daryl McCullough
ORA Corp.
Ithaca, NY
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