HDTenEightyP/NetNews huggingface dataset:
From: jbaez@riesz.mit.edu (John C. Baez)
Subject: Physics puzzle - antigravity device!
Organization: MIT Department of Mathematics, Cambridge, MA
Date: Sun, 22 Nov 92 23:41:25 GMT

I just got back from the University of Utah, where the physics
department provided excellent hospitality.  In particular, Richard Price
told me the following puzzle (our of a book of his, apparently).  

Part 1 - Place a conducting hollow (and evacuated) spherical
shell on the table.  Since (at least some) of the electrons are free to
move in the conductive shell, gravity will pull them downwards a little
bit.  Of course, when there are more electrons near the bottom of the
shell, they produce a repulsive electric field.  Thus the electrons will
come into an equilibrium where there are slightly more electrons near
the bottom of the shell - distributed in such a way that the electric
field they produce is just enough to cancel the gravitational pull on 
the electrons.  (This effect will be very small.)  Show that the
resulting configuration has the following nice property: for any
electron placed *inside* the evacuated shell, the gravitation downwards
force will be equal and opposite to the electrostatic force created by the
electrons on the shell.

This part is for real, and according to Price this effect has actually
been observed.  Note that protons or neutrons would fall in this shell
since they have a different charge/mass ratio.  

Part 2 - Now *imagine* that there are 2 kinds of mobile charge-carrying
particles on the surface of the shell, the electron and the "selectron"
say, with different charge-mass ratios.   One can use the same argument
as in the answer to part 1 to show that a particle with *any*
charge-mass will levitate in the shell.  Thus one has an anti-gravity
chamber!

This part is bogus.  But when someone gives the answer to number 1 I
will show how to use that answer to "prove" part 2, and then you can
have fun trying to spot the error in my argument.

So try part 1 first.
From: gsmith@lauren.iwr.uni-heidelberg.de (Gene W. Smith)
Newsgroups: sci.physics
Subject: Re: Lowneheim-Skolem theorem (was: Continuos vs. discrete models)
Date: 20 Nov 92 13:48:39 GMT
Organization: IWR, University of Heidelberg, Germany

In article <1992Nov18.133219.6664@sei.cmu.edu> firth@sei.cmu.edu
(Robert Firth) writes:


>Necessary, but not, I fear, sufficient.  If you are to replace the
>continuum with a *single* discrete manifold, then you must show that,
>for any uncountable set with certain properties, there exists a
>*single* countable set with all the same properties.

What does countability have to do with continuity anyway?  Suppose I
define my manifolds over the recursive reals.  These are dense, and so
support continuous functions, but are also countable.



-- 
     Gene Ward Smith/Brahms Gang/IWR/Ruprecht-Karls University 
               gsmith@kalliope.iwr.uni-heidelberg.de
Newsgroups: sci.physics
From: palmer@sfu.ca (Leigh Palmer)
Subject: Re: UFO EVIDENCE VS. Carl Sagan
Organization: Simon Fraser University
Date: Wed, 18 Nov 1992 22:50:22 GMT

In article <1992Nov18.185422.1598@fs7.ece.cmu.edu> snyder@henry.ece.cmu.edu
(John Snyder) writes:
>In article <kkretsch.721999974@unix1.tcd.ie> kkretsch@unix1.tcd.ie (kevin
patrick kretsch) writes:
>>In <16NOV199212515920@utkvx2.utk.edu> djpegg@utkvx2.utk.edu (PEGG, DAVID J)
writes:
>>
>>>In article <kkretsch.721932625@unix1.tcd.ie>, kkretsch@unix1.tcd.ie (kevin
patrick kretsch) writes...
>>>>         Apparrently, the most closely guarded secret
>>>>in the U.S. government regards how the UFOs were 
>>>>powered. This, I believe, involves harnessing the
>>>>potential energy of the earth's magnetic field.
>>
>>>The obvious question is:
>>>      If they're powered by the earth's magnetic field, how
>>>did they get to earth in the first place
>>
>>All right David, perhaps I should have generalised the statement.
>>Let's say the following:
>>              .....Powered by harnessing the potential energy of
>>the magnetic field of an arbitrary planet.
>
>However the question remains:  What do they do between planets, out in space,
>travelling the mostly empty space between solar systems?  The (mainly dipole)
>magnetic field of a planet dies-off rather quickly with distance (something
>like 1/r**3).  So, how are they powered out there?
>
>Or do they use an entirely different type of starship, and the UFO's that
>we see are merely "shuttlecraft"?
>
>Enquiring minds want to know...

I hope I won't be mistaken for a UFO believer, but I thought I'd point out
that, according to modern theory (I. Newton, q.v.), one doesn't *need* power
between the planets. One of the biggest kicks I get out of "Star Trek" is all
of the fighter-pilot maneuvering they do out there. It appears you have bought
that specification for "starships", yet you doubt their existence. Are
planetary magnetic fields a less likely source of "energy" than "dilithium
crystals"?

Leigh
Newsgroups: sci.physics
From:  (Thomas Mc Neill)
Subject: Re: ufo evidence VS. CARL SAGAN
Followup-To: sci.physics
Organization: Loughborough Uni. Technology
Date: Wed, 18 Nov 92 14:45:40 GMT

In article <1992Nov11.204055.2280@cnsvax.uwec.edu>, mcelwre@cnsvax.uwec.edu
wrote:
> 
> 
>           
>           
>                            UFO EVIDENCE VS. Carl Sagan
> 
>                I watched all of Dr. Carl Sagan's updated "Cosmos" 
>           programs on PBS during summer 1991.  In one of them, he STILL 
>           maintains that there is no physical evidence for UFO 
>           Spacecraft, "just stories". 
>     
>                I should think that by now he would have heard about the 
>           Roswell Incident in which UFO WRECKAGE and ALIEN BODIES were 
>           found on a ranch (in New Mexico, I think), gathered up by the 
>           U.S. military, and hidden away in an Air Force hanger 
>           somewhere. 

How come these ufo's always crash in the States on Ranches in the middle of
nowhere and in easy reach of the US military.

Why hasn't one crashed where the media could get to it first?
                                        

Tom Mc Neill
Loughborough University
Leics.,UK, LE11 3TU
Email: T.Mcneill@lut.ac.uk
Newsgroups: sci.physics
From: dacosta@prl.philips.nl (Paulo da Costa 42147)
Subject: Re: TIME HAS INERTIA.   Att:  Da COSTA   FUND. THM. OF ALGEBRA 
Keywords: Explanation  re: Abian's proof of  FUNDAMENTAL THM. OF ALGEBRA 
Organization: none
Date: Sun, 22 Nov 1992 14:09:04 GMT

In article <By19zL.F1C@news.iastate.edu> abian@iastate.edu (Alexander Abian) writes:
>Mr Da Costa, you wrote:
>
>> so the expansion is not valid in the vicinity of z=0, where he
>>proceeded to use it (the expansion converges for z *outside* a radius
>>of convergence that includes all zeros of his polynomial .......
>> It's bullshit. Satisfied?
>
>      My answer to you is:
>
>Yes, you are absolutely correct;  the expansion converges for z OUTSIDE
>A RADIUS OF CONVERGENCE THAT INCLUDES ALL ZEROS OF MY POLYNOMIAL.
> 
>     BUT, but, you forgot that we ASSUMED THAT THE POLYNOMIAL HAS NO ZEROS 
>and therefore the expansion is valid EVERYWHERE [...]

No, it isn't. "Long division" gives you two possible Laurent
expansions, one in _ascending_ and one in _descending_ powers of z. If
your polynomial has no root, one of these will be valid everywhere, the
other won't be valid at all. By pointing out the obvious fact that the
latter does _not_ converge in the vicinity of z=0, the only thing you
do is to prove that the former (the Taylor series) is the one which
converges everywhere, and you shoot yourself in the foot.

Once again, what a load of crap.

-- 
-- Paulo da Costa           /\/\   Minha terra tem palmeiras   /\/\
-- dacosta@prl.philips.nl   \/\/   Onde canta o sabia'...      \/\/
From: leemike@eecg.toronto.edu (Michael Lee)
Newsgroups: sci.physics
Subject: Re: Detecting crackpots - for laymen?
Date: 18 Nov 92 07:59:27 GMT
Article-I.D.: jarvis.1992Nov18.025927.28395
Organization: CSRI, University of Toronto

In article <1992Nov18.064129.25859@CSD-NewsHost.Stanford.EDU> pratt@Sunburn.Stanford.EDU (Vaughan R. Pratt) writes:
>In article <1992Nov17.231944.13221@meteor.wisc.edu> tobis@meteor.wisc.edu (Michael Tobis) writes:
>>I call your attention to his "proof" that 1/(1 + z + z^2)
>>is unequal to 1/(z^2 + z + 1), for instance. 
>
>If there's something wrong with Abian's proof of the FTA, it isn't
>that.  He had supposed (a case of) the FTA was false in order to arrive
>at a contradiction.  That 1/(1 + z + z^2) is unequal to 1/(z^2 + z + 1)
>was that contradiction.
>
>My only complaint with the proof is that it used a lemma I hadn't
>seen.  I'm assuming this lemma conceals the bulk of the real proof, but
>that's just a layman's guess.  Anyone know for sure?
>-- 
>Vaughan Pratt	  		A fallacy is worth a thousand steps.

I usually avoid reading Abian's postings simply because he seemed to
basically post, ad nauseum, about his time/inertia/energy idea, granted
his postings were a response to a number of protests, nevertheless, his
replies became uninteresting very quickly.  However, I've become interested
in Abian's responses once again; since I've probably missed all of them, I 
wonder whether anyone would be willing to email, repost Abian's proof 
of FTA, or merely blurt out the lemma that V. Pratt mentions above.
regards,
  michael lee
Newsgroups: sci.physics
From: kim@Lise.Unit.NO (Kim Gunnar St|vring \yhus)
Subject: TIME HAS INERTIA
Organization: Norwegian Institute of Technology
Date: Wed, 18 Nov 92 13:05:44 GMT


Warning to new readers of Abians postings concerning his principle.

If you post something about his principle, no matter how polite you
formulate it, the usual thing for Abian is to either answer rudely and with
no real content, or ignore you.

It has been proved that his principle is informationless, unusable, and not
science, but he still lingers on in this newsgroup.

Abian feeds on replies. Please don't feed him.

Kim0
Newsgroups: sci.physics
From: lvh@jhunix.hcf.jhu.edu (Larrie Hutton)
Subject: Graduate schools of physics using neural networks
Organization: Johns Hopkins University - Homewood Academic Computing
Date: Thu, 19 Nov 1992 10:15:37 GMT


Summary: Looking for neural network-oriented programs in departments of physics


Expires: 
Followup-To: 
Distribution: 
Organization: HAC - Johns Hopkins University, Baltimore
Keywords: phsics graduate programs, neural networks


I have had some requests from undergraduate students who are interested in pursuing 
neural network applications and theory, but within a physics department.
If you are aware of any such, please e-mail to me and I will post.
From: sichase@csa3.lbl.gov (SCOTT I CHASE)
Newsgroups: sci.physics
Subject: Re: Top 10 Cited References in the 80's
Date: 23 Nov 1992 12:06 PST
Organization: Lawrence Berkeley Laboratory - Berkeley, CA, USA
Distribution: world
NNTP-Posting-Host: 128.3.254.198
News-Software: VAX/VMS VNEWS 1.41    

In article <Nov.22.20.37.14.1992.16349@ruhets.rutgers.edu>, bweiner@ruhets.rutgers.edu (Benjamin Weiner) writes...
>andrew@rentec.com (Andrew Mullhaupt) writes:
>>Here's my suggestion: Publish an incorrect [top 10 cited] list. Everyone who complains
>>gets his tenure (or equivalent) revoked. Next suggestion: Physics should
>>order authors alphabetically. Final suggestion: all journals drop little
>>biographies and pictures of authors, and authors use initials instead
>>of names.
> 
>I like the first one!!  But the next is bad, you'd just have people refusing 
>to work with anyone who came ahead in the alphabet.  

Unfortunately, human behavior being what it is, this is a non-trivial 
problem.  For example, when I think of physics papers that I have read, I 
can often only remember (or remember best), the first author.  For example,
I know the name F. Abe (from the CDF collaboration), S. Ahlens, A. Bamberger,
R. Albrecht, and a host of other A,B, and C's, and I identify them with
their experiments.  Some of these names (not the ones listed) are only
graduate students, but happen to be first in the alphabetical ordering
of their collaboration lists.  

So there is some cause for for complaint on the part of the W, X, Y and 
Z's of the world.  (With the exception of A. Zee, whose name is impossible
to forget.)  Unfortunately, I know of no equitable solution to the 
problem.  Random ordering of names from paper to paper would only create
confusion, and no other system guarantees fairness.

-Scott
--------------------
Scott I. Chase			"It is not a simple life to be a single cell,
SICHASE@CSA2.LBL.GOV		 although I have no right to say so, having
				 been a single cell so long ago myself that I 
				 have no memory at all of that stage of my 
				 life." - Lewis Thomas
Newsgroups: sci.physics,alt.sci.physics.new-theories
From: sarfatti@well.sf.ca.us (Jack Sarfatti)
Subject: Sarfatti's candidacy for "moderator" of sci.physics
Organization: Whole Earth 'Lectronic Link
Date: Mon, 23 Nov 1992 19:18:53 GMT


OK - the test of a real scientist, as opposed to a crackpot, is to admit
when he is dead wrong. Quantum connection communication is impossible
in standard quantum mechanics. Brian Josephson is right, if it does
exist in living beings and if it is required for mind and esp etc. then
it means that quantum mechanics will have to be modified - probably at
the quantum gravity level which Penrose thinks is important for ordinary
measurement at our low energy level.

Some one said that I could not be moderator because I have an axe to
grind - my hobby horse of quantum connection communication. Well I no
longer believe in it. Let no one dare call me "crackpot" because no
crackpot would ever admit he was wrong on so fundamental an issue. I
have done what Feynman told me to do as we drove around Hollywood in
my Jaguar "Sarfatti, always try to prove yourself wrong!" Well, finally
I did - it took 30 years! But the issue is important. It means the
world view of Tao of Physics etc. is all wrong! The NEW AGE is based on
wrong physics - there is no connection of mysticism and quantum mechanics
etc.

Therefore, since I no longer advocate faster than light communications as
part of standard quantum mechanics the objection to me as moderator is
removed. S. Weinberg apparently has a nonlinear extension of QM that is
worth looking at.
From: lnh@soliton.physics.arizona.edu (sometimes a Wombat)
Newsgroups: sci.physics
Subject: A small Abian digression
Keywords: TIME, INERTIA, MATTER
Date: 12 Nov 92 16:02:36 GMT
Distribution: na
Organization: Society for the Appreciation of Janni Lee Simner

Abian does sound like an Eliza sometimes, and I have to admit that
"Please do not feed the Abian" *IS* a catchy phrase; but it would not
be polite or respectful to say so, so I won't.

abian@iastate.edu (Alexander Abian) writes:
> 
> To those who ask what do you mean by TIME HAS INERTIA my answer 
> is, I mean TIME IS MATTER

I assume other people are as mentally bent by this statement as I am.

	Larry "No --- really?" Hammer
--

                         \   The work is rather too light, and bright,
LNH@physics.arizona.edu   \  and sparkling; it wants ... a long chapter
sometimes a Wombat         \ of solemn specious nonsense. -- Jane Austen
Newsgroups: sci.physics
From: baez@guitar.ucr.edu (john baez)
Newsgroups: sci.physics,alt.sci.physics.new-theories,sci.optics
Subject: Re: Quantum connection communication is impossible in standard quantum mechanics. Therefore, "remote viewing" etc is not consistent with known physics. Ramsay, Gallis et-al right after all.
Date: 24 Nov 92 01:07:35 GMT
Followup-To: sci.physics
Organization: University of California, Riverside

In article <By6nA0.IL0@well.sf.ca.us> sarfatti@well.sf.ca.us (Jack Sarfatti) writes:
>
>Well John Baez will have to agree with me on this. Like Nixon - you won't
>have Sarfatti to kick around as a "crackpot" any more - no crackpot ever
>can admit his GENIUS idea is dead wrong! (using capital letters is not
>a sufficient criterion for crackpotness) -
>
>Sarfatti now admits: Quantum Connection Communication is an Illusion!

Yay!  Let's quickly celebrate before you devise a nonstandard approach 
to quantum mechanics in order to continue your quixotic quest!

Seriously, I am very impressed.
From: pratt@Sunburn.Stanford.EDU (Vaughan R. Pratt)
Subject: Re: TIME HAS INERTIA.   Att:  PRATT  FUND. THM. OF ALGEBRA 
Keywords: CORRECTION        FUNDAMENTAL THM. OF ALGEBRA
Organization: Computer Science Department,  Stanford University.
Date: Thu, 19 Nov 1992 07:49:30 GMT

In article <1992Nov18.175601.18259@prl.philips.nl> dacosta@prl.philips.nl (Paulo da Costa 42147) writes:
>In article <abian.722071648@pv343f.vincent.iastate.edu> abian@iastate.edu (Alexander Abian) writes:
>>In <abian.721303213@pv343f.vincent.iastate.edu> abian@iastate.edu (Alexander Abian) writes:
>[...]
>>>(3)   1/(kz^n + ...+ bz + a)  =  (1/k) z^(-n) + ........
>>> 
>>>But (3) shows that  0  is an essential isolated singularity of 
>>>                   
>>>                    1/(kz^n + ...+ bz + a)
>>> 
>>>contradicting (2).  Hence our assumption is false and the Theorem is
>>>proved.
>
>This step fails miserably. Reality check: You must have a<>0 (otherwise
>your polynomial would have a root at z=0, contrary to your assumption).
>In this case, the inverse of the polynomial at z=0 is just 1/a.

You've just argued that the step succeeds.  The proof assumes the
negation of the FTA and works towards a contradiction.  As soon as a
reality check (or anything else) produces a contradiction then the
proof is complete.

The gist of Abian's proof is that expansion (3) indicates a singularity
where, as both you and Abian point out, there can't be one.

I was hoping someone would pronounce on the validity of (3), and if it
is valid, whether proving it requires essentially the full force of the
FTA.  If (3) is not valid then Abian owes $500 to anyone taking him up
on his bet.  If (3) is valid but proving it is as much work as proving
the FTA, then Abian would technically win his bet, but his proof would
be about as sound as proving the FTA by assuming it (so a bush lawyer
might try to collect anyway :-).
-- 
Vaughan Pratt	  		A fallacy is worth a thousand steps.
Newsgroups: sci.physics,alt.sci.physics.new-theories
From: sarfatti@well.sf.ca.us (Jack Sarfatti)
Subject: re:Ramsay's "diminishing returns".
Organization: Whole Earth 'Lectronic Link
Date: Sun, 22 Nov 1992 01:39:11 GMT


Just as things get interesting, challenging preconceptions, Ramsay goes
into a state of denial saying that these problems are elementary exercises.
Well, maybe so, but pride goeth before the fall. I'm "stupid", and think
there is a great discovery to be made here.  Those of you who think this is
stupid use the control K kill command. It's working fine now for me for
abian, astrology and religion. But to those few brave souls willing to risk
being stupid, I salute you!  I am only looking for a few good men and women
for the Great Hermetic Work that has continued for thousands of years and
will continue to the ends of time and space and beyond!
Newsgroups: sci.physics,sci.astronomy
From: pentangl@spdcc.com (Scott Moir)
Subject: Unwelcome encounter with comet Swift-Tuttle?
Organization: S.P. Dyer Computer Consulting, Cambridge MA
Date: Wed, 18 Nov 1992 17:06:46 GMT

From Science News, Nov. 14, 1992 (Vol 142, #20) pg 331

UNWELCOME ENCOUTER WITH SWIFT-TUTTLE?

Astronomers last month hailed Comet Swift-Tuttle's return to 
Earth's vicinity after an  absence of 130 years. The visit set a 
record, making Swift-Tuttle the longest-period comet whose calculated orbit
has been confirmed by observations (SN:10/10/92, pg 230). But Swift-Tuttle's
next visit to the inner solar system may prompt a less enthusiastic greeting.
     Brian G. Marsden of the Smithsonian Astrophysical Observatory in 
Cambridge, Ma, calculates that there's a small chance-- no greater than one in
10,000--that the 10-kilometer-wide comet will crash into the Earth in the year
2126. He predicts that the comet will reach perihelion--its closest approach 
to the sun--on July 11, 2126. If so, not to worry: By the time Swift-Tuttle 
crosses Earth's orbit some 19 days later, our planet will be about 15
million miles away. Marsden notes, however, that the unpredictable nature of
of such non-gravitational effects such as cometary outbursts of gas may mar his 
predictions.  ANd if Swift-Tuttle reaches perihelion 15 days later, on 
July 26, 2126 then Earth could be in for big trouble.
     Astronomers can improve this prediction by monitoring Swift-
Tuttle for the next 5 years, Marsden says, when nongravitational
effects dominate. As for the myriad schemes to avoid a future doomsday , 
such as bombing the comet, he says these are best left to future 
generations. Besides, he notes, in the 2060's two asteroides, Hathor and the 
apt sounding Nereus-- may pass even closer to Earth than Swift-Tuttle.
-end of article----

Hmm. It's too bad people may reccomend this for future generations. It's an 
interesting physics problem, a lesson in humility, and a headache
for we of the "future generations" 30 years from now. 
I'll still be here, hopefully. Has any talk of plans of actions for this kind of
thing been heard on the newsgroup? Or is it something we are
burying under the rug in our society?

Dee




-- 
Deanne Taylor, undergrad, Wellesley College.|  My candle burns at both ends
Email address: dtaylor@lucy.wellesley.edu   |  It will not last the night 
Opinions are probably not S.Moir's. Okay?   |  But ah my foes and oh my friends
____________Quote: Edna St. Vincent Millay. |  It gives such lovely light!
Newsgroups: sci.physics
From: jbaez@riesz.mit.edu (John C. Baez)
Subject: Re: Continuos vs. discrete models Was: The size of electrons, ...
Organization: MIT Department of Mathematics, Cambridge, MA
Date: Thu, 19 Nov 92 00:34:54 GMT

In article <Nov.17.22.13.13.1992.11029@ruhets.rutgers.edu> bweiner@ruhets.rutgers.edu (Benjamin Weiner) writes:

>Let's put a stop to this.  Cells are not cellular automata and I don't 
>think you could find too many respectable biologists who would use 
>cellular automata in their studies.  They're too busy studying cells.
>Anyone who thinks a cell is a finite state machine needs to read some
>biology.  

I essentially agree.  Just to forestall objections, let me note that
while all sorts of things can be modelled as finite state machines
(after all, that's what any computer simulation amounts to), this does
not means that cellular automata are a very good tool for seeing what
real live cells do.