HDTenEightyP/NetNews huggingface dataset:
From: bhoughto@sedona.intel.com (Blair P. Houghton)
Newsgroups: sci.physics
Subject: Re: Religion & Physics Don't Mix
Date: 8 Nov 1992 23:52:02 GMT
Organization: Intel Corp., Chandler, Arizona
NNTP-Posting-Host: alfalfa.intel.com

In article <BxBpHs.DtF@unixhub.SLAC.Stanford.EDU> sschaff@roc.SLAC.Stanford.EDU (Stephen F. Schaffner) writes:
>You simply can't do science without the 
>"unquestioning belief" (usually unconscious) in the foundations upon which 
>it is built.

NOT.

One makes assumptions, or alludes to the work of others (which
also is based on assumptions), and deduces the next level of
facts[*] from those assumptions.

But, in many cases, logic does not require assumptions of
any kind, since it can make the assumptions irrelevant to
the results; i.e., the results support themselves.

If everywhere in the self-supporting loop there are observable
and repeatable phenomena, then you have an assumptionless
fact, and faith is not necessary.

Even if it is necessary to maintain the assumptions, one
can produce grander assumptions through logic and
experiment, thus progressing to new knowledge.  Then one
can use other assumptions to produce other new knowledge.
Faith is not necessary, since conscientious science tests
all possibilities of the assumptions, exhaustively if
necessary.

(Thomas Edison made no assumptions; that's why it took over
six thousand prototypes to make a profitable incandescent
light-bulb; there was no faith, there was only risk and
persistence and a passing observation that electrically-
heated materials can glow).

Science seeks to reward the questioners, especially if
their question leads to new knowledge.

The only time a scientist is unquestioning is when there's
no time to question, only time to grind out the next answer
from the current state of the assumptions.

				--Blair
				  "The only time an engineer is
				   unquestioning is during scheduling."

[*] "Facts," not "truths;" the truth is in the presentation
and the mathematics, not the results themselves.
Newsgroups: sci.physics
From: u926135@tasman.cc.utas.edu.au (Adrian Hassall Lewis)
Subject: Re: jokes & sexisim in physics
Keywords: sexism women women-physicists nursing
Organization: University of Tasmania, Australia.
Date: Fri, 6 Nov 1992 00:02:17 GMT

baez@ucrmath.ucr.edu (john baez) writes:

>For some basic information on this subject, try "Sex Differences in the
>Brain" by Doreen Kimura in the Sept. 1992 Scientific American.  Let me just quote
>the last paragraph:

>The finding of consistent and, in some cases, quite substantial sex differences
>suggests that men and women may have different occupational interests and
>capabilities, independent of societal influences.  I would not expect,
>for example, the men and women would necessarily be equally represented in 
>activities that emphasize spatial or math skills, such as engineering or
>physics.  But I might expect more womone in medical diagnostic fields where perceptual
>skill are important.  So that even though any one individual might have
>the capacity to be in a "nontypical" field, the sex proportions as a whole
>may vary.

>I am not an expert in this subject so please don't flame me (but
>feel free to dispute Kimura's methodology!).  I will only note that she
>considers physiological evidence as well as "test scores".

On the ABC's (Australia) _Science_Show_ recently, a very interesting point has
been raised several times.  Basically it is this -
	Science/engineering/etc have traditionally been dominated by the
	"male"/"analytical" approach, whereas woman have a "perceptual"
	approach,	BUT SO WHAT,	this very difference means that
	they are able to approach/contribute to/and _solve_ problems from
	a new perspective; which is potentially valuable.

Adrian
From: quest@iowegia.uucp (Steve J. Quest)
Newsgroups: sci.physics
Subject: Re: a question on powerful lasers
Date: Wed, 11 Nov 92 00:56:52 CST
Distribution: world
Organization: Iowegia Public Access Usenet/UUCP, Clive IA USA.

mlevin@husc8.harvard.edu (Michael Levin) writes:

> 
>      Are there any lasers available which will actually cut things?
> The ones I see for sale in catalogs (like Edmund Scientific) seem only
> to be for demonstration purposes. Is it possible to obtain a laser
> that will cut metal, or are they only industrial ones that weigh tons
> and cost millions? If anyone has any info on this (company names,
> etc.) please reply to mlevin@husc8.harvard.edu.
> 
> Mike Levin


Michael,

        Pulse dye lasers and CO2 gas lasers can be columated to 
cut metals.  Argon gas lasers are CW (continuous wave) lasers that 
can cut (make that vaporize/burn) human flesh.  Most air cooled 
argons and HeNe lasers are visual only devices- they do not burn.  
There is optical lasers (Krypton/Argon) such as the Coherent 
"Purelight" series lasers which can be dialed up to burn flesh 
right out of the tube- without columation!  I have burns on my 
thumb to prove this.  Never let your body fall in the path of a 
beam while adjusting mirrors.  If you are too busy watching the 
mirrors alignment, you may see smoke BEFORE you feel burning 
flesh.  Laser burns are quite painful...........sq

(The purelight laser at work draws a maximum of 25,000 watts of 
3 phase electric power to produce 8,000 milliwatts- that's eight 
watts of optical laser power.  Eight watts is a VERY powerful beam 
tho- ignites paper instantly.  Burns flesh almost as fast.....)

Newsgroups: sci.physics
From: crb7q@kelvin.seas.Virginia.EDU (Cameron Randale Bass)
Subject: Re: Religion & Physics Don't Mix
Organization: University of Virginia
Date: Fri, 6 Nov 1992 19:01:31 GMT

In article <73878@hydra.gatech.EDU> cegtitd@prism.gatech.EDU (Tim Dodd) writes:
>In article <1992Nov5.221645.26360@murdoch.acc.Virginia.EDU+ crb7q@kelvin.seas.Virginia.EDU (Cameron Randale Bass) writes:
>+In article <73795@hydra.gatech.EDU+ cegtitd@prism.gatech.EDU (Tim Dodd) writes:
>++Words can also refer to concepts.  A word can be regarded as meaningful
>++if the concept it refers to exists, but if there are no real referents
>++for the concept, then the concept is meaningless in the same way as a
>++word would be.
>+
>+     How can a concept *not* exist?  Simply actualizing it provides
>+     existence.
>
>This is true, but if the concept has no correspondence to any elements
>in reality, or is defined in such a way that such a correspndence can
>never be established, then by definition, the concept is meaningless.
>I did not say anything about concepts not existing, but about whether
>or not they should be regarded as meaningful.

     Your statement was that 'a word can be regarded as meaningful
     if the concept it refers to exists'.  So, every concept is meaningful.

>Again, you have not paid attention to what I said.  I was not speaking of
>a "subject existing outside of a conceptual universe" but of whether or
>not the "subject *pertains* to anything outside" the conceptual universe
>(emphasis added).

     I paid complete attention (or at least as complete as I'm wont to
     do).  How can there be a concept outside of the conceptual universe?

>+     Well, you have a rather odd way of looking at the concepts of 
>+     'meaning' and 'reality'.  Am I to take it that concepts are defined
>+     as 'existing' and 'meaningful' and 'real' only when *you* want them
>+     to be meaningful.  This seems perfectly consistent, but it is probably
>+     not widely shared.
>
>No, this is exactly what I am arguing against!  Meaning is established
>by the semantic mapping between words or concepts and their referents.
>Since the existence of these referents must be empirically verifiable
>in principle, and reality is something we all share, then the presence
>or absence of meaning is something we can all agree on.

     So now they must be 'empirically verifiable'?

     Have you ever said 'I love you'?

                            dale bass
-- 
C. R. Bass                                          crb7q@virginia.edu        
Department of Mechanical, 
     Aerospace and Nuclear Engineering
University of Virginia                              (804) 924-7926
From: ucap22w@ucl.ac.uk (Martin S T Watts)
Newsgroups: sci.physics
Subject: Re: TIME HAS INERTIA
Date: 12 Nov 92 20:16:46 GMT
Organization: Bloomsbury Computing Consortium


sichase@csa1.lbl.gov (SCOTT I CHASE) writes:

>In article <1992Nov09.192052.25358@bas-a.bcc.ac.uk>, ucap22w@ucl.ac.uk (Martin S T Watts) writes...

>>balanced - why can't you? For another thing, they are not. The one thing that
>>you give Einstein credit for is something he probably never said. As Hermann
>>Bondi has pointed out [Physics Bulletin _38_ (1987) p62], in all known physical
>>processes energy and mass are in fact conserved separately. Energy has mass
>>is a more useful statement than energy and mass are equivalent.

>Maybe so, in all physical processes known to Hermann Bondi!  But any 
>student who has spent two days in a particle physics class knows better.

Any student who's spent two days in a particle physics class knows better than
Hermann Bondi? Now there's a sweeping statement.  :-)

(And if you think that, say, positron-electron annihilation is an example of
the destruction of mass, then think again.)

>And how clever of you to reference a magazine so obscure that even *I*
>couldn't find it, with all the resources of the University of California
>Library system at my disposal.  I am told by our local LBL physics librarian
>that Physics Bulletin was a cross between the APS bulletin with it's
>abstracts, and a small-scale Physics Today, with newsy items, appointments,
>obits, that sort of thing.  It has been replaced by Physics World.  The
>U.C. Library, which saves office memos and old toilet paper, never bothered
>to keep its copies of Physics Bulletin.

It wouldn't surprise me if American Universities were turfing out copies of
J. Phys. A! I only included the reference in case people doubted the
authenticity of my claim - I hadn't thought people would go to the trouble
of looking it up. I dug out the original article, though, and found the 
following recommended reading, in case you're interested:

Warren, JW 1976 "The mystery of mass-energy" Phys. Educ. _11_ p52-54 and
letter _11_ p453-4

Bondi, H 1965  Relativity and Common Sense (London: Heinemann) pp72-108, 155-9

Rogers, EM 1960  Physics for the Enquiring Mind (Princeton: Princeton University
Press and London: Oxford University Press) pp403-6

>So I guess that the wisdom of Hermann Bondi is just lost to me...

Well, I hope not. You'd do well to look out this article if you sincerely think
that energy and mass are interconvertible - it's a very common misconception.
The article's published by the Institute of Physics, so it shouldn't be 
impossible to get hold of.

Martin Watts.
Newsgroups: sci.physics
From: sarfatti@well.sf.ca.us (Jack Sarfatti)
Subject: Is John Baez nonlocal?
Organization: Whole Earth 'Lectronic Link
Date: Wed, 11 Nov 1992 18:41:41 GMT


I notice that John Baez uses at least three different e-mail addresses
almost simultaneously. Is this evidence for the many worlds interpretation
of quantum mechanics?
Newsgroups: sci.physics
From: jbaez@riesz.mit.edu (John C. Baez)
Subject: Re: The size of electrons, and Fanciful misc SAGA
Organization: MIT, Department of Mathematics
Date: Sat, 7 Nov 92 21:43:29 GMT

Dave Griffiths writes:

>There is no such thing as infinity. Physicists are going to have to bite
>the bullet and develop a discrete TOE at some time or other. To do so
>may require going right back to basics to develop an information based
>theory. But with so much momentum in current theories, so much resistance
>to the radically new, so little money to be made from such a reformulation,
>I wonder if it will ever happen.

This is what computer scientists often say.  We eagerly await the day
when one of them actually does some physics.  :-)  Do physicists go
around saying that present-day computers are inadequate for physics
because they are digital and not analog?  Maybe some do, but
that would be equally misguided.  

The main point is that "there is no such thing as infinity" is an
extremely vague and misleading statement.  Is there such a thing as a
universal Turing machine?  (I've never seen one.)  Is there such a thing
as the square root of minus 1?  All these things are mathematical
constructs which can play an important role in modeling reality - all
three can also be misused.  

Secretly, my theory about computer scientists' love of discrete physics
is that it's a still poorly-understood side-effect of staring at pixels
all day.  I have long had a humorous battle with Nate Osgood over this
issue, replete with such slogans as "Wreck the rectangle!" (which I
stole from Zippy the Pinhead), "Crush the continuum!" and "Death to the
discrete!"  

By the way, I have nothing against discrete physics as long as it's not
claimed as a panacea.  I have, in fact, long been working on a paper on
mathematical methods for discrete mechanics.  It seems as I may soon
have a grad student, and I may inflict this topic on him, since there is
a lot of nice stuff to do with it.  (In case James Dolan is reading this
- no, I don't mean you.)

Work in discrete physics *is* proceeding nicely, *not* because some
folks hope the universe is just like a computer, but because it's nice
to understand the sort of quasi-physical processes that a digital
computer can simulate exactly.

Newsgroups: sci.physics
From: adam@muskwa.ucs.ualberta.ca (Adam Mark)
Subject: Question on alternate theory of relativity
Summary: Has anyone heard of this ...?
Keywords: relativity
Organization: University Of Alberta, Edmonton Canada
Distribution: sci
Date: Fri, 13 Nov 1992 23:28:42 GMT



	I remember reading an aricle in Maclaen's or something
a while back that said someone out there had a theory
in which the speed of light was tied to the inertial frame
of the body (eg Earth or sun) to which it was closest, but I
forget the rest. Also said that some experimental evidence
supported this.
        Does anyone out there know the author/status of this
work?     
		Inquiring minds want to know.
Newsgroups: sci.physics
From: jbaez@riesz.mit.edu (John C. Baez)
Subject: Re: Do Balloons fly?
Organization: MIT Department of Mathematics, Cambridge, MA
Date: Fri, 6 Nov 92 03:16:15 GMT

In article <1dbs8vINNau0@agate.berkeley.edu> aephraim@physics.Berkeley.EDU (Aephraim M. Steinberg) writes:
>In article <1992Nov5.130316.28438@kth.se> e92_anh@vaxkab.lne.kth.se () writes:
>>This will probably sound like a silly question to a lot of you, but WHY
>>does a helium-filled balloon rise upward? Is it because of the
>>difference in air-pressure at the balloon's top and bottom, causing the
>>resulting force to press it upward?

>Yes, amazingly enough.

And now for the natural next question - so, does that mean that a
lead-filled balloon falls because the difference in air pressure is
reversed in that case?

:-)


Newsgroups: sci.physics
From: torkel@sics.se (Torkel Franzen)
Subject: Re: Einstein and Judaism
Organization: Swedish Institute of Computer Science, Kista
Date: Mon, 9 Nov 1992 19:42:31 GMT

In article <emc.721244750@tristan> emc@doe.carleton.ca (Eli Chiprout) writes:

   >Einstein fought against Quantum Theory until his last days because he
   >felt that it completely contradicted God as he understood God to be.

  Einstein didn't "fight" QT, he thought it was incomplete. As for his
reasons, or if you like, philosophical prejudices, he made them clear enough.
They were quite ordinary realistic philosophical prejudices. He didn't
base them on any ideas about God, as far as his actual writings and reported
explanations indicate. Almost invariably, people who imagine that Einstein
proceeded from theology to philosophy and physics base this view on nothing
more than one or two aphoristic formulations.

Newsgroups: sci.physics
From: kim@Lise.Unit.NO (Kim Gunnar St|vring \yhus)
Subject: Re: Religion & Physics Don't Mix
Organization: Norwegian Institute of Technology
Date: Fri, 6 Nov 92 13:00:55 GMT

In article <1992Nov4.182157.17016@murdoch.acc.Virginia.EDU>, crb7q@kelvin.seas.Virginia.EDU (Cameron Randale Bass) writes:
 > In article <1992Nov4.171314.22145@ugle.unit.no> kim@Lise.Unit.NO (Kim Gunnar St|vring \yhus) writes:
 > >That's not my definition of 'truth'. Not my friends either.
 > >What kind of language are you using? It seems to me that your use of 'truth'
 > >makes possible conflict between 'truth' and 'reality', which are synonyms to mee.
 > 
 >      I don't think 'truth' is a scientific concept, and 'reality' only
 >      seems so insofar as it is a reflection of experimental results.  So,
 >      'reality' is mutable.  So within science, I see absolutely no conflict
 >      between 'truth' and 'reality'.  And since I would deny that 'truth'
 >      is within the domain of science, I do not see how this could generate
 >      conflict anywhere else.

When I use 'reality', I refer to everything that can have any consequence on me.
This means my reality stop to exist when I do, but may continue as the part it
was of another reality.

When I use 'truth', I talk about a model, preferably the simplest, of
reality that predicts everything about reality. I also use 'truth' as
reference to a similar model encompassing all logic.

You obviously have a different definition of 'truth' and 'reality'.
And I don't know what yours is.

 > >>      Why do certain people have such difficulty with the proposition
 > >>      that there are domains which 'science' and 'logic' can never reach?
 > >>                                 dale bass
 > >Because it's a false proposition.
 > 
 >      Prove it false.

Science is not about proving things. It's about finding good models by
comparing different models with reality, and thus guessing the truth.

But since you ask, I will prove it ;->

Aksiom 1.  All propositions are false.

Aksiom 2. "There are domains which 'science' and 'logic' can't reach"
           is a proposition.

Aksiom 2.
Aksiom 1.
__________
It's false.  :-)

Kim0
Newsgroups: sci.physics
From: zowie@daedalus.stanford.edu (Craig "Powderkeg" DeForest)
Subject: Re: Campfire and plasma musings
Organization: Stanford Center for Space Science and Astrophysics
	<1992Nov7.192607.23040@galois.mit.edu>
Date: 8 Nov 92 17:36:59

In article <baz> jbaez@riesz.mit.edu (John C. Baez) writes:
   In article <bar> sichase@csa1.lbl.gov (SCOTT I CHASE) writes:
   >In article <foo>, slovick@Apple.COM (Linda Slovick) writes...
   >>2.) Is a flame a plasma?
   >Yes. 

   Anyone know HOW ionized a campfire flame is?

Not very.  If you assume that the ionization potential of a typical
air molecule is ~10V, (Nitrogen's is 14V, according to my handy CRC),
you'd need to get ~10eV/particle of thermal energy to ionize most of
the gas.  The temperature is just 10eV/Kb, or 110,000K (210,000F).
This is about a factor of 20 times hotter than a typical campfire
flame!

Campfire flames glow because they're hot enough (~3,000K) to give off orange
light by blackbody radiation, not because their charges are re-associating.

The best/most common places to see plasmas on the Earth are (a) fluorescent
lights, including most city street lights, and (b) spark discharges 
(lightning, spark plugs in cars, etc.).


	
--
Craig DeForest -- astrophysicist for hire.   DoD#314159; PhD#271828
From: dougp@hplsla.hp.com (Doug Passey)
Date: Thu, 29 Oct 1992 16:30:54 GMT
Subject: Re: WHO MURDERED ALBERT EINSTEIN?
Organization: HP Lake Stevens, WA
Newsgroups: sci.physics

Hear a favorable review of it on National Public Radio this morning.
The author is Todd Gitlan(sp?).
From: dbc@ecs.soton.ac.uk (Bryan Carpenter)
Newsgroups: sci.physics
Subject: Re: GR with no Einstein? (Was: Re: No big crunch?)
Date: 10 Nov 92 11:47:30 GMT

In <1992Nov6.232435.15628@galois.mit.edu> jbaez@riesz.mit.edu (John C. Baez) writes:

>In article <1992Nov6.042306.899@murdoch.acc.Virginia.EDU> crb7q@kelvin.seas.Virginia.EDU (Cameron Randale Bass) writes:

>>     Suppose, as I have been, that you *don't even have* GR.
>>     In 1906, there was no certainty that GR would be developed.
>>     In fact, if Einstein had died in 1906, I'm quite sure it 
>>     wouldn't have been.

>Oh good, let's argue about this, since it is utterly contrafactual.  I'm
>sure GR would have been developed (though not in 1906!).  Einstein was
>not the only person working on trying to come up with relavistic
>theories of gravity.  Other people came up with some that were getting
>sort of close (sorry, I don't have references on this - it would be fun
>to know just *how* close).  And more importantly, the mathematical
>infrastructure had already been laid by Riemann and was being studied by
>Cartan and Hilbert, who were sort of into physics.  So I am quite sure
>someone would have come up with GR after a while.

In fact, isn't there some old chestnut about Hilbert presenting
Einstein's field equation some time before Einstein published it?
I suppose Hilbert had probably been influenced by what Einstein had
been saying for the previous ten years, though.

(Also, I seem to remember that Einstein ``had'' his equation some
time before he finally published it, but he originally thought it
had some physical pathology, and abandoned it for a while).

Bryan
From: aephraim@physics.Berkeley.EDU (Aephraim M. Steinberg)
Newsgroups: sci.physics
Subject: Re: Do Balloons fly?
Date: 5 Nov 1992 19:22:07 GMT
Organization: University of California, Berkeley
NNTP-Posting-Host: physics.berkeley.edu

In article <1992Nov5.130316.28438@kth.se> e92_anh@vaxkab.lne.kth.se () writes:
>This will probably sound like a silly question to a lot of you, but WHY
>does a helium-filled balloon rise upward? Is it because of the
>difference in air-pressure at the balloon's top and bottom, causing the
>resulting force to press it upward?

Yes, amazingly enough.

>
>Thus, consider this: If the air surrounding the balloon had exactly the
>same density on all sides, then the balloon would not move (I think).

No, actually it would sink, I think, because there is still the effect
of gravity.  (The two effects are equal if the balloon has the same
density as air, which is why for Helium the air pressure dominates.)
Furthermore, density alone does not determine pressure; your statement
is true if the temperature is the same above and below the balloon.

If you try to construct a naive equilibrium model of the atmosphere,
where pressure gradients exactly compensate gravity, I seem to remember
that you find temperature decreasing monotonically as altitude increases,
and reaching absolute zero at an altitude on the order of 50 miles.
Amusing since, though the model fails to describe at all the actually
quite complicated dynamics of the atmosphere, 50 miles is the figure
typically taken as an arbitrary "end of the atmosphere, beginning of
space" estimate.  (I guess before the shuttle that was as high as anything
resembling an airplane had flown, too.)

-- 
Aephraim M. Steinberg                    | "WHY must I treat the measuring
UCB Physics                              | device classically??  What will
aephraim@physics.berkeley.edu            | happen to me if I don't??"
                                         |       -- Eugene Wigner
From: bhoughto@sedona.intel.com (Blair P. Houghton)
Newsgroups: sci.physics
Subject: Re: Religion & Physics Don't Mix
Date: 5 Nov 92 21:31:55 GMT
Organization: Intel Corp., Chandler, Arizona
NNTP-Posting-Host: alfalfa.intel.com

In article <1992Nov5.174347.20746@murdoch.acc.Virginia.EDU> crb7q@kelvin.seas.Virginia.EDU (Cameron Randale Bass) writes:
>     Ohno.  Not evolution again.

Not again; always.

>     Karl Popper would be turning over in
>     his grave (that is, if he were dead).

Or a vampire.

				--Blair
				  "It could haaaappen..."
				  -Judy Tenuta
Newsgroups: sci.physics
Subject: No Spin in 2 Dimensions?
From: <CCB104@psuvm.psu.edu>
Date: Tue, 10 Nov 1992 00:25:15 EST
Organization: Penn State University

I heard it said by a former physics grad student that a certain professor
of his said that it is *obvious* why there is "no spin in 2 dimensions"
(i.e. in a 2-dimensional differentiable manifold of some sort?). What might
they have meant, please? Any ideas?
Thanks,
Carey
Newsgroups: sci.physics