HDTenEightyP/NetNews huggingface dataset:
From: stieger@cco.caltech.edu (Ronald David Stieger)
Subject: Re: FTL
Organization: California Institute of Technology, Pasadena
Date: Fri, 28 Aug 1992 19:12:25 GMT

mppu3@syma.sussex.ac.uk (Conor McMenamin) writes:

>	Some people don't know when to leave it. I'm one. How's about
>this. The uncertainty principle states that there is a degree of
>uncertainty in position and velocity such that the product of the two
>uncertainties is greater than or equal to something with a h in it and
>probably some 2 pi's and stuff. (Less chance of being flamed if I keep
>it vague). If something is going at speeds near c, where is it? Try
>pointing at it. Therefore delta x is BIG. And delta v is correspondingly
>small.
>	But the basic result is, if you're dealing with things in terms
>of the uncertainty principle, you're never going to observe it, so why
>does it matter?

Remember that the uncertainty principle does NOT say anything about
uncertainty in velocity.  It talks about uncertainty in MOMENTUM.

delta x * delta p_x <= h (or h/2 or hbar, i don't remember)

And momentum, in SR is gamma * m * v, which goes to infinity as v
approaches c.  So a particle travelling at a velocity less than c
cannot, by uncertainty, be said to maybe be travelling faster than c.
And a particle with nonzero mass cannot travel at c, and even if it did,
what difference would it make?  Momentum of infinity +/- delta p, hmm...
sure sounds like it's still infinity to me!  Now light's momentum is 
based on it's wavelength, p = h/l, so again uncertainty doesn't affect
the velocity.  In fact, light MUST travel at exactly c, or it doesn't 
exist (i.e. has no energy, E = gamma * m * c^2, if m = 0, gamma = infinity
==> v = c), and of course c is implicit in Maxwell's equations.

Well I hope this helped.

-- 
--Ron Stieger
  stieger@cco.caltech.edu
"Everybody wants a rock to wind a piece of string around."-They Might Be Giants
From: DOCTORJ@SLACVM.SLAC.STANFORD.EDU (Jon J Thaler)
Newsgroups: sci.physics
Subject: Re: Satellite spying
Date: 26 Aug 92 22:57:18 GMT
Organization: Stanford Linear Accelerator Center

For a discussion of satellite reconnaissance, including resolution,
look at "Science, Technology and the Nuclear Arms Race," by Dietrich
Schroeer.  Pages 372-377.
Newsgroups: sci.physics,sci.astro,sci.math,sci.philosophy.tech
From: ron@mlfarm.com (Ronald Florence)
Subject: Re: About my papers (Calendar (NEW), Ancient Times, Surface Algebras, Struc
Organization: Maple Lawn Farm, Stonington, CT
Date: Tue, 1 Sep 1992 12:36:59 GMT

hporopudas@tnclus.tele.nokia.fi writes:

	I would like to put one my E-mail comment about my papers here, because
     I consider it significant.

     [email exchange deleted]

My effort to spare us all unnecessary bandwidth backfired.  I wrote to
urge the author of the space potato[e] cosmology and the Structure of
Time to post only the AVAILABILITY of his papers, with an ftp, uucp,
or mail address for those interested in the complete text.  He
apparently considers his papers so important that even those of us who
aren't interested, and those who pay for news, will be subjected to
his every word.

It seems the only recourse is 

  (gnus-kill "From" "hporopudas@tnclus\\.tele\\.nokia\\.fi")

or the equivalent for other news readers.
-- 

				Ronald Florence
				ron@mlfarm.com
From: hcart@vax.oxford.ac.uk
Newsgroups: sci.physics
Subject: Block seriation
Date: 25 Aug 92 07:29:14 GMT
Organization: Oxford University VAX 6620


    Does anyone know of any interesting applications of block seriation
in the physical sciences?

    Hugh Cartwright
    Physical Chemistry, Oxford.
From: matt@physics16.berkeley.edu (Matt Austern)
Newsgroups: sci.physics
Subject: Re: Facts and Values (was Where it came from)
Date: 25 Aug 92 19:37:34
Organization: Lawrence Berkeley Laboratory (Theoretical Physics Group)
Distribution: na
	<25623@dog.ee.lbl.gov> <1992Aug21.094831.7995@u.washington.edu>
	<13497.2a9a1cc6@ohstpy.mps.ohio-state.edu> <25732@dog.ee.lbl.gov>
	<schinder.714773737@leprss.gsfc.nasa.gov>
	<MATT.92Aug25140738@physics16.berkeley.edu>
	<schinder.714786893@leprss.gsfc.nasa.gov>
Reply-To: matt@physics.berkeley.edu
NNTP-Posting-Host: physics16.berkeley.edu
In-reply-to: schinder@leprss.gsfc.nasa.gov's message of Tue, 25 Aug 1992 23:54:53 GMT

In article <schinder.714786893@leprss.gsfc.nasa.gov> schinder@leprss.gsfc.nasa.gov (Paul J. Schinder) writes:

> >This is more nearly correct that pi x 10^7 seconds; the point is that
> >in one calendar year, it is realistic to assume that you will be
> >taking data for about 10^7 seconds.
> 
> You're joking!  You mean HEP grad students get to *SLEEP*!!!!  Gee, I
> never knew what an incredibly soft field it is!

Oh dear, of course not.  At Fermilab (and, I'm sure, at other major
accelerators), the day is divided into three eight-hour shifts, and
there are certainly people there (usually grad students) for all three
shifts.

The point is just that it is realistic to assume that all of the
apparatus will be working correctly about one third of the time.
--
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: jlg@cochiti.lanl.gov (Jim Giles)
Subject: Re: Impure Mathematics
Organization: Los Alamos National Laboratory
Distribution: na
Date: Fri, 28 Aug 1992 19:29:54 GMT

In article <Aug.28.13.28.14.1992.13802@ruhets.rutgers.edu>, bweiner@ruhets.rutgers.edu (Benjamin Weiner) writes:
|> [...]
|> What I wanted to say is, does Suzanne really need to make a well-
|> reasoned argument that jokes about rape aren't funny?  Just sit back
|> and think about it for a moment.  They're _obviously_ not funny, and
|> people who can't figure that out are probably beyond hope.

Is this really true, or are you being overly sensitive?  *ALL* humor
with the exception of puns (that's the only exception I can think of)
is based on the suffering or ridicule of the characters involved in 
the humorous situation (puns derive their humor from the suffering 
they promote among the audience :-).  Where do you draw the line?  
Tune into prime-time television *any* night and see jokes which 
ridicule characters, jokes about pain and/or injuries to characters, 
etc.. And what about jokes about the Challenger accident?  The JFK 
assasination?  The possibility Bush or Clinton might be elected
this fall?  They're _obviously_ not funny.

What about a movie in which one of the characters happily goes about
throwing books onto a fire?  In the context of pre-WWII Germany, this
wouldn't be funny at all.  Yet, it's in a Marx Brothers film of that
very era.  I found the scene vaguely unsettling *NOW*.

Yes there is a line between good taste and bad taste.  Where that line
is depends on the sensitivities of the culture the humor is embedded in.
The Impure Mathematics sketch probably crosses that line these days.
Dropping a safe on someone's head would possibly be just as shocking to
people if some major beloved figure died that way - yet it's a component
of the popular movie "Who Framed Roger Rabbit?" (as well as a lot of 
pseudo-sexual innuendo - like blackmailing someone to play `paddy cake').
Yet we show this stuff to our kids and think nothing of it.

People are more sensitive these days to jokes about rape than about
brutal murders: that is a function of social context not an objective
position.  When you find an *objective* criterion for what kinds of
misfortune are not appropriate for humor, let us know.  Or is all
humor bad?

-- 
J. Giles

P.S. The joke above about puns is obviously not itself a pun, yet I'm
hardpressed to decide who is ridiculed or suffers by it.  Whatever 
form of humor it is, it exemplifies another form that hurts no one.
I'm not sufficiently informed in the language of humorists to supply
the name for this form of humor.
From: bweiner@ruhets.rutgers.edu (Benjamin Weiner)
Newsgroups: sci.physics
Subject: Re: What's New
Date: 1 Sep 92 22:00:26 GMT
Distribution: na
Organization: Rutgers Univ., New Brunswick, N.J.

"Biologists the world over are tingling with anticipation" is, I
believe, one of Robert Park's usual cynical, and wholly justified,
jabs at the enormous expenditure - often by NASA - on experiments
of little or no scientific interest.  I'm sure Park knows that nobody
(OK, no biologists) care.
Newsgroups: sci.physics
From: crb7q@kelvin.seas.Virginia.EDU (Cameron Randale Bass)
Subject: Re: Radar Invisibility
Keywords: Swirls Sux Flux
Organization: University of Virginia
Date: Fri, 28 Aug 1992 21:37:54 GMT

In article <4110@cruzio.santa-cruz.ca.us> snarfy@cruzio.santa-cruz.ca.us writes:
>
>                            STREET SHEET TECH BRIEF # 4
>
>                    " In Search of ...the Lost Mach Principle"

  [stuff deleted]

>     An  example  that immediately comes to mind , when considering metallic
>   radar targets such as iron battleships , is the losses that occur in  the
>   iron  cores  of  transformers  and  inductive  ballasts (solenoids). In a
>   transformer that is delivering power to a load , the energy that  is  not
>   transferred  to the load is converted to electromagnetic radiation in the
>   form of heat (infrared). What might start out as  a  60  cycle  input  is
>   amazingly  upconverted  by  some  process into a THz output!

     Shockingly amazing, this conversion of 60 Hz input to an output
     with a higher frequency.  What *will* they think of next?

>    Radio wave propagation has often been described using  the  means  of  a
>   fluid  analogy  ,i.e.  "ripples" in a pond of water.  This description is
>   somewhat limiting , given the four dimensional  nature  of  ripples  (one
>   dimension each for frequency , amplitude, linear distance from the source
>   and  radial direction) . Radio waves have an additional dimension in that
>   they can be detected in other than a single  planar  orientation  to  the
>   transmitter.  

     I prefer my own personal additional dimensions 'flopsy', 
     'mopsy' and 'cottontail'.

                                dale bass
-- 
C. R. Bass                                           crb7q@virginia.edu
Department of Mechanical and Aerospace Engineering
University of Virginia
Charlottesville, Virginia                            (804) 924-7926
From: johan@blade.stack.urc.tue.nl (Johan Wevers)
Newsgroups: sci.physics
Subject: Re: Facts and Values (was Where it came fr
Date: 26 Aug 92 07:55:28 GMT
Organization: MCGV Stack, Eindhoven University of Technology, the Netherlands.

baillie@physics.ucla.edu writes:

>Are you using the famous "small circle approximation", where Pi is approximatel
>equal to 1?

I didn't knew that the value of \pi=3.1415..... depended on the size of the
circle. Can you please explain this a bit?

>Grant Baillie

******************************************************************** 
* J.C.A. Wevers                *         u\  _\       /e+        2 * 
* johan@blade.stack.urc.tue.nl *     1 |   \ u \  X  /         |   * 
******************************** P = - |    >   >---<     + ...|   * 
*     The only nature of       *     N |   /   /     \         |   * 
*     reality is physics       *         u/   /d     u\            *
********************************************************************
From: hagerman@ece.cmu.edu (John Hagerman)
Newsgroups: sci.physics
Subject: Radioactive Materials
Date: 1 Sep 92 03:29:16 GMT
Distribution: sci
Organization: Carnegie Mellon University

The long thread on kids eating radioactive stuff started with the fact
that some lightbulbs have such stuff in them, but that was discussed
so long ago that I have now forgotten: Why is a radioactive material
used in the first place?

Actually, what I'd really like to know is: What commercial uses are
there for radioactive materials, and why those materials?  I'm mostly
interested in uses that are for reasons *other* than the radioactivity
aspect of the material.

- John
--
hagerman@ece.cmu.edu
From: mitsu@nic.cerf.net (Mitsuharu Hadeishi)
Newsgroups: sci.physics
Subject: Re: Report on Philosophies of Physicists
Date: 1 Sep 92 21:36:00 GMT
Organization: CERFnet


	Not only Bohr, but also Heisenberg found a parallel between
Eastern philosophy and quantum physics.  In any case, Eastern philosophy
is hardly to be made equivalent to "New Age mysticism"; what I call
Eastern philosophy has nothing to do with religious dogma or
metaphysical assumptions.  It is simply a system of approaching
the understanding of the world, just as, say, logical positivism
could be said to be such a system, with absolutely no implied
metaphysics or dogma.  (Though there are systems of metaphysics
associated with some Eastern religions, these systems are thought to
be approximations or metaphors and are up for debate and possible
change.  There is no set of fixed tenets that you have to "believe in"
as is the case with many Western religious systems.)  As a system,
the basic modes of thought do indeed have parallels to the kinds of
philosophical issues raised by QM; in Eastern philosophy, ordinary
truth-value logic is considered to be a "classical approximation",
just as in physics Newtonian mechanics are thought to be a "classical
approximation" of QM.  This might be illustrated by the Zen
saying: "Before enlightenment, a cup is a cup and a mountain is a mountain.
While you are striving for enlightenment, a cup is no longer a cup, and
a mountain is no longer a mountain.  After enlightenment, a cup is again
a cup, and a mountain is again a mountain."  This is a metaphorical
way of referring to the fact that ordinary or "classical" logic is
a kind of approximation.  The difference between before and after is
similar to the difference between before you study QM and after; before
you might think classical physics is all there is, after you realize
you can still use classical physics for many situations, but it is
just an approximation.  The standard Western boolean logic is
clearly an approximation; not even a very good one in many cases.
Because Eastern philosophy subsumes "ordinary" logic as a subset,
it happens to be quite adequate to deal with both classical and
quantum physics.

Mitsu
Newsgroups: sci.physics
From: prim!dave@germany.eu.net (Dave Griffiths)
Subject: Uncertainty Principle
Organization: Primitive Software Ltd.
Date: Fri, 4 Sep 1992 17:08:47 GMT


I just read (Stephen Hawking) a nice explanation of the Uncertainty Principle:
to measure the position accurately, you need very short wavelength photons
which will have such a high energy that they will bash the particle so hard
that it's momentum becomes uncertain.

My question is, is this explanation a simplification for laymen, or is that
how the UP was really derived? I thought that the UP was somehow more
"fundamental" and not just related to practical difficulties of measurement.

Does it make any sense to talk about a particle having an unknowable, but
precise, position and momentum (which would be the case if the problem was
simply one of measurement)?

Dave Griffiths
From: cegtitd@prism.gatech.EDU (Tim Dodd)
Newsgroups: sci.physics
Subject: Re: Axiom of Physics
Date: 26 Aug 92 19:42:53 GMT
Organization: Georgia Institute of Technology

In article <1992Aug26.174922.6115@pellns.alleg.edu> frisinv@alleg.edu writes:
>A friend and I have a small disagreement about the existance of an axiom  
>of physics. She claims that all assumptions in physics are made from  
>empirical evidence and therefore there are no axioms in physics. I  
>maintain that the conservation of mass/energy is an axiom. Here is my  
>argument: an axiom must be based on evidence. Euclid didn't just say  

Axioms are not empirically based.  Axioms are DEFINITIONS.  f=ma is
axiomatic in that it is a DEFINITION of what we mean by "force".  Newton
postulated the original equation not by observing masses in motion and
the forces applied, (this would imply that we already had a good definition
of "force") but by realizing that we needed a more precise definition of
the term "force".

Tim

-- 
Tim Dodd, Research Scientist, Georgia Tech  cegtitd@prism.gatech.edu
From: doug@netcom.com (Doug Merritt)
Newsgroups: sci.physics
Subject: Re: Status of FTL QM Communication
Date: 26 Aug 92 18:54:43 GMT
Organization: Netcom - Online Communication Services  (408 241-9760 guest)

In article <1992Aug24.214512.15728@bcars64a.bnr.ca> schow@bqneh3.bnr.ca (Stanley T.H. Chow) writes:
>In article <nz=n-al.doug@netcom.com> doug@netcom.com (Doug Merritt) writes:
>> [discussion on communication, corrolation, randomness, ...]
>>
>>This again makes for fun speculation but there isn't any reason to
>>think it'll pay off.
>
>But favorites are so boring! This, of course, is the reason why most people
>don't get Nobel prizes (or any other major fame and glory of your choice).

I agree...like I said, it makes for fun speculation.

I threw in the disclaimer about pay off simply to point out that it's
in the category of a potential solution looking for a problem. Even
with speculation it helps to have some linkage to some unresolved
question.

Note also my standard .signature, after all. :-)
	Doug
-- 
Doug Merritt	Preferred: doug@netcom.com   (or: doug@eris.berkeley.edu)
Professional Wild-eyed Visionary	Member, Crusaders for a Better Tomorrow
From: baez@ucrmath.ucr.edu (john baez)
Newsgroups: sci.physics
Subject: Re: The Big Bang and the Copenhagen Interpretation of QM.
Date: 4 Sep 92 19:19:02 GMT
Article-I.D.: galaxy.22208
Organization: University of California, Riverside

In article <2964@ucl-cs.uucp> G.Joly@cs.ucl.ac.uk (Gordon Joly) writes:

>If the Schro\"dinger's Cat argument is a good thought experiment in
>the school of thought that suggests (that in Quantum Mechanics) "there
>is nothing without QM observation, by which we mean the collapse of
>the wavefunction", then in The First Three Minutes of the Universe
>after the Big Bang, were all the particles (or superstrings or
>spacetime-ons) busy observing each other?

They were certainly interacting with each other.  The only definition of
when an "interaction" counts as an "observation" seems to be: when a
system that can talk interacts, it calls it an "observation".

Anyway, I don't buy your "if"... so let's turn to:

>If not, how did the Universe arrive (after the initial singularity) is
>any state at all, let alone its initial state?

There's no big problem about it being in SOME state or other.  Every
physical system is in some state or other, although only certain ones
bother to talk about it.  Nobody knows why it was in the particular
From: crb7q@kelvin.seas.Virginia.EDU (Cameron Randale Bass)
Newsgroups: sci.physics
Subject: Re: Axiom of Physics
Date: 26 Aug 92 19:57:27 GMT
Organization: University of Virginia

In article <66942@hydra.gatech.EDU> cegtitd@prism.gatech.EDU (Tim Dodd) writes:
>In article <1992Aug26.174922.6115@pellns.alleg.edu> frisinv@alleg.edu writes:
>>A friend and I have a small disagreement about the existance of an axiom  
>>of physics. She claims that all assumptions in physics are made from  
>>empirical evidence and therefore there are no axioms in physics. I  
>>maintain that the conservation of mass/energy is an axiom. Here is my  
>>argument: an axiom must be based on evidence. Euclid didn't just say  
>
>Axioms are not empirically based.  Axioms are DEFINITIONS.  f=ma is
>axiomatic in that it is a DEFINITION of what we mean by "force".  Newton
>postulated the original equation not by observing masses in motion and
>the forces applied, (this would imply that we already had a good definition
>of "force") but by realizing that we needed a more precise definition of
>the term "force".

    They can be empirically based just as well as they can be pulled out
    of your hat.  An axiom is just the assumption that is the basis of
    your argument, unprovable within the argument.

                                 dale bass
-- 
C. R. Bass                                           crb7q@virginia.edu
Department of Mechanical and Aerospace Engineering
University of Virginia
Charlottesville, Virginia                            (804) 924-7926
Newsgroups: sci.physics
From: bhoughto@sedona.intel.com (Blair P. Houghton)
Subject: Re: My son would like to know about photons...
Organization: Intel Corp., Chandler, Arizona
Date: Tue, 1 Sep 1992 18:51:41 GMT

In article <17u6gpINNs9s@smaug.West.Sun.COM> Richard.Mathews@West.Sun.COM (Richard M. Mathews) writes:
>For every photon there exists a reference frame in which the photon is
>any given energy, so all photons are the same "size".  It is the matter
>they are passing which is different.

Two photons with different energies in one reference frame
have different energies in all reference frames including
their own (shared one), therefore not all photons are the
same "size."

				--Blair
				  "What color is your
				   Civic del Sol?"
Newsgroups: sci.physics
From: nextc.Princeton.EDU!mdd (Mark D. Doyle)
Subject: Re: Length scales in physics 4 - the Planck length
Originator: news@nimaster
Reply-To: mdd@nextc.princeton.edu
Organization: Princeton University
Date: Tue, 25 Aug 1992 17:58:10 GMT

In article <1992Aug25.085942.20864@nuscc.nus.sg> matmcinn@nuscc.nus.sg  
(Mcinnes B T (Dr)) writes:
> nextc.Princeton.EDU!mdd (Mark D. Doyle) writes:
> : In article <1992Aug25.044413.12331@nuscc.nus.sg> matmcinn@nuscc.nus.sg  
> : (Mcinnes B T (Dr)) writes:
> : > Well, John, it's rather interesting that you cite the example of the
> : > Schwarzschild radius. A couple of weeks ago the question was raised
> : > here: to what radius would you have to compress the Earth in order  
to
> : > get a black hole, in view of the fact that the S radial coordinate  
does
> : > not measure distance. Nobody knew the answer or was willing to  
guess.
> : Would you believe about 4 millimeters? 
> 
> Well, actually, no I would not.Not until you tell me your interior
> metric for the earth.
> 
Ooops. Missed the point of your post. Sorry. 

Mark
From: mcirvin@husc8.harvard.edu (Mcirvin)
Newsgroups: sci.physics
Subject: Re: Less Groups! More Representations! (was: Symmetries, groups, and categories)
Date: 3 Sep 92 22:27:08 GMT
Article-I.D.: husc8.mcirvin.715559228
 <COLUMBUS.92Aug25114146@strident.think.com> <22035@galaxy.ucr.edu>
Distribution: na

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

>In article <COLUMBUS.92Aug25114146@strident.think.com> columbus@strident.think.com (Michael Weiss) writes:

>>As to the original topic, "should the first course in abstract algebra
>>teach something about group representations", I'd say yes.  In fact such a
>>course often does. 

>Often?  You're lucky.  I've never run across it.

Indeed, the first course I took in abstract algebra dealt *only* with
finite Abelian groups!  We thought a lot about factoring things into
Z sub n's.  I didn't know what a representation was until grad school.
-- 
Matt McIrvin, Cambridge, Massachusetts, USA