HDTenEightyP/NetNews huggingface dataset:
From: dietz@cs.rochester.edu (Paul Dietz)
Subject: Re: Entropy of the Universe, (was Re: Genesis - fact or fiction)
Organization: Computer Science Department University of Rochester
Distribution: na
Date: Sun, 23 Aug 1992 20:01:41 GMT

In article <1992Aug23.175650.14850@alchemy.chem.utoronto.ca> mroussel@alchemy.chem.utoronto.ca (Marc Roussel) writes:

>     I think you're missing the point of such experiments.  No one is
> claiming that these experiments represent realistic prebiotic
> evolutionary mechanisms.  Rather, these reactions are simple models
> which we can hope to understand.  This sort of chemical modeling is done
> all the time when the real process we are interested in is too difficult
> for us to study immediately.  The other example which springs to mind
> is so-called model or artificial enzymes, usually made from
> organometallic complexes; no one claims that these are exactly like
> biological enzymes, but the models yield some insight into the function
> of real enzymes and tell us what to look for in biochemical systems.
> Similarly, the simple self-replicators tell us what to look for in more
> realistic prebiotic evolution mechanisms.


"Model" is too strong a term.  The analogy with artificial enzymes in
flawed: we *know* enzymes exist, so we know the artificial enzymes
model something.  We don't know that such simple self replicating
systems ("naked genes") were around at the start of life.  The
existence of model systems is no more evidence of their relevance than
statues ("models") of unicorns are evidence of the existence of real
unicorns.

The highly unrealistic conditions required by these model systems also
make their relevance questionable.  Show me a self replicating system
using only simple molecules that could be expected to be produced
abiotically that is tolerant of the presence of large quantities of
contaminants and maybe it would be more interesting.

The fundamental problem in all of this is that the theories of
biogenesis are so vague as to be unfalsifiable.

	Paul F. Dietz
	dietz@cs.rochester.edu

Newsgroups: sci.physics
From: jejones@microware.com (James Jones)
Subject: Re: The dangers in microwaved food...
Summary: exploding pseudo-omelet
Organization: Microware Systems Corp., Des Moines, Iowa
Date: Tue, 25 Aug 1992 21:34:56 GMT

In article <10200@vice.ICO.TEK.COM> hall@vice.ICO.TEK.COM (Harold F Lillywhite) writes:
>Or eggs.  Unless the membrane is pierced they can build up a lot of
>internal pressure.  The same probably applies to any food with a
>reasonably impervious layer on the outside.  The quick heating of a
>microwave oven can turn it into a potential bomb which can explode 
>when some poor soul cuts it or pokes it with a fork.

Or bites into it, as happened to me three days ago at a local establishment
selling pseudo-omelets (microwaved egg with cheese on bagel).  Fortunately
the pressure wasn't *that* high, but the skin over my hard palate did NOT
appreciate it.  (Not to mention that the egg didn't taste all that great
from overcooking.)

	James Jones
From: balbes@ohstpy.mps.ohio-state.edu
Newsgroups: sci.physics
Subject: Re: quantization of angular momentum
Date: 1 Sep 92 10:46:27 EDT
Distribution: sci.physics

In article <TK.92Aug31202517@wheat-chex.ai.mit.edu>, tk@ai.mit.edu (Tom Knight) writes:
> I'd like to understand the quantization of angular momentum better.
> On the one hand, we are told that L is quantized, but we (naively)
> recall that L = r x p, and note that neither the position nor the
> momentum is quantized; presumably, the error or complexity lies in the
> classical definition of the angular momentum, and if we had only
> turned these into operators on the wave function "it would all be
> clear."  Perhaps that's sufficient for some of you, but I'd like a
> little better insight.  Maybe I'm just asking for insight into
> something which is intrinsically not amenable to insight.  If so,
> perhaps that will be some consolation.  Thanks.


It's because we are taught to think in terms of Schroedinger's 
version of QM where the operators are constant and the wave function
evolves in time.  Classically, it's the operators (p,x,L, etc) which
evolve over time.  In the Heisenberg picture of QM, the wave function
stays constant and the operators evolve as we are used to from 
classical physics.  The equivalence of the two QM pictures should
be discussed in any basic QM text (like Park, Schiff,  or Merzbacher).

You should also be careful distinguishing between the L operator (rxp)
and the eigenvalues of the operator which are quantized.

Hope this helps.
Mark Balbes
Newsgroups: sci.physics
From: tolman%asylum.cs.utah.edu@cs.utah.edu (Kenneth Tolman)
Subject: Redshifted light wonders
Date: 30 Aug 92 22:44:46 MDT
Organization: University of Utah, CompSci Dept

  If the universe is expanding merrily away, and photons fly across this,
there are some peculiar things that result.... how can these things be 
resolved?

  1) Is there some minimal energy state that a photon can be redshifted to?
Is there some minimal energy which a photon can have before it effectively
ceases to exist?  (read next question to make more sense of this)

 2) Is there a continuous energy change for a particular photon, or does
it get redshifted across jumps?  Does not quantum mechanics imply that
there are only certain meaningful energy values, and as such would not a 
photon move from one to the other?  If not, this would imply that there
would be undetectable photons- high energy photons which did not correspond
to any absorption frequency of any detection device.  Unless of course, the
detection devices were somewhat forgiving.... is this the case?

 3) Are these photons losing energy for the whole universe?  Is energy not
being conserved, or is it?

  I am very interested in being enlightened on the above questions :)
Any advice or comments would be very appreciated.

Thanks,
From: toon@moene.indiv.nluug.nl (Toon Moene)
Newsgroups: sci.physics
Subject: Differential Geometry and Physics, was: Re: Misner et al.
Date: 2 Sep 92 21:02:15 GMT
Organization: Moene Computational Physics, Amsterdam, The Netherlands

In article <1992Aug31.040423.15975@nuscc.nus.sg> matmcinn@nuscc.nus.sg  
(Mcinnes B T (Dr)) writes:
[ ... Friedman vs. Misner, Thorne, Wheeler vs. Weinberg ... ]
> : -- 
> I recommend Friedman for the discussion of the fundamental principles,
> not for the technicalities. For that, Wald is good. Plus a good solid
> differential geometry book. MTW is essential reading because it has been
> so influential. By the way, Weinberg's book is notorious for the claim
> that you don't really need geometry to understand GR. But somebody once
> told me that Weinberg retracted this bizarre claim. Can anyone verify?

I took a course in differential geometry at the same time I took a course  
in GR based on Weinberg's book. Note: The book would be half as thick if  
he just used the most basic things from differential geometry - what a  
waste ...
I've never understood what's wrong with DG so that physicists shouldn't be  
exposed to it; it turns up in every field in physics sooner or later.
(If you're interested in DG in weather forecasting, just drop me a note -  
I can spew half dozen literature entries in a minute, no problem)

--
Toon Moene (toon@moene.indiv.nluug.nl)
Kantershof 269, 1104 GN  Amsterdam, The Netherlands
Tel.: + 31 20 6982029; Fax: + 31 20 6003411
No Disclaimers; a NeXT at home protects against this occupational hazard.
From: andrew@rentec.com (Andrew Mullhaupt)
Newsgroups: sci.physics
Subject: Re: Entropy of the Universe, (was Re: Genesis - fact or fiction)
Date: 25 Aug 92 16:29:11 GMT
Distribution: na
Organization: Renaissance Technologies Corp., Setauket, NY.

In article <VSUMMERS.92Aug24162806@polaris.cv.nrao.edu> vsummers@polaris.cv.nrao.edu (Vince Summers) writes:
>Logically, if there is a God, he had a reason for creating us.

I worry about assuming that we can reliably make statements about what looks
like a reason enough for God and what looks like reason enough for us. In
the case of an omniscient omnipotent, God, that's about the extent of what
you can say. The meaning of freedom or necessity to God should not be
automatically taken to be that which we are comfortable with. God may have
a reason for the universe, but we could be looking right at it, writ large,
but does that mean we would make any sense of it? What you seem to be saying
is that the reason for the universe would be made available to man. I don`t
feel comfortable telling God that if he doesn't interpret the fine print for
us that we will not believe in God. If there is God, is God not how we find
God, rather than what he make God?

>  What is it?

You have to ask God for this.

>If there is an answer somewhere, should we ignore it?

No. Such an answer would be of the highest importance. I don't know anybody
who isn't looking for it, one way or another, even if God is not the author.

Later,
Andrew Mullhaupt
From: Richard.Mathews@West.Sun.COM (Richard M. Mathews)
Newsgroups: sci.physics
Subject: Re: Satellite spying
Date: 25 Aug 1992 12:45:20 -0700
Organization: Sunsoft Inc., Los Angeles, CA.
NNTP-Posting-Host: smaug.West.Sun.COM

ted@physics3 (Emory F. Bunn) writes:
>Even taking into
>account the fact that this is a very rough calculation, that seems
>hard to believe.  It's significantly better than the best ground-based 
>telescopes, which get about 0.5 arc-second resolution on a good day.  
>Naively, one would expect those two resolutions to be comparable,
>since they're both limited by "seeing" (atmospheric turbulence).

Atmospheric seeing effects instruments looking up more than those looking
down because most of the air which causes the blurring is closer to the
former.

Consider a cone of light going from a source to a telescope.  The apex
of the cone is at the source, and the base is the objective of the scope.
To determine seeing, you need to know how much the wavefront is deformed
as it reaches the scope.  With a telescope which is looking up, the wide
part of the cone is deep in the atmosphere, and the light travel time
can be substantially different through the different air masses.  On the
other hand, when looking down, it is the narrow part of the cone which
is deep in the atmosphere.  All the light passes through essentially the
same air masses, so the travel time is comparatively constant.  By the
time the light diverges far apart at the wide end of the cone, the air
is too thin to make much difference.

Richard M. Mathews			Lietuva laisva = Free Lithuania
Internet:   richard@locus.com		Brivu Latviju  = Free Latvia
UUCP:	    ...!uunet!lcc!richard	Eesti vabaks   = Free Estonia
MIL/BITNET: richard%lcc@UUNET.UU.NET	        WE  DID  IT!!!
From: bwood@diva.Berkeley.EDU (Blake Philip Wood)
Newsgroups: sci.physics
Subject: Re: ELECTRON HELIX : ITS POWER AND POSSIBLITIES
Date: 3 Sep 1992 14:14:16 GMT
Organization: /etc/organizaton
NNTP-Posting-Host: diva.berkeley.edu

In article <1992Sep2.135558.7756@murdoch.acc.Virginia.EDU> crb7q@kelvin.seas.Virginia.EDU (Cameron Randale Bass) writes:

>>You can't accelerate with a magnetic field; F = Q V x B.
>
>     "Particles within a stochastic - or chaotic - web in 
>     phase space can be accelerated to high energies even by
>     weak magnetic fields."  A.A. Chernikov /etal, Nature 326:559 (1987).
>
>                              dale bass

Read Chernikov's article a bit more closely - it is the interaction of the
B-field with an oscillating perpendicular E-field that produces the stochastic
web.  The web forms when there is a resonance between the gyromotion and the 
frequency of the E-field.  In effect, the acceleration is provided by the 
E-field.  The B-field simply brings the particle around for repeated kicks.

See also A.J. Lichtenberg and B.P. Wood, Phys Rev A, (39) 2153 (1989) for 
a synopsis.



-- 
                 Blake P. Wood - bpw@ctxsys.lanl.gov (505) 665-6524
                 Group P-1, MS-E526, LANL, Los Alamos, NM  87545

Newsgroups: sci.physics
From: barry@arnold.math.ucla.edu (Barry Merriman)
Subject: Re: Report on Philosophies of Physicists
Organization: UCLA, Mathematics Department
Date: Fri, 28 Aug 92 13:57:58 GMT

In article <1992Aug28.083903.10804@u.washington.edu>  
billiksh@milton.u.washington.edu (Shoshana Billik) writes:
> 	Anyhow, as a result of doing this survey and thinking about the 
> responses, I have come up with a career goal for myself: to be a philosopher 
> and to teach philosophy of science, metaphysics, and general philosophy to 
> college students.

Oh my god, what have we done!

I didn't fill out you survey, as I thought the questions were all 
slanted towards the self-serving, mystical view of physics so favored
by new agers but so removed from anything really to do with physics.

But, I'd think that if you learned anything from the survey, it
would have been that this mushy, warm fuzzy philosphy is not the
way to understand nature. You should be distressed by the way 
philosophical tracts such as the Tao of Physics and Dancing Wu-Li 
Masters have warped physics to fulfil some philosphical need, and
sucked you into their fantasy. I can't believe you want to follow
in their footsteps.

Why not become a _real_ scientist, instead of an intellectual gadfly.
I take it you're at U of Washington? Take my advice (I went there 
10 years ago, BS Math, BS Phys): run on over to the physics dept, 
and stay away from the philosphy dept. The more you learn, the more you will be  
glad you did.

(I took plenty of philosophy courses---easy way to fulfil humanities
requirements...:-)


--
Barry Merriman
UCLA Dept. of Math
UCLA Inst. for Fusion and Plasma Research
barry@math.ucla.edu (Internet; NeXTMail is welcome)
From: jac@ds8.scri.fsu.edu (Jim Carr)
Newsgroups: sci.physics
Subject: Re: Axiom of Physics
Date: 31 Aug 92 14:40:37 GMT
Reply-To: jac@ds8.scri.fsu.edu (Jim Carr)
Organization: SCRI, Florida State University

In article <mcirvin.715198792@husc8> mcirvin@husc8.harvard.edu (Mcirvin) writes:
>jac@ds8.scri.fsu.edu (Jim Carr) writes:
>
>>A better example than the one discussed in this thread, the conservation 
>>laws, might be the axioms of QCD.  Here one states that the interaction 
>>between quarks is governed by the generators of the mathematical "group" 
>>known as SU(3), with an empirical coupling constant, and procede to 
>>derive or compute the properties of protons etc etc and compare them 
>>to experiment.  
>
>If only this could actually be done!  In QCD today, there are usually
>a large number of extraneous assumptions that have to be made  ...  

What ! <he says tongue in cheek> I thought that QCD was the perfect 
theory and the standard model explained *everything*.  

Of course the low energy sector has not been solved yet, but the high-Q^2 
does work well even if you have to use models for the hadronization 
problem.  Note that I said "procede to" -- I never intended to imply that
it had been completed.

>                 ....                          It's interesting that
>the gauge groups that have been incorporated into the standard model 
>(SU(3), SU(2), and U(1)) are all groups that originally came up in
>different physical contexts (hadron flavors, spin, and nonrelativistic 
>wave functions, respectively).  

They, and others (including ones explored for GUTs), also came up in 
other physical contexts in nuclear physics (rotational and vibrational 
models, triaxial nuclei, etc) as well as materials physics. 

--
J. A. Carr                                    |  "The New Frontier of which I  
jac@gw.scri.fsu.edu                           |  speak is not a set of promises
Florida State University  B-186               |  -- it is a set of challenges."
Supercomputer Computations Research Institute |   John F. Kennedy (15 July 60)
Newsgroups: sci.physics
From: barry@arnold.math.ucla.edu (Barry Merriman)
Subject: Re: Misner et al.
Organization: UCLA, Mathematics Department
Date: Thu, 3 Sep 92 03:58:29 GMT

In article <1992Aug31.222201.23107@galois.mit.edu> jbaez@riesz.mit.edu (John C.  
Baez) writes:
> 
> As Segal has said of the University of Chicago, "It's not very good -
> it's only the best there is." 

Very true! (Phd, Chicago, 1989 :-)

>This may no longer be true of MTW; I like
> Wald quite a bit.  But when it came out I think it was true.  

I took Walds class at UC out of his book when it first came out.
Great book, and he's a pretty good teacher, too. He gets
you all the way up to speed in GR in < 100 pages, including introductory
material on SR and geometry.

--
Barry Merriman
UCLA Dept. of Math
UCLA Inst. for Fusion and Plasma Research
barry@math.ucla.edu (Internet; NeXTMail is welcome)


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: Sun, 30 Aug 1992 21:22:56 GMT

In article <10506@sun13.scri.fsu.edu> jac@ds8.scri.fsu.edu (Jim Carr) writes:
>In this sense, you cannot split a photon since it has no constituent 
>parts; a photon is an elementary particle.  

But Daddy, why are some photons bigger than others?

				--Blair
				  "And why are some cans of worms
				   more dead worms than live ones?"
From: Richard.Mathews@West.Sun.COM (Richard M. Mathews)
Newsgroups: sci.physics
Subject: Re: My son would like to know about photons...
Date: 31 Aug 1992 15:29:45 -0700
Organization: Sunsoft Inc., Los Angeles, CA.
NNTP-Posting-Host: smaug.West.Sun.COM

bhoughto@sedona.intel.com (Blair P. Houghton) writes:
>But Daddy, why are some photons bigger than others?

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.

     Richard M. Mathews			Lietuva laisva = Free Lithuania
					Brivu Latviju  = Free Latvia
Richard.Mathews@West.Sun.COM		Eesti vabaks   = Free Estonia
					        WE  DID  IT!!!
From: cbettis@unlinfo.unl.edu (clifford bettis)
Subject: Re: Axiom of Physics
Organization: University of Nebraska - Lincoln
Distribution: na
Date: Fri, 28 Aug 1992 13:43:01 GMT


How about these as axioms for physics: Properly done experiments yield
reproducible results (boy, that's a loaded one: imagine trying to 
precisely define an "experiment" or "result"); or the laws of physics 
should be expressed in a mathematical form and physical law should be 
subject to experimental test.
Cliff Bettis
Newsgroups: sci.physics
From: popetz@ux1.cso.uiuc.edu (Clinton C. Popetz)
Subject: Re: E=MC^2
Organization: University of Illinois at Urbana
Date: Mon, 31 Aug 1992 11:07:46 GMT

Eric_S_Klien@cup.portal.com writes:

>What is one gram of matter equal to in energy?  In other words, how 
>do you figure out E = MC^2?
> 
>                                                         Eric Klien

If you can REALLY get the entire gram of whatever you are talking about to
turn into energy, you get:

			9e13 Joules.  

Just get your units right, and you're ok.  
(i.e.  if you use .001 kg, use c=3e8 m/s and your answer is in Joules)

I hate units.

"The '1 over 4 pi e not' is there because the coulomb is a fundamentally
 stupid unit of charge."		
				-My Special Relativity Prof

|^^^^^^^^^^^^^^^^^^^^^^^^|^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^|
|    Clinton C. Popetz   | "I want to know how God created the world.  I am   |
| popetz@ux1.cso.uiuc.edu|  not interested in this or that phenomenon, in the |
|    The University of   |  spectrum of this or that element; I want to know  |
|         Illinois       |  his thoughts; the rest are details."              |
|     Champaign-Urbana   |                    -A. Einstein                    |
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
From: de5@ORNL.GOV (Dave Sill)
Newsgroups: sci.physics,sci.environment,misc.consumers
Subject: Re: Radioactivity and Superstition; was: Re: Are Your Light Bulbs Radioactive?
Date: 2 Sep 92 17:25:49 GMT
Organization: Oak Ridge National Lab, Oak Ridge, TN

In article <1992Aug29.000626.16080@u.washington.edu>, whit@milton.u.washington.edu (John Whitmore) writes:
>In article <l9ns6oINNmol@utkcs2.cs.utk.edu> de5@ORNL.GOV (Dave Sill) writes:
>
>>Few of which are radioactive, since most folks don't have concentrated sources
>>laying around their house...unless they have smoke detectors or compact
>>flourescents.  Which is *exactly* the point the originator of this thread was
>>trying to make.  Radioactivity *is* a different kind of threat than most
>>parents are used to dealing with. 
>
>	This is not true; ALL organic foods are radioactive (carbon-14,
>remember?), and potassium contains 0.01% of K-40... so an eight-year-old
>child (just about hammer-wielding age) has a 'safe and adequate'
>recommended dietary intake of circa 1 gram of potassium per day...
>which comes to about two microcuries.

Which of my statements is not true?  Do you consider organic foods
concentrated sources of radioactivity?  I think they are only in the literal
sense, i.e., they're more radioactive than air or water.  But if they are as
concentrated as the sources in smoke detectors and compact fluorescents, why
don't the manufacturers just use a chunk of cucumber and remove the warning
label?

-- 
Dave Sill (de5@ornl.gov)	   For every Bill Joy there is a Kirk McKusick.
Martin Marietta Energy Systems     For every Bill Gates there is a Richard
Workstation Support                Stallman.                     --Paul Graham
Xref: sparky sci.physics:14115 sci.math:11009 sci.logic:1349
From: baez@ucrmath.ucr.edu (john baez)
Newsgroups: sci.physics,sci.math,sci.logic
Subject: Re: Report on Philosophies of Physicists
Date: 4 Sep 92 18:52:12 GMT
Followup-To: sci.physics
Organization: University of California, Riverside

In article <5261@tuegate.tue.nl> johan@blade.stack.urc.tue.nl (Johan Wevers) writes:
>barry@arnold.math.ucla.edu (Barry Merriman) writes:
>
>>The above is all at the most metaphorical level. Is there any situation
>>in the experience of the Eastern philosophers in which boolean logic 
>>was strictly violated? (I.e. a situation precise enough to be
>>cast into predicate logic, in which the logical operators did
>>not work properly). I think not. Therefore we conclude they were
>>either very interested in non-logical modes of thought, or they
>>incorrectly understood what boolean logic was (quite likely).
>>
>>What this has to do with QM is not clear to me.
>
>In QM, you often can't answer a question with `true' or `false'.
>In the case of the double slit experiment, you know that the electron
>has a chance of 1/2 to pass each slit, but you can't tell through which
>slit it went.

Yes, you can.  Just stick some measuring apparatus right behind one
slit.  The point is that you can't find out the answer to this question
while also finding out the answer to other "complementary" questions
corresponding to non-commuting projections.

>Some people invented quantum logic: a 3 valued logic. 

This logic, due to Lukaiewicz (spelling wrong no doubt), is not what
people refer to as quantum logic.  Quantum logic is much more
interesting than just "true/false/maybe".  It uses a nondistributive
lattice.  That is, "and" does not distribute over "or" (and vice versa)
the way it does in Boolean logic.  For a good intro to this check out
Jauch's "Foundations of Quantum Mechanics" (rough title).   There is a
lot that has been done on this.