HDTenEightyP/NetNews huggingface dataset:
From: ted@physics.Berkeley.EDU (Emory F. Bunn)
Newsgroups: sci.physics
Subject: Re: How old is the universe?
Date: 27 Sep 1992 06:09:35 GMT
Organization: /etc/organization
NNTP-Posting-Host: physics.berkeley.edu

In article <17584@ucdavis.ucdavis.edu> carlip@landau.ucdavis.edu (Steve Carlip) writes:
>In article <19tid9INNo1h@agate.berkeley.edu> ted@physics.Berkeley.EDU (Emory F. Bunn) writes:
>>[much deleted...]
[more deleted...]
>> What bothers me about
>>this is that there is no natural measure one can impose on the set
>>of possible initial conditions for Universes in order to make that
>>statement meaningful.
>>[...]
[more deleted...]
>
>If I understand you correctly, you are claiming that there is no
>possible measure on the space of three-geometries (or maybe
>three-geometries plus initial configurations of matter fields).
>This seems unlikely to me; do you have a proof or a reference?
>Would you argue that a path integral is impossible in principle
>in general relativity, for instance?
>

I was making the assertion you attribute to me, and I made it with
more confidence than I probably should have.  I believe, based on my
admittedly limited understanding of measure theory, that the space
of 3-geometries is simply "too big" to admit a well-behaved measure
that would allow one to talk about probabilites.  (I have formed
some vague arguments in my mind in support of this position,
but they're far from being rigorous enough to convince anyone else.)

I hope that I am wrong about this, as I think it would be very nice 
to have such a measure.  Is there anyone out there who can be more 
definitive about this than I can?

-Ted

(By the way, I think that path integrals are pretty ill-founded
in ordinary quantum field theory, so I am not too sanguine
about applying them in GR.  That's another story, though.)
From: matt@physics10.berkeley.edu (Matt Austern)
Newsgroups: sci.physics
Subject: Re: Feynmann diagrams
Date: 4 Oct 92 10:42:43
Organization: Lawrence Berkeley Laboratory (Theoretical Physics Group)
Reply-To: matt@physics.berkeley.edu
NNTP-Posting-Host: physics10.berkeley.edu
In-reply-to: brahm@cco.caltech.edu's message of 3 Oct 1992 06:29:47 GMT

In article <1ajekrINNn5b@gap.caltech.edu> brahm@cco.caltech.edu (David E. Brahm) writes:

> I just acquired FeynArts and FeynCalc by anonymous ftp to 131.225.10.4, in
> directory pub.  These are packages for Mathematica 2.1; the former
> constructs Feynman diagrams, and the latter calculates them.  I haven't
> gotten to try them yet, but I'm told they're great, sure to be a big hit
> with the kids this Christmas!

Presumable "Feynman diagrams" here means tree-level diagrams with a
small number of particles in the final state?  I'd be *very* impressed
with a Mathematica program that could calculate the four-loop
contribution to the muon anomalous magnetic moment!
--
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!
From: markrose@spss.com (Mark Rosenfelder)
Newsgroups: sci.physics
Subject: Re: Make time stop?
Date: 30 Sep 92 00:04:23 GMT
Organization: SPSS Inc.

In article <1992Sep29.171040.26549@hellgate.utah.edu> tolman%mindblow.cs.utah.edu@cs.utah.edu (Kenneth Tolman) writes:
>  A frame of reference moving very very fast has a time dilation, correct?
>(That is, if we are still and looking at someone moving they are "slow")
>When we look out into the universe- all galaxies are moving away from us,
>and the very far away galaxies are moving near the speed of light.

So far so good.  When you look into the night sky, you're looking into 
the past-- a few years ago for the nearby stars, a few billion years ago
for distant galaxies.

>Therefore, THEIR TIME HAS BARELY BEGUN.  Their civilization's have not 
>started, and they live in a "young" universe.  

Whoops, no.  It's true that we see Andromeda as it was two million years 
ago.  But it's not that Andromeda is stuck in the past.  It continues to
exist, in the present; it's just that our news from there is two million 
years out of date.

>Thus, if we could travel
>faster than light, we could jump backwards and live this whole universe
>through once again.  

No; even if you could travel instantaneously, you could only arrive in
the Andromeda of today (whose light won't reach us back on Earth for two
million years), not the Andromeda we see (that of two million years ago).
Newsgroups: sci.physics
From: chungy2@aix.rpi.edu (Yau Felix Chung)
Subject: Books for sale
Organization: Rensselaer Polytechnic Institute, Troy, NY
Date: Sat, 3 Oct 1992 19:37:33 GMT

				BOOK SALE!!



Through The Telescope by Michael R. Porcellino (hard cover)........$14.00              
Local Area Networks: The Next Generation by Thomas W. Madron.......$20.00           
Surface Physics by M. Prutton......................................$13.00

The Boundary Value Problems in Mathematical Physics by 
	O. A. Ladyzhenskaya (hard cover)...........................$52.00           
The Physcis of Structurally Disordered Matter: An Introduction
	by N. E. Cusack............................................$60.00           
Subatomic Physics by H. Frauenfelder & E. M. Henley (hard cover)...$57.00           
Applications of Group Theory in Physics and Mathematical Physics
	by M. Flato, P. Sally & Gregg Zuckerman (hard cover).......$70.00             
A First General Relativity by Bernard F. Schutz (hard cover).......$20.00                 


	* All prices are negociable
	* Shipping charges are paid by buyer

		If interested please e-mail chungy2@aix.rpi.edu
From: jbaez@riesz.mit.edu (John C. Baez)
Newsgroups: sci.physics
Subject: Stocklmeier's Misdirected Taunts
Date: 29 Sep 92 19:05:06 GMT
Followup-To: alt.flame
Organization: MIT Department of Mathematics, Cambridge, MA

In article <1992Sep29.003556.3472@sjsumcs.sjsu.edu> b5249-23@mathcs.sjsu.edu (Kurt Stocklmeir) writes:
>John Baez
> his article

>You must be doing a lot of homework at MIT.  By the time you get
>out, you will be worn down and not ever be able to do any good research.

Sorry, pal, I'm not doing any homework at MIT, I already flunked out,
and I'm just hanging out here bumming quarters from students at 77 
Mass. Ave..   I like sneaking into the computer room and reading
sci.physics late at night.

Seriously, you should beware ad hominem arguments in physics.  For one,
they don't prove anything.  Moreover, when you don't know who you are
making fun of, they can backfire rather amusingly.
From: Gordon_Wong@mindlink.bc.ca (Gordon Wong)
Newsgroups: sci.physics
Subject: Re: RESONANT AIR COLUMN EXPERIMENT
Date: 26 Sep 92 15:22:55 GMT
Organization: MIND LINK! - British Columbia, Canada
Distribution: world

> Jim Carr writes:
>
> In article <246@mindlink.bc.ca> Gordon_Wong@mindlink.bc.ca (Gordon Wong)
> writes:
> >My question: Which (the fundamental, the 1st overtone, or the 2nd overtone)
> >would yield the more accurate value for the wavelength; or does it matter?
>
> Good question.  Your experiment should help you answer it.
>


Experiments show that the results using the 2nd overtone result in a more
accurate value for the wavelength and thus the speed of sound. I am just
wondering why. My guess is that somehow with a longer tube length, the
correction plays less of a factor?????


Newsgroups: sci.physics
From: jcf@world.std.com (Joseph C Fineman)
Subject: Re: Poynting power flux wrong?? 
Organization: The World Public Access UNIX, Brookline, MA
Date: Sun, 4 Oct 1992 03:44:44 GMT

A. Satish Pai <Pai-Satish@CS.Yale.Edu>  writes:

>In what form is the energy circulating, then? Are the fields in motion even
>though they are being maintained by static sources? If not, what is moving? 
>Are the potentials time-varying? Are there any photons corresponding to this
>energy flux? Can the energy circulation be detected by any means?  

It has been a long time since I studied this, and I don't follow a lot of
the discussion below.  However, it is perhaps worth saying that I did not
imagine the e&m *fields* to be in motion.  It is not even clear what that
would mean.  What is circulating, if anything, is a sort of ghostly,
abstract *energy* that pervades the space.  It would seem that only
suitable integrals of this flux can be measured.  It is, however, very
cute, not to say startling, that one of them, namely the one for the
angular momentum, gives the right answer -- and that this angular momentum
is hidden in the sense that it is nonzero in a system in which nothing is
moving.  Marianne Moore demanded that poets produce "imaginary gardens with
real toads in them", but it appears that physicists can do the trick too.

%^)  Joe  jcf@world.std.com
From: JCJ@mailbox.bison.mb.ca (JCJ)
Newsgroups: sci.physics
Subject: Re^2: hanna-maria1.gif (01/03)
Date: 24 Sep 92 13:56:17 CST

Organization: Huh?

In article <1992Sep22.082704.1@tnclus.tele.nokia.fi> hporopudas@tnclus.tele.nokia.fi writes:
>
>  These unbusinesslike kind of comment does not belong to sci.physics or
>  sci.astro. Try to concentrate yourself to the model proposed.
>

Actually, Hannu, your space potato and Hanna-Maria's "divine"
inspirations belong in something like alt.newage.science or a similar 
group.  I will now follow Scott's (I think) advice...

 * Origin: The Electronic Mailbox (1:348/7.0)
From: phillies@wpi.WPI.EDU (George D. Phillies)
Newsgroups: sci.physics
Subject: tenure-line faculty position
Date: 1 Oct 1992 20:51:23 GMT
Organization: Worcester Polytechnic Institute
Distribution: world
NNTP-Posting-Host: wpi.wpi.edu

The following will appear in the October and November issues of
Physics Today.  I am prepared to answer questions about this
position.  However, applications for the position must be sent
by paper mail to Professor S. N. Jasperson at the address given below.

 *George Phillies*
Professor of Physics
phillies@wpi.wpi.edu


                  TENURE-TRACK FACULTY POSITION
                 WORCESTER POLYTECHNIC INSTITUTE

A tenure-track faculty position (rank open) in condensed matter physics, 
optical physics or in physics pedagogy is available in the WPI Physics 
Department as of August 1993.  The successful candidate is expected to 
establish an externally funded research program that complements ongoing 
WPI research or that addresses the teaching of physics.  Ongoing 
research includes experimental areas 1) Brillouin scattering and 
semiconductor superlattice spectroscopy (D. F. Nelson); 2) photon 
correlation spectroscopy and complex fluids (G. D. J. Phillies); fiber 
optics and optical properties of impurity ions in solids (R. S. Quimby); 
and theoretical areas 1) quantum optics of squeezed states (P. K. 
Aravind); 2) quantum statistical mechanics of glassy materials (M. W. 
Klein): 3) linear and nonlinear optical properties of quantum 
semiconductor heterostructures (L. R. Ram-Mohan).  Postdoctoral research 
and teaching experience will be valued.  Candidates are expected to have 
a supporting record of research publication.  WPI has a tradition of 
excellence in project-based undergraduate education: thus, candidates 
must be committed to undergraduate research projects as well as to 
undergraduate and graduate teaching.  Applicants should send a c.v., 
publication list, and letter describing teaching interests and research 
plans at WPI.  Also, they should arrange for three letters of 
recommendation, one or more addressing teaching as well as research 
credentials, to be sent to S. N.  Jasperson, Head, Department of 
Physics, Worcester Polytechnic Institute, Worcester, MA 01609.  All 
materials are due by January 8, 1993.  EOE/AA.  Women, minorities and 
others are encouraged to apply.
From: crb7q@kelvin.seas.Virginia.EDU (Cameron Randale Bass)
Newsgroups: sci.physics
Subject: Re: Mattel protest
Date: 5 Oct 92 16:24:55 GMT
Distribution: usa
Organization: University of Virginia

In article <1992Oct5.082935.7423@news.nd.edu> jmorzins@grumpy.helios.nd.edu (jacob morzinski) writes:
[all sorts of stuff deleted]
>From: Kevin Niles Reed <reed@owlnet.rice.edu>
>
>I promise.  I called.  They really are making such a doll.
>PLEASE call and bring these people back to the real world.
>----------------------------Original message----------------------------
>
>Regarding the message below, I called the number given, and they con-
>firmed that a doll REALLY is being made which says "math class is tough"
>PLEASE, call and register your complaint.  They really do count.
>Ashley Reiter
>----------------------------Original message----------------------------
>
>This is an outrage.  I just received it over the net this morning.
>We all know better than most how hard it is for women in math and
>scinece as it is.  Act upon this if you so desire.
>
>Date: Wed, 30 Sep 92 11:41:15 -0400
>
>Dear Courant Community and Friends:
>
>        Mattel has just released a new product. A Barbie doll that says
>"Math is tough".
>
>        This thoughtless attack on mathematics education in general and
>women in particular should not be allowed to happen without a significant
>protest from the mathematics and scientific community.
>
>        Do not assume that corporate actions like these are final and
>that your voice means nothing. Every complaint made over the telephone
>lines is recorded and every complaint received by mail is collected
>by the Consumer Affairs Division. I was informed that many people
>have already voiced their upset.  Let's continue letting Mattel know
>that their thoughtlessness treatment of our young people and science
>will not be tolerated.
>
>        Please call and write lodging your dissatisfaction with Mattel's action.
>Joe Juliano
>Associate Director for Administration

     I take it then that y'all did not find math to be tough?

                               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
Subject: Re: TIME TRAVEL 5
From: mcirvin@husc8.harvard.edu (Mcirvin)
Date: 2 Oct 92 23:06:45 GMT

matmcinn@nuscc.nus.sg (Mcinnes B T (Dr)) writes:

>The worst thing about closed timelike worldlines is that you have to
>read the same crazed articles in sci.physics again and again.

That's why I've invented the Faster-Than-Light Anticausal Killfile!
It also kills threads that haven't even begun yet, and eliminates
crossposting along spacelike intervals!

-- 
Matt McIrvin, posting nonsense again
From: pk03+@andrew.cmu.edu (Paul Karol)
Newsgroups: sci.physics
Subject: Re: Can you figure this joke out?
Date: 5 Oct 92 10:19:59 GMT
Organization: Chemistry, Carnegie Mellon, Pittsburgh, PA

It's an ancient pun...Sex=f(un).

{It's an experimentalist's joke.  Theorists won't get it.]
From: matmcinn@nuscc.nus.sg (Mcinnes B T (Dr))
Newsgroups: sci.physics
Subject: TIME TRAVEL 5
Date: 28 Sep 92 08:10:00 GMT
Organization: National University of Singapore

The worst thing about closed timelike worldlines is that you have to
read the same crazed articles in sci.physics again and again.
From: matmcinn@nuscc.nus.sg (Mcinnes B T (Dr))
Newsgroups: sci.physics
Subject: Re: TIME TRAVEL 4
Date: 28 Sep 92 08:12:35 GMT
Organization: National University of Singapore

sarfatti@well.sf.ca.us (Jack Sarfatti) writes:
: 
: 
: THE TIME TRAVELLER'S HANDBOOK 4
: 
: 14.	"If time travel is possible, it will certainly mean
: abandoning some cherished beliefs about the nature of
: reality - but it won't be the first time physicists have
: had to do that in the past hundred years." p.185
: 
: 15.	"Causality is a hypothetical law that says that causes
: always precede their effects. ... there is actually nothing
: in the laws of physics that requires causality to be
: true."p.186
: 
: 16.	"The most worrying aspect of this resolution of the granny
: paradox is the extent to which it seems to remove our
: capacity for free will and truly independent action." p.187
: 
: 17.	Sarfatti Commentary: It is the apparent loss of free will,
: inherent in the teleological conjecture of the creation of
: history from the future by the nonlocal top-down quantum
: forces of destiny, that so enrages critics of the boswell
: set.
: 
: 18.	Precognitive remote viewing in the military operations of
: the First Crusade : "he was called ... R. Salomon ha-
: Zarfati (the Frenchman) by Jews outside of France ... p.33
: RASHI by Maurice Liber translated by Adele Szold for Jewish
: Publication Society 1906 "I see," Godfrey said to him,
: "that thy wisdom is great. I should like to know whether I
: shall return from my expedition victorious, or whether I
: shall succumb. Speak without fear." "Thou wilt take the
: Holy City, " Rashi replied, 'and thou wilt reign over
: Jerusalem three days, but on the fourth day the Moslem will
: put thee to flight, and when thou returnest only three
: horses will be left to thee." "It may be," replied Godfrey,
: irritated and disillusioned in seeing his future pictured
: in colors so sombre. "But if I return with only one more
: horse than thou sayest, I shall wreak frightful vengeance
: upon thee. I shall throw thy body to the dogs, and I shall
: put to death all the Jews of France!" Well what do you
: think happened? Tune in to the next episode of THE TIME
: TRAVELLER'S HANDBOOK at this computer terminal soon!
: 
: 
I'm sorry, we read all about it next year; consequently all subsequent
installments are entirely superluminally superfluous.



: 
: 
: 
Newsgroups: sci.physics
From: dooley@helios.physics.utoronto.ca (Kevin Dooley)
Subject: Re: Top 10 List (was Re: Another Cute Math Joke)
Organization: University of Toronto Physics/Astronomy/CITA
Date: Sat, 3 Oct 1992 17:35:23 GMT

I actually once used the excuse upon being late for relativity class
that when I realized that it was almost time for class I ran very very 
fast to get to the physics building and now, despite what the clock on
the wall may say, the time on my watch says that I am early.  Needless
to say, the prof didn't believe me.  He pointed out that I should have
been out of breath!

K
Xref: sparky sci.physics:15819 sci.astro:10357
From: carlip@landau.ucdavis.edu (Steve Carlip)
Newsgroups: sci.physics,sci.astro
Subject: Re: Expansion
Date: 2 Oct 92 20:26:32 GMT
Followup-To: sci.physics
Organization: Physics, UC Davis

I'm cross-posting to sci.astro in the hope that some cosmologist who's
more up-to-date on the current literature can help out.  The question
being discussed in sci.physics --- surely a FAQ somewhere ---  is 
whether a small gravitationally bound system experiences the expansion 
of the universe.

In article <Sep.29.16.54.08.1992.28530@ruhets.rutgers.edu> bweiner@ruhets.rutgers.edu (Benjamin Weiner) writes:
>ynecgan@cid.aes.doe.CA writes:
>[...]
>I think a usual rule of thumb is that if a system is [in the Newtonian
>gravitational approximation] gravitationally bound, it's not
>correct to apply the simple expansion-of-space rule to it.

I've heard this rule of thumb, but my impression is that there are still
some open questions.  My reference is Ellis and Stoeger, "The 'fitting
problem' in cosmology" (Class. Quantum Gravity 4 (1987) 1697).  The
problem their title refers to is that of fitting together a small scale,
"lumpy" solution of the field equations of general relativity and a
large scale, smooth cosmological solution.  The have a section that
specifically discusses the effect of cosmological expansion on local
physics, and basically answer, "we don't know."  (In their approximation,
there is an effect, but they cite other authors with different
approximations and different results.)  The issue is confusing because
you have to separate out real physics from coordinate-dependent effects,
but there are certainly invariant questions that can be asked (e.g., do
circular orbits close?)

My reference is five years old, though, and I imagine there has been more
recent work.  I know that Ellis and Stoeger have written papers on their
program since then, but it's outside my field, and I haven't kept up.
Does anyone have more recent results?

Steve Carlip
carlip@dirac.ucdavis.edu

Newsgroups: sci.physics
From: terry@aslws01.asl.dl.nec.com (Terry Bollinger)
Subject: Re:  Simple observation about Quantum Kitty Cats
Organization: NEC America, Inc. Irving, Texas
Date: Tue, 29 Sep 1992 06:22:15 GMT

Howdy howdy,

In article <1992Sep28.214420.18300@galois.mit.edu>
jbaez@riesz.mit.edu (John C. Baez) writes:

> In article <1992Sep27.073401.3486@asl.dl.nec.com>
> terry@aslws01.asl.dl.nec.com (Terry Bollinger) writes:
>
> | Again my question to MWI advocates:  Does MWI say *anything* at all that
> | has the courtesy of being testable in *any* conceivable fashion?  If not,
> | how can you seriously claim the MWI to have any meaning?
>
> The thing about "interpretations of QM" is that for the most part
> they are not really physical theories...  Indeed, most of the decent
> interpretations of QM are designed to be "operationally equivalent..."

Wasn't really banging on you, Dr. Baez.  You've stated the value of the
Everett formalism (vs. MWI) several times, and stated it well.

.....

How about the non-trivial issue in my same email -- that is, whether
my quantum/non-quantum bullet analysis is correct or not?  Anyone?

				Cheers,
				Terry
From: pug2@quads.uchicago.edu (mary claire pugh)
Newsgroups: sci.physics
Subject: Darcy's Law--when does it apply?
Date: 28 Sep 92 02:07:21 GMT
Reply-To: pug2@midway.uchicago.edu
Organization: University of Chicago Computing Organizations


I was wondering under what conditions Darcy's law is a good
approximation for fluid flow.

I know that it's used for fluid flowing through a porous medium.
And wasn't it invented to explain how to construct fountains in
public parks?  

If you know of any systems other than porous medium flow that 
use Darcy's law, and you have the time and inclination to tell
me about them, could you send me email?

Thanks!
Mary
mary@math.uchicago.edu
Newsgroups: sci.physics
From: jbaez@riesz.mit.edu (John C. Baez)
Subject: Re: Understand...!!!!
Organization: MIT Department of Mathematics, Cambridge, MA
Date: Tue, 6 Oct 92 17:16:02 GMT

In article <1992Oct05.135406.24173@cubic.com> hees@cubic.com (Phil Hees) writes:
>Interesting.  I think Einstein would have disagreed with you.  In fact, if
>memory serves me correctly, he himself once said that "Time is that which
>a clock measures."  (Granted, this is an argument by appeal to authority,
>but I don't think that such tactics are entirely without merit when the
>authority cited is _the_ authority.)

I thought it was Aristotle.  Anyway, yes, 

"Time is what clocks measure"

and

"Clocks are what measure time"

so if you know what one of these terms mean you figure out the other.

>Remember Mach's Principle.

Perfect sentence to launch McIness into another (accurate) diatribe
against this dubious principle.  

Newsgroups: sci.physics
From: ag206@yfn.ysu.edu (David Barzilai)
Subject: Physics project
Reply-To: ag206@yfn.ysu.edu (David Barzilai)
Organization: St. Elizabeth Hospital, Youngstown, Ohio
Date: Tue, 29 Sep 1992 19:45:40 GMT


Hello.  I am currently taking a first-year honors physics course in
which quarterly physics projects are required.  A am a highly motivated
student who is willing to invest as much time as necessary to make a
good project.  Unfortunately, I have been having trouble coming up 
with ideas for a project that does not require difficult to access lab
equipment, and yet is creative(novel) and challenging.  Any ideas you
have for such a project would be greatly appreciated.  Thank You,

-D.B.
Newsgroups: sci.physics,sci.math