HDTenEightyP/NetNews huggingface dataset:
Newsgroups: sci.physics


Hello sci.physics

I've been trying to formulate my thoughts and would like some
net.criticism concerning them. Here goes...

Consider a simple universe with only two particles contained therein:
Particles One and Two. Now One has charge +Q and Two has charge -Q, so
this universe is charge neutral. One has spin +1/2 and Two has spin -1/2,
so this universe is spin neutral. Both have the same rest mass M. Use a
frame of reference whose origin is coincident with the center of mass.
Impose an initial condition that these two are in a positronium ground
state configuration; the M, Q, and S are not necessarily those of electrons
and positrons.

Consider the evolution of this universe. The particles annihilate and
produce two photons with equal energy E, opposite spins +-1, and opposite
momentums +-P.

Now here's the result I desire: the photons' E is enough to bend space
closed. The photons orbit this space and collide produceing particles
exactly equivalent to the initial condition of particles One and Two.
Einstein's "The Meaning of Relativity" includes a description of a space
metric (I forget if it's Einstein's or De Sitters' Universe) which has the
property of a photon performing a closed orbit of a distance R in some
time T. A duo-photon black hole of sorts.

Is this possible mathematically, within the framework of GR and QED?

Can't hurt to ask,

--------------------------------------------------------------------
Ric Peregrino   c/o Hewlett Packard Co.    I represent only myself
ric@spd.hp.com  1501 Page Mill Rd Bldg 5M  I may be wrong, maybe not
415-857-7526    Palo Alto, CA 94304        Do DC photons exist?
--------------------------------------------------------------------
From: ethan@emx.cc.utexas.edu (Ethan T. Vishniac)
Newsgroups: sci.physics
Subject: Re: Speed of neutrinos
Date: 12 Jan 1993 09:02:11 -0600
Organization: The University of Texas at Austin, Austin, Texas
NNTP-Posting-Host: emx.cc.utexas.edu

The neutrino burst from SN 1987A arrived a few hours before the
star began to brighten.  This time delay is consistent with
supernova models.  Core collapse is the first stage in the
supernova.  The brightening of the star begins as the shock
reaches the photosphere.  I suppose the exact timing of
the delay can be fiddled with since these models are not
all that precise.  Still, the uncertainty in the exact
size of the delay couldn't be more than an hour. (I'd be
surprised if it's that large, but I'm trying to be generous.)
SN1987A was about 52 Kpc away. (I don't remember the latest estimate,
but this must be right to within about 10 per cent.)
This implies that if neutrinos travel at some velocity
systematically different from c then the difference amounts
to less than 1 part in 1.5x10^9.

Of course, this applies to neutrinos with energies of several
MeV (with a comparable spread).  Operating within standard
physics one can use the observed spread in arrival times
(several seconds) to set an upper limit on the mass of the
neutrinos.  Depending on who did the analysis one gets a 
limit between 10 and 20 eV.  Naturally the upper limit is
the one people take seriously.

This may be more than you wanted to know.
-- 
"Quis tamen tale studium, quo ad primam omnium rerum causam evehimur,
tamquam inutile aut contemnendum detractare ac deprimere ausit?"-Bridel
Ethan T. Vishniac, Dept. of Astronomy, The University of Texas at Austin
Austin, Texas, 78712                   ethan@astro.as.utexas.edu
Xref: sparky sci.physics:22534 sci.math:18003
From: wolf@doppel.first.gmd.de (Wolfgang Koehler)
Newsgroups: sci.physics,sci.math
Subject: Re: Ansatz (as used in mathematical physics)
Date: 12 Jan 93 00:17:31 GMT
Reply-To: wolf@first.gmd.de
Followup-To: sci.physics
Organization: GMD-FIRST, Berlin
In-reply-to: siegman@EE.Stanford.EDU's message of 11 Jan 93 02:51:32 GMT


Since I am a German I believe it's possible for me to throw my two pence
into this discussion.
"Ansatz" is really a german word and it is used eg. if you have an 
differential equation and chose some function to solve it (possibly
a good guess with some free parameters).
We use it especially as "Loesungsansatz" that is solution-"ansatz"
I think it is drifted into english science vocabulary like others,
eg. "eigen-value".

wolf


--
-------------------------------------------------------------------------
    ... always look on the bright side of life ... (Monty Python)
-------------------------------------------------------------------------
Wolfgang Koehler                               wolf@first.gmd.de
GMD-FIRST an der TU Berlin              German National Research Centre 
Tel. (Berlin 030/049) 6704-2650              for Computer Science
From: bweiner@ruhets.rutgers.edu (Benjamin Weiner)
Newsgroups: sci.physics
Subject: Re: knots and stat.mech.
Keywords: invariant polynomials, partition functions, knots
Date: 11 Jan 93 21:01:32 GMT
Organization: Rutgers Univ., New Brunswick, N.J.

srihari@sam.cchem.berkeley.edu (Srihari Keshavamurthy) writes:
>  ... Another question is that if you are describing
>a knotted system like say DNA or some such physical system then does the
>indep. variable in the knot polynomial correspond to some physical
>parameter? 

Knot to be obnoxious but I don't think DNA forms knots at all
(other than the trivial not-really-knotted forms).  Neither do
proteins, although the study of how proteins fold into their
complicated structures is an official Hot Topic right now, which
incidentally may involve a fair amount of sophisticated
statistical mechanics.  Anyone who knows more about protein folding
is invited to shed some light ...
From: dwr2560@zeus.tamu.edu (RING, DAVID WAYNE)
Newsgroups: sci.physics
Subject: Re: Okay, it's not the inverse sprinkler problem...
Date: 12 Jan 1993 22:47 CST
Organization: Texas A&M University, Academic Computing Services
Distribution: sci
NNTP-Posting-Host: zeus.tamu.edu
News-Software: VAX/VMS VNEWS 1.41    

schnitzi@cs.ucf.edu (Mark Schnitzius) writes:
>|> Suppose you are stopped in your car at a stop light.  In
>|> your rearview you see an approaching car that is moving
>|> too fast to stop -- it is going to plow into you.  You
>|> have just time enough to do one of two things -- apply
>|> the brake, or apply the clutch.  From a personal survival
>|> standpoint, which choice would be in your best interest?

Some thoughts:

1) You're already in neutral so the clutch doesn't do anything significant.

2) If the impact were instantaneous, the brakes would not help. In
fact they would not slow the car much within the first 1/10 sec. So
one should not expect them to reduce the initial impact even in realistic
cases.

3) Applying the brakes will push you hard forward after the impact, and
the steering wheel is not as soft as your seat.

4) If there is cross traffic to worry about the brakes are important.

5) Perhaps the most dangerous possibility is that your seat back will
collapse, allowing your neck to collide with the hard rear seat panel
which is sometimes being pushed toward you by the other guy's bumper.
(This is a common cause of paralysis). Pushing the brakes increases
the force against the seat back a little.

6) As you accelerate backwards (please no flames) you will be off
the brakes anyway. So the question may be moot.

7) If you have time to do that, you have time to lay across the front seat.

Dave Ring
dwr2560@zeus.tamu.edu
Newsgroups: sci.physics,alt.sci.physics.new-theories
From: jbaez@riesz.mit.edu (John C. Baez)
Subject: Re: sci.physics.research: proposed panel of moderators
Organization: MIT Department of Mathematics, Cambridge, MA
Date: Sat, 9 Jan 93 00:23:24 GMT

Mark Corscadden writes:

In article <1993Jan8.160818.19578@galois.mit.edu> jbaez@riesz.mit.edu
(John C. Baez) writes:
>...  We will be excluding such things as: *bian's
>endless thread, discussions of religion and politics (which threads on
>sci.physics often turn into), endless repeats of questions that are in
>the FAQ, re-re-rehashes of discussions ofthe interpretations of quantum
>mechanics, etc..

How did re-re-rehashes of the interpretations of quantum mechanics make
it's way onto the scrap heap?  How does eliminating such discussions fit
in with the goal of making sci.physics.research "lightly" moderated?
(No, I did not miss the "re-re-re" in "re-re-rehashes".)

-------
If folks - and especially the other moderators!! - think I've gone
overboard here, I would gladly recant, especially if we follow Corscadden's
suggestion and label quantum mechanics interpretation posts in such a
way as to make them easily kill-filed.  The general issue of threads
that endlessly chase their own tail is perhaps inadequately addressed in
Austern's proposal; I had the sense from discussions with moderators
that such threads would be discouraged... but maybe I was mistaken.
Newsgroups: sci.physics
From: steve@fulcrum.oz.au (Steve Taylor)
Subject: Re: TIME HAS INERTIA ABIAN'S LOUSY COMPLEX ANALYSIS 
Keywords: Not only does Abian mess up logic, he's hopeless with all math.
Organization: The Fulcrum Consulting Group
Date: Tue, 12 Jan 1993 01:40:35 GMT

tao@fine.princeton.edu (Terry Tao) writes:

[... lots of stuff about Abians demented logic ...]

>I await a refutation of all these above claims by Abian, or else a total
>withdrawal of him from sci.physics.

But deep in your heart, you know that neither will happen :)


							Steve
Newsgroups: sci.physics
From: palmer@sfu.ca (Leigh Palmer)
Subject: Re: Budding Physicist
Organization: Simon Fraser University
Date: Thu, 7 Jan 1993 23:50:42 GMT

In article <93007.112134BAV2@psuvm.psu.edu> <BAV2@psuvm.psu.edu> writes:
>You have a bright kid, howevere. It would be a shame if he will be
>spoiled by the rotten American education system

I've replied by mail to the original questioner. However I could not let this
comment pass unchallenged. There is nothing rotten about the American
educational system. I came through it as did most of the correspondents in this
newsgroup, and I don't think we were badly served at all. I infer from your
syntax and name that you did not, and that you are an immigrant to the United
States, just as I am an immigrant to Canada. The "system" here is also not
rotten, and it is substantially the same as that in the US. My children came
through the Canadian system and they were not spoiled, either.

The rot in this system probably resides much closer to home, among parents who
expect that the schools should do the full task of educating their children for
them. The person who asked the question originally is not such a parent, and I
expect his son will make out quite well, thank you.

The questioner is from a Canadian university, by the way, in case you had not
noticed.

Leigh
Newsgroups: sci.physics
From: bcr@cernapo.cern.ch (Bill Riemers)
Subject: Re: sci.physics.research: Important unresolved issues!
Organization: CERN, European Research Center for High Energy Physics
	<COLUMBUS.93Jan11100318@strident.think.com>
Date: Mon, 11 Jan 1993 23:21:18 GMT


One thing I should point out, is that much of this discussion
has taken place while people were away for the holidays.  When
I left, the idea was just first proposed, now I see that some
figure everything is worked out...  I for one would like to
know what exactly has been worked out!  For one thing, I 
gather that someone asked someone else to decide who to
recuite as moderators and he did just that.  From what I
seen posted, these people are well qualified and willing
should make good moderators.  However, before I left I 
remember several other people expressing an interest.  I
don't want to be hard to get along with, but shouldn't
we follow a democratic procedure?  Right now, I think
the list we have is adiquate to go ahead and create
the news group.  However, we need to decide on rules as
to how moderators will be determined and who will replace
who.

One idea that I think will work is:
  1. Post a list of candidates and qualifications.
  2. Each person votes for thier four favorite
     candidates.
  3. The four candidates with the most votes are 
     the moderators.
  4. When one of the moderators leave, repeat steps 1-3.

In this synopsis a candidate is anyone who accepts a
nomination, or volunteers.

Maybe the net already has rules to cover this?  I just 
feel like I we having something pushed that few of the
readers of this group actually understand.


                            Bill
--
"Yeti!  Saw them in the London Underground twenty years ago.  Ghosts!
A headless woman used to walk through my bedroom at midnight.  Mermaids?
Grandpa was rescued from the Marie Celeste by one.  Vampires?  I always
wondered where my dad went to at night.  Telepathy?  Right now you're
thinking that I'm talking crap.  So what can you tell me that I won't
believe in?" - Andrew Hunt, "CAT'S CRADLE: WITCH MARK"
From: leffler@physics.ubc.ca (Steve Leffler )
Newsgroups: sci.physics
Subject: Re: Accellerating Spaceship (yet another bird in a plane)
Date: 12 Jan 1993 23:47:37 GMT
Organization: The University of British Columbia
Distribution: world
NNTP-Posting-Host: physics.ubc.ca

ynecelc@sx.mont.nec.com (Ellison Chan) writes:

>In article <6850@tuegate.tue.nl> johan@blade.stack.urc.tue.nl (Johan Wevers) writes:
>>jdsiegel@garnet.berkeley.edu (Joel Siegel) writes:
>>
>>Yes, if it was true. But matter with a negative mass would react just
>>the same as matter with a negative electrical charge. 2 negative
>>{charged or mass} particles attract each other, 1 negative and one positive
>>{charged or mass} particle repulse each other. And negative electricity
>>doesn't give you a perpetual motion :-(

>As a matter of fact, there is such a natural occurence.
>(For the electrical case only)

>It's call the "electron-positron" pair. They are unstable and very short-
>lived. During their life, they orbit each other, but eventually annihilate 
>each other.

>However, in search for the perpetual motion machine, could not the
>ATOM be considered as such? Since the electrons are in constant motion
>around the nucleus and does not radiate away it's energy -- or does it
>have to be on a macroscopic level to be considered a machine? 

   To be useful, you have to be able to get some energy out of a perpetual
motion machine without interfering with its operation (ie. you can keep taking
energy out of it indefinitely).  There is nothing in the laws of physics which
forbids a perpetual motion machine as long as you don't want to get any
energy out of it.  The simplest example of a practical perpetual motion machine
is an object spinning in outer space.  Without any friction, such an object
will continue to spin more or less indefinitely.  This is not very useful
as an energy source, however, which is what most designers of "perpetual
motion machines" are after.
   An atom is not a useful perpetual motion machine for the same reason.  
An electron-positron pair isn't really a perpetual motion machine because the
energy you get when they annihilate is just equal to the energy that was
needed to produce the pair in the first place.  In any event, the annihilation
is a quantum mechanical event and has nothing really to do with electro-
magnetism.

				     ---Steven Leffler
					leffler@physics.ubc.ca
From: Richard.Mathews@West.Sun.COM (Richard M. Mathews)
Newsgroups: sci.physics
Subject: Re: General Relativity Tests
Date: 5 Jan 93 21:27:23 GMT
Organization: Sunsoft Inc., Los Angeles, CA.
NNTP-Posting-Host: astro
Keywords: Advancement in Perihelion, Einstein, Ritz, Tolman
Originator: richard@astro

rsf1@Ra.MsState.Edu (Robert S. Fritzius) writes:
>		   m^2      c^2
>	 6 * pi  * ---  *  -----      Tolman          (8)
>		   r^2      v^2
> 
>	    24 * pi         v^2
>	  -----------  *   -----     Einstein         (3)
>	   (1 - e^2)        c^2
> 
> 
>Note that Tolman's (v^2/c^2) got inverted, as compared to that in the
>simplified Einstein expression (3).  Comments?

First, you got the Einstein formula off by a factor of 4.  You used
<v> = pi * a / T when it should be <v> = 2 * pi * a / T.  Thus the
correct Einstein formula expressed as above should say "6 * pi".

In the Tolman formula, note that for a circular Newtonian orbit,
m / r = v^2 / G.  Substituting this brings the v^2 back to the top.
The differences in c's and G's are probably due to using c=G=1
somewhere when deriving Eq 8 above (note that Eq 3 has the right
units for an angle, but Eq 8 does not).  The (1-e^2) is different
because I used a circular orbit to get rid of Tolman's m.

As for why retarded potentials added to Newtonian gravity is not the
right answer: it may give the right periastron shift, but it does not
conserve angular momentum.

     Richard M. Mathews			D efend
					 E stonian-Latvian-Lithuanian
Richard.Mathews@West.Sun.COM		  I ndependence
From: jones@cs.sfu.ca (John Jones)
Newsgroups: sci.physics
Subject: Liquid metals
Date: 12 Jan 93 16:58:10 GMT
Distribution: sci.physics, sci.chem
Organization: CSS, Simon Fraser University, Burnaby, B.C., Canada

Why is mercury a liquid, while its neighbours in the periodic table
are high-melting-point solids?  A simple answer might be that the
interatomic bonds in mercury are unusually weak, but then what is
responsible for the weakness of these bonds?
Newsgroups: sci.physics,news.groups
From: crb7q@kelvin.seas.Virginia.EDU (Cameron Randale Bass)
Subject: Re: sci.physics.research: Are there important unresolved issues?
Organization: University of Virginia
Date: Sun, 10 Jan 1993 20:28:43 GMT

In article <1993Jan10.190054.25683@sfu.ca> Leigh Palmer <palmer@sfu.ca> writes:
>
>I'd like to see one more credential, however, before I lend my
>unquestioning support to these estimable gentlemen. I'd like each to
>publish his killfile (if he has one). While I will not volunteer to
>moderate (I'm an immoderate type by nature), I will tell you that I do
>not have a killfile, but I read selectively, choosing articles from a
>menu like a table of contents, in a newsreader which runs on a Macintosh.
>
>I feel that revelation of these killfiles cannot diminish my respect for
>any of the gentlemen proposed (why are there no ladies?) and that
>self-examination of them may help at least some among them to become
>better moderators.

     Unquestioned support is an amazing degree of support.  For that,
     maybe we *should* publish our killfiles.  Unfortunately, I have none.
     Self-imposed exile never seemed to me to be the way to nirvana;
     it's too easy to scan and discard, or to pick through threads
     for the interesting/entertaining things.

     And now that I've reached 14.4K on the phone line, the space bar
     actually seems to work faster than the kill mechanism.
     
                               dale bass

-- 
C. R. Bass                                          crb7q@virginia.edu        
Department of Mechanical, 
     Aerospace and Nuclear Engineering
University of Virginia                              (804) 924-7926
From: dwr2560@zeus.tamu.edu (RING, DAVID WAYNE)
Newsgroups: sci.physics
Subject: time dilation inside sphere
Date: 12 Jan 1993 23:09 CST
Organization: Texas A&M University, Academic Computing Services
Distribution: world
NNTP-Posting-Host: zeus.tamu.edu
News-Software: VAX/VMS VNEWS 1.41    

Was the question about time dilation inside a sphere ever answered? If
not, could the poster repost, or email me?

Dave Ring
dwr2560@zeus.tamu.edu
Newsgroups: sci.physics
From: Leigh Palmer <palmer@sfu.ca>
Subject: Re: sci.physics.research: Are there important unresolved issues?
X-Xxmessage-Id: <A778E31D2C021C21@rs16-annex3.sfu.ca>
X-Xxdate: Tue, 12 Jan 93 05:05:33 GMT
Organization: Simon Fraser University
X-Useragent: Nuntius v1.1.1d16
Date: Wed, 13 Jan 1993 05:03:49 GMT

In article <richard.726782672@astro> Richard M. Mathews,
Richard.Mathews@West.Sun.COM writes:
>I would rather not see the moderator's name cluttering the subject line.
>Accountability comes from the "Approved: <name>" line which the news
>software requires in any article posted by a moderator.

I feel that publication of names of accepting referees of articles in the
traditional journals would go a long way toward solving the problems I
perceive exist there. I would like to see the reviewer's name on each
article accepted.

I might also suggest that the moderators consider some referal procedure
when they recognize that a submission is outside their area of competence
while still within physics. If this is to be a truly high level research
discussion group that will happen quite often.

Leigh
Xref: sparky sci.physics:22506 sci.math:17990
From: andrew@rentec.com (Andrew Mullhaupt)
Newsgroups: sci.physics,sci.math
Subject: Re: Ansatz (as used in mathematical physics)
Date: 11 Jan 93 18:21:21 GMT
Followup-To: sci.physics
Organization: Renaissance Technologies Corp., Setauket, NY.

In article <1993Jan11.025132.18641@EE.Stanford.EDU> siegman@EE.Stanford.EDU (Anthony E. Siegman) writes:
>   I've seen the term Ansatz used (in English) to describe the

An ansatz is a hypothesis or supposition which simplifies a situation.
satz in general means theorem or proposition, and for example hilfsatz
(help - theorem) is essentially a lemma (a result which helps to prove
another result).

Later,
Andrew Mullhaupt
From: kenny@castle.ed.ac.uk (K J MacDonald)
Newsgroups: sci.physics
Subject: Greenfield Algorithm - What is it ?
Date: 5 Jan 93 15:45:44 GMT
Organization: Edinburgh University

Dear Netters,
	I've got a piece of old fortran code (1971) which uses something
called the Greenfield Algorithm. Does anybody have any references to
this ?

Program: EMCAL
Synopsis: EMCAL calculates the Earth Response Functions for a 2 D
resistivity flat earth model. It builds a network of conductances, with
sources along the top and left, then solves for the voltages at each
node. This is where the Greenfield Algorithm comes in.

	Any help would be much apprecieted, PLEASE E-MAIL.

	Thanks, and Happy New Year,

		Kenny.

-----------------------------------------------------------
Kenneth MacDonald		E-mail kenny@castle.ed.ac.uk
Dept. of Geology & Geophysics
University of Edinburgh		Scotland
-----------------------------------------------------------
Newsgroups: sci.physics,alt.sci.physics.new-theories,sci.skeptic,alt.conspiracy,alt.alien.vi
From: gjm11@cus.cam.ac.uk (G.J. McCaughan)
Subject: Re: Weird message - does any one know meaning?
Organization: U of Cambridge, England
Date: Sun, 10 Jan 1993 03:25:19 GMT

In article <9wo5wB1w165w@status.gen.nz>, jonc@status.gen.nz (Jon Clarke) writes:
> sarfatti@well.sf.ca.us (Jack Sarfatti) writes:
> 
> > From: uucp@mv.MV.COM (0000-uucp(0000))
> > Subject: Warning From uucp
> > Apparently-To: sarfatti@well.sf.ca.us
> > 
> > Subject: Warning From uucp
> > 
> >         virgin!mail unhtel!virgin!nhstrat!rlyeh!cthulhu   (Date 01/07)
> > The job will be deleted in several days if the problem is not corrected.
> > If you care to kill the job, execute the following command:

               ...

>  Assuming this message is real, it says your news(article) batch 
>  "virginn3725" has not been processed at mv.com .  It is asking if
>  you want to delete it else it will autodelete if you do not call
>  the sysadmin at mv.com to sort it out.


No, no, no. It's really very simple. Mr Sarfatti is an adherent of a pagan
religion, and this is telling him how to sacrifice virgins by remote control.

-- 
Gareth McCaughan     Dept. of Pure Mathematics & Mathematical Statistics,
gjm11@cus.cam.ac.uk  Cambridge University, England.    [Research student]