HDTenEightyP/NetNews huggingface dataset:
From: dwr2560@zeus.tamu.edu (RING, DAVID WAYNE)
Newsgroups: sci.physics
Subject: Re: Black hole insights
Date: 27 Jan 93 22:41:00 GMT
Organization: Texas A&M University, Academic Computing Services
NNTP-Posting-Host: zeus.tamu.edu
News-Software: VAX/VMS VNEWS 1.41

bbowen@megatest.com (Bruce Bowen) writes...
>  This same thing has occured to me.  I haven't yet seen a satifactory
>explanation.  Also, locally, there's nothing really "stressful" about
>spacetime at the horizon, so why would an infaller see anything there;
>unless to him the evaporation radiation appeared to emminate from the
>singularity.

Well, he doesn't see the singularity of course. First of all, I think
an infalling observer does not have enough time to measure the temperature.
(Perhaps this should be an uncertainty principle?) Secondly, a horizon is a 
globally defined entity, so he should see radiation from his personal global
horizon.

I've always wondered what happens if you throw a cat in. As the cat
gets to the horizon it seems to you to be in an infinite temperature heat
bath. So it should be destroyed. But from the cat's point of view, she passes
right through the horizon unharmed. This is not necessarily a contradiction
since you can't communicate with the cat after it passes through. But it sure
is spooky. I wish someone would tell me why this is wrong. :-)

>  Say, we have a black hole of mass M.  We drop a small test mass into
>it.  We wait long enough for it to get within a small distance epsilon
>of the horizon.  We then radially symmetrically dump another amount of
>mass M in on top of it.  Very soon in observer/coordinate time the
>event horizon has moved far above the position of our small test mass,
>so it is well within the event horizon in a finite amount of
>schwartzchild "t".  What now is it's coordinate time to reach the
>central singularity?

There are two schwartzchild coordinate patches in this problem. It
takes infinite internal coordinate time for the test mass to pass r=2M.
The internal motion is independent of the mass shell. It is interesting
that the spacetime point when the shell reaches 4M is at infinite external
time, but finite internal time. Thus the test mass seems to slow down.

>between the two coordinate systems.  What does one get for "r" and "t"
>when one maps back into schwartzchild coordinates after the particle
>has passed the horizon, and does anyone give these values
>significance?

r=2M t=infinity at that moment. r<2M t finite later. r has significance.
t not much.

>               What is the final value of "t" when an infalling
>particle reaches the central singularity?

Depends on the trajectory, but it's finite. MTW has some nice pictures of
trajectories in both coordinate systems.

Dave Ring
dwr2560@zeus.tamu.edu
Newsgroups: sci.physics,alt.sci.physics.new-theories,sci.skeptic,rec.arts.startrek.fandom,rec.arts.startrek.creative,alt.paranormal,alt.alien.visitors,alt.conspiracy
From: klauck@dfki.uni-kl.de (Christoph Klauck)
Newsgroups: sci.physics
Subject: "Feynman Diagrams"
Date: 28 Jan 1993 09:18:34 GMT
Organization: DFKI Kaiserslautern
Distribution: world
NNTP-Posting-Host: ws-300.dfki.uni-kl.de

This is the result of my request on "Feynman Diagrams"

There is a LaTeX Routine for Generating Feynman Diagrams Version 1.0
by Michael Levine (Oct. 21, 1988)
see on your LaTeX server (e.g. rusmv1.rus.uni-stuttgart.de)

Thanks for the help!

Christoph
Newsgroups: sci.physics
From: djclute@cwis.unomaha.edu (Daniel Jonathan Clute)
Subject: What causes electrical shock?
Organization: University of Nebraska at Omaha
Date: Thu, 21 Jan 1993 20:10:40 GMT

	On a recent vacation, I stayed in a hotel room full of static;
whenever I tried to turn on a light, I was shocked. Needless to say, 
each time I was shocked, I thought more and more about what actually
causes static shock so that I could somehow alleviate the problem. 
Vacation over, I'm still seeking the answers to two particular questions:
1) what causes static shock (low humidity?), and 2) what is the proper
technique to "ground out" (rub on wood?).

					Simply inquistive,
					Daniel Clute
					djclute@cwis.unomaha.edu

Newsgroups: sci.physics,alt.sci.physics.new-theories,sci.skeptic,alt.paranormal,alt.conspiracy,alt.pagan,alt.magick,alt.alien.visitors,rec.arts.startrek.tech
From: danwell@IASTATE.EDU (Daniel A Ashlock)
Subject: Re: New University - Call for Faculty and Students
Reply-To: danwell@IASTATE.EDU (Daniel A Ashlock)
Organization: Iowa State University
Date: Wed, 27 Jan 1993 16:32:23 GMT

   Degree mill ad capslock?

Dan
Danwell@IASTATE.EDU
Newsgroups: sci.physics
From: sarfatti@well.sf.ca.us (Jack Sarfatti)
Subject: re: attracting top physicists
Organization: Whole Earth 'Lectronic Link
Date: Thu, 28 Jan 1993 19:45:52 GMT


Matt you should contact John Horgan at Scientific American. He told me
some months ago that he was interested in how scientists use computer
conferences.
From: mkagalen@lynx.dac.northeastern.edu (michael kagalenko)
Newsgroups: sci.physics
Subject: Re: female mentors in science
Date: 27 Jan 93 21:04:11 GMT
Organization: Northeastern University, Boston, MA. 02115, USA

In article <1993Jan27.055231.23117@nuscc.nus.sg> scip2124@nusunix1.nus.sg (MARC PAUL JOREF VAN LOO) writes:
>michael kagalenko (mkagalen@lynx.dac.northeastern.edu) wrote:
>
>: All this talk about "female science" looks suspiciously similar to 
>: other well known distinctions : "Ariahn" vs "Non-Ariahn", "proletarian"
>: vs "bourgeous" science....
>
>    Are you a nut?
>
>

Are you PC ?
From: phuar@csv.warwick.ac.uk (Mr T Moxey)
Newsgroups: sci.physics
Subject: HELP!
Date: 25 Jan 1993 13:15:10 -0000
Organization: Computing Services, University of Warwick, UK
Distribution: world
NNTP-Posting-Host: tansy.csv.warwick.ac.uk


I'm at university in my second year at the moment and am studying physics.
Next year we are allowed to take a year out and get industrial placements, or
research in a higher education lab, please can you give me an idea of how easy
it would be to gain any neccessary visa's and any companies that I could
contact. I'd like to go to The US, Japan, or Germany, preferably, but I'm not
limited to any country.

Thanks
tim
From: mcirvin@husc8.harvard.edu (Matt McIrvin)
Newsgroups: sci.physics
Subject: Re: Magnetic monopoles?
Date: 27 Jan 93 23:12:13 GMT
Article-I.D.: husc.mcirvin.728176333
 <MERRITT.93Jan25150507@macro.bu.edu> <1993Jan27.055742.24399@galois.mit.edu> <1993Jan27.150751.26245@ramsey.cs.laurentian.ca>

andre@ramsey.cs.laurentian.ca (Andre Roberge) writes:

>In <1993Jan27.055742.24399@galois.mit.edu> jbaez@riesz.mit.edu (John C. Baez) writes:

>>First, while naive monopoles change dF = 0, *d*F = J to the
>>nicer-looking dF = K, *d*F = J (where F is the field strength, J the
>>electric current, and K is the magnetic current), this destroys the 
>>gauge symmetry of the equations! 

>Not really...  You're able to rewrite them as dF' = 0 and *d*F' = J'
>by using  a duality transformation (see Jackson Sect. 6.12) and thus still
>be able to write F' = dA'    (where the ' refers to the transformed
>fields).  Of course you can only do that if all particles have the same
>ratio of magnetic to electric charge.  But I bet you (I've never seen it
>mentioned) that this is exactly what you get out of any decent GUT.

No.  If that were the case the "magnetic monopoles" would be no
magnetic monopoles at all-- the duality transformation you've described
would illustrate that the electromagnetic part of the theory was just
monopole-free QED in disguise!  If you perform the transformation on
electromagnetism as we know it you can re-identify every charged
particle as a "magnetic monopole" of this variety, and the physics
remains the same as it is with no monopoles.

When people talk about magnetic monopoles, what they mean is a
situation in which particles can have *different* ratios of 
magnetic to electric charge.  By convention (well, in the context of
the GUT I suppose it's not entirely convention, but if you just look
at the electrodynamics it's totally arbitrary) we say that the kind
of charge electrons and protons have is the electric charge, and
then these monopoles can *still* have magnetic charge-- I think GUT
monopoles are electrically neutral, in fact.
-- 
Matt McIrvin
From: paul@mtnmath.UUCP (Paul Budnik)
Newsgroups: sci.physics
Subject: Re: hidden variables
Date: 25 Jan 93 17:52:49 GMT
Organization: Mountain Math Software, P. O. Box 2124, Saratoga. CA 95070

In article <1993Jan25.055132.12040@cs.wayne.edu>, atems@igor.physics.wayne.edu (Dale Atems) writes:
][...]  
] Well, here is a rather half-baked proposal based on what I said
] earlier. Let the left and right kets in the singlet state vector
] be in the internal spaces of *distant* wavefronts. I have in mind
] wavefronts corresponding to distinct photons; thus they are emitted
] simultaneously in opposite directions. As each wavefront encounters
] a polarizer, expand its kets in a basis aligned with that polarizer.
] The encounters need not be simultaneous, but the result is that the
] relative angle @ in the formula
] 
]       |psi> = 2^(-1/2) (cos@ |x>|x'> + sin@ |x>|y'>
]                        -sin@ |y>|x'> + cos@ |y>|y'>)
]  
] is the angle between the polarizers at the time the two encounters
] occur in a reference frame in which they are simultaneous.

This is an explicitly nonlocal wave function that cannot be
derived within QM. The amplitude of `psi' is a function of `@' which
is the angle between two spatially separated polarizers. Changing either
polarizer instantaneously changes the amplitude of a distant wave function.
Such a wave function cannot be Lorentz invariant and cannot be derived
from the relativistic Shrodinger equation.

][...]  
] I have no idea if this can be made mathematically rigorous in
] the wave equation formalism. I think it is in the spirit of the
] QM description and shows that, at least on the conceptual level,
] one need not invoke collapse or nonlocal interactions to obtain
] the expected probabilities and timing.

On the contrary I think it helps to illustrate why you have to invoke
collapse. A non Lorentz invariant wave function cannot be derived within
QM. The only mechanism QM provides for deriving violations of locality
involve collapsing the wave function to be consistent with an observation
at one site and then using this collapsed function to compute the
probability of detection at the other site.

Paul Budnik
Newsgroups: sci.physics
From: abian@iastate.edu (Alexander Abian)
Subject: TIME HAS INERTIA  -   INDRA  SINHA's  REMARKS
Organization: Iowa State University, Ames IA
Date: Mon, 25 Jan 1993 02:42:36 GMT

  
                       Att:  Messrs  AUSTERN and KEPLEY



Perhaps you misunderstood Mr. SINHA's REMARKS:

I do not think that he assumes  Newton, Einstein, Planck, Bohr, 
Schroedinger, Heisenberg, Pauli, etc to be necessarily virtuous
and nonvirulent people.  In fact I do not !
What Mr. Sinha meant is that:

   On Judgment day, I, Abian will put on trial (among other things)
   the Newtonian, Einsteinian, Planckian, Bohrian, Schroedingerian, 
   Heisenbergian, Paulian,etc creations and   *their* (whomever
   Mr. Sinha was addressing) names will not be  up there along those 
   names since  *they* have created absolutely nothing having any 
   content worth judging!  *they* have produced only noise, kicks,
   and supercilious idiotical little gestapo-type organization
   to have control over some idiots and use any intimidating,
   almost terroristic tactics to uphold *their* contentless pathetic
   authority and suffocate any opposing voices and ideas.
   
With love.           Alexander ABIAN

-------------------------------------------------------------------    
THE NEW PHYSICS WILL BE BASED ON THE REVOLUTIONARY IDEA THAT TIME
HAS INERTIA.        




Newsgroups: sci.physics
From: mkagalen@lynx.dac.northeastern.edu (michael kagalenko)
Subject: Re: Home made monopoles
Organization: Northeastern University, Boston, MA. 02115, USA
Date: Sat, 23 Jan 1993 23:27:01 GMT

Article 12391 of sci.physics:
Newsgroups: sci.physics
From: mkagalen@lynx.dac.northeastern.edu (michael kagalenko)
Subject: Re: Home made monopoles
Organization: Northeastern University, Boston, MA. 02115, USA
Date: Sat, 23 Jan 1993 23:19:42 GMT

In article <1jr3uiINNcjk@mirror.digex.com> bdoa@digex.digex.com (Barry Adams) writes:
>   
>
>                     Home made magnetic monopoles
>                     ============================
>
>   Contrary to popular belief , magnetic monopoles exist and are easy to
>make . Take a Steel hemisphere and cut a concentric hemisphere cut of the
>middle , now magnetize the hemisphere such that the domains of the object
>are aligned with the north (south) pole pointing outwards. Now stick two of
>the hemispheres together forming a sphere  (glue strong enough to resist
>the magnetic repulsion of the hemispheres is required) you now have your
>magnetic monopole :-) , since any observer will see the object having a north
>pole only (unless they cut it open).
>   Of course the configuration is unstable and the domains will slowly try
>to rearrange themselves to a more stable state. And the magnetic force still
>decays like a dipole. Such objects might to useful as frictionless bearings.
>
>Barry Adams
>

Are you just kidding or want us to insert your name into our Kill-files ?           




Newsgroups: sci.physics
From: bweiner@ruhets.rutgers.edu (Benjamin Weiner)
Newsgroups: sci.physics
Subject: Re: female mentors in science
Date: 29 Jan 93 05:04:45 GMT
Organization: Rutgers Univ., New Brunswick, N.J.

I don't quite comprehend the sentiments going on here (well, really
I do, but I'm being polite).  I see nothing wrong with asking about
women as mentors to other women in science, in fact this is something
I often see acknowledged in interviews with women scientists.  I also
see nothing wrong with *asking* whether there is a difference in the
work that female and male scientists do.  Personally, I've never seen
any.  I sent a polite email message to the original poster saying this.
[Flame bait: I also mentioned that I think women scientists are on
average better at handling people, especially their students.]  

Maybe that is a better way of answering the question, (and persuading
the questioner), rather than turning up the conversational heat.  If 
this is how we respond to a reasonably rational request for information 
and opinions, no wonder people think scientists are a bunch of [sexist] 
hardasses.
Newsgroups: sci.physics
From: matmcinn@nuscc.nus.sg (Lieutenant Ripley at The Institute for Telling Lice)
Subject: Re: gravitons
Organization: National University of Singapore
X-Newsreader: Tin 1.1 PL4
Date: Tue, 26 Jan 1993 09:03:35 GMT

DTC3@psuvm.psu.edu () writes:
: 
: In any event, a prime assertion of General Relativity is that gravity
: is *not a force*, but a characteristic of the geometry of spacetime;
: it seems, then, that the notion of a force propagator (the graviton)
: moving about in spacetime is not consistent with this assertion.  And
: as there are  no   direct experimental data regarding the behavior of
: gravity at the quantum level, can the existence of a neutral, massless,
: spin-2 graviton be justified on symmetry grounds alone?
: 
: Any thoughts?
: 
Gravitons are the particles emitted by the brain of a particle theorist
when he thinks that gravity is just another field in Minkowski space.
From: carlip@landau.ucdavis.edu (Steve Carlip)
Newsgroups: sci.physics
Subject: Re: Super-Strings
Date: 27 Jan 93 02:08:49 GMT
Organization: Physics, UC Davis

In article <74300@cup.portal.com> lordSnooty@cup.portal.com (Andrew - Palfreyman) writes:
>I wonder if the fad with string theory and superstrings is simply
>Occam's Razor in action, or is it perhaps something at a deeper
>level? I mean that one could just as easily have chosen a primitive
>of higher dimensionality.

There is, in fact, some work on "membrane theory," the higher dimensional
generalization of string theory.  In general, membranes don't work very
well for particle physics purposes.  For instance, strings have a
discrete energy spectrum, yielding particle-like excitations of
different masses; membranes typically have a continuous spectrum,
and would lead to a continuous range of particle masses.  

There may now be ways of fixing this --- I'm not up on the most
recent literature.

Steve Carlip
carlip@dirac.ucdavis.edu
Newsgroups: sci.physics
From: matmcinn@nuscc.nus.sg (brett mcinnes)
Subject: Re: Super-Strings
Organization: National University of Singapore
X-Newsreader: Tin 1.1 PL4
Date: Wed, 27 Jan 1993 03:00:20 GMT

baez@guitar.ucr.edu (john baez) writes:
: 
: Yes, people have studied "p-branes," but they are supposedly much less
: well-behaved; when you quantize them they give infinities that people
: apparently have not been able to renormalize away.  
: 
One problem with 2-branes is that at some point you need to know whether
the Poincare conjecture is true. I recall reading the following amusing
exchange:								  
Q: How are you going to proceed without the Poincare conjecture?          
A: Well, if I were Ed Witten I'd turn that around, and give you a
brane-theoretic proof of the Poincare conjecture..........[laughter].
Newsgroups: sci.physics
From: mkagalen@lynx.dac.northeastern.edu (michael kagalenko)
Subject: Re: gravitons
Organization: Northeastern University, Boston, MA. 02115, USA
Date: Sat, 23 Jan 1993 22:54:46 GMT

In article <mcirvin.727660223@husc.harvard.edu> mcirvin@husc8.harvard.edu (Matt McIrvin) writes:
>mcirvin@husc8.harvard.edu (Matt McIrvin) writes:
>
>>nariani@utdallas.edu (Sushil Nariani) writes:
>
>>>If light cannot escape a blackhole, how can gravitons escape to pass on
>>>the message of blackhole gravity to the rest of the universe?
>
>>One answer is that the "virtual particles" that mediate forces 
>>according to quantum field theory aren't bound by ordinary laws of
>>motion.  They can therefore get out of black holes with no trouble
>>at all.  How they do this without conveying information out of a
>>black hole is a complicated story.
>
>Contemplating this further, I think that this statement is a little
>misleading.  I don't know what the graviton propagator really looks 
>like (I haven't seen the expression recently), but if you work in
>Feynman gauge and examine the propagator of a *massless* spin-1
>boson like a photon, I think that in spacetime (rather than in
>momentum-energy space) it is confined to the light cone.  If gravitons

You're wrong here : propagator is not zero outside light-cone.

>behave the same way, then the explanation for how they get out of the
>hole is the same as the classical explanation for how the field can
>persist:  they're relics from the time before the hole formed.  It's
>only *massive* particles that have tails to their propagators that
>lie outside the light cone-- for them the situation is as nontrivial
>as I suggested above.
>-- 
>Matt McIrvin
From: ted@physics1 (Emory F. Bunn)
Newsgroups: sci.physics
Subject: How to write integrals (was Re: The confusion of tongues (was ...))
Followup-To: sci.physics
Date: 21 Jan 1993 20:38:23 GMT
Organization: Physics Department, U.C. Berkeley
Distribution: usa
NNTP-Posting-Host: physics1.berkeley.edu

In article <COLUMBUS.93Jan21101415@strident.think.com> columbus@strident.think.com (Michael Weiss) writes:

>On the topic of mathematicians' vs. physicists' notation, does anyone know
>why most mathematicians will write an integral as shown below on the left
>(unless they omit the dummy variable x entirely), whereas physicists prefer
>the form on the right?
>
>         /                       /
>         |  f(x) dx              | dx f(x)
>         /                       /
>

This is an interesting question.  I sometimes write one and sometimes the
other.  In general, I write \int f(x) dx if I'm just doing a single integral
(\int is an integral sign, for those who don't TeX), but if it's a multiple 
integral, then I write

\int dx \int dy f(x,y)

I think that the reason I usually put the dx at the end is that that's
the way it was in my first calculus textbook, and the reason I put the
dx next to the integral sign in multiple integrals is that it makes it
instantly clear which integral sign (and hence which limits of integration)
go with which variable.  

-Ted
Newsgroups: sci.physics
From: u108502@beta.lanl.gov (Andrew Poutiatine)
Subject: Re: satellite orbits
Organization: Los Alamos National Laboratory
Date: Thu, 21 Jan 1993 21:36:32 GMT

In article <376oXB3w165w@netlink.cts.com> bigbro@netlink.cts.com (Kenneth Sullivan) writes:
>Quick easy question, this is mostly to settle an arguement
>
>a.)what keeps a satellite in orbit
>and 
>b.)just how wrong is the idea of centrifugal/centripidal "force"?
>thanks
>
>--                    
>INTERNET:  bigbro@netlink.cts.com (Kenneth Sullivan)
>UUCP:   ...!ryptyde!netlink!bigbro
>NetLink Online Communications * Public Access in San Diego, CA (619) 453-1115

First, what keeps the satellite in orbit is its obeying Newtons laws (this is
of course not the entire truth, but for our purposes close enough).  At any 
instant, for an ideal orbit, the satellite is moving with a velocity that is
tangent to its orbit, and the gravitational force acting on it is subjecting
it to a free fall.  The only problem is, that for a stable orbit, the 
satellite  keeps effectively missing the Earth, because it has a velocity.  It
is constantly falling, but the Earth seems to be constantly moving out from
under the satellite.

This is about as simplistic an explaination as I can conjure up.  It is all,
of course described very neatly by Newtonian Kinetics, and more accurately
by Relativity.

If the satellite is moving too slowly initially to maintain a stable orbit, 
then it falls, speeding up, until a stable orbit is maintained, unless of 
course it enters the atmosphere or hits the ground or something.

The gravitational force is toward the Earth, and is hence a centripital force.
In this simple example there is no centrifugal force.  It is a common
misconception since as we swing a ball on a string around our heads we can 
feel a force pulling on the string, right?  Well, yes and no.  In fact our
hand does feel a centrifugal force form the string, which is balanced by our
hand exerting a centripital force on the string in return.  There is nothing
pulling the ball away from the hand, no other strings, nothing, and thus it
is wrong to say that the ball has a centrifugal force acting on it.

The real question to ask is this:  what stops the satellite from moving in 
a straight line, doing its first-law thing, and leaving the earth forever?
The answer is gravity.  What keeps the satellite from coming crashing to 
Earth?  Answer:  it keeps falling, but moves fast enough _tangentially_ so 
that it keeps missing the earth.

Lastly, imagine throwing a baseball, with no air on earth to worry about.  It
goes 50 or so yards and hits the ground.  Now what if you throw it harder, so
that by the time it has fallen a few feet, it is hundreds of miles away, and
the curvature of the Earth has caused the ground to have fallen a few feet 
also?  You now have an orbit.

-AIP
From: weemba@sagi.wistar.upenn.edu (Matthew P Wiener)
Newsgroups: sci.physics
Subject: Re: Super-Strings
Date: 25 Jan 93 16:17:53 GMT
Reply-To: weemba@sagi.wistar.upenn.edu (Matthew P Wiener)
Organization: The Wistar Institute of Anatomy and Biology
In-reply-to: brahm@cco.caltech.edu (David E. Brahm)

In article <1k09cpINNsg7@gap.caltech.edu>, brahm@cco (David E. Brahm) writes:
>One could, and people do ("super-membrane theory"),

For some reason, the membrane is always a p-dimensional object.  They
are called p-branes for short.  This is not a joke.
-- 
-Matthew P Wiener (weemba@sagi.wistar.upenn.edu)
Newsgroups: sci.physics