HDTenEightyP/NetNews huggingface dataset:
From: rsf1@Ra.MsState.Edu (Robert S. Fritzius)
Subject: Re: General Relativity Tests
Keywords: Advancement in Perihelion, Einstein, Tolman
Organization: Mississippi State University
Date: Wed, 6 Jan 1993 03:17:03 GMT

 
This rehash relates to Einstein's and Tolman's expressions for the
advancement in perihelion of a planet.
 
In article <richard.7262692433@astro> Richard Mathews writes:
 
> 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
 
> 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 / T.  Thus the
> correct Enstein formula expressed as above should say "6 * pi".
 
	    Oops!
 
> 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.
 
This would give us:
 
		    v^2  *  c^2
	6 * pi  *  -------------     Tolman        (8a)
			G^2
 
[I have to keep in mind that Eq 8 (not Tolman's original equation) may
be the product of a "Slick Willy" mindset on my part.]
 
> The differences in c's and G's are probably due to using c=G=1
> somewhere when deriving Eq 8 above...
 
Maybe so, but  v^2 * c^  in the numerator of Eq 8a does not strike the
right chord for me.  Even if we set the constants to unity, is there not
a residual sense of their dimensionality?
 
Does Eqn 8a seem to be in accord with Tolman's thrust?
 
Robert S. Fritzius    rsf1@ra.msstate.edu
		      I have a drool proof terminal.
 
 

Newsgroups: sci.physics,rec.arts.startrek.tech
From: gunnarh@dhhalden.no (GUNNAR HORRIGMO)
Subject: Re: Accellerating Spaceship (yet another bird in a plane)
Organization: Ostfold College
Date: Tue, 12 Jan 1993 00:35:53 GMT

In article <6850@tuegate.tue.nl> johan@blade.stack.urc.tue.nl (Johan Wevers) writes:
>From: johan@blade.stack.urc.tue.nl (Johan Wevers)
>Subject: Re: Accellerating Spaceship (yet another bird in a plane)
>Date: 6 Jan 93 12:21:04 GMT
>jdsiegel@garnet.berkeley.edu (Joel Siegel) writes:
>
>>>For example, if you had two chunks of matter, one negative and
>>>one positive, the negative chunk would move away from the positive
>>>chunk because of repulsion.  However, the positive chunk would move
>>>toward the negative chunk, trying to catch up.  So, toss a chunk of
>>>negative matter out the door of your spaceship, and away you go!
>
>>Ahhh... perpetual motion?  That could be better than warp drive! :-)
>
>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 :-(

But what if you had a chunk of negative mass and positive charge?


          /\           | I didn't say this.      | "When there's no 
        /    \         | My supervisor would     |  more room in hell,
      /        \       | kill me if i did.       |  the dead will     
    /    (<>)    \     |_________________________|  walk the earth."
  /                \   |Gunnar Horrigmo          |
/____________________\ |gunnarh@sofus.dhhalden.no| 

Newsgroups: sci.physics,news.groups,sci.misc,alt.sci.physics.new-theories
From: paul@mtnmath.UUCP (Paul Budnik)
Newsgroups: sci.physics
Subject: Re: A proof that quantum mechanics is an incomplete theory
Date: 6 Jan 93 16:09:29 GMT
Organization: Mountain Math Software, P. O. Box 2124, Saratoga. CA 95070

In article <1993Jan5.181411.27622@lmpsbbs.comm.mot.com>, bhv@areaplg2.corp.mot.com (Bronis Vidugiris) writes:
> Using the simple principle that QM generally predicts what classical 
> experiments based on Maxwell's equation would indicate, phrased in terms
> of particle probabilities rather than radiation intensities, I predict that
> the time delay between a polarizer changing and the change in proability of
> detecting the particle will be equal to t =  d / c, where d is the distance
> the light travels from the polarizer to the detector.  This assumes the
> polarizer is very thin. [...]

I do not understand how this argument applys to the case I presented.
Maxwell's equations are a local theory. You cannot get a violation of
Bell's inequality using them. If Maxwell's equation's could be used
to predict a delay it could not be any *shorter* then the time it takes
for light to travel from either polarizer to the more distant detector
and this would be in contradiction with quantum mechanics.
Of course there is nothing like a pair of singlet state photons in Maxwell's
theory and that theory cannot applied to the problem of testing Bell's
inequality.

Paul Budnik
From: jarleb@athena.uio.no (Jarle Brinchmann)
Newsgroups: sci.physics
Subject: Re: Request info on Cold Dark Matter
Keywords: cold dark matter, cosmology
Date: 9 Jan 93 14:18:30 GMT
Reply-To: jarleb@athena.uio.no (Jarle Brinchmann)
Organization: Institute for Theoretical Astrophysics


Chris Metzler writes:
>I wrote:
|>I recently read (or is
|> reading) a preprint from A. Kashlinsky, in which he argues that with our
|> current observations of high-z objects, there is not easy to get enough
|> power on small scales with CDM. Not easy means virtually impossible in
|> his opinion, but then he is not very supportive of CDM.....
|> 

(Sorry for the typos :-)

>Well, I'll have to look at the preprint.  We may have it around; we get
>Kashlinsky's stuff.  The volume of published results, let alone preprints,
>is way above what one can keep up with any more.  But I suspect that's true
>of any field.

Couldn't agree more, as a starting grad. student, I'm more than overwhelmed
by the number of articles it would have been nice to have read. But, I
guess it's an indication of the rapid development of the area...
(I read Kashlinskys article because it by chance dealt with the same
issues as I should have done in my grad thesis (or the Norwegian equivalent,
luckily it came before I had started !)

>Anyway, this would indeed be an interesting result if Kashlinsky got it
>with unbiased CDM, since other results suggest too much small-scale power.
>Hmmmmm.

Well, I should say that he is not using unbiased CDM. He assumes a bias
parameter of about 2 in the discussion, and calculates results for b=1 and 2.


				Jarle.



      ---------------------------------------
       Internet: jarleb@medusa.uio.no         
       or        Jarle.Brinchmann@astro.uio.no
      ---------------------------------------
Newsgroups: sci.physics
From: scip2124@nusunix1.nus.sg (MARC PAUL JOREF VAN LOO)
Subject: Re: The Big Bang Never Happened
Organization: National University of Singapore
X-Newsreader: TIN [version 1.1 PL6]
Date: Thu, 7 Jan 1993 09:04:48 GMT

  To say that there is no observation against the
  Big-bang is simply wrong.
  Read Sandage's overview paper (1988 or 1989) in
  annual review of astronomy and astrophysics
  (or something close to that title).


Newsgroups: sci.physics
From: crb7q@kelvin.seas.Virginia.EDU (Cameron Randale Bass)
Subject: Re: sci.physics.research: research-level only?
Organization: University of Virginia
Date: Sat, 9 Jan 1993 02:40:27 GMT

In article <24790@galaxy.ucr.edu> baez@guitar.ucr.edu (john baez) writes:
[examples deleted]

>like other moderators to say a bit more about what they think the group 
>should be like.  There seems to be a sentiment among the moderators that
>about 20 posts a day is a nice volume level, and if that were a goal 
>each moderator would aim to accept about 5 posts a day, and deal with the
>quality issue accordingly, though one shouldn't be too constipated about this
>sort of thing. 

    This is a good point.  Though I agree we should probably  be relaxed about
    specific numbers, 5 per day seems about right.  And I think it is 
    suitable to be more relaxed about 'hoary chestnuts' of limited 
    duration if the candidate stream is 6 per person per
    day rather than 40 per person per day.

    My feeling, though, is this is not exactly Physics-101 (nor is 
    sci.physics for that matter).  This medium is notoriously bad
    at 'teaching' basic matters that one should probably get from 
    more standard sources.  This is simply because much of the information is 
    incomplete or misleading or bad.  Usenet is definitely not
    a substitute for actually learning something.     

    So, my feeling is that 'hoary old chestnuts' should not be included      
    if there is a strong chance the audience is going to groan
    "Oh, I've seen that four thousand times", even if it is not 
    explicitly in the FAQ.  Most of the SR 'paradoxes' seem to come 
    under this heading.  It seems that SR paradoxes are sci.physics's
    counterpart to sci.math's 'Monte Hall problem'.

    I hope sci.physics.research becomes a medium place where people can 
    comfortably discuss more interesting matters of physics.

                          dale bass


-- 
C. R. Bass                                          crb7q@virginia.edu        
Department of Wildebeest
Transvaal                                           (804) 924-7926
Newsgroups: sci.physics
From: ucap22w@ucl.ac.uk (Martin S T Watts)
Newsgroups: sci.physics
Subject: Re: TIME HAS INERTIA - STRICTLY FOR DEVOTED READERS OF: TIME HAS INERTIA
Keywords: Attention Mr. ELI HAWKINS
Date: 8 Jan 93 14:16:14 GMT
Organization: Bloomsbury Computing Consortium

abian@iastate.edu (Alexander Abian) writes:

>Dear Eli, I hope that you will observe that your comments, my
>remarks about your comments, our understanding of "Superiority"
>of this and that over this and that ARE ALL MADE BY MEANS OF THE
>MIRACULOUS ORDINARY LANGUAGE!

There's only one thing to say to that: sdjhfgds ikuetithhjkv bkjhkhggdk
hkdgh gf kghvnfkhvnfl fjhnhnv jfhvdlaslit mnnnnjrrkkkkkk!

>I am exhausted now and have to stop and hear Chopin's Etude in C major.

Didn't Chopin write two C major Etudes? I presume it's Op.10 No.1 you're
referring to?

Cheers,
Martin Watts.
Newsgroups: sci.physics
From: jbaez@riesz.mit.edu (John C. Baez)
Subject: Re: "SPIN," Micro- vs. Macroscopic . . . .
Organization: MIT Department of Mathematics, Cambridge, MA
Date: Fri, 8 Jan 93 01:30:37 GMT

In article <1ii9krINNivt@gap.caltech.edu> allenk@ugcs.caltech.edu (Allen Knutson) writes:
><CCB104@psuvm.psu.edu> inquires:
>
>>What's the difference between the spin of a globe or
>>disk (e.g. beachball or frisbee), say, and the spin of an
>>electron, photon, phonon, Bloch spin wave, proton, etc.?
>
>One's quantized and the other isn't (in an infinite universe).
>Luckily, I can give (part of) a more useful answer.

The rest of the answer looks fine as far as it goes (no disparaging
intent here - there's a long way to go!) but it's worth noting that according
to QM even the angular momentum of macroscopic objects like beachballs
is quantized and comes in units of hbar.  A full answer - which I don't
have time to give - would include something on the difference between
"orbital" angular momentum (which results from the spatial dependence of
the wavefunction, i.e. something actually moving around in circles, and
comes in integer units of hbar) and "spin" or "intrinsic" angular
momentum (so-called because it is intrinsic to a given elementary
particle, and which can come in integer or half-integer units of hbar).
From: corleyj@helium.gas.uug.arizona.edu (Jason D Corley )
Newsgroups: sci.physics
Subject: Re: Gravity & Rubber Sheet Analogy Problem
Keywords: gravity, general relativity
Date: 12 Jan 93 03:31:54 GMT
Distribution: usa
Organization: University of Arizona, Tucson

In article <79814@hydra.gatech.EDU> gt1057a@prism.gatech.EDU (gt1057a JOHNSTON,KEITH) writes:
>In almost all explanations of gravity as warped space, the analogy
>But what if the first mass is Earth, and I set the moon in its
>depression, with no initial velocity.  What would pull it "down"
>toward the Earth, whicsits at the b bottom?  Why wouldn't it
>just sit there in the depression?  Unless there is some other force
>pushing it down the slope, which would mean an external "gravitational"
>force outside the rubber-sheet universe, why would it move?
>
>						Keith J
Because once you put the Earth down on the sheet, the sheet is no longer
flat.  When you put the Moon down, it makes its own depression, true,
but that depression is within the first (since gravity acts at infinite
distance, we should assume both depressions to be infinite in size, but
this is kind of hard to imagine).  What this means is that the Earth
goes a little bit towards the Moon (because of the smaller depression)
and the Moon goes a lot towards the Earth.  The rubber sheet model is
pretty neat, but gets harder to visualize the more accurate you make it.
A lot like most physics, I've found...
	Jason
	Not The Jason At Oxford, But I Had A Good Xmas Anyway
Newsgroups: sci.physics
From: firth@sei.cmu.edu (Robert Firth)
Subject: Re: Quantum Collapse and Bell's Inequality
Organization: Software Engineering Institute
Date: Tue, 12 Jan 1993 08:45:36 EST

In article <1993Jan12.080512.14221@cs.wayne.edu> atems@igor.physics.wayne.edu (Dale Atems) writes:

>Paul, I think the crux of any disagreement between us is whether you need
>to invoke quantum collapse to predict the correlations that violate Bell's
>inequality.

You don't.  The "many-worlds" picture does fine, without needing to assume
collapse.  Here are the equations.

Place in Kansas City a Friedman-Clauser apparatus that emits pairs of
photons in opposite directions, towards New York and Los Angeles.  Each
pair is in an arbitrary state of polarisation, but both photons will be
in the same state of polarisation.  Call the photons Castor and Pollux
(what else?).  If we use the (|h>,|v>) basis, their wave equation is

	kh.|hc>.|hp> + kv.|vc>.|vp>

with arbitrary coefficients k.

At both NY and LA, stick a chunk of calcite or whatever, that sends
horizontally-polarised photons left and vertically-polarised ones
right, into two detectors.  After the experiment, the apparatus is
then in either the state |left> or the state |right>, thus:

	A|x> => |Aleft>.|hx> + |Aright>.|vx>

Now let the photon pair interact with the apparatus in NY.  The result is

	NY ( kh.|hc>.|hp> + kv.|vc>.|vp> ) =>

		kh.|NYleft>.|hc>.|hp> + kv.|NYright>.|vc>.|vp>

And then with the identical apparatus in LA:

	LA ( kh.|NYleft>.|hc>.|hp> + kv.|NYright>.|vc>.|vp> ) =>

	    kh.|NYleft>.|LAleft>.|hc>.|hp> + kv.|NYright>.|LAright>.|vc>.|vp>

Compute the amplitude, integrating over the wave functions and the
coefficients k.  The result, clearly, is the prediction

	(1/2) ( NYleft.LAleft + NYright.LAright )

which is the perfect correlation we observe.

No collapse, no hidden variables, no action at a distance,
and the right answer.

Newsgroups: sci.physics,alt.sci.physics.new-theories,sci.skeptic
From: sarfatti@well.sf.ca.us (Jack Sarfatti)
Subject: re: New Physics of The Force of Star Wars  
Organization: Whole Earth 'Lectronic Link
Date: Mon, 4 Jan 1993 19:09:34 GMT


re: New Physics of The Force of Star Wars
hidden 249 is an important summary of status of quantum connection
communication up to the moment. It is alive and well as a plausible
falsifiable model of the world that involves an minimal generalization of
standard quantum mechanics to non-standard quantum mechanics that violates
unitarity but still conserves probability.

It also suggests that putting in the quantum gravity cut-off into Feynman's
formulae for QED suggests that the bare mass and charge of electron are zero
rather than infinite and that the observed values are all vacuum fluctuation
finite self-energy and screening effects. There is a simple classical model
of point electron including gravity via equivlaence principle that gives a
finite self-energy as well.
Newsgroups: sci.physics
From: sarfatti@well.sf.ca.us (Jack Sarfatti)
Subject: re: sci.physics.moderated - lectures?
Organization: Whole Earth 'Lectronic Link
Date: Tue, 12 Jan 1993 19:20:06 GMT


I am getting good e-mail response to both my lecture threads on Feynman's
QED papers and Kaiser's book of wavelets. I write these lectures not as
a pundit - but as a "student" for other students in a collective learning
experience. This is pioneering a new mode in professional training using
the usenet - world wide "seminars". I encourage people reading the lectures
to post questions, ideas, comments etc.

I suspect there should be a moderated sub-conference sci.physics.lectures
separate from sci.physics.research.
Newsgroups: sci.physics
From: geg@beep.mis.semi.harris.com (Gregory E. Garland)
Subject: Re: Okay, it's not the inverse sprinkler problem...
Date: Tue, 12 Jan 1993 16:23:07 GMT
Distribution: sci
Organization: Manufacturing Systems, Harris Semicondutor

In article <schnitzi.726849584@eola.cs.ucf.edu>, 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?
|> 
|> At first it seems that "hitting the clutch" would be the
|> proper answer, so your car would provide the least resistance
|> to the oncoming car.  But consider -- shouldn't your goal
|> be to reduce the sudden acceleration that you will be 
|> experiencing?  If that's the case, then maybe hitting the
|> brake would be the correct answer.
|> 

Consider the two extremes:

In a completely elastic collision between two equal sized cars, the car behind
stops and your car blasts forward with the momentum it had; so the driver's
seat in your car is going to hit you with the same impact the other car 
would have if you were just standing in the intersection and got run over.

In a completely inelastic collision the resultant squash of two cars would
be only be moving forward with half the speed at best; it will be less
depending on how much friction your tires make with the road.  

Thus standing on the brakes cuts the impulse you get in half, right off the
bat; you would have to do a lot of non-trivial engineering to make up
for that factor to argue the other case.

-- 
Greg Garland - Alive, occupying space, and exerting gravitational force

MS 62-024, Harris Semiconductor Sector, PO Bx 883, 
Melbourne  FL 32905.  geg@beep.mis.semi.harris.com

"Never let the facts interfere with your perception of reality."

Newsgroups: sci.physics
From: minsky@media.mit.edu (Marvin Minsky)
Subject: Re: infinite universe
Cc: minsky
Organization: MIT Media Laboratory
Date: Tue, 5 Jan 1993 05:56:13 GMT

In article <1993Jan5.041650.7437@nuscc.nus.sg> matmcinn@nuscc.nus.sg (MAWENZI lieutenant of Kibo) writes:
>dseeman@novell.com (Daniel Seeman) writes:
>: On this very non-rigourous (even symplistic) level, there can be no boundary to
>                                   ^^^^^^^^^^^                            
>  This is my favourite neologism for 1993 so far.                         

Yah.  The word 'simplistic" reminds me of a good example of how to
imagine something that is three-dimensional and finit, yet unbounded,
namely by properly constructing 5 simplexes.  A three-dimensional
simplex (in topology) is simply a tetrahedron -- that is, a triangular
pyramid.  Here's the trick:  Take a simplex A and then glue four more
onto it by constructing an extra point above each of the four faces.
Then each new point with the three face-points determine a new
simplex.

Now this 5-pyramid gadget has a lot of boundary, namely twelve
triangles.  However, these form six facing-pairs that each share an
edge of the original simplex A.  Fold them so that the face-pairs
close.  (When you do this, two of the new, external points may come
together.)  After all the six facing pairs are closed, there will
remain no external boundary at all.  All the four external points
will have come together at a single point -- and that point will now
be in the interior of the completed object!

If you try to do this in three-dimensions (you're allowed, in
topology, o stretch things any way you want, so long as you don't tear
them) you'll find that you can't quit manage to close it all up at
once -- but in four dimensions you'll find no difficulty at all to do
it.  Then you have what is called a "3-sphere".  

.

Newsgroups: sci.physics
From: sarfatti@well.sf.ca.us (Jack Sarfatti)
Subject: re: do physics don't waste time belly aching etc.
Organization: Whole Earth 'Lectronic Link
Date: Fri, 8 Jan 1993 18:48:07 GMT


From: "Terry Tao" <tao@math.Princeton.EDU>
To: sarfatti@well.sf.ca.us
Subject: Re: DO PHYSICS DON'T TALK ABOUT MODERATING IT!
Newsgroups: sci.physics
Organization: Princeton University
Cc:

In article <C0IznA.8p7@well.sf.ca.us> you write:
>
>Will some one do a statistical analysis of all the mediocre hack level
>academic apparatchuk committee blather about moderating the conference
>without any real idea - and many of these same pundits only make snide
>ad-hominums when any one tries to present an original physics thought.

If a thought cannot stand up to commentary then it is not worth much.

If you label your thought "speculative only at this point", then there is
no problem.  The only problem is when someone presents a new theory and
claims that it is completely true without proof, NOT just speculative.
(like Abian).

Terry

& r
To: sarfatti@well.sf.ca.us tao@math.Princeton.EDU
Subject: Re: DO PHYSICS DON'T TALK ABOUT MODERATING IT!

I have no objection about commenting on ideas and disagreeing with them.
To the contrary, I welcome it. Sci.physics should be a forum for debate and
testing half-baked ideas. Personal attacks do little to advance knowledge
and retard it.

I was referring to all the posts regarding organization. If people would:
1. simply ignore styupid posts.
2. respond politely.
3. post their own interesting ideas or interesting stuff in physics they
have read and want to share - we would have no problem. Abian is only a
problem because all you guys respond to him.
Newsgroups: sci.physics
From: m23364@mwunix (James Meritt)
Subject: Re: Speed of gravity 
Organization: MITRE Corporation, McLean VA
Date: Thu, 7 Jan 1993 13:26:49 GMT

In article <MATT.93Jan6204814@physics.berkeley.edu> matt@physics.berkeley.edu writes:
}In article <1ig87tINNc5i@spim.mti.sgi.com> jackc@vermont.mti.sgi.com (Jack Choquette) writes:
}
}> This reminds me of a question I came up with a while ago.  Is the
}> effect of gravaty instantaneous or is it also limited by the speed
}> of light?
}
}This question comes up on sci.physics periodically.  A real expert
}could doubtless tell you far more than you want to know, but I'll just
}make a few comments:
}	(2) The most widely accepted theory, General Relativity, is quite
}	    complicated.  You have to be careful to define the problem
}	    carefully; the answer to this question depends on exactly
}	    what question you ask.

I'll buy that.  Is he referring to graviton propagation speeds or a time-
space fold.  If the latter, I'm not sure at all what he means...

}	(3) In my opinion, the correct question is: "What is the speed
}	    of gravitational radiation."  The predicted answer is that
}	    gravitational radiation propagates at the speed of light.

If it is radiation....


Newsgroups: sci.physics