HDTenEightyP/NetNews huggingface dataset:
From: dwr2560@zeus.tamu.edu (RING, DAVID WAYNE)
Subject: Re: Aristotle and the Modern Physicist
News-Software: VAX/VMS VNEWS 1.41    
Organization: Texas A&M University, Academic Computing Services
Date: Mon, 27 Jul 1992 23:29:00 GMT

matmcinn@nuscc.nus.sg (Mcinnes B T (Dr)) writes...
>Dave Ring: The gravitational constant measures the correlation between
>the Einstein tensor and the presence of matter. It is not a coupling
>constant. In this connection: the Einstein equation is in no way
>comparable to, say, Maxwell's equation. There can be no question of
>prescribing the sources and then solving for the field.

One can't do it in E+M either since the field inevitably has an effect
on the sources.

>                                                              If you
>had asked Newton why free particles move along straight lines at
>constant speed, he would probably have asked you what else they should
>do. It is deviation from such motion that requires explanation.

Somehow I doubt that Newton would consider the most important of his
life's work as trivial. Remember that before him, people believed that
the interaction with the air caused things to keep moving. Newton showed
basically that we DON'T know why things behave that way and that we have
to accept it as a postulate.

I believe that one can deduce Newton's laws from quantum field theory in
minkowski space. Thus the equivalence principle is enough to guarantee,
as you have put it, that things go straight if there are no forces. I would
point out that the equivalence principle is inevitable in any quantum theory
of a massless spin two field, so identifying the metric as a quantum field
finally allows us to explain that which Newton first postulated. 

>                                     If the idea of "quantizing spacetime"
>makes any sense, then it must make sense for all spacetimes. Among these
>is Minkowski space. What would "quantized Minkowski space" be like?

I confess I don't understand the question. Minkowski space is one state of
spacetime. One quantizes a _theory_ . It's like asking how to quantize the
electric field E=(1,0,x). 

Anyway, at times I have held the point of view you are suggesting. Not quite
with your level of certainty, but I still keep it in the back of my mind.
Here, however, I am playing devil's advocate.

Dave Ring
dwr2560@zeus.tamu.edu
From: bssbru01@uctvax.uct.ac.za
Newsgroups: sci.physics
Subject: Re:Time near a black hole?
Summary: j
Date: 22 Jul 92 13:25:16 GMT
Reply-To: ari.huttunen@hut.fi
Followup-To: sci.physics
Distribution: sci
Organization: University of Cape Town

In article <ARI.HUTTUNEN.92Jul19015723@wonderwoman.hut.fi>, Ari.Huttunen@hut.fi (Ari Juhani Huttunen) writes:
> A light ray emitted at the event horizon can never escape the black hole.
> A light ray emitted an infitinitely small distance outside the event horizon
> will take an infinitely large time to reach an observer far away.
> 
> I interpret this to mean that at the event horizon time goes infinitely
> slowly relative to an outside observer.
> 
> Now, when a star collapses to a black hole and the star approaches the
> status of a "black hole", time will go more and more slowly relative to
> an outside observer. 
> 
> Thus, no matter when the collapse of a star began, it cannot have yet
> reached the state of a "black hole", since an infinitely long time required
> to form a black hole has not yet gone by. 
> 
> Also, if indeed the time goes infinitely slowly at the event horizon, then
> an object could not fall into a black hole in finite time and all such
> objects approaching the black hole would stay at the event horizon as seen
> by an outside observer.
> 
  The only flaw in your reasoning is that you don't destinguish between proper
  time and time as measured by observers far from the event horizon - i.e 
  coordinate time. It does take an infinite amount of coordinate time for an
  object to fall through the event horizon, but the falling object only takes
  a finite amount of proper time to do the same. The light coming from the 
  falling  object  is  also   infinitely  shifted  out  of  the  visible 
  spectrum so that the object effectively disappears. A particularly good
  discussion of this stuff can be found in "Gravitation" by Misner,Thorne
  and Wheeler in the chapter on black holes. As for the rest of your 
  queries, you would have to chuck out general Reletivity to get them to
  work!
Newsgroups: sci.physics,sci.geo.fluids
From: hatay@spot.Colorado.EDU (Ferhat F. Hatay)
Subject: J. Leorat from Observatoire de Meudon
Organization: University of Colorado, Boulder
Date: Tue, 21 Jul 1992 17:01:12 GMT

Can anyone help me contact Jacques Le'orat 
from Observatoire de Meudon in France?

-- 
Ferhat F. Hatay                        || Disclamer: |||||||||||||||||
Aerospace Engineering Sciences         || I speak for myself unless || 
University of Colorado, Boulder        || otherwise indicated.      ||
e-mail: hatay@spot.colorado.edu        |||||||||||||||||||||||||||||||
Newsgroups: sci.physics,sci.astro
From: sulkanen@xanth.msfc.nasa.gov (Martin Sulkanen - NRC/ES65)
Subject: transition probs for He-like ions
Summary: transition probs for He-like ions
Keywords: atomic physics
Organization: NASA/MSFC
Date: 30 Jul 92 17:01:19 GMT

I am looking for references on the transition probablities &
branching ratios for He-like ions, specifically for Fe+24. 
We have made a search of Atomic Data and Nuclear Tables, but
we could only find such a table for H-like ions (Omidvar, K. vol
28, (1983)). Any partial table for n < 6 would be of help. Thanks
you in advance!

|_________________________________________________________________|
| martin sulkanen      ][ internet: sulkanen@xanth.msfc.nasa.gov  |
| es 65                ][ span    : ssl::sulkanen                 |
| nasa/msfc            ][ voice   : 205/544-5823                  |
| huntsville, al 35812 ][ fax     : 205/544-7754                  |
|_________________________________________________________________|
From: nicho@vnet.ibm.com
Newsgroups: sci.physics
Subject: Re: ZERO Nuclear impact (was: Is car pooling for real? etc)
Date: 24 Jul 92 08:56:43 GMT
Reply-To: nicho@vnet.ibm.com

In <1992Jul23.171618.9386@vexcel.com> dean alaska writes:
>Wow.  I tought a terrorist was someone who killed people in order to create
>fear.
 No a terrorist is someone who's modus operandi is to instill terror.
Political terrorists do it by killing people. Eco-terrorists do it
by playing on FUD. It's the same end, they cannot support their case
with reasoned fact, so resort to instilling fear in the general
population.
>It makes about as much sense as referring to nuclear supporters as
>destroyers of the earth.
  Umm .. the eco-terrorists _do_ refer to nuclear supporters in these
terms, it's part of the terror inducing paradigm, to assume that
anything 'nucular' is capable of destroying Earth.

 -----------------------------------------------------------------
               ** Of course I don't speak for IBM **
Greg Nicholls ... nicho@vnet.ibm.com or nicho@cix.compulink.co.uk
                  voice/fax: 44-794-516038
Newsgroups: sci.physics,sci.astro,sci.philosophy.tech,talk.religion.misc
From: matmcinn@nuscc.nus.sg (Mcinnes B T (Dr))
Subject: Re: Structure of Time
Organization: National University of Singapore
Date: Wed, 29 Jul 1992 03:46:12 GMT

Should we really believe that somebody reported this guy to his
employer? Are there really such bastards out there?
From: snyder@henry.ece.cmu.edu (John Snyder)
Newsgroups: sci.physics
Subject: Re: ... an infinite mesh of 1ohm resistors ...
Date: 27 Jul 92 21:09:47 GMT
Organization: physics department, Carnegie Mellon Univeristy

In article <1992Jul25.210947.12316@cs.yale.edu> A. Satish Pai <Pai-Satish@CS.Yale.Edu>  writes:
>
>
>>>> "MM" == minsky@media.mit.edu (Marvin Minsky) writes:
>
>MM> It's a superposition trick.  Imagine attaching a current source
>MM> between points A and B, and forcing 1 ampere through the circuit.
>MM> There's a theorem (I forget the name) which says that this is
>MM> equivalent to the sum of two separate experiments of forcing 1 amp
>MM> into A and of sucking 1 amp out of B.  The first experiment would push
>MM> 1/4 amp into the resistor from A to B, and so would the second
>MM> experiment!  So we find that 1/2 amp flows through the resistor, hence
>MM> the voltage between A and B is 1/2 volt.  Then because R = E/I, we get
>MM> the resistance must be 1/2 volt over 1 amp at the terminals, so the
>MM> resistance is 1/2 ohm.  Wonderful example of a sort of circular reasoning.
>
>I imagine that the superposition theorem works when the two (or more) states
>that are being superimposed are themselves real in the sense that they can in
>principle be achieved in an experiment?
>
>This is not clear to me at all in this case. What does "forcing 1 amp" into the
>network at any point mean? What does "sucking 1 amp" out mean?  You have an
>infinite grid of resistors facing you. You're trying to inject current at one
>point, presumably by applying a high potential - but if there's no sink, what's
>to ensure that your potential is high with respect to any point on the grid? I
>don't see why any current should flow at all. Where is the potential difference
>for it to flow? Where does the current flow to? To "infinity"? What does that
>mean? 
>
>If "forcing" the current and "sucking" it out are both impossible things to do
>(at least it seems so to me), what could it mean to superimpose these two
>impossible events to get a nice and simple event that is possible (the case
>where there are both a source and a sink)?
>

I believe that you are missing the point of the previous post here.  The 
trick that the previous poster described is a *MATHEMATICAL* trick.  It
is a thought process that one can use to solve a circuit.  In this case,
one imagines connecting an ideal current source across two terminals of
in the circuit.  An ideal current source is a mathematical idealization
of a constant current source that one can use in a laboratory.  The
big difference is that an ideal current source is capable of putting
out *ANY* voltage in order to keep its output current at the set value.
Obviously such a beast does *NOT* exist.  However, it is useful to imagine
for computational purposes, particularly in simplifying complicated
circuits, and using Norton's Theorem.

John
snyder@henry.ece.cmu.edu
From: braham@physics.ubc.ca (Stephen Braham)
Newsgroups: sci.physics
Subject: Re: Quantum Cosmological Boundaries and Determinisim?
Keywords: Quantum cosmology
Date: 22 Jul 92 17:40:31 GMT
Organization: University of British Columbia, Vancouver, B.C., Canada

jbaez@riesz.mit.edu (John C. Baez) writes:

>In article <braham.711770201@physics.ubc.ca> braham@physics.ubc.ca (Stephen Braham) writes:

>> [stuff by me deleted]

>What do you mean by an "intermediate state"?

>By the way, lots of mathematicians use "state" to refer both to pure
>states (typically represented by unit vectors in Hilbert space) and
>mixed states (aka density matrices).

Yes, I'd better be careful- I used state in that sense later. I'm
really talking about an intermediate density matrix or wavefunction
here, vs. a more general quantum state (or quantum description
of the system). By intermediate, I mean intermediate in time, i.e.,
between 'measurements.' In ADH, we try to give meaning to just
HISTORIES, and we bury the idea of a density matrix or wavefunction
at a particular time. For a _Hamiltonian_ ADH (which isn't general
enough for quantum cosmology, probably), one can go to a generalized
approach with both final and initial conditions, and you get a system
that cannot be described by a density matrix at any intermediate time,
but is fully predictive. Wehn the final state density matrix is
just the identity, you get back to pretty standard Copenhagen
style Hamiltonian quantum mechanics, and you can almost say that
each projection operator IS a Cophenhagen style collapse. I prefer
Jim's way of looking at it though, in which you say that you're
looking at a purely conditional question, and the collapse is
nothing except the standard conditional probability rule. This
shouldn't be confused with the _dynamical_ collapse of the
wavefunction, induced by decoherence processes- that's a statement
on a Shroedinger picture density matrix, and ADH is a lot more
general than that.

>What is the most lucid and interesting single reference on the
>alternative decohered histories approach?  I've read a bit about it but
>could stand some more.

Ewww, hard one. I think I'll have to give you two, because things
are in flux, and Gell-Mann and Hartle are redefining their
concept of quasiclassical domains. The Jerusalem Winter School (1989)
notes are probably the best single description, they're in
Quantum Cosmology anb Baby Universes, ed. S. Coleman, J. B. Hartle and
T. Piran (World Scientific, Singapore, 1990). The later, modified,
stuff is Alternative Decohering Histories in Quantum Mechanics,
UCSBTH-90-56.

			Steve 
--
| Name: Stephen P. Braham | Perversion: Quantum Cosmologist|
| Hangout: UBC physics    | Signature:  Euclidean          |
|          Vancouver, BC  |--------------------------------+
|          Canada         | E-mail: braham@physics.ubc.ca  |
Xref: sparky sci.physics:12108 sci.skeptic:13469
From: dinda@cae.wisc.edu (Dinda Peter)
Newsgroups: sci.physics,sci.skeptic
Subject: Re: help needed with a thought problem
Date: 31 Jul 92 15:01:14 GMT
Article-I.D.: doug.1992Jul31.100115.26757
Organization: U of Wisconsin-Madison College of Engineering

In article <1992Jul28.235824.18389@ibmpa.awdpa.ibm.com> chesky@squirrel.austin.ibm.com (Bill Chesky) writes:
>Suppose there is this gigantic rod floating out in space.  Just for
>fun, says its, oh, 1,000,000 miles long.  Further this rod is made
>out of some super-duper-futuristic-space-age-pleiadian-uri-geller-
>don't-even-think-about-it type material and is thus perfectly rigid.  Now 

Here's the problem.  It can't be "perfectly rigid" and thus any impeled
action would propagate along the rod at much slower than the speed of
light.

>suppose you have some mechanism on one end whose purpose is to push and 
>pull (longways) on the rod.  Is this not a FTL communications device 
>since when you push on one end it is going to instantly move at 
>the other end, thus sending a signal to the other end in 0 seconds
>wheras it would have taken 5 or 6 seconds if you were using radio or
>light?

Here's another one for you:  A pair of scissors is in fact an FTL
device - a perfect demonstration of the FTL propagation of phase waves.
Think about it.
Xref: sparky sci.physics:12105 sci.philosophy.tech:2919 talk.religion.misc:13118
From: jbaez@riesz.mit.edu (John C. Baez)
Newsgroups: sci.physics,sci.philosophy.tech,talk.religion.misc
Subject: Re: Structure of Time (LAST COMMENT)
Date: 31 Jul 92 14:28:36 GMT
Organization: MIT Department of Mathematics, Cambridge, MA

In article <1992Jul31.091010.1@tnclus.tele.nokia.fi> hporopudas@tnclus.tele.nokia.fi writes:

>   I would only like to say about Hanna-Maria that I'am a religious man,
> I believe that God exists, because He is Existence Himself, and if someone
> is arguing that Existence Himself does not exist, then he/she argues at the
> same time that he/she himself/herself does not exist.

This is one of the funnier versions of the ontological argument for the
existence of god that I've heard.  But don't you mean to say that "I
believe that God exists, because He/She is Existence Himself/Herself"?

I believe in existence (I think) but calling it "god" is rather misleading.

>I also believe that
> almost everything is possible for our God. This is a matter that we don't
> understand at the moment, because we are still so undeveloped compared
> to Him. These are the main reasons why I don't need to explain to myself
> this Hanna-Maria's part in my paper "Structure of Time". I simply believe it.

For the same reasons, I don't need to explain why you and your
daughter's ideas are a bunch of baloney.  I simply attribute it to the
great ability of God to create confused people.  See?  This works both ways.
From: graeme@castle.ed.ac.uk (G J Ackland)
Newsgroups: sci.physics
Subject: Re: ... an infinite mesh of 1ohm resistors ...
Date: 30 Jul 92 14:03:07 GMT
Organization: Edinburgh University

This source / sink argument is all very nice.
Doesn't it give the wrong answer for a Bethe lattice though?
  
__/  \__
  \__/
__/  \__/
  \  /  \

where the absence of cicuits mean the solution is trivially 1 ohm, but
the three-way split of the current appears to give 2/3ohm using this
source/sink argument.
From: bweiner@ruhets.rutgers.edu (Benjamin Weiner)
Newsgroups: sci.physics
Subject: Re: Blue Sky
Date: 28 Jul 92 19:41:22 GMT
Organization: Rutgers Univ., New Brunswick, N.J.

Francois Yergeau (yergeau@phy.ulaval.ca) writes:
>BTW, the often quoted requirement that the body must be much smaller
>than lambda is implicit in the assumption that the radiated amplitude
>is proportional to V.  If the body is too big, dipole radiation from
>different parts of it will be out of phase and cancel out, and the
>total amplitude will not grow as V anymore.

Yes, or you could see the d << lambda (d being the dimension of the
scatterer) as allowing you to work the problem in the quasi-static
approximation (really of course this is the same thing as your
assumption).  Without it the problem of scattering is much harder.

With regard to dimensional analysis, basically any dipole radiation
has k^4 dependence, but dimensional analysis just doesn't seem to be
very convincing here.

Ben Weiner
From: ttyytt@mixcom.com (Adam Costello)
Newsgroups: sci.physics
Subject: Re: ... an infinite mesh of 1ohm resistors ...
Date: 30 Jul 92 02:54:52 GMT
Article-I.D.: mixcom.1992Jul30.025452.23086
Organization: Milwaukee Internet Xchange BBS, Milwaukee, WI U.S.A.

In article <1992Jul28.093201.10671@fs7.ece.cmu.edu> snyder@henry.ece.cmu.edu (John Snyder) writes:
>In article <1992Jul28.000844.27051@mixcom.com> ttyytt@mixcom.com (Adam Costello) writes:
>>In article <1992Jul27.210947.5820@fs7.ece.cmu.edu> snyder@henry.ece.cmu.edu (John Snyder) writes:
>>>
>>>I believe that you are missing the point of the previous post here.
>>
>>But I think you are missing the point of the second post.  The "solution"
>>involved imagining that you could inject an amp of current into a network
>>of resistors.  No capacitors!  Where is the charge supposed to go?
>                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>
>Hunh?  What do capacitors have to do with it?
>Surely, you can pass 1 amp through a network of resistors with
>no capacitors present.  We solved *MANY* such problems in Electrical
>Engineering 101 (groan! (:^)).  The current goes in at terminal A, and 
>out at terminal B.  I cannot seem to locate the original problem, but my 
>recollection is that there were 2 terminals involved.

The original "solution" went something like this:  Imagine connecting a
one amp current source between A and B.  Now split this image into two
separate cases which we will later superimpose.  In one case, the current
goes in to terminal A, but doesn't come out anywhere.  In the other case,
the current comes out terminal B, but doesn't go in anywhere.  I doubt
you ever did anything like this in EE 101.  (I sure didn't!)

By the way, if you've forgotten the original problem, here it is in a
nutshell:

What is the resistance between the two ends of any resistor in an
infinite square lattice of 1 ohm resistors?

AMC
From: bhoughto@sedona.intel.com (Blair P. Houghton)
Newsgroups: sci.physics
Subject: Re: Magnetic lenses
Date: 29 Jul 92 23:28:01 GMT
Distribution: na
Organization: Intel Corp., Chandler, Arizona

In article <1992Jul29.141543.12833@unlinfo.unl.edu> cbettis@unlinfo.unl.edu (clifford bettis) writes:
>The optical phase information is lost in the recording
>process (i.e. the TV camera only records intensity) and therefore the 
>information necessary to reconstruct a complete image is missing. 

What you're trying to say is that an image is made up of a set of
points (small regions of acuity), and your poor vision (due to
myopia, the inability to focus properly, such that the virtual
image is formed in front of the retina instead of on the retina)
turns each point into a blob, covering more retinal receptors than
it should, overlapping with blob-smear from adjacent points,
creating a fuzzy image; and it is not possible to create an
arrangement of points which is then made fuzzy by this myopia, such
that this fuzzy image actuall forms some clear image on the
retina.

Is that what you're trying to say?

Phase information isn't an issue.

>To make a TV capable of such feats the band width of the signal would 
>have to be on the order of the frequency of light.

It's strictly a pixel problem; bandwidth isn't an issue.
If Matisse (or was it Manet?) couldn't do it, we can't.

				--Blair
				  "What am I saying?"
Xref: sparky sci.physics:11845 sci.environment:10189 sci.energy:3750
From: gary@ke4zv.uucp (Gary Coffman)
Newsgroups: sci.physics,sci.environment,sci.energy
Subject: Re: Is car pooling for real? (was Re: Are bikes really less polluting?)
Date: 28 Jul 92 16:30:32 GMT
Reply-To: gary@ke4zv.UUCP (Gary Coffman)
Organization: Gannett Technologies Group

In article <1992Jul27.175448.11019@hellgate.utah.edu> tolman%asylum.cs.utah.edu@cs.utah.edu (Kenneth Tolman) writes:
>
>You fail to see this because we charge so little for oil.  Soon, oil will run
>out (100yrs soon) and then we will not be able to afford our stupid energy
>consumption extravagences.  We are no closer to any realistic plan because
>we are so shortsided we are pissing into the wind, and it soon will blow
>back into our face.

$1 a gallon gasoline won't last forever, made from sweet crude oil. 
But $1.50 a gallon *synthetic* gasoline is available from coal with the
Fischer process (and several others), and we have a 3,000 year supply 
in the continental US. Tar sands are another vast untapped source of
oils suitable for synthetic gasoline production. The Peace River, Wabasca,
and Cold Lake deposits in Canada alone hold 890 billion barrel equivalents.
Shale oil in the Western US is another vast untapped supply. $1.75 a gallon 
ethanol from biomass is indefinitely available. 

Other countries tax gasoline so heavily that it costs greater than $4
a gallon *today*, yet their automotive transport system has not collapsed.
All of the alternatives to natural gasoline listed above are cheaper than
that.

We may choose to go to the more environmentally friendly nuclear power 
instead of tapping some of these resources. That will require good 
electric cars or a hydrogen economy. It should still cost less than
$4 a gallon equivalent and advanced breeder cycles are good for millions
of years.

Gary
>
>
>Just because I own no bed and earn 40% less than the poverty level doesn't
>mean I am poor.
>
>
>