Subject: Re: Black Holes Are Quark Stars
From: sena@news.oswego.edu (Adam David Sena )
Date: Fri, 1 Nov 1996 18:42:45 GMT
Mike Hammond (mhammond@access5.digex.net) wrote:
: While not making the claim that BH's are quark stars, would it be possible
: for a quark star to exist?
: And on a related subject: is the singularity simply a point in space where
: matter once existed, or is it possible to actually be a small point of
: matter. I recall reading something about the smallest diameter of an
: object under extremely high compression (such as found in a BH) could not
: be less than one Planck length.
Right now, not enough is known about how big or small a black hole is.
All we can really figure out is what the diameter of the event horizon
is. If by definition that is the black hole, then so be it. After all,
once you cross the event horizon, nothing else will ever matter. But for
arguments sake, what is the size of the matter part of a black hole. It
is known that regular stars are kept from collapsing under their own
gravity by degenerate electron pressure. That is the electrons of all the
atoms are pressing against each other. Some stars that are massive enough
at the end of their life, crush the electrons and collapse until the
neutrons of the nucleus keep it from collapsing further. This is a
neutron star. A black hole is when there is so much mass (2 to 3 solar
masses or more) that even degenerate neutron pressure isn't enough to
stop it. But how far it collapses no one knows for sure. At the moment,
if there is no other force to stop the contraction, then the black hole
collapses to a singularity. But it is hard to imagine something with a
given mass, zero volume and infinite density. Maybe degenerate quark
pressure exists. Maybe there are even smaller particles we don't know
about that keep the black hole at some (although very small) size.
I believe most of this is correct. It's been several years that I have
really studied astronomy. All that I know is due to my Astronomy professor
here at Oswego, Dr. Chaldu. Any mistakes in here are mine and mine alone,
but I believe most if it is at least mostly accurate.
_______________________________________________________________________
( | )
( Adam Sena | email to: sena@oswego.edu )
( English/Writing Arts BA | )
( Student Operator | )
( Instructional Computing Center | )
( SUNY Oswego, Oswego, NY 13126 | phone: (315) 341-4380 )
( | )
( "Keep your options open and your pants down." )
(__________________________________|____________________________________)
Subject: Re: Hermeneutics and the difficulty to count to three...
From: moggin@nando.net (moggin)
Date: 1 Nov 1996 19:46:49 GMT
moggin:
> |> >Understandable. I would have stayed out of this one, if you had
> |> >let me.
Matt:
> |> Then do so. Either admit you do not have the background or just drop
> |> the subject.
Candy:
> Well, moggin made the point a while ago that someone more educated
> in the hard sciences might better "carry the [Newton is wrong] flag"
> for him. Nevertheless, he continues to post.
And you continue to reply. Strange, huh? The exchange you mention
went like this:
* * *
[Lew:]
> I'll just say that I have a lot of ambivalent feelings and
> opinions about this thread (i .e. "Newtown was wrong" )
> Newtonian dynamics is certainly a "living theory" and
> SR is still treated pedagogically as an elaboration
> on it. This is a simple sociological fact of science, and
> it seems most of the argument has been in justification
> of this practice, which I should think would be beside
> the point. ( ... which point itself was made among the
> numerous exchanges, to be sure. )
>
> On the other hand, it seems it used to be scientifically
> popular to enthuse over the mind-boggling revolutionary
> qualities of SR, and I'm a little nonplussed to see this
> idea pooh-poohed, leaving the hated pomos ( you ) as the
> standard bearer for it. All due to the exigencies of
> rhetoric I suppose.
[moggin:]
: I'm sure you would have done a much better job of carrying the
:flag -- in fact, I wish that you had. But since it fell to me, I
:did the best I could, given my very limited knowledge of physics.
:Next time I'll leave the field to you, o.k.?
* * *
Jeff:
> I just about fell over when he didn't recognize the form of "gamma",
> and wondered what such a thing had to do with the present discussion.
Shame about that inner-ear disorder -- I wonder if it could be
associated with your reading problems? The exchange went as follows:
* * *
[moggin:]
> > Honestly, Richard, tear yourself away from that fish -- it's
> > my opponents, naturally enough, who keep pointing to the areas where
> > Newton works. For my part, I haven't disputed any of their examples.
> > However, I _have_ pointed out that the areas where he works and the
> > areas he doesn't _aren't_ strictly delimited -- to call them "areas"
> > is a convenient fiction.
[Jonathan Stone:]
> Moggin, would you kindly clarify a point of fact?
> Do you know what the Lorentz transform is, or a \beta, or \gamma?
> The answer would seem to bear significantly on the point at hand.
[moggin:]
: Can't you guess? I've made no secret that I don't know much
:phsyics -- I said in so many words that I've got a physics-for-poets
:understanding of the subject. Maybe you just wanted to hear it again
:-- o.k., there you go. Now kindly explain how, as "a point of fact,"
:what I know about the Lorentz transform or a \beta has a significant
:bearing on the utility of Newton's laws: I never realized I had that
:kind of power, and I'd like to learn more.
* * *
-- moggin
Subject: Re: What is the Cause MM's Null Result.
From: Keith Stein
Date: Fri, 1 Nov 1996 19:43:19 +0000
, "Paul B.Andersen" writes
>If the speed of light was always relative to the air,
>that would explain the null result of the MMX.
Right, and thanks for the acknowledgement of that, Paul.
>
>In that case there should be no aberration of starlight.
>
But i can't agree with you on this one Paul. Clearly if light moves
relative to the air, then any motion of the air will be added to the
velocity of light in the medium. Now since the air moves with the Earth
in its journey around the Sun, we would surely expect the light to be
bent in the direction of the Earth's motion by an anlge equal to
arctan (v/c)
I rather think this was Bradley's original explanation, but it is
certainly the one given in the first Science Dictionary i picked up in
Birmingham reference library today, so it's not just me making this up,
as some posters seem to think. Nevertheless i am most gratefull to all
those posters who pointed out that the direction of this aberration is
wrong.
I really do not think it is wrong, but i must admit that the derivation
of aberration given in many physics textbooks(including mine) does give
the opposite sign to that obtained by simple vector addition of the
velocities. The alternative derivation makes the unlikely assumption
that the light is essentially unaffected by the motion of the air, and
shows the aberration to be towards the direction of motion.
>The fact that aberration of starlight is observed shows that
>the speed of light cannot be relative to the air.
>Do you not agree ?
>
No, as i said, but we really must sort out this direction thing,Paul.
Can any astronomer help us out i wonder ?
WHICH DIRECTION IS THE ABERRATION REALLY. ?
but don't anyone just look it up because I know that some books say one
thing, and some another.I've got both answers right here in front of me,
in black and white.
--
Keith Stein
Subject: Re: What is the Cause of Time Dilation?
From: bjon@ix.netcom.com (Brian D. Jones)
Date: Fri, 01 Nov 1996 19:47:57 GMT
throopw@sheol.org (Wayne Throop) wrote [in part]:
>: bjon@ix.netcom.com (Brian Jones)
>: And the time difference for the reunited clocks is an absolute one,
>: so must have an absolute cause.
>Ok, fine. But this absolute cause does not have to be space and time
>measures in some absolute reference frame, as bjon continually
>(invalidly) claims.
>--
>Wayne Throop throopw@sheol.org http://sheol.org/throopw
> throopw@cisco.com
I am not sure what you are saying (wording), but I really don't claim
that there's a usable abs. frame.
My point was that there are absolutes in SRT and in Einstein's views.
Absolutes exists, but are just not (yet, if ever) detectable.
§§ ßJ §§
bjon @ ix. netcom. com
Subject: Re: What is the Cause of Time Dilation?
From: "Paul B.Andersen"
Date: Fri, 01 Nov 1996 16:25:28 +0200
Larry Richardson wrote:
>
> Richard Mentock wrote:
> >
> > Eric Baird wrote:
> >
> > > There's also a variation on the effect, when you take signal timelags
> > > into account. As a result a photographed object appears to be longer
> > > if it's approaching than if it is receding. Simple, simple, simple
> > > kiddie-level stuff.
> > > I've never managed to get a physicist to admit to the existence of
> > > that effect, either (not for want of trying). Textbooks don't mention
> > > an observed length-dilation effect for approaching objects, therefore
> > > it can't exist .
> > > -
> > > =Erk=
> >
> > Fascinating stuff. What are we talking about? "an object appears
> > smaller in a photograph if the object is further away from the camera."
> > Do you mean that of two identical objects, the one that is farthest from
> > the camera will have the smallest extent on the photo? What kind of
> > objections did the physicist raise to that?
> >
> > I've never heard of the receding/approaching effect either. How does
> > that work, using your "signal timelags" explanation.?
> >
> >
>
> I believe this is a reference to the fact that the photons arriving from
> the trailing end of an approaching object left that object at an earlier
> time than photons arriving from the leading end, and during the time
> difference, the leading end had moved nearer the observer, therefore
> giving the object a "stretched" look - the reverse would be true if the
> object were receding.
>
> Larry Richardson
This effect is real. But a quick calculation of what the speed
must be for the effect to be detectable (not to mention what the
exposure time of the camera must be), will show that it is
quite safe to say that nobody has ever observed this effect.
A 10 m long object approaching at 1 km/sec (fighter at mach 3)
would appear 30 micrometers stretched. The exposure time would have
to be less than 30 picoseconds to resolve the stretching.
What we all have observed, however, is that approaching or receding
objects look stretched (and blurred) on photos because they have
moved during the exposure time.
Paul
Subject: Re: Can Science Say If God Exists? (long)
From: tmkoson@umich.edu (Todd Matthew Koson)
Date: 1 Nov 1996 19:47:52 GMT
Jones (mrjones@yoss.canweb.net) wrote:
: On 31 Oct 1996 06:36:15 GMT, tmkoson@umich.edu (Todd Matthew Koson)
: typed something like:
: >: >Once again, fascist Nazi lovong Mr. Jones is bashing judaism. What a
: >: >surprise. Would you care to repost your responses in favor of the
: >: >Holocaust?
: >
: >
: >: Wow, you are really in need of a hobby.
: >
: >As long as you are here smashing the good name of atheism Im giving up on
: >stamp collecting.
: You make me laugh. You are like a christian who says I am bashing
: Christianity when I ask him to prove his god and the son of said god
: exists.
No see, butt-lick, that's the point. Your arguments for and against are
misdirected, poorly formed and idiotic. Doesn't help the casue at all,
makes you worse than the christianic bleaters - death from the inside.
:
I'm actually very sympathetic to what people call atheism, however
: that does not mean I never question it. I am not a fanatic moron like
: you who only believes in their own ego.
And it still amazes me that you can type with your head up your ass. Your
very first post to me, which incidentally had nothing to do with you
whatsoever, started off with that "fanatic" atheist bullshit. Its a
contradiction in terms that only you would take the time to type.
: >
: >: Is your life really so empty?
: >
: >: I feel quite sorry for you.
: >
: >Not half as bad as I feel for you. I write something and compel you to
: >write back. AND YOU DO IT!!! This is great you little ago trip in human's
: >clothing.
: Ago trip?
OH PLEASE CORRECT MY TYPING OH WISE ONE!!!
: and I wrote first,
: you responded
: I'm just being polite.
No, as my little 4 year old cousin said to the three year old - you
started it. But your a little hit and run pussy, so I thought we'd dance
for awhile, cupcake.
: >
: > : I am the first one to enjoy a good scrap, but you seem to have
: >gone
: >: out of your way to continue it, in every thread you can find.
: >
: >Yeah, troll I don't hit and run like you, SS, and Lindauer.
: Who are these people you keep talking about?
: Are they famous?
: Or imaginary friends of yours?
Jesus, you really are the stupidest fuck on a.a. WE ALL KNOW WHO SAVED
SOUL. DAVID LINDAUER are!! PLEASE PROFESS YOUR STUPIDITY TO a.a.
: > I'll shadow
: >your ass
: Oh baby, now you are turning me on.
: >as long as your here making an ass out of atheists.
: But you really do a fine job without me.
Never made an ass out of any atheists here, only you (we know what you're
real agenda is anyhow).
: "Art is making something out of nothing and selling it."
: -- Frank Zappa
--
Todd M. Koson
University of Michigan
College of Literature, Science, and the Arts
"In truth, there was only one Christian, and he died on the cross."
- Nietzsche _The Antichrist_ (39)
"The Christians have never practiced the actions Jesus preached to them; .
. . the Buddist does not act like the non-Buddist, the Christian acts like
*all the world*, and has a Christianity of ceremonies and *moods*."
- - - _The Will to Power_ (191)
Subject: Re: Using C for number-crunching (was: Numerical solution to Schrodinger's Eq)
From: shenkin@still3.chem.columbia.edu (Peter Shenkin)
Date: 1 Nov 1996 19:48:58 GMT
In article <$37sUHAD1$dyEwNK@jessikat.demon.co.uk>,
Robin Becker wrote:
>>Essentially this means that the code you have shown, although all
>>compilers I know would accept it, does not conform to the Fortran 77
>>standard.
>Then surely it's up to implementors of standard conforming compilers etc
>to detect and flag it. ...
No. The Fortran standard tells the *user* what he must do to create a
standard-conforming program. Then it says something about what a
standard-conforming compiler must do with such a program. It deliberately
says nothing about what the compiler should or shouldn't do with a
non-standard-conforming program.
At least this was true of the Fortran77 standard; I'm not sure about f90.
The ANSI C standard mandates much more about what the compiler must
do (e.g., put out a diagnostic) in the case of specific violations
of the standard by the user.
-P.
--
****************** In Memoriam, Bill Monroe, 1911 - 1996 ******************
* Peter S. Shenkin; Chemistry, Columbia U.; 3000 Broadway, Mail Code 3153 *
** NY, NY 10027; shenkin@columbia.edu; (212)854-5143; FAX: 678-9039 ***
MacroModel WWW page: http://www.cc.columbia.edu/cu/chemistry/mmod/mmod.html
Subject: Re: When will the U.S. finally go metric?
From: Achim Recktenwald
Date: Thu, 31 Oct 1996 18:22:28 -0500
Andreas Karrer wrote:
>
> In article <326d3c71.679832@news.cris.com>, Darren Garrison wrote:
>
> >English is one of the most dirivative
> >languages in the world; it absorbs and produces words constantly.
> >That makes among the most flexable languages in the world, but that
> >also makes it one of the most difficult to learn.
The latter claim is pure nonsense. As somebody who is quite comfortable
in two languages (German, English), and having received extensive
education in two more (Latin, French), I find English to be by far the
easiest language to learn. You might be correct with your statement
about the constant absorption and production of new words, but most
people find it rather easy to increase their vocabulary. The difficult
part is usually the grammer, and the English grammer is very very
simple, compared to the German, Latin or French one.
> >British children
> >have to learn that "re" is pronounced "re" unless it is in metre,
> >litre, theatre, or the such, in which case it is pronounced "er."
> >Same in both countries for words like knife, or phone, which should
> >logically be spelled nife and fone.
>
> All languages adopt words from other languages, but somehow, in
> english, people insist on spelling them in the original way, even if
> the original meaning and pronunciation are long lost. Italians have no
> problem with writing "Fisioterapia" (Physiotherapy), because that's
> the way they pronounce the word. In german, "Telefon" is seen more
> often than "Telephon" today. In english, by comparison, you cannot
> in general deduce the pronunciation from the spelling, and certainly
> not the other way 'round. This makes _spelling_ in english very
> difficult, not only for foreigners, but not learning words per se. I
> don't think the US school exercise know as "spelling bee" is used in
> Germany, Spain, or Italy.
>
> --
Subject: potential theory
From: koenemann@abmx.rz.rwth-aachen.de
Date: 1 Nov 1996 19:15:24 GMT
Dear all,
I am interested into the theory of potentials as it relates to a
certain physical problem. The problem is not really the subject of this
posting. But I have read it someplace that a volume of mass may be
reduced to a point source (such that one point in space is supposed
to represent the location in space of the entire mass of the body in
question) only if that body does not interact with other bodies mechanically.
There were more conditions as to when such a simplification is permitted.
I am aware that in astronomy, the sun and the earth and the stars
are routinely treated as point sources which causes no problems.
Also, I have read it someplace explicitly that if a volume of space
is continuously filled with matter it may not be dissolved into a
continuum of sources, but one has to treat it as a distributed source,
where the potential in some given state must be considered to be
scaled per unit mass (and therefore per unit volume). The best example
is, in my opinion, the thermodynamic system.
Now my problem: I am familiar with the book by Kellogg 1929, and by
some short intros to potential theory, e.g. Mary Boas, Mathematics
in the physical sciences. But for my life I cannot remember where I read
the above conditions for treating volumes of mass as point sources.
I would be very grateful for a pointer where I can find this, and if some
one knows of a more modern (and just as thorough) textbook on potential
theory I would appreciate this as well (Kellogg's book uses a style of
writing and a mathematical terminology which are precise, but they appear
to be a little oldfashioned these days).
Please reply to my personal address: koenemann@rwth-aachen.de
Thank you very much,
Falk
Subject: Re: Hermeneutics and the difficulty to count to three...
From: candy@mildred.ph.utexas.edu (Jeff Candy)
Date: 1 Nov 1996 20:33:42 GMT
Jeff:
|> > >> Ca va? In fact, it has EXACTLY the structure:
|> > >> Table 2: -------------------------------
|> > >> | Newt says a = 1 |
|> > >> | |
|> > >> | Stein says a = 1/sqrt(1-x) |
|> > >> -------------------------------
moggin:
|> > |> Excuse me? Newt says all cats are black; Stein says no, it
|> > |> seems they aren't. I don't know how you worked a square root in
|> > |> there.
Jeff:
|> > moggin, this is EXACTLY the form of the difference (in the simplest
|> > case) between classical and relativistic mechanics, where x=v/c.
moggin:
|> You're offering it as an account of the differences between Newt
|> and Stein on the subject of cats. And it doesn't even begin fit the
|> case.
This is a job for the analogy police ...
I am offering it as an account of the difference between Newton
and Einstein. You deleted my first analogy days ago and replaced
it with the Newt/Stein story. While you are free to construct any
analogy you choose, it is obviously pointless to fashion it with
the logical structure of Table 1 if one hopes to understand the
situation in Table 2. I have attempted over and over to recitify
the situation by showing you that the logical structure of the
Newton/Einstein story is in fact EXACTLY that of Table 2, right
down to the square-root.
|> That's not Stein's theory (although I can't speak for whatever
|> reality you're posting from).
see above.
-------------------------------------------------------------------
Jeff Candy The University of Texas at Austin
Institute for Fusion Studies Austin, Texas
-------------------------------------------------------------------
Subject: Re: When will the U.S. finally go metric?
From: ketil@kvatro.no (Ketil Albertsen)
Date: 01 Nov 1996 16:20:54 GMT
Gene> Well, the fear of the number 13 actually has a clinical name...
Gene> 13 is considered "unlucky" by many in this country, and I'm sure elsewhere.
Gene> If the 13th of the month falls on a Friday, it is defintely noted as an
Gene> "unlucky day."
Well, here in Norway it is considered an indicator of bad luck being
run over 13 times by a steam roller on a Friday.
And if Christmas Day happens to fall on a Friday 13th, that is
considered a bad sign, too...
ka.
Subject: Re: Hermeneutics and the difficulty to count to three...
From: candy@mildred.ph.utexas.edu (Jeff Candy)
Date: 1 Nov 1996 20:48:22 GMT
Jeff:
> I just about fell over when he didn't recognize the form of "gamma",
> and wondered what such a thing had to do with the present discussion.
moggin:
|> Shame about that inner-ear disorder -- I wonder if it could be
|> associated with your reading problems?
Odd how you turn *your* ignorance into *my* problem. For future
reference:
1
gamma = ---------------
sqrt(1-beta^2)
beta = v/c
v = velocity of particle
c = speed of light
There, now you know what gamma and beta are, assuming you don't
have a reading problem.
Classical mechanics typically takes gamma -> 1 + (1/2) beta^2,
which is appropriate for small beta.
-------------------------------------------------------------------
Jeff Candy The University of Texas at Austin
Institute for Fusion Studies Austin, Texas
-------------------------------------------------------------------
Subject: Re: MOST IMPORTANT FOSSIL (A human skull as old as coal!)
From: David Weinstein
Date: Fri, 1 Nov 1996 18:37:11 +0000
In article <5573ab$9st@news.ptd.net>, Ed Conrad
writes
>
>The WORLD'S MOST IMPORTANT FOSSIL, unquestionably, is
>a petrified human skull embedded in a boulder which was discovered
>between anthracite veins in Carboniferous strata near Shenandoah, Pa.
>
>It means man -- in almost our present form but considerably larger --
>had existed on earth multi-million years before the initial emergence
>of the earliest cat-size, monkey-like primate which science texbooks
>have long proclaimed to be our most distant ancestor.
>
>A color photo of the skull, with one side protruding from the boulder,
>can now be seen in all its intriguing magnificence at
>> http://www.access.digex.net/~medved/conrad/skulla.jpg
>
>The photograph is a direct link from
>> http://www.access.digex.net/~medved/conrad/conmain.htm
>where photos of other Carboniferous fossils, also found between coal
>veins, can be viewed.
>
>Meanwhile, another photo -- comparing the petrified human cranium
>in the boulder with a modern human skull -- can be seen at
>> http://www.access.digex.net/~medved/conrad/skullb.jpg
>
>
>l
>
>
How in the hell can this be possible? The most advanced life
back then weren't even vertebrates. This is either a very stupid,
pointless hoax, either for advancement or a joke, or else a case of
seriously bad practise of science, with no regard to the proper
scientific method. Surely thios cannot be true.
--
David Weinstein
Turnpike evaluation. For information, see http://www.turnpike.com/
Subject: Re: Relativity and Rotation Question
From: kiekeben@ix.netcom.com(Franz Kiekeben)
Date: 1 Nov 1996 20:56:20 GMT
In kfischer@iglou.com (Ken Fischer) writes:
>
>Franz Kiekeben (kiekeben@ix.netcom.com) wrote:
>: If all motion is relative, so is rotational motion. But in that >:
case,
>: stars move around the earth at speeds in excess of c; and distant
>: galaxies move at millions times c relative to a spinning top.
>: What is the answer? Is rotation not relative? And if so, how can
>: straight line motion be relative?
>
> Just because motion is relative, that doesn't mean
>that effects of acceleration are relative, and rotation of
>anything larger than a point produces acceleration.
I realize that, but I just don't see how any motion can be relative if
rotation isn't. Rotation can be broken down into a bunch of small
straight line motions. For simplicity, take just two of these straight
line motions: a given object X moves for a given distance in direction
A and then for a given distance in direction B. Can it be said that
there was a change of motion for object X which was absolute? It seems
that, in order to regard rotation as absolute, we must (in addition,
this appears to be necessary in order to solve the twin paradox.) But
if there is an absolute change of motion for object X, then X cannot
consider himself at reast throughout the ordeal, from any reference
frame. Is that what you mean by:
> Even linear motion has restrictions on it, even
>though it can be observed as a relative process.
>
>Ken Fischer
Franz Kiekeben
Subject: Re: Gravity and Electromagnetism:Unified Field Theory
From: odessey2@ix.netcom.com(Allen Meisner)
Date: 1 Nov 1996 20:59:07 GMT
In <19961031.110715.445@vnet.ibm.com> jonathan_scott@vnet.ibm.com
(Jonathan Scott) writes:
>
>In article <55677h$ilc@sjx-ixn9.ix.netcom.com>,
> on 30 Oct 1996 00:24:17 GMT,
> Allen Meisner writes:
>>jonathan_scott@vnet.ibm.com (Jonathan Scott) wrote:
>>
>>>In what sense interesting? The total angle by which space is curved
>>>across an elementary particle of mass m, assuming its size to be of
a
>>>similar order of magnitude to its de Broglie wavelength, is around
>>>Gm^2/(hbar c), which is around 10^-39 for a proton.
>>
>> Since you seem to want an answer, I would like to point out the
>>misunderstanding. I am talking about the curvature of the proton and
>>electron themselves, not the curvature they produce.
>
>I don't see how you can make a distinction. If we are talking about
>gravity, the curvature is produced by the mass/energy of the particle.
>
>> I imagine this
to
>>be quite astronomical. Assuming dimensions for the proton to be in
the
>>10^-27 meter range, the energy density is very large. The equivalent
>>energy density of one cubic meter would be about 10^60 joules/m^3.
>
>Why do you assume a proton to be that small? The radius of a proton
or
>neutron is thought to be around 1.5 * 10^-15 m.
>
>If you want curvature rather than angle, divide 10^-39 radians by
10^-15
>meters and you get 10^-24 radians per meter, or to put it another way,
a
>radius of curvature of 10^24 meters.
>
>A large block of similar material is a different matter because the
mass
>would be proportional to the cube of the size but the radius from the
>center would only be proportional to the size, so the gravitational
>potential at the surface would be proportional to the square of the
size
>and the curvature would be proportional to the size. A solid block of
>nucleon material 1 meter across would therefore have curvature about
>10^15 times that of a single proton, giving around 10^-9 radians per
>meter, or a radius of curvature of 10^9 meters. (This is like the
>material within a small neutron star).
>
>If by "interesting" curvature you mean curvature of the same order as
>the size of the object, you are talking about a black hole, large or
>small.
>
>Jonathan Scott
>jonathan_scott@vnet.ibm.com or jscott@winvmc.vnet.ibm.com
Yes, but as I said, I am talking about the curvature of the mass
itself, not the gravitational curvature produced in the spacetime
surronding the mass. You are right about the dimensions. Still the
energy density would then come out to be 10^30 joules/m^3. You are
right that this corresponds to a black hole, but scientists have known
this for a long time and it does not seem to bother them.
Edward Meisner
Subject: Re: What kind of fakery? (was: Sophistry 103)
From: nanken@tiac.net (Ken MacIver)
Date: Sat, 02 Nov 1996 00:32:33 GMT
turpin@cs.utexas.edu (Russell Turpin) wrote:
>-*--------
>In article <55botq$blp@news-central.tiac.net>,
>Ken MacIver wrote:
>> ... I think it is wrong for a writer to have as a goal the
>> submission of a phony article to an editor. ...
[snip of long post attempting to justify Sokol and includes the
below]:
(5) Sokal *did* say outrageously false things
>about some of the works and authors he worked into his article.
>These provide, perhaps, the easiest ground for condemnation.
[snip more of the same]
I suspect, though that
>those who condemn Sokal for fakery have something else in mind.
I had in mind Sokol's own statement, as reported in this newsgroup,
that he committed a "hoax" on the magazine. If he is now saying that
he submitted a valid article, what is the brouhaha all about. If not,
do you believe that it is okay for a writer to have as a goal the
submission of a phony article to an editor [as long as you think it is
for a *worthy* cause]?
Ken
Subject: Re: Hermeneutics and the difficulty to count to three...
From: jti@santafe.santafe.edu (Jeff Inman)
Date: 1 Nov 1996 21:23:24 GMT
moggin@nando.net (moggin) writes:
>Michael Stewart:
>Jeff Candy:
>> Q2: what is a not-wrong theory of mechanics?
>
> Guess I haven't mentioned it lately, but I'm steering clear of
>metaphysics, just this once. I notice that Jeff Inman and Andy Dinn
>are around -- you could probably inveigle them into discussing it.
Just passing by, and ... what's this? I'm getting volunteered to
discuss metaphysics with a bunch of folks who -- hmmm, well never
mind. You'd have to twist my arm. Okay, okay, leggo, leggo. Just
remember that I'm not speaking for Moggin, here.
A "not-wrong theory of mechanics" is one which is in accord with
whatever the existing metaphysics is.
If this makes you tip your head sideways, wrinkle your forehead and go
"hmmHMM?" like my former-girlfriend's amusing black lab does, then I'm
just going to answer you the same way I answer him, namely, by
repeating what I just said in an even more exaggerated and
interrogative tone, to see how deep I can make the wrinkles go. He
was pretty smart though, and didn't have much trouble with
metaphysics.
[Jeffrey?] Davis claims that, just this week, I have uttered the
"stupidest thing [he's] ever read on r.a.b", or something like that.
(Perhaps the runner up would be his subsequent post, responding to
that same utterance, which he suddenly finds interesting.) It would
be quite a feat to manage this twice in the same week.
--
"But among those whom this story reached were were also the woman's
in-laws, and they decided, without telling her a word, to find this
angel and to see if knew how to fly ..."
Subject: Re: Masquerading human flesh as beef?
From: sterner@sel.hep.upenn.edu (Kevin Sterner)
Date: 1 Nov 1996 21:21:10 GMT
In article , OX-11 writes:
> There is a somewhat disturbing rumor floating around the net--that the
> government is selling human flesh as beef and pork in the local markets
> (possibly as a way to eliminate political enemies). My question is this:
> is there a way to treat human flesh so people would think they are eating
> beef, or possibly pork? and , just how could you tell what you were bying
> at the market? I know this sounds crazy, but I have recently come across
> an individual too scared to eat red meat who have cited the above rumor
> as a reason they avoid pot roast.... :-(
Don't spare the pot roast! Human flesh is not red meat.
It's that pork shoulder you should worry about. Human flesh is...I have
heard...very much like pork, so much so that one cannibal culture calls
pork "short pork" and human flesh "long pork".
But anyway, why would someone go to the trouble of marketing human
flesh when A) pigs are cheap and B) there are cheaper ways of getting
rid of bodies. Not only that, but you'd have to kill thousands of
humans for their flesh in order to become a meat supplier of any use
to any retailer.
Still and all, it's economically more feasible than the suggestion that
McDonald's hamburgers are made from kangaroo meat, and that rumor
had quite a bit of life in it.
-- K.
-------------------------------------------------------------------------------
Kevin L. Sterner | U. Penn. High Energy Physics | Smash the welfare state!
-------------------------------------------------------------------------------
Subject: Re: What is the Cause of Time Dilation?
From: throopw@sheol.org (Wayne Throop)
Date: Fri, 01 Nov 1996 22:05:29 GMT
:: Bjon likes to refer to some physically-undefined "same instant", and
:: to pretend this is unambiguous. But repetition doesn't make it so.
: bjon@ix.netcom.com (Brian D. Jones)
: Not so.
So.
: It is a fact that there are two clocks.
It't a given of the hypothetical, sure.
: It is a fact that both have readings at absolutely the same time, as
: long as both are operating.
Nope. Bjon hasn't established that there IS any such physical thing as
"absolutely the same time".
: All I am asking you is what are these readings. You have only two
: choices: Both read zero at absolutely the same time, or one reads zero
: while the other reads something else.
Or three, there isn't any such a thing as absolute time.
SR doesn't logically require one of bjon's two alternatives
(though it doesn't rule them out either).
Perhaps bjon thought that everything not forbidden was mandatory?
: We need not bring up "coordinate systems" in order to discuss these
: simple clock readings.
Presumably bjon doesn't see the irony (or self-contradiction) in this.
: Just pick up a piece of plain white paper, and draw a couple of clocks
: meeting a light ray.
:
: You will instantly see that it is not possible for the rear clock to
: read zero at the time (absolute) that the front reads zero because
: this will not result in "c" for light's speed. Also, as I have
: already pointed out, SRT disallows truly set clocks (or clocks that
: both read the same).
Oh, well, now you're talking about a paper frame of reference.
That wasn't in the original problem. Sure, as soon as you specify
a frame of reference WRT which the rod is in motion, the front and
rear clocks are not setting-synchronized in that coordinate system.
Anybody can see that; it's obvious.
On the other hand, it's also obvious that nothing but bjon's whim
requires one to introduce such a reference scheme in the first place.
The physical interactions of clocks, light, and rod don't require it,
and SR's analysis of such doesn't require it.
: So, even in your (unnecessary) "reference system setup," how do you
: know that the rear clock reading is zero when the front one reads
: zero?
Same way bjon knew that the light took D/c in this coordinate
system for the light to reach the rear clock.
--
Wayne Throop throopw@sheol.org http://sheol.org/throopw
throopw@cisco.com
Subject: Re: Why zooming?
From: paul@austin.ibm.com (Paul Wadehra)
Date: 1 Nov 1996 22:02:31 GMT
tcox@us1.ibm.com wrote:
>
>The retina of the eye has a higher density of rods and cones near
>the center, giving a clearer image than at the edges of vision.
>
>Tony
Actually, I always thought that while the cones are more concentrated
in the center, the rods are more concentrated around the outside.
This has been borne out by my own testing: at night, dim stars disappear
when I look right at them, then reappear when I look at them with
my peripheral vision. Since rods are responsible for night-vision,
the theory is supported.
Paul
--
------------------------------------------------------------------------
Paul Wadehra (512) 838-1132 IBM RS/6000 Division
Internet: paul@austin.ibm.com AIX Multimedia Development
-------- Opinions expressed are not necessarily my employer's. ---------
Subject: Re: What is the Cause of Time Dilation?
From: bjon@ix.netcom.com (Brian D. Jones)
Date: Fri, 01 Nov 1996 21:43:36 GMT
throopw@sheol.org (Wayne Throop) wrote [in part]:
>: bjon@ix.netcom.com (Brian Jones)
>: Nothing ambiguous there. I said clearly that the front clock read
>: zero when the light ray "hit" it. I later referred to this very same
>: front clock reading.
>Bjon also clearly asked what the reading on the REAR clock was
>"at time zero (per the front clock)". This is clearly ambiguous,
>and simply trying to point to portions of the whole that are not
>ambiguous (eg, events only at the front clock) do not suffice to
>validate bjon's attempt to sneak an unambiguous meaning of
>"at the same time" for two distant clocks.
>: If both the clocks read "zero" at the same instant (as you said above,
>: or at least this is the only way anyone can take it),
>Why not take it the way I said it? Which is, that in the coordinate
>system in which the front clock is at rest, the rear clock reads
>zero when the light strikes the front clock? That gives physical
>meaning to all the claims; we've physically said how to set up
>coordinate systems, we've got physical clocks and a physical rod.
>Bjon likes to refer to some physically-undefined "same instant",
>and to pretend this is unambiguous. But repetition doesn't make it so.
Not so. It is a fact that there are two clocks. It is a fact that
both have readings at absolutely the same time, as long as both are
operating. All I am asking you is what are these readings. You have
only two choices: Both read zero at absolutely the same time, or one
reads zero while the other reads something else.
We need not bring up "coordinate systems" in order to discuss these
simple clock readings. Just pick up a piece of plain white paper, and
draw a couple of clocks meeting a light ray.
You will instantly see that it is not possible for the rear clock to
read zero at the time (absolute) that the front reads zero because
this will not result in "c" for light's speed. Also, as I have
already pointed out, SRT disallows truly set clocks (or clocks that
both read the same).
>: Both the clocks cannot read "D/c" at the same time because this is
>: absolute synch, a forbidden type of synch.
>I made no reference to absolute anything. I specifically did not
>say anything about "the same [absolute bjonian] instant". If bjon
>wants to import his own errors into the discussion and then debunk them,
>fine, but don't attribute reference to this superfluous "absolute time"
>to me, thank you very much.
>--
>Wayne Throop throopw@sheol.org http://sheol.org/throopw
> throopw@cisco.com
So, even in your (unnecessary) "reference system setup," how do you
know that the rear clock reading is zero when the front one reads
zero?
§§ ßJ §§
bjon @ ix. netcom. com
Subject: Re: Relativity and Rotation Question
From: nurban@csugrad.cs.vt.edu (Nathan M. Urban)
Date: 1 Nov 1996 16:50:13 -0500
[Followups to sci.physics.relativity]
In article <55d2kv$1rg@dfw-ixnews7.ix.netcom.com>, kiekeben@ix.netcom.com(Franz Kiekeben) wrote:
> If all motion is relative, so is rotational motion.
Not exactly. I hate it when pop-science books say "all motion is
relative" because they never say precisely what that means. You cannot
distinguish one frame of inertial (constant-velocity) motion from
another, but you can distinguish between non-inertial (accelerating)
frames; just measure the acceleration.
> But in that case,
> stars move around the earth at speeds in excess of c; and distant
> galaxies move at millions times c relative to a spinning top.
No.. this is where the relativity principle fails; in accelerating
non-inertial frames such as rotating ones. You can patch up this
problem sometimes with another relativity principle, the equivalence
principle, which says that you cannot distinguish gravity from accelerated
motion, _locally_, but that still doesn't help when talking about distant
objects.
> Are there any books or articles that address this issue?
Though I've never read it, from the title and authors I would suspect
that _Gravitation and Inertia_ by Wheeler and some other guy (Ciufolini
or something like that) would be the best bet. They say quite a bit
about noninertial frames and Mach's principle and such.
Also, consult the Relativity FAQ.
--
Nathan Urban | nurban@vt.edu | Undergrad {CS,Physics,Math} | Virginia Tech
Subject: Re: Hermeneutics and the difficulty to count to three...
From: meron@cars3.uchicago.edu
Date: Fri, 1 Nov 1996 22:18:26 GMT
In article , moggin@nando.net (moggin) writes:
>
>> >> This however still doesn't mean that much. If relativity would
>> >> consist of abandoning all or most of the notions of classical
>> >> mechanics and buikding from scratch then you could claim that in
>> >> principle classical mechanics is wrong and it just happens to yield
>> >> good results over some region due to a lucky coincidence. This is not
>> >> the case however. Relativity carries over almost all the notions of
>> >> classical mechanics, intact. It changes exactly one aspect, the issue
>> >> of transformations between reference frames and even this one is
>> >> changed in such way that classical mechanics resides within relativity
>> >> as a special or limiting (sorry, couldn't avoid it) case. Thus by all
>> >> rights relativity can be considered a generalization of classical
>> >> mechanics.
>
>Mati:
>
>> > No, not "by all rights" -- by a definition of "generalize" that
>> >permits the "generalization" to depart from the "generalized," since
>> >Einstein's model differs from Newton's in many significant respects.
>
>Matt:
>
>> Do you know of any of those respects? Please give a few examples other
>> than the frames of reference mentioned above.
>
> I've given a slew of examples, and since you've been here since
>the beginning, you've seen them all -- as I said, you want to repeat
>the whole debate, presumably in hope of doing better the second time.
>
You did give a slew of examples. You didn't realize though that (as
far as SR is considered) all of them are the results of a one, and
only one thing. SR is different from classical mechanics in one
respect (I trust you remember what it is). And it is the form of this
difference that makes it obvious why it is a generalization.
Mati Meron | "When you argue with a fool,
meron@cars.uchicago.edu | chances are he is doing just the same"
Subject: Re: Hermeneutics and the difficulty to count to three...
From: candy@mildred.ph.utexas.edu (Jeff Candy)
Date: 1 Nov 1996 22:23:26 GMT
Jeff Candy:
>> Q2: what is a not-wrong theory of mechanics?
Jeff Inman:
|> A "not-wrong theory of mechanics" is one which is in accord with
|> whatever the existing metaphysics is.
Objectivist metaphysics.
What is a not-wrong theory of mechanics?
|> If this makes you tip your head sideways, wrinkle your forehead and go
|> "hmmHMM?" like my former-girlfriend's amusing black lab does, then I'm
|> just going to answer you the same way I answer him, namely, by
|> repeating what I just said in an even more exaggerated and
|> interrogative tone, to see how deep I can make the wrinkles go. He
|> was pretty smart though, and didn't have much trouble with
|> metaphysics.
Coincidence?
-------------------------------------------------------------------
Jeff Candy The University of Texas at Austin
Institute for Fusion Studies Austin, Texas
-------------------------------------------------------------------
Subject: Re: Is glass a solid?
From: peter@cara.demon.co.uk (Peter Ceresole)
Date: Fri, 01 Nov 1996 22:03:45 +0000
In article <3279104E.7E56@eskimo.com>,
Stephen La Joie wrote:
>Wow, Peter! I bet you are just as lucid and insightful in all your
>academic endeavors.
If I had any, I'm sure I would be.
I was thinking of all those FAQs that have slumbered in vain. And somebody
has just brought them out again; not surprising. After all, they have been
invoked each of the past five times. Each time the thread dies gracefully,
the forces of flow routed, and then new liquidisers come out of the
woodwork. It's spontaneous generation, like cockroaches at the Chelsea
Hotel.
--
Peter
Subject: Re: When will the U.S. finally go metric?
From: Paul Skoczylas
Date: Fri, 01 Nov 1996 15:54:25 -0700
Markus Kuhn wrote:
>
> A4 paper can also be ordered in
> the U.S., because the U.S. gets most paper from Canadian manufacturers,
> which also deliver a lot of paper to Europe, Japan, and other countries.
> Very new laser printers are delivered even in the U.S. with paper trays
> that can be configured between U.S. letter and ISO A4.
I've never actually used A4 paper (here in Canada) and I've only seen it
once. I took a European brochure to the photocopier and was quite
surprised that it didn't match the "letter" size lines, but rather the
"A4" lines.
(The point there, is that although you may be able to buy A4 paper from
Canada, it may be difficult to buy it in Canada! The same goes for
lumber, though. I don't know that the ISO specs are for lumber, but I
know that Canadian mills sell lots abroad. Try buying a stud other than
a 2x4 in 8' or 12' lengths in a lumber yard here, though.)
A switch to A4 (or to ISO lumber sizes for that matter) should be
reasonably painless, because all our photocopiers and laser printers are
built to accept both, either with a new cartridge or an adjustable one.
Buy new binders along with the paper (you'd probably need new binders
anyway), etc...
-Paul
Subject: Re: When will the U.S. finally go metric?
From: crowl@philmont.eng.sun.com (Lawrence Crowl)
Date: 1 Nov 1996 22:48:12 GMT
In article <55a5j4$jlk@electra.saaf.se>,
Paul Schlyter wrote:
>A sexagesimal (base 60) system would be even better. We actually
>already have this when measuring time: hours-minutes-seconds. When
>measuring angles arc-minutes and arc-seconds are often used for small
>angles. 60 is evenly divisible with: 2, 3, 4, 5, 6, 10, 12, 15, 20
>and 30 whereas 12 only is evenly divisible with 2, 3, 4 and 6.
The only objection I have to base 60 is that it would be very hard to
learn the arithmetic tables. I remember the 12x12=144 tables I learned
being very hard. I shudder to think what pain 60x60=3600 tables would
have caused me.
--
Lawrence Crowl 415-786-6146 Developer Products, SunSoft
Lawrence.Crowl@Eng.Sun.Com 2550 Garcia Avenue, UMPK16-303
http://www.cs.orst.edu/~crowl/ Mountain View, California, 94043
Subject: Re: When will the U.S. finally go metric?
From: crowl@philmont.eng.sun.com (Lawrence Crowl)
Date: 1 Nov 1996 22:45:25 GMT
In article <327A42EF.E45@cs.purdue.edu>,
Markus Kuhn wrote:
>In a system where the base is a power of two, you do not need any
>tables, as conversion to the binary system is trivial and the algorithms
>for elementary calculations also do not need any lookup tables.
True enough, but calculating in binary will result in more steps, which
slows the process.
>> (3) How many distinct small factors does the base have?
>> Commerce favors selling in quantities that can be easily
>> divided.
>
>Then select the quantities you sell as a multiple of 60 in a reasonable
>small unit (gram, millimeter, mol, etc.). I still do not see a need to
>give special names to multiples of the module sizes, as the module
>factor will vanish anyway after the division.
I don't know of any products in the U.S. sold in 600ml containers.
They're all 1l or 500ml.
>Giving special names to
>certain powers of the base on the other hand does not make any
>calculations more difficult. And for practically all commercial
>purposes, 1000/3=333.3 has more than sufficient precision anyway.
Well, the issue falls away if I have a measuring cup of 1/3 liter, or
have a 1/3 liter line marked on the bottle.
>> >[Reference for those interested in what Martin digits are:
>> >Communications of the ACM, Vol 11, No. 10, October 1968, p. 658.]
>>
>> Can you give us a short summary of Martin digits?
>
>The essential idea is that the shape of the digits of a base 16 system
>should make it especially easy to convert the digits in the
>corresponding bit group for binary calculations. Martin digits do not
>require anyone to remember B=1011, as the shape of the digit is directly
>related to the bit pattern. With digits designed carefully this way and
>some with some practice you can do addition and multiplication without
>remembering any tables.
>
>Its a pretty cool concept and it would have been nice if the arabic
>mathematicians who invented our base 10 system or Fibonacci who made it
>popular in Europe had already been aware of these ideas, but it is
>certainly unrealistic to change the base 10 representation today.
>
>As far as the metric system is concerned: less than 250 million (<5%)
>out of over 5200 million people on this planet do not yet use the metric
>system and related international standards. The required effort for a
>change is therefore orders of magnitude smaller than changing to a
>different base.
Other units are still in wide use throughout the world, so it's not
quite accurate to say taht all 5200 million people use the metric
system (exclusively, anyway). And the cost of conversion is not
related to the number of people, but to the capital investment. I'll
concede one order of magnitude, but no more.
>The USA are very isolated by not using the metric system.
True. I favor a metric conversion, I just don't want the cost and
difficulty underestimated.
>May be, we should spread the word that there is nothing wrong with the
>13, but that a 14 after a missing 13 will bring you *really* bad luck as
>you tried to betray the 13 and it will therefore be *very* angry on you.
I like it!
>Well, as I look at the Halloween pumpkin that is still sitting on my
>workstation monitor here, I must admit that I start to consider this
>argument myself to be pretty convincing ... (see attachment ;-)
My mailer doesn't do attachments or base64. The problem with standards
is that there are so many of them.
--
Lawrence Crowl 415-786-6146 Developer Products, SunSoft
Lawrence.Crowl@Eng.Sun.Com 2550 Garcia Avenue, UMPK16-303
http://www.cs.orst.edu/~crowl/ Mountain View, California, 94043