HDTenEightyP/NetNews huggingface dataset:
From: bweiner@ruhets.rutgers.edu (Benjamin Weiner)
Newsgroups: sci.physics
Subject: Re: Why does the moon keep the same face to the Earth?
Keywords: Moon Rotation Inertia Momentum
Date: 25 Jan 93 06:00:06 GMT
Organization: Rutgers Univ., New Brunswick, N.J.

acampane@magnus.acs.ohio-state.edu (Angelo Campanella) writes:
>I conjecture that a slight nonumiformity of the moon's mass distribution
>exists, and that the face of the moon pointed at us carries a mass bulge.

This is of course true, because the earth raises tides on the moon which
tend to elongate it along the earth-moon axis.

>This would then make the rotational moment of inertia of the earth-moon
>system at a minimum, and hence be in stable rotation.

This is known as "tidal locking"; what happens is, if the moon rotates
nonsynchronously, then the tidal bulge is moving about on the surface
of the moon; the moon is stretching and contracting, and this dissipates
energy.  So this tidal friction retards the moon's rotation until it 
slows to being locked.

>One wonders if energy dissipation mechanisns such as our ocean tides are no 
>absorbing rotational energy, and that another permanent equilibrium should 
>someday exist; the earth pointing always one face at the moon.

A stronger effect is that, while the moon now rotates slowly, the earth
is still rotating quickly; hence the tidal bulge on the earth rotates
"out from under" the moon, and leads the moon in its orbit.  (Obviously 
there has to be some time constant for deformation/relaxation of the
earth's shape for this to happen ...)  The leading bulge exerts a little
more force on the moon than the trailing bulge does, so it tends to
speed the moon up, which moves the moon to a higher orbit.  The back
reaction tends to slow the earth's rotation.

According to the book I'm looking at ("Astronomy: the cosmic journey", gee
wow!, by W.K. Hartmann), eventually the earth becomes tidally locked to the
moon, partly due to the _solar_ tides on earth; then the solar tides slow
the earth's rotation further, the day becomes _longer_ than the month, and
the moon starts getting closer again.  Unfortunately he doesn't mention
any timescales.  Another amusing fact he gives is that there is evidence
for the changing day and month; certain marine animals have daily and monthly 
bands in their shells, and the fossil record suggests that 2.8 billion years 
ago the month was only 17 days long.
From: bweiner@ruhets.rutgers.edu (Benjamin Weiner)
Newsgroups: sci.physics
Subject: Re: THE DIVINE MASTERS OF THE UNIVERSE
Keywords: meshuggene
Date: 28 Jan 93 06:04:23 GMT
Organization: Rutgers Univ., New Brunswick, N.J.

mcelwre@cnsvax.uwec.edu (One Meshuggene Human Being) writes:
  (much deleted)
>          [ ALWAYS use the "KING JAMES VERSION".  Later
>          versions are PER-VERSIONS! ]   

Uh, I th... oh, never mind.  This reminds me of the sheriff in Texas
who, explaining his opposition to bilingual education, said,
"If English was good enough for Jesus, it's good enough for me!"
Newsgroups: sci.physics
From: matmcinn@nuscc.nus.sg (brett mcinnes)
Subject: Re: Black hole insights
Organization: National University of Singapore
X-Newsreader: Tin 1.1 PL4
Date: Wed, 27 Jan 1993 03:05:21 GMT

ted@physics3 (Emory F. Bunn) writes:
: 
: One rather strange thing is that for r<R, r is a timelike coordinate and
: t is spacelike.  So that means that the singularity r=0 is not a 
: single point in space that exists at all times; rather, it is a single
: point in time that exists at all "distances" t.  This makes it clear
: why you can't avoid the singularity once you've crossed the horizon.
: Since the singularity is a future point in time, you can't alter your
: world line to avoid hitting it, any more than you can alter your world
: line to avoid hitting next Thursday.
: 
Right, and this also makes it clear that it is nonsense to speak of
"gravity being so strong that even light is pulled into the central
singularity". Would anyone say that some force is pulling him 
into next Thursday? 
Newsgroups: sci.physics
From: jbaltz@watsun.cc.columbia.edu (Jerry B Altzman)
Subject: Re: Physics News Update #111 (1/21)
Keywords: physics news interesting banana
Reply-To: jbaltz@watsun.cc.columbia.edu (Jerry B Altzman)
Organization: mailer daemons association
Date: Fri, 22 Jan 1993 18:19:51 GMT

In article <1993Jan22.053914.21600@midway.uchicago.edu> revu@midway.uchicago.edu writes:
>the scientists in this Maryland-AT&T-Berkeley collaboration use
>the prefix milli-atto to denote 10 raised to the -21st power, the
>official name for this prefix is "zepto," or just z.  For those who
>would go further yet, the name for 10**-24 is "yocto."  (Science
>News, 16 Jan. 1993.)

I am to assume then that 10^-27 is the "harpo" and the very small 10^-30 is
a "groucho" then?

//jbaltz
jerry b. altzman   Entropy just isn't what it used to be      +1 212 650 5617
jbaltz@columbia.edu      jbaltz@sci.ccny.cuny.edu      (HEPNET) NEVIS::jbaltz
From: corleyj@helium.gas.uug.arizona.edu (Jason D Corley )
Newsgroups: sci.physics
Subject: Re: Debate question of the day!!!!!
Date: 22 Jan 93 00:07:28 GMT
Organization: University of Arizona, Tucson

In article <1993Jan21.210443.22118@newsgate.sps.mot.com> wied@animal.sps.mot.com (Bill Wied) writes:
>Hello all you physic buffs,
>
>We were having a debate today about what makes a balloon full of air propel.
>There were two theories expressed as to what is the major cause of propulsion.
>
>The two theories go as follows:
>
>1) Is it caused primarily by the effect of conservation of momemtum. That is,
>   the propelling of the air mass in the ballon out at a high velocity causing
>   the ballon to travel in the opposite direction with the same momemtum.
>
My newsreader cut you off here.  But the answer is YES.  Reasoning:
Tie off the balloon.  Air on the inside is pushing the outer walls at
the same rate all over the inside (Reasoning: It ain't moving.)
Open the balloon.  Air next to hole shoots out.  That means there's more
air pushing on the other side, still at that same constant force.
Shwooooom.

This is the first question I've been able to answer confidently on this
group!  Usually I'm the asker, not the askee!  (pause) So...I wonder if
I got it right...?
>
>2) Is it caused primarily from the air being expelled at a high velocity,
>   pushing against the exterior atmosphere thus creating high air pressure
>   outside the ballons opening, which thrusts the balloon forward.
>
Nope.   Reasoning: Put the balloon in a vacuum.  Let it go.  See? Still
works.

--
***************************************************************************
"I was pleased to be able to answer promptly, and I did.  I said I didn't
 know."----- Mark Twain, _Life on the Mississippi_
Jason "corleyj@gas.uug.arizona.edu" Corley Was Here But Isn't Anymore
From: brahm@cco.caltech.edu (David E. Brahm)
Newsgroups: sci.physics
Subject: Re: Super-Strings
Date: 25 Jan 1993 08:46:17 GMT
Organization: California Institute of Technology, Pasadena
Distribution: world
NNTP-Posting-Host: punisher.caltech.edu
Summary: Why 1+1 dimensions is so nice

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

One could, and people do ("super-membrane theory"), but there is something
particularly nice about 1+1 dimensions (the world sheet of a string),
called (I believe) conformal invariance.  Whenever you write an action in
curved spacetime, it looks like
  S = \int d^D x  \sqrt{g} g^{\mu \nu}  ...stuff...
where "g" is the determinant of g_{\mu \nu}, the inverse of the metric.  In
2D, the metric has 3 degrees of freedom, but 2 can be eliminated by
coordinate transformations; what remains can be written
  g^{\mu \nu} = \eta^{\mu \nu} e^\phi
where "\eta" is the Minkowski (flat) metric.  Then "g" is proportional to
e^{-\phi}, and "\phi" drops out of S!  This only works in 2D, and is
important to the rest of the development of string theory.  See Green,
Schwartz & Witten p.23 (that's about as far as I ever got in it! :-)

Furthermore, 2D is better than 1D (the world lines of point particles)
because 1D interactions (e.g. one particle splits into two) occur at a
single spacetime point, which can lead to singularities and infinities.
String interactions, on the other hand, are not localized to a point.

So conformal invariance and finiteness are the nice features of strings.

--
Staccato signals of constant information,  |  David Brahm, physicist
A loose affiliation of millionaires and    |  (brahm@cco.caltech.edu)
  billionaires and Baby ...                |---- Carpe Post Meridiem! --
These are the days of miracle and wonder,  | Disclaimer:  Forgive me, Lord,
And don't cry, Baby, don't cry, don't cry. | I have defended String Theory.
Newsgroups: sci.physics,sci.skeptic,alt.paranormal,alt.sci.physics.new-theories,rec.arts.startrek.tech
From: afzal@divsun.unige.ch (Afzal Ballim)
Subject: Re: New Physics, Healing, Paranormal
Reply-To: afzal@divsun.unige.ch
Organization: University of Geneva, Switzerland
Date: Wed, 27 Jan 1993 08:09:27 GMT

In article <1k436cINNfe5@emx.cc.utexas.edu>, ethan@emx.cc.utexas.edu (Ethan T. Vishniac) writes:
|> 
|> In cases like this the request for appropriate references
|> is doomed to failure, but making the request makes a point
|> so....
|> 
|> How about CARP?  
|> 
|> Cite Appropriate References Please

How about CRAP?

Cite References And Proof

-- 
Afzal Ballim	             |BITNET,EARN,MHS,X.400: afzal@divsun.unige.ch
 ISSCO, University of Geneva |UUCP: mcsun!divsun.unige.ch!afzal
 54 route des Acacias	     |JANET: afzal%divsun.unige.ch@uk.ac.ean-relay
 CH-1227 GENEVA,Switzerland  |CSNET,ARPA: afzal%divsun.unige.ch@relay.cs.net
From: matt@physics2.berkeley.edu (Matt Austern)
Newsgroups: sci.physics
Subject: Re: Magnetic monopoles?
Date: 26 Jan 93 22:48:37
Organization: Lawrence Berkeley Laboratory (Theoretical Physics Group)
	<MERRITT.93Jan25150507@macro.bu.edu>
	<1993Jan27.055742.24399@galois.mit.edu>
Reply-To: matt@physics.berkeley.edu
NNTP-Posting-Host: physics2.berkeley.edu
In-reply-to: jbaez@riesz.mit.edu's message of Wed, 27 Jan 93 05:57:42 GMT

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

> Hmm, I don't.  First, while naive monopoles change dF = 0, *d*F = J to the
> nicer-looking dF = K, *d*F = J (where F is the field strength, J the
> electric current, and K is the magnetic current), this destroys the 
> gauge symmetry of the equations!  Why trade a hefty infinite-dimensional
> symmetry group for a measly U(1)?

Is this really true?  I've never thought very deeply about this, but
it seems reasonably plausible to me that you can have a version of
electromagnetism with "symmetric" looking Maxwell's equations if you
just change the gauge group from U(1) to U(1)xU(1), with electric
charges as the sources for one vector potential and magnetic charges
as the sources for the other.

Aside from the objection that U(1)xU(1) is an awfully ugly gauge
group, is there something obviously wrong with this idea that I've
overlooked?

--
Matthew Austern                   Just keep yelling until you attract a
(510) 644-2618                    crowd, then a constituency, a movement, a
austern@lbl.bitnet                faction, an army!  If you don't have any
matt@physics.berkeley.edu         solutions, become a part of the problem!
Newsgroups: sci.physics
From: dannyb@panix.com (Daniel Burstein)
Subject: Re: What causes electrical shock?
Organization: PANIX Public Access Unix, NYC
Date: Fri, 22 Jan 1993 11:38:07 GMT

In <1993Jan21.201040.15276@news.unomaha.edu> djclute@cwis.unomaha.edu (Daniel Jonathan Clute) writes:

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

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

the shock is courtesy of statci electricity which developed as you walked
and rubbed against a carpet or similar material.

Methods of reducing static buildup unclude such things as increasing
humidity, using different materials, etc.  I'm sure you'll hear hundreds
of suggestions.

to reduce the shock, I sugegst you hold your key in your hand, and have
the key make the initial contact with the doorknob.  this will do a pretty
good job of disbursing the current and reducing (in fact, usually
eliminating) any shock to you.  If you still get zapped, rest assured that
it is only 1/100th (??) of what you'd have gotten originally.

take care

dannyb@[anix.com
From: frenkel@stcst1.mrl.uiuc.edu (David Frenkel)
Newsgroups: sci.physics
Subject: Re: sci.physics.research: Are there imp
Date: 24 Jan 93 18:10:06 GMT
Article-I.D.: news.C1DEGu.7Hv
Organization: Dept of Physics, Univ of Illinois, Urbana

In article <1541700025@gn.apc.org> antennae@gn.apc.org writes:
>
>
>You don't need moderators.  You've already hounded Hannu off the net...
> ...
>It worries me to hear you discussing how 'tough' you should be - as
>though this newsgroup was a place to show off cleverness rather than
>a point of communication for everyone on the net interested in physics
>and physics-related issues.

  Strong stuff, but a couple of points are due.

(1)  There is a large number of moderated newsgroups out there.
     How did they come about?
     Let us not forget that one of the roles the moderators would play
     is to weed out the more vicious replies. If this is coupled with
     a sufficiently broad-minded approach to what questions can
     be asked, the end result may be quite positive. Let us give it
     some time to see if it works.

(2)  We live in an information age, where all of us are overloaded.
     If you think of it, FAQ's are a way to deter people from posting;
     regular users do not wish to see the same elementary stuff
     rehashed over and over.
     Surely, it has not escaped anyone that the majority of
     current postings deal with foundational issues of physics,
     and there is precious little that is related to what the
     majority of physical scientists (either practitioners
     or interested observers) would care about on a regular basis.
     Why is it so unreasonable to somewhat limit that stuff
     on one  group, so those of us who do not think of these
     matters on regular basis have enough breathing space to
     talk about other things?


-- 
David Frenkel                        | e-mail:   frenkel@stcst1.mrl.uiuc.edu 
Department of Physics,               | 
University of Illinois at            |
Urbana-Champaign, Urbana, IL, USA    |
From: terry@asl.dl.nec.com
Newsgroups: sci.physics
Subject: Re: What is Yttria stabilised zirconia??
Keywords: HTS, substrate, yttria stabilised zirconia
Date: 22 Jan 93 19:27:24 GMT
Organization: (Speaking only for myself)
Originator: terry@aslss01

In article <1jp5jrINNl9c@matt.ksu.ksu.edu>
ame@matt.ksu.ksu.edu (Abdulrahman M El-Koubysi) writes:

> I was reading an article lately about High temperature superconductors. The
> article mentioned that they use yttria stabilised zirconia substrates. What
> is special about this substrate? what makes it different than previously 
> used substrates such as silver? Are there companies out there that 
> commercially produce these substrates or are they custom made??

If I recall my book on natural and synthetic gemstones correctly, the
"yttria stabilized zirconia" is more commonly known as "cubic zirconia" --
the best (and cheapest) material for simulating diamonds.  (I could be wrong
about that too, so any flames from more informed folks are welcome.)

The added yttria forces zirconium oxide to crystalize in the cubic system.
The resulting material is insulating, refractory, reasonably hard, and
(of course) has a cubic crystal structure.

Such characteristics plus (perhaps) a good match of the crystal lattice
unit of CZ with whatever they are putting on top of it might be what would
make it a good high-temp substrate.  The mismatch of crystal lattices is
always a problem with such substrate approachs, since it leads to defects
in the semiconductor that was laid down on top of it.

				Cheers,
				Terry Bollinger
Newsgroups: sci.physics,alt.sci.physics.new-theories,rec.arts.startrek.fandom,rec.arts.startrek.creative,sci.skeptic,alt.paranormal,alt.alien.visitors
From: mcirvin@husc8.harvard.edu (Matt McIrvin)
Newsgroups: sci.physics
Subject: Re: The confusion of tongues (was: Trouble understanding bra-ket notation)
Date: 22 Jan 93 00:23:55 GMT
Article-I.D.: husc.mcirvin.727662235
 tech.edu> <1jlhucINNrtj@darkstar.UCSC.EDU> <COLUMBUS.93Jan21101415@strident.think.com>
Distribution: usa

columbus@strident.think.com (Michael Weiss) writes:

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

>         /                       /
>         |  f(x) dx              | dx f(x)
>         /                       /

My guess:

Some mathematicians like to view an integral as integrating a differential
form; instead of grouping the dx with the integral sign as an "integral
operator," they think of f(x) dx (they'd be more likely to 
just write f dx, actually) as a single object, a "1-form", or "cotangent
vector" -valued function.  You integrate this thing over a one-
dimensional manifold to get a number.  Each point in the manifold has
a linear space associated with it called the cotangent space; the
basis of this space consists of the single cotangent vector dx.
So then the ordering f dx corresponds to the usual way of writing
vector-valued things, where you write the coefficient before the
basis vector.  To represent the integral you just stick an integral
sign in front of the 1-form.

Physicists, on the other hand, view this integration as primarily
something you do to a number-valued function, so they put the measure
over next to the integral sign to get all the integration machinery
in one place.  (Personally I use either according to mood.)
-- 
Matt McIrvin
Newsgroups: sci.physics,sci.skeptic,alt.paranormal,alt.sci.physics.new-theories,rec.arts.startrek.tech
From: alex@csn.org (ALEX MATTHEWS)
Subject: Therapeutic Touch (was: Re: New Physics, Healing, Paranormal)
Followup-To: sci.skeptic
Organization: University of Colorado, Boulder
Date: Thu, 28 Jan 1993 21:26:04 GMT


In article <-xq3+jr@rpi.edu> petitc@nuge112.its.rpi.edu (Christopher Jon Petit) writes:
>
> Properly done therapudic touching can help heal sicknesses by making the
>subject feel cared for...

CRAP, please.  The Rocky Mountain Skeptics today confront the Colorado
State Nursing Board about the accreditation of therapeutic touch
courses for continuing ed credits for nurses.  The Board's mandate
is to regulate the practice of nursing according to available 
scientific evidence.  The board has released its "scientific"
evidence, a bibliography of over 200 articles, most from the popular
press.  Of the true scientific papers, only a few claim extremely
marginal positive results, and NO POSITIVE RESULTS ARE REPLICATED.  
This is probably the most comprehensive bibliography available because 
one of the most published and influential TT researchers is a prof 
at CU in Denver, and she supplied the bibliography to the Board.

If you have additional information, we'd be very happy to add it
to the bibliography and review it. 

(Followups to sci.skeptic.  Anybody who's interested, read the SI
Winter 1993 issue, or yesterday's article in the local paper, The 
Daily Camera, 1/27/93.)
-- 
- Alex Matthews  (new address: alexm.csn.org)

  "A typical Grand Prix race.  High noon.  Tension mounts.  Throttles clench."
                        Patricia Zonker, _Murdercycles_
Newsgroups: sci.physics
From: kimball@stsci.edu (Timothy Kimball)
Subject: Re: Relativity book for a 9 year old
Organization: Space Telescope Science Institute
X-Newsreader: TIN [version 1.1 PL6]
Date: Thu, 28 Jan 1993 14:13:57 GMT

wellison@kuhub.cc.ukans.edu wrote:
: 
: lasers...lasers...The only book I have on the 
: subject is written by the maser himself (Hawkins) and I don't even understand
                            ^^^^^

Sometimes the typos work, don't they? :^)

--

/* tdk -- Opinions are mine, not my employer's. */
Newsgroups: sci.physics
From: mkagalen@lynx.dac.northeastern.edu (michael kagalenko)
Subject: Re: photon 'detectors' - how reliable?
Organization: Northeastern University, Boston, MA. 02115, USA
Date: Sat, 23 Jan 1993 22:46:08 GMT

In article <1jms14$ibn@agate.berkeley.edu> aephraim@physics3 (Aephraim M. Steinberg) writes:
>In article <wwadge.727584610@csr> wwadge@csr.UVic.CA (Bill  Wadge) writes:
>>I was browsing through one of the many 'pop' physics books,
>>where they are describing one of the stock quantum mechanics
>>experiments, and noticed something along the lines of
>>
>> .. towards a detector which records every photon ..
>>
>>Is this possible? Can one really build a device so sensitive that it will
>>detect 100% reliably every photon that enters it, and never
>>go off by accident?
>>
>>Seems unlikely, but then I'm not a physicist ...
>
>Does seem unlikely, doesn't it?  But it will happen one day (just about).
>
No, it won't. It's general property of QM that if you have inelastic
scattering (photon-detector interaction is inelastic, of  course), there
always exists non-zero elastic part in the cross-section (see Landau's
QM I, chapter about non-elastic scattering). 



>
>Anyway, don't trust everything you read.  The same physics book that
>mentioned 100% efficient photodetectors could well have mentioned frictionless
>pulleys and massless ropes: With many of the former and one of the latter,
>one could construct a 100% efficient photodetector simply by amplifying
>the "light pressure" acting on a ball attached to one end of the rope!

The cross-section of photon-ball int. includes elastic part, so your
detector is not 100% efficient.

Newsgroups: sci.physics
From: matmcinn@nuscc.nus.sg (brett mcinnes)
Subject: Nonlinear effects of Gravity Waves
Organization: National University of Singapore
X-Newsreader: Tin 1.1 PL4
Date: Thu, 28 Jan 1993 04:59:47 GMT


I have heard about a preprint by Christodoulou in which he claims that
non-linear effects can affect the outcome of gravity wave detector
experiments. [ ie the non-linear things can be as important as the linear
effects normally considered.] Does anyone have an update on this?