HDTenEightyP/NetNews huggingface dataset:
From: bweiner@ruhets.rutgers.edu (Benjamin Weiner)
Newsgroups: sci.physics
Subject: Re: Hubble constant?
Date: 19 Aug 92 01:15:05 GMT
Organization: Rutgers Univ., New Brunswick, N.J.

John Baez writes:
>Okay, my curiosity is piqued: what's a Pop III star remnant?  After a
>star pops 3 times all that's left is remnants?  :-)

Hope no one minds a little astro-essay.  This post comes with no
implied warranty of reliability or fitness for advertised use.

As Ted Bunn said, population III stars are (hypothetically) formed
early and would now all be essentially invisible collapse remnants.
In defense of the tortured notation, pop I and pop II stars were named
that a long time ago before the relation was known.  It's not quite
true that pop II are just predecessors of pop I though.  Pop II stars
are old, hence the big short-lived ones have all died, sending
enriched gas out into the galaxy, out of which condense new stars;
our sun is considerably younger than the galaxy.  However there are
plenty of old stars still around, especially in the globular clusters;
these are the smaller, redder Pop II stars which are much longer lived
(and give us problems by seemingly being older than the universe :-)

Clearly there is a whole continuum of star ages, beginning at the
formation of the galaxy, so why the division into only two categories?
Well, although there are stars of all ages around, the most light
comes from essentially two classes of stars: bright old red giant stars 
(which despite the name are only about one solar mass), and bright
young blue stars.  Hence, Pop II, and Pop I.  Globular clusters and
elliptical galaxies are red, almost all Pop II stars; the light from
spiral arms is mostly from Pop I bluish stars even though there are
plenty other stars in the arms.  In fact the beautiful photos of
spiral galaxies exaggerate the density of the arms relative to the 
rest of the disk, because 1) there are more young bright stars in the
arms and 2) the photographic plates are usually more sensitive to blue
than red.  As usual in astronomy, appearances are deceiving.

>Photinos don't sound dull to me, unless like all superpartners they are
>designed to be utterly indetectible.

They'd be great for physics, but they wouldn't do anything interesting
other than gravitate for astronomy.  For example there's a certain lowest
metallicity (= % of elements above H and He) for all measured galactic
stars.  There are no stars known to have zero metallicity.  One way to
explain this is to invoke a now-invisible generation of Pop III stars
which pre-enriches the protogalactic gas to some nonzero metallicity.
Photinos can't do that (especially if they don't exist heh heh).

>I have a theory that everyone here on usenet has a superpartner: an evil
>twin that looks just like them but is 1000 times heavier.  The reason
>why nobody has ever seen one of these superpartners is that they never
>make their appointments.  :-)

I'm Dale Bass's evil twin.  Or maybe I'm Dale Bass.  Have you ever
seen me and Dale in the same room at the same time?

Ben Weiner
Xref: sparky sci.physics:13131 sci.math:10443
From: matt@physics2.berkeley.edu (Matt Austern)
Newsgroups: sci.physics,sci.math
Subject: Re: Is the Action a Component of a more general object?
Date: 20 Aug 92 10:38:07
Organization: Lawrence Berkeley Laboratory (Theoretical Physics Group)
Reply-To: matt@physics.berkeley.edu
NNTP-Posting-Host: physics2.berkeley.edu
In-reply-to: voros@physics.monash.edu.au's message of 20 Aug 92 17:39:55 +1000

In article <1992Aug20.173955.89822@physics.monash.edu.au> voros@physics.monash.edu.au (Joe Voros) writes:

> As I was musing with Feynman's path integral approach to QM, I wondered
> if the action S is a component of a more general object.  What I have in
> mind is something analogous to the energy being connected with the
> time-time component of the energy-momentum tensor.  Does anyone know of
> anything at all related to these musings?  Work? References?  Ideas?

The energy of an object is the 0 component of a four-vector, that
object's four-momentum.  To say this equivalently, but more verbosely:
an object's energy does not transform as a Lorentz scalar---its value
is not the same in all inertial reference frames---but transforms as
a component of a four-vector.

This is not the case with the action, however; in the relativistic
formulation, it is defined so that it does transform as a scalar.
--
Matthew Austern              I dreamt I was being followed by a roving band 
(510) 644-2618               of young Republicans, all wearing the same suit,
matt@physics.berkeley.edu    taunting me and shouting, "Politically correct
austern@theorm.lbl.gov       multiculturist scum!"... They were going to make
austern@lbl.bitnet	     me kiss Jesse Helms's picture when I woke up.
Newsgroups: sci.physics,alt.religion.kibology,talk.bizarre
From: bhoughto@sedona.intel.com (Blair P. Houghton)
Subject: Re: Kibocolliders (was: Re: Super Conducting Supercollider)
Organization: Intel Corp., Chandler, Arizona
Distribution: na
Date: Fri, 14 Aug 1992 05:53:29 GMT

In article <1992Aug14.043730.28531@ichips.intel.com> bhoughto@sedona.intel.com (Blair P. Houghton) writes:
>Speaking of which, did you know that when a kibo
>decays you get an election and two morons?
>				  "I'll have to check
>				   Feynman for the resulting
>				   distribution of initial
>				   whirl--er spin..."

I'm sorry; I got it backwards.

Feynman says that when a moron decays you get an election
and two newtkibos,
             _       _
    m  -->  e  + k + k

with the election's whirl--er, spin--preferentially
directed parallel to that of the moron.

				--Blair
				  "Three red books;
				   Three red books;
				   See how they teach;
				   Ain't research a peach?
				   But you'd better put out
				   for the grant committee;
				   Or they'll cut off your project
				   And it won't be pretty
				   As three red books..."
From: aw3@ukc.ac.uk (A.Wilson)
Newsgroups: sci.physics
Subject: Re: Review of the premiere of "A Brief History of Time"
Date: 19 Aug 92 10:35:57 GMT
Reply-To: aw3@ukc.ac.uk (Alan Wilson)
Organization: Chemical Laboratory, University of Kent at Canterbury, CT2 7NH, UK

In article <l90dnhINNjfk@news.bbn.com> ahsiung@labs-n.bbn.com (Anita Hsiung) writes:
>On Saturday evening, Cal Tech and The Planetary Society presented the
>world premiere of the film version of Stephen Hawking's book "A Brief
>History of Time".  Beckman Auditorium was filled to capacity and
>overflowing when Hawking arrived a few minutes late, but that's what
>happens when "theoretical physicists talk about time", according to
>Louis Friedman, chairman of the Society.
>

[Stuff deleted....]

>| Anita Hsiung       | "See how easy life can be?" -- Johnathan Raven     |
>| ahsiung@bbn.com    |                                                    |
>| BBN Canoga Park    | "Someday we'll look back on this moment...and      |
>| California, USA    |  run smack into the car in front of us."  -- Ski   |
>---------------------------------------------------------------------------

Some "premiere"....!!!!!!!!!

I dont like to nit-pick, but this film was shown in the UK several months
ago.

[Flame on]

Egocentric or what? (ie if it aint shown in USA then it doesnt matter)

[Flame off]

Alan

--
Alan Wilson        (insert YOUR favourite witty remark..........)

"You would NOT believe what has been going on behind there" 
================================================================= 
Newsgroups: sci.physics
From: sarfatti@well.sf.ca.us (Jack Sarfatti)
Subject: Theatrical Physics ActI SceneI
Organization: Whole Earth 'Lectronic Link
Date: Fri, 14 Aug 1992 08:07:56 GMT


Topic  56:  The Omega Point? A likely story
# 10: Richard Lubbock (rcl)      Thu, Aug 13, '92  (21:28)      33 lines

Misc thoughts:

  1) I wonder whether Sarfatti is perhaps not the Camille Paglia of
 physics. There's certainly something Dionysian about his physics.
 That's why the Nobellists can't see what he's driving at. In
 Apollo's eyes Dionysus is invisible. As a result, the Dionysian
 hounds can easily tear the Apollonian apart. See James Wolcott's
 superb piece in the new Vanity Fair.

  2) These tangled time loops seem to require that we get our karma
 from the future as well as the past. Dionysus again. It certainly
 makes a mess of all our moral plans. We're being punished for what
 we haven't done yet. Is that just? Gimme a break.

  3) Sarfatti has by-the-way found the answer to the riddle of
 jokes--which defeated Freud as well as Koestler. The key's in his
 respose to Solovay in sci 274 #137:-

  "That is not my assertion. What I am asserting is quite
 orthogonal to your irrelevant theorem."

 Orthogonality is the spice of wit. Thus:
-
 Oscar Wilde   I can make a pun on any subject.
 Interlocutor  Make a pun on Queen Victoria
 Oscar Wilde   Queen Victoria is not a subject.

 Stranger outside theatre (to Sir Arthur Sullivan): Call me a cab.

 Sullivan:    You're a four-wheeler, Sir.
 Stranger:    What the devil do you mean by that?
 Sullivan:    I could hardly call you hansom.

 Thus: boswell must be swarthy.  I can't think of him as fair.


Topic  56:  The Omega Point? A likely story
# 11: Jack Sarfatti (sarfatti)      Fri, Aug 14, '92  (00:15)      12
lines

Ladies and Gentlemen. Hear ye! Hear ye! Go thee to the Science Tent
topic 274 today where the Great Superluminal Debate is reaching a
critical point. The existence of Mr. Omega depends upon whether or not
the cosine of the reflection phase shift of an electromagnetic wave off
a lowly beam splitter is not or is equal to 90 degrees! This is a most
precise physics test for the Existence of God whose simplicity
astonishes even the Great Sarfatti - modesty not being one of my false
virtues. If the shift is not 90 degrees then God or Omega most likely
exists and I am God's Channel so to speak. But if the shift is 90
degrees -I mean exactly 90 degrees with no fluctuations then God is Dead
as Nietszche said and I, Sarfatti will go down in our brutish and short
history as the God Slayer! But if it's not 90 degrees, then I am the God
Saver.

Topic  56:  The Omega Point? A likely story
# 12: Jack Sarfatti (sarfatti)      Fri, Aug 14, '92  (00:21)       4
lines

Mr. Lubbock, Sir, you're the tops! Even if the physics is wrong and
Mr.Omega's existence is only virtual rather than real - we have the
makings of some really good theater here. Remember, I was Cornell
Savoyard lead tenor in my day.
Newsgroups: sci.physics
From: dwr2560@zeus.tamu.edu (RING, DAVID WAYNE)
Subject: Re: Hubble constant?
News-Software: VAX/VMS VNEWS 1.41    
Organization: Texas A&M University, Academic Computing Services
Date: Sat, 15 Aug 1992 04:54:00 GMT

scip1061@nuscc.nus.sg (Marc Paul Jozef) writes...
>"The perturbation is not small. In fact it changes the
> large scale geometry"
>So you say. But Einstein doesn't agree with that.

:-) Are we channeling now or were you doing physics in 1955?

>                                                   As I
>understand it, we have no dispute over the following
>points:
> 
>1. The global metric has a Friedmann shape.
>2. Globally, the stress-energy tensor can be
>   represented by a delta tensor.

Or, in your case by a bunch of them.

>3. Einstein's equation (which in this case
>   reads: G(g) = d, i.e. G(g) = 0 nearly everywhere).
> 
>Now you try to convince me that G(g) is not equal to
>zero. In other words, your global stress-energy tensor
>T = G(g) is _nowhere_ zero, which violates 3.

"G(g) is not the zero function"  " 'G(g)=0 everywhere' is a false statement"
Niether of these implies "G(g) is _nowhere_ zero". If you're going to put
words in my mouth, please be sure my logic is valid! :-)

>Your toy model fails to convince me, for several reasons:
> 
>- As shown above, its 3-dimensional counterpart is not
>  compatible with 1, 2, and 3, for G(g) = d (0) has no
>  solutions with positive spatial curvature.

G(g)=0 has zero curvature. G(g)=d (where d represents a bunch of singularities)
has zero curvature almost everywhere, and infinite curvature in a bunch of
isolated lines through spacetime.

>- You assumed at the outset that your toy universe
>  expanded from a big bang and recontracted to a
>  big crunch (the pumpkin), i.e. that it behaved like
>  a `classical' solution with positive curvature.
>  I missed the proof of that.

Actually, I think it could also be parabolic or hyperbolic, but it can't be
flat. Because flat is the solution for no matter present. Note that each
segment of the pumpkin is flat. That's because it is empty. Note that you
can fold a flat segment, but such a straight fold does not introduce curvature,
so that fold does not correspond to a point mass's world line. Note that
the folds in the pumpkin cannot be pressed flat. That's because of the
curvature.

Think of it another way, what matter distibution will produce the pumpkin
cosmology? The pumpkin cosmology is then the correct solution to Einstein's
equation for that matter distribution.

>- You can unpaste whatever you want, but you can't
>  make matter disappear. So your `unpasted' segments
>  are still the worldlines of the point masses, and
>  in particular not empty. 

Right. The segments are empty, the edges are not.

>By the way, how do you people copy other folks' text?

My news software does it automatically when I followup.

Dave Ring
dwr2560@zeus.tamu.edu
From: sichase@csa3.lbl.gov (SCOTT I CHASE)
Newsgroups: sci.physics
Subject: Re: The dangers in microwaved food...
Date: 20 Aug 92 19:50:16 GMT
Organization: Lawrence Berkeley Laboratory - Berkeley, CA, USA
Distribution: na
Reply-To: sichase@csa3.lbl.gov
NNTP-Posting-Host: 128.3.254.198
News-Software: VAX/VMS VNEWS 1.3-4   

In article <1992Aug20.161034.2920@murdoch.acc.Virginia.EDU>, crb7q@kelvin.seas.Virginia.EDU (Cameron Randale Bass) writes...
> 
>    After rigorous experimentation, I have concluded that it
>    is difficult to get most eggs to actually explode in the microwave.
>    Most of them seem to have flaws that rupture before a good
>    pressure differential can be built up.  Or I could have just
>    had a bad batch of eggs...

Too much DDT, probably.  But look here for a minute.  It seems to me that
although there is nothing wrong with a little joking that the original poster
might be getting the wrong idea.  There is nothing wrong with posing a 
question about the risks of microwave cooking, either from expose to the 
microwaves during cooking, or from the consumption of microwaved food.  
It's a perfectly legitimate concern, which I am sure has been addressed
at least in part in references which I cannot provide.  From the barrage of
witty cracks and diversions, you would think that this poor guy was posting
about space potatos or something.

-Scott
--------------------
Scott I. Chase			"The question seems to be of such a character
SICHASE@CSA2.LBL.GOV		that if I should come to life after my death
				and some mathematician were to tell me that it
				had been definitely settled, I think I would
				immediately drop dead again."      - Vandiver
From: ecc_jim@ecc.tased.edu.au
Newsgroups: sci.physics
Subject: Re: BLACKHOLES IN THE CENTRE OF THE EARTH
Date: 20 Aug 92 13:01:39 +1000

In article <5117@tuegate.tue.nl>, johan@blade.stack.urc.tue.nl (Johan Wevers) writes:
> ecc_jim@ecc.tased.edu.au writes:
>>
>>Would it necessarily fall to the *centre* of the Earth. I'm no physicist but I
>>certainly remember back in my pre-university days being taught in a physics
>>class that within a solid spherical body of uniform density the gravitational
>>attraction is uniform throughout the body.
> 
> That's not correct: the gravitational potential in such a body rises linear
> from 0 to V_0 from the centre to the edge, and then falls with V_0/r^2.
> 
> The situation you describe holds for an empty sphere.
> 

This and other mail have confirmed that this indeed was for an empty sphere and
not a solid body.

As I said it was thirteen years ago, but above all I can still say I learnt
something!

Jim Palfreyman

jim@r140.tased.edu.au
From: muttiah@stable.ecn.purdue.edu (Ranjan S Muttiah)
Newsgroups: sci.physics
Subject: Re: The dangers in microwaved food...
Date: 20 Aug 92 19:50:03 GMT
Distribution: na
Organization: Purdue University Engineering Computer Network

In article <25626@dog.ee.lbl.gov> sichase@csa3.lbl.gov writes:
>From the barrage of witty cracks and diversions, you would think that 
>this poor guy was posting about space potatos or something.
				             ^

I just couldn't resist.  You forgot the "missing" e Scott! :-).  It's
an election year you know :-).
From: sichase@csa2.lbl.gov (SCOTT I CHASE)
Newsgroups: sci.physics
Subject: Re: the nature of exclusion
Date: 20 Aug 92 02:52:29 GMT
Organization: Lawrence Berkeley Laboratory - Berkeley, CA, USA
Distribution: na
Reply-To: sichase@csa2.lbl.gov
NNTP-Posting-Host: 128.3.254.197
News-Software: VAX/VMS VNEWS 1.3-4   

In article <1992Aug18.214628.9544@math.ucla.edu>, barry@arnold.math.ucla.edu (Barry Merriman) writes...
> 
>It would seem that this way I can compress spatially (by pushing with
>my hands) and compress in the velocity coordinate (by cooling), so 
>that I am achieving a compression on phase space. Now, how does
>the "statistical repulsion" kick in to resist this?
> 

The best way to understand this effect is by optical analogy.  Imagine doing
an optical interference experiment, and putting some kind of detector at 
a minimum in the interference pattern.  You record no photons.  What force
drove the photons away from emerging from the interferometer at that angle?
When you understand the answer to this question, then you also understand
why you can never measure two identical fermions in the same phase space cell.

-Scott

--------------------
Scott I. Chase			"The question seems to be of such a character
SICHASE@CSA2.LBL.GOV		that if I should come to life after my death
				and some mathematician were to tell me that it
				had been definitely settled, I think I would
				immediately drop dead again."      - Vandiver
Newsgroups: sci.physics
From: nicho@VNET.IBM.COM
Newsgroups: sci.physics
Subject: Re: Fossil Paradox (was: Structure of Time)
Date: 12 Aug 92 14:16:21 GMT
Reply-To: nicho@vnet.ibm.com

In <1992Aug12.091957.14414@vax5.cit.cornell.edu> cpyy@vax5.cit.cornell.edu writes:
>This paradox is often used in proofs against backward time travel.
   Hmmm, let me see if I've got this straight. We invent a scenario
which may or may not be valid, and then use it as a proof against
something which may or may not be possible ... interessant.
 -----------------------------------------------------------------
               ** 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
From: jbaez@riesz.mit.edu (John C. Baez)
Subject: Re: An easy problem in general relativity
Organization: MIT Department of Mathematics, Cambridge, MA
Date: Thu, 13 Aug 92 17:51:30 GMT

In article <1992Aug13.042442.3209@nuscc.nus.sg> matmcinn@nuscc.nus.sg (Mcinnes B T (Dr)) writes:
>JB: Really? The loop representation indicates that the singularities go
>away? So what happens to things falling "into" the singularity?

If there are no singularities, there's no issue about what happens when
things fall into singularities!  Notice that there still could be event
horizons, black holes etc..  Anyway, the loop representation is not well
developed enough yet to do calculations about what black holes would
look like.  We're working on it though.

>I know you don't want to argue about it, but I wonder what you will say
>when it turns out that we are in fact inside a stupendous
>Reissner-Nordstrom black hole already. In that connection, I note that
>llamas did in fact come out of a naked singularity.

Let me know when it turns out that we are in a black hole.  

>ps can you send me a preprint of your naked llama paper? Under plain
>cover, please.

I'm sorry, this paper is classified.
Newsgroups: sci.physics
From: xie@phoenix.Princeton.EDU (Yan-bo Xie)
Subject: Re: any equations that can help determine ice melting rate?
Originator: news@nimaster
Organization: Princeton University
Date: Fri, 21 Aug 1992 16:19:44 GMT

From article <5135@tuegate.tue.nl>, by johan@blade.stack.urc.tue.nl (Johan Wevers):
> [A lot about collissions between air and ice deleted]
> 
> You totally neglected the influence of radiation !! If a piece of ice lies
> in a room at 20^o C, it will certainly melt slower than when the same
> piece lies in the sunlight. To calculate this, the albedo of the ice
> should be known. As the Voyager pictures from the moons of Neptune showed
> us, this can be very important.

Yeah, I agree with you that the ice can absorb photons a little bit.
But the main cause for the melting is still the contact with the ground.

Actually, for the pure water (ice), the absoption rate is very low
for the visible light (penetration depth could be greater than 10 meters).
Therefore for a ice bulk with 300lb the absorption of light is almost
neglegible.

However, the absorption for the (far) infrared) photons may be
important. Still many photons are reflected directly.

The phenomena you mentioned about the difference between in a room
or in the sun-light is not comparable mostly.
In fact, the ground temperature in the sunshine is significantly
greater than the room temperature (not very precise).  

It is not clear to me whether the light absorption is less or more
important than the air collision.  However, one can roughly think
about the bottle which keeps water inside warm or cold (I forget
the terminology about this).  In fact the important thing is that
people make
air density between out-shell and in-shell very small.  This
suggests that the radiation effect is less than the air collision
effect even when air disturbance is small.  

Definetely you are right about the existence of radiation effect.
Actually, in the low temperature physics, the radiation effect
becomes important.     

Again I emphasize that the ground-ice contact effect is the
most important effect in most cases (unless the ice is
hang on by a small rope....) (A rough estimation of this
effect is given in a previous post.).
From: sichase@csa3.lbl.gov (SCOTT I CHASE)
Newsgroups: sci.physics
Subject: Re: Facts and Values
Date: 23 Aug 92 03:41:24 GMT
Reply-To: sichase@csa3.lbl.gov
Distribution: na
Organization: Lawrence Berkeley Laboratory - Berkeley, CA, USA
NNTP-Posting-Host: 128.3.254.198
News-Software: VAX/VMS VNEWS 1.3-4

In article <MeZaD2a00VogMG8kRB@andrew.cmu.edu>, ag3l+@andrew.cmu.edu (Arun K. Gupta) writes...
> 
>When physics fails to reveal the location of heaven, the existence of
>soul, and reveals the insignificant rather than central position of 
>human existence in the universe, then all the above lose their logic,
>and we begin to find them wrong.  So much so, that a modern person
>can barely understand why those practices ever existed and would
>outright label them as wrong and evil.  But, within the beliefs and 
>knowledge those ancient societies had, those practices were justified.

Come on, Arun.  I know that you are capable of clearer thinking than this.
Name me the experiment in which a physicist tried to reveal the location of
heaven.  Or give me the proof that there is no afterlife.  Neither of these
things are in the domain of physics.  

You talk about Jihad and torture of innocent people as if physics has 
eliminated them. Turn on your TV set and watch the evening news.  War
and violence do not have their justification in religion, though 
leaders certainly exploit their followers religious beliefs when convenient.
If there is a day when religion dissappears, I doubt that war or violence
will fade away as a result.

-Scott

--------------------
Scott I. Chase			"The question seems to be of such a character
SICHASE@CSA2.LBL.GOV		that if I should come to life after my death
				and some mathematician were to tell me that it
				had been definitely settled, I think I would
				immediately drop dead again."      - Vandiver