HDTenEightyP/NetNews huggingface dataset:
Newsgroups: sci.physics
Subject: My son would like to know about photons...
From: phys169@csc.canterbury.ac.nz
Date: 26 Aug 92 14:29:15 +1200
Organization: University of Canterbury, Christchurch, New Zealand

I have a question on behalf of my 9-year old son...

If you can split atoms, can you split photons?

(Could somebody help me with a suitable explanation, or point me to a book for
inquisitive youngsters without having to go into too much jargon - e.g. without
"quark" or "MeV" anywhere in the explanation??)

Mark Aitchison, University of Canterbury.

Newsgroups: sci.physics
From: daryl@oracorp.com (Daryl McCullough)
Subject: Re: Axiom of Physics
Organization: ORA Corporation
Date: Fri, 28 Aug 1992 15:21:16 GMT

In article <66942@hydra.gatech.EDU>, cegtitd@prism.gatech.EDU (Tim
Dodd) writes:

> Axioms are not empirically based. Axioms are DEFINITIONS.  f=ma is
> axiomatic in that it is a DEFINITION of what we mean by "force".
> Newton postulated the original equation not by observing masses in
> motion and the forces applied, (this would imply that we already had a
> good definition of "force") but by realizing that we needed a more
> precise definition of the term "force".

There was a discussion of the status of Newton's law earlier in this
group. I don't remember what the concensus was, but personally, I
don't think that f=ma can be considered a *definition* of force, since
there is no independent definition of mass. If you look at mathematics
for examples of axiomatic theories, you will find that in general
axioms do not define the basic objects, but merely state relationships
among them. For example, we can axiomatize the natural numbers by
saying: 1. 0 is a natural. 2. The successor function on naturals is
one-to-one. 3. Every natural except zero is in the range of the
successor function., etc. These axioms don't *define* 0 or the
successor function, but merely show how they are related. Similarly,
Newton's laws don't define mass or force, but show how they are
related.

Daryl McCullough
ORA Corp.
Ithaca, NY
From: junipero@academ01.mty.itesm.mx (Junipero Rodriguez Rivera)
Newsgroups: sci.physics
Subject: abot  Maxwell's demond
Date: 2 Sep 92 01:20:52 GMT


  Where can i find about Maxwell's demon??? or
where can i find in this net about american scientist (jan-70, jan 71)

please send me a e-mail (junipero@academ01.mty.itesm.mx)
                        (junipero@mtecv2.mty.itesm.mx)

thanks!!!

Jose A. Rodriguez
ITESM campus monterrey 
Mexico


Xref: sparky sci.physics:13370 sci.chem:3165
From: dietz@cs.rochester.edu (Paul Dietz)
Newsgroups: sci.physics,sci.chem
Subject: Re: Entropy of the Universe, (was Re: Genesis - fact or fiction)
Date: 24 Aug 92 01:18:04 GMT
Distribution: na
Organization: Computer Science Department University of Rochester

In article <1992Aug24.003627.7447@ccu.umanitoba.ca> ens@ccu.umanitoba.ca writes:

>In a discussion about the existence of God, the technical
>details are largely beside the point. To cite recent "beaker-shaking"
>experiments in response to a creationist's challenge is to admit that
>in the absence of such experiments he might have a point.
>
>He didn't have a point 50 years ago before the experiments, and he
>won't 50 years hence when biogenesis may or may not be better
>understood. And the greeks didn't have a point when they thought the
>sun was a god because they didn't understand it. The absence of
>understanding is not evidence for the supernatural.


I am utterly amazed.  Are you really claiming that evidence that
contradicts creationism is immune to the normal checks and balances
of science?  Is your scientific integrity really so easily discarded?

The creationists peddle myth as science.  Not surprisingly, they
can detect when others do the same (if not consciously).  But agreeing
with a criticism that creationists have made is not the same as
supporting creationism.  After all, evidence that a competing theory
is wrong is not evidence that "creation science" [sic] is right.

Back to beaker shaking: despite decades of effort, no one has ever
made nucleosides, let alone nucleotides, RNA or DNA, in a Miller-type
experiment.  The idea that your just have to shake, zap and bake and
shazamm! life appears, is unsupported by evidence.  I.e., it's myth,
not science.

The truly scientific response is "all the theories around today
have enormous problems, so we really don't know how life originated."
There is *no* implication here that creationists have a clue.
"We don't know" is a perfectly fine scientific answer.

	Paul F. Dietz
	dietz@cs.rochester.edu
Newsgroups: sci.physics
From: dwr2560@zeus.tamu.edu (RING, DAVID WAYNE)
Subject: Re: My son would like to know about photons...
News-Software: VAX/VMS VNEWS 1.41    
Organization: Texas A&M University, Academic Computing Services
Date: Fri, 4 Sep 1992 00:54:00 GMT

bhoughto@sedona.intel.com (Blair P. Houghton) writes...
>Two photons with different energies in one reference frame
>have different energies in all reference frames including
>their own (shared one), therefore not all photons are the
>same "size."

I'm not sure what the reference frame of a photon means, but two photons
can have the same energy in one frame and different energies in another.

Dave Ring
dwr2560@zeus.tamu.edu
From: csuah@warwick.ac.uk (~WISP at CU~)
Newsgroups: sci.physics
Subject: Re: Inertial drive?
Date: 1 Sep 92 08:25:53 GMT
Organization: Computing Services, Warwick University, UK

In article <1992Aug31.231110.26645@wdl.loral.com> mab@wdl39.wdl.loral.com (Mark A Biggar) writes:
>In article <0fhS02Go20x701@JUTS.ccc.amdahl.com> drp40@cd.amdahl.com writes:
>>An office mate recently mentioned having heard about something called
>>an "inertial drive" which was an enclosed device with some sort of motor
>>and geared arrangement which would produce a force in a single direction
>>by converting rotational inertia into "linear" (??) inertia.  Sounds
>>pretty bizarre.  Anyone have any details on this?
>
>This is the "Dean Drive" made famous in the early to mid 60's in
>Analog Magizine.  General Opinion is that it was a fake.  Dean applied
>for patents but no one has been able to reproduce the effect since.
>Because Dean would not let anyone else touch his prototype one one was able
>to perform the obvious experment of suspending it from wires and seeing if
>it didn't hang straight (if it hangs displaces sideways and doesn't occilate
>then it is producing a unidirectional force).  For a possible explaination
>of how it could work see references to "Davis" mechanics which proposes
>that there is an additional force law like Newtons involving forces
>proportional to changes in acceleration (called jerk).  Modeling using
>"Davis" machanics shows that it is very unlikely the a mechanical device
>such as Deans could work, but suggest that driving a plasma in a tube
>using the proper frequency saw-tooth wave might work (See the novel
>"Stardriver" by Lee Corey for a fictional account based on this idea).
>

Is this related to that ridiculous "anti-gravity drive" that's basically a
precessing gyroscope? Caused a bit of a stir in the UK (Tomorrow's World etc.)
about two years ago... (Anyone remember more details?).

The Wisp.
-- 
-----------------------------------------------------------------------------
     Chris Williams <csuah@uk.ac.warwick.csv> aka <csuah@csv.warwick.ac.uk>
"Tony Greig in the slips, legs apart, waiting for a tickle"
                                      Brian Johnson (thanks to A. Simha 8^>)
From: G.Joly@cs.ucl.ac.uk (Gordon Joly)
Newsgroups: sci.physics
Subject: Rotating Bucket of Water in a Gravitation Field
Date: 4 Sep 92 10:43:44 GMT

BRUTON, WILLIAM DANIEL writes:
 > Anyone ever proved that the surface of water in a bucket rotating
 > in a gravitational field is a paraboloid? 
 > I remember seeing this problem worked out is some text, but I can't seem to
 > relocated it.  I seem to remember using Bernoulli's Equation....but
 > the form of Bernoulli's Equation that I have seen is not gereralized
 > to rotational motion.
 > If you could point me to a text or remind me how to solve it that 
 > would be great.
 > 
 > Thanks,
 > Dan

Actually, I thought it had something to do with Mach's Principle! How
would you distinguish the case of a rotating universe and static bucket
with the above?

____

Gordon Joly      Phone  +44 71 387 7050 ext 3703      FAX  +44 71 387 1397
Internet: G.Joly@cs.ucl.ac.uk        UUCP: ...!{uunet,uknet}!ucl-cs!G.Joly
Computer Science, University College London, Gower Street, LONDON WC1E 6BT
From: abrown@hpcvcaj.cv.hp.com (Allen Brown)
Newsgroups: sci.physics
Subject: Re: Low Temperature (T=4K) LEDs
Date: 29 Aug 92 23:29:16 GMT
Article-I.D.: hpcvca.1992Aug29.232916.18183
Distribution: na
Organization: Hewlett-Packard Company, Corvallis, Oregon USA

Did you test the LEDs after you reheated them?  77K is quite a thermal
stress.  The failure may have been caused by the package rather than
the semiconductor.  The LED may work to a lower temperature if you
remove the package first.  But I have a feeling you won't be able to
get one to work at 4K in any case.
--
  Allen C. Brown  abrown@cv.hp.com or hplabs!hpcvca!abrown or "Hey you!"
    Not representing my employer.
    Reality is for those who cannot handle fantasy.
Newsgroups: sci.physics
Subject: Re: Report on Philosophies of Physicists
From: mcirvin@husc8.harvard.edu (Mcirvin)
Date: 2 Sep 92 00:01:53 GMT
 <1992Aug31.093101.17646@u.washington.edu> <2634@news.cerf.net>

mitsu@nic.cerf.net (Mitsuharu Hadeishi) writes:

>	Not only Bohr, but also Heisenberg found a parallel between
>Eastern philosophy and quantum physics.

Parallels are fine.  I agree with the previous poster who said
that the real problem is that people are using quantum mechanics
as proof of or evidence for a particular metaphysics, or, worse,
using the alleged insanity of the subject as an excuse to believe
anything. 

>  In any case, Eastern philosophy
>is hardly to be made equivalent to "New Age mysticism" [...]

This is, of course, another thing that needed saying.  People
spreading nonsense are doing a disservice to more than just the
physicists. 

-- 
Matt McIrvin, Cambridge, Massachusetts, USA 
Newsgroups: sci.physics
From: matmcinn@nuscc.nus.sg (Mcinnes B T (Dr))
Subject: Re: Length scales in physics 4 - the Planck length
Organization: National University of Singapore
Date: Wed, 26 Aug 1992 08:11:07 GMT

dwr2560@zeus.tamu.edu (RING, DAVID WAYNE) writes:
: matmcinn@nuscc.nus.sg (Mcinnes B T (Dr)) writes...
: >Well, John, it's rather interesting that you cite the example of the
: >Schwarzschild radius. A couple of weeks ago the question was raised
: >here: to what radius would you have to compress the Earth in order to
: >get a black hole, in view of the fact that the S radial coordinate does
: >not measure distance. Nobody knew the answer or was willing to guess.
: >Would you care to contribute an estimate, together with the amount of
: 
: Part of the problem is, this is not a physical question. In order to
: have the earth remain stable, even though its surface is just outside
: it's S radius, you have to postulate infinite stresses. These stresses
: have a degree of arbitrariness, which might allow you to get any 'internal
: radius' you want. A physical question would be: what if you compressed
: the earth from the outside? What would be the 'internal radius' as the
: final collapse began. The answer would be only a few times the S radius
: by analogy with neutron star collapse.
: 
Sorry, I don't see how you know that it is only a few times. Won't it
depend on the degree of compression?

 : >But let me have a try at this. Take a point mass m inside a hollow
: >uniform shell of mass M and radius a. On dimensional grounds, the force
: >should clearly be GmM/a^2. OK, can anyone tell me the value of
: >[dimensional analysis estimate]/[actual force] ? Is it out by more than
: >a factor of 10? :)
: 
: You've hit the nail on the head here. When dimensionless numbers turn out
: to be very different from 1, one can expect that there is some kind of
: 'conspiracy' going on. In this case, the shell is perfectly uniform
: and perfectly spherical.
: 
OK, good point. But the point is that you were able to spot the error
here because you know the physics. In the case of the Planck length,
nobody does. That's the problem.

: A better example would be the force on an individual star due to the mass
: of the galaxy. I will leave it as an exercise, but you will find the
: answer quite close (as measured by the galactic rotation rate)
: 
: >In short, I am not convinced that eg the Planck length has any
: >particular meaning or significance. People can waffle on about "buckets
: >of dust" until they spacetime foam at the mouth...but where does it get
: >you? We hear that superstrings are of "length" 10^-33 cm, at which
: >length spacetime is replaced by something else, so depriving words like
: >"length" and "string" of their meaning....
: 
: String theory doesn't really replace spacetime, but treats it as a field
: living on the worldsheet.
: 
errr....meaning what? how do you "treat spacetime as a field?"
 : Dave Ring
: dwr2560@zeus.tamu.edu
From: balbes@ohstpy.mps.ohio-state.edu
Newsgroups: sci.physics
Subject: Re: Report on Philosophies of Physicists
Date: 31 Aug 92 10:11:46 EDT

In article <1992Aug30.001443.22249@noose.ecn.purdue.edu>, muttiah@stable.ecn.purdue.edu (Ranjan S Muttiah) writes:
> I wonder whether the discoveries in physics (say in terms of QM
> and relativity) made in the 20th century were really such a big
> deal after all.  I suspect the prevalence of the popular media
> are in large to blame. 

Now wait a minute.  I think you are trivializing two major advances.
QM and relativity are a big deal and very hard to comprehend.  Sure,
we have 20-20 hindsight and can say that they are obvious.  We've
also been conditioned all our lives to think at least in part, in
terms of these theories.  But imagine knowing only classical mechanics
and having just a few problems left that are  unsolved.  How many
of us could make the jump to QM or relativity.  I doubt I would've
thought of it.  In fact, most of the great physicists of the time,
even after learning about them, didn't believe it.

Any time someone makes a breakthrough, it always seems obvious after
the fact.  There's an aesthetically pleasing idea in physics that
when someone finally discovers the fundamental physical law that
it will be so intuitively obvious that people will wonder why
it hadn't been thought of before.


Mark Balbes
From: sichase@csa2.lbl.gov (SCOTT I CHASE)
Newsgroups: sci.physics
Subject: Re: E=mc2?
Date: 1 Sep 92 18:40:44 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 <5258@dove.nist.gov>, gilligan@bldrdoc.gov (Jonathan Gilligan 303-497-3861) writes...
> 
>Of course, it's reasonably easy to measure the mass-difference in
>nuclear reactions.  I don't know of any measurements of
>mass-differences due to chemical reactions.

They're getting very close to being able to do this kind of thing in 
atomic traps.  Using a Paul trap, I believe, at least one group has measured
mass differences down to a few * 10 eV.   In the next few years a little
improvement will allow the measurment of mass differences due to different
electron configurations - weighing chemical bonds.

-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: snarfy@cruzio.santa-cruz.ca.us
Newsgroups: sci.physics
Subject: Snarfy's Program
Keywords: BASIC Ohm's Resonance
Date: Tue, 01 Sep 92 08:21:36 PDT
Reply-To: snarfy@cruzio.santa-cruz.ca.us


   Hi group-

   Last  week  (8/25)  I  posted  an  ASCII file listing of a BASIC computer
   program entitled "Snarfy's Ohm's Law for resonant circuits demonstrator".
   For  three  days  following  that  posting  ,my  newsfeed (Cruzio@Netcom)
   apparently  suffered  some  kind of malfunction. Now , from my end ,there
   appears to be a gap of time (8/25 through 8/28) where  no  articles  were
   posted  to  the  sci.physics  newsgroup.  I  checked  with a local who is
   directly connected to netcom and he tells me  there  were  "zillions"  of
   articles posted during that time.

   Is  anyone aware of any responses to the above mentioned posting that may
   have appeared during that time? I'd really appreciate any "reviews" (good
   or bad) that the program might have received. For those who  did  respond
   during the time mentioned ,please re-post.

   Thanks

   Jim Ostrowski(..netcom!cruzio!snarfy)
From: acase@reed.edu (Andrew Case)
Newsgroups: sci.physics
Subject: Re: Fun with droplets
Date: 26 Aug 92 00:29:46 GMT
Article-I.D.: reed.1992Aug26.002946.16373
Organization: Reed College, Portland, OR

Philip Bond objects to the air layer explanation of floating droplets.
Suggests there must be other factors at work, since details of fluid
composition have a marked effect.
(I hope that is a relatively accurate summary)

The air - layer effect has been verified by interferometry. It is
pretty much unassailable as the dominant cause of this phenomenon.
Droplets show a wide scatter in lifetimes for drops under 
identical conditions (I mean _WIDE_ here). Coalescence occurs
when the drop comes into contact with the bulk fluid underneath it.
This process is obviously affected by the details of the fluid
composition, since capillary waves and similar small scale
disturbances in the drop and the bulk liquid depend on the
details of the liquid composition. I argue that the variability
in lifetime depending on fluid composition is due to variations
in the magnitude of the various factors which directly lead to
coalescence, rather than to a support mechanism which depends
on the fluid of the drop and the underlying fluid.


Off the top of my head, I ca surfactants, electric fields,
vibration, and temperature gradients (I know this because
I carried out an experiment involving floating drops, and
had to control for all these factors, and more). 

An important effect of surfactants is to alter the coupling
between the air (trapped in a 'lens' beneath the drop) and the
bulk fluid, as the air flows out from under the drop. Hence
surfactants can either increase or decrease the lifetime of 
the drops. All the other factors listed above reduce drop
lifetime, with the exception of vibration, which at low
frequencies (I investigated the range 15-35 Hz) increases
lifetime, and at high frequencies appears to decrease
lifetimes (the paper I saw was investigating frequencies
in the kilohertz range).

send email for a list of references.

Andrew Case
acase@reed.edu
From: bweiner@ruhets.rutgers.edu (Benjamin Weiner)
Newsgroups: sci.physics
Subject: Re: Sarfatti Bio FYI
Date: 26 Aug 92 21:50:46 GMT
Organization: Rutgers Univ., New Brunswick, N.J.

sarfatti@well.sf.ca.us (Jack Sarfatti) writes:
[quoting Lee Myers]
>Now that Jack has completed his theory he is ready for such
>[administrative] chores.  Younger physicists are quite interested
>in his work. 

Uh-huh.

>9 It can safely be said that Jack Sarfatti is the greatest living
>conceptual artist using mathematical physics as the medium for his message.

Insofar as conceptual art usually involves the sketching out of plans
for an action or work of art, and then defines the plans as the actual
artwork, generally leaving them [the plans] unexecuted, this is quite
accurate: Sarfatti has great plans for a "new physics," but he just
isn't quite capable of actually constructing it.

Anyway, get with the program, Jack, conceptual art is OUT.  If you
wanna be hip you gotta take more action - the happening stuff these
days is activist, outward-looking art; like, say, Barbara Kruger or
the Guerilla Girls.  Even stuff that in the past might have been
labeled "process art" is now seen more in the social-documentary vein,
a la Ed Ruscha et al.  You've gotta take it to the people, start 
putting your equations on handbills and slapping them up on utility
poles, that kind of thing.  Forget Macarthur, it's just bourgeois
co-optation. 

Ben Weiner
---careful, some of this BS is true
Newsgroups: sci.physics
From: bucknerb@bnr.ca (Brent Buckner)
Subject: Re: FTL Microwave Signal
Organization: Bell-Northern Research, Ontario, Canada
Distribution: na
Date: Wed, 26 Aug 1992 20:27:07 GMT

In article <25777@dog.ee.lbl.gov> sichase@csa3.lbl.gov writes:
>In article <1992Aug26.021649.4507@augean.eleceng.adelaide.edu.AU>, dabbott@augean.eleceng.adelaide.edu.AU (Derek Abbott) writes...
>> 
>>None of the critics asked the obvious question which is: how do the
>>authors propose to transfer any useful information on a single leading
>>wavefront?? Surely you can only transfer one bit of data at FTL, which isn't
>>too useful.

Aside:  usefulness is not a necessary condition for many people to find
something worthy of study.

>
>I think that the point is that if even one bit of information is transmittable
>FTL, then we will all go off in search of the correct reformulation of
>mechanics.  If we then find such a theory, we presumably would *then*
>know how to exploit the effect in a serious way.
>

Here's a set of assumptions under which the effect could be
useful:

1.  We can usefully transform the FTL data transfer into backward-
    in-time data transfer (essentially, given that the transfer is from
    A to B, then we can put A and B into sufficiently
    different frames of reference).

2.  We only get closed timelike loops.

3.  Atomic decay is non-deterministic.

Let's say that we can send a bit backward in time an hour
(see assumption 1).
Further, you've got a question that you want answered _now_,
that your computer can verify within fifty minutes.

Your computer is attached to a true random number generator
(see assumption 3), and a Time-Modem (tm).

The time is 1:00.  Set your computer to receive a bit from the
future.  It receives this bit at 1:01.  At 1:02, your computer
reads a random number.  This number is the answer to your
question.

From 1:02 to 1:52, your computer is verifying that answer.
There are two cases:  the answer is incorrect or the
answer is correct.

If the answer (the random number) turns out to be incorrect,
then at 2:01 the computer sends back the opposite bit to that which it
received at 1:01.  This violates assumption 2; you received
a "1" but sent a "0" (or vice-versa).

Thus, the answer was correct.

-- 
at Bell-Northern Research
voice:        (613) 765-2739
Canada Post:  P.O. Box 3511, Station C, Ottawa, Canada, K1Y 4H7
I do not claim that BNR holds these views.