HDTenEightyP/NetNews huggingface dataset:
From: campo@sunthpi3.difi.unipi.it (Massimo Campostrini)
Newsgroups: rec.arts.sf.science
Subject: Niven's teleportation & 2nd law of thermodynamics (was: Superconductors + the 2
Keywords: Niven, teleport
Date: 2 Sep 92 12:42:36 GMT
Article-I.D.: cine88.1992Sep2.114236.428
Reply-To: campo@sunthpi3.difi.unipi.it
Distribution: world
Organization: Istituto Nazionale di Fisica Nucleare, Pisa, Italy


   After reading several (very entertaining) short stories by
Larry Niven discussing teleportation, I've always wondered why the
author pays attention to conservation of energy and momentum, but
ignores the 2nd law of thermodynamics. As an example, N. supposes
that teleporting a space probe upward (in a gravitational field)
takes no energy, but the probe cools down.
   Any comment on this? Maybe the 2nd law of thermodynamics is
supposed to be "less fundamental" or "less established" than the
1st by non-physicists?
   As a related comment, I can state that causality IS considered
less fundamental then the above laws by many physicists.

-- 
        Massimo Campostrini,  Theoretical Physicist,
Istituto Nazionale di Fisica Nucleare, Sezione di Pisa,
Piazza Torricelli 2, I-56126 Pisa, Italy  ||  Phone: (+39)(50)42093
Internet: campo@sunthpi3.difi.unipi.it    ||  Fax:   (+39)(50)48277
Newsgroups: rec.arts.sf.science
From: S_TITZ@iravcl.ira.uka.de (Olaf Titz)
Subject: Re: Ringworlds
Organization: Fachschaft Informatik, Uni Karlsruhe
Date: Thu, 27 Aug 1992 13:00:28 GMT
X-News-Reader: VMS NEWS 1.23

In <BtMFzD.IMs@acsu.buffalo.edu> majcher@acsu.buffalo.edu writes:

>  
>  	Okay, call me a heretic, call me ignorant, call me what you
>  will, but I've never read any SF that deals with a ringworld.  (Aside

Correct me if I haven't understood right :-)

I suppose you mean those cylindrical or wheel-shaped rotating space
stations? There has been a very cynical short story by Josella Playton
in the German computer magazine c't last year dealing with software
problems operating such a thing, containing a description of how it is
constructed and supposed to work.

[Josella Playton, pragma INTERFACE, c't 1/1990, pp.344-350]
(I don't know if this has been published elsewhere or in other
languages.)

MfG,
        Olaf
-- 
Olaf Titz - comp.sc.student - Univ of Karlsruhe - s_titz@iravcl.ira.uka.de -
uknf@dkauni2.bitnet - praetorius@irc - +49-721-60439 - did i forget something?
Der gr"une Punkt ist halt genauso sinnvoll wie ne T"UV-Plakette
 auf nem Schrotthaufen. - Thomas Volkmar Worm
Newsgroups: rec.arts.sf.science
From: iwsbarke@acs.ucalgary.ca (I W Scott Barker)
Subject: Re: dragons were dinosaurs?
Date: Thu, 27 Aug 92 21:29:23 GMT
Organization: The University of Calgary, Alberta, Canada
X-Newsreader: Tin 1.1 PL5

Larry Smith (smith@ctron.com) wrote:
>Science does not _prove_ things are true, it _proves_ things that are not true
>and continues to try to prove the remainder not true.  What has not been
>proven false is accorded a truth value that ranges from "maybe" to "eternal
>as far as we can tell", depending on how many tests it had withstood.  The
>latter is "proven" as far as any mortal really need care.  This category
>includes evolution and the non-cohabitation of humans and dinosaurs.  The
>probability of either of them being disproven is virtually nil.  Like Newton's
>"Law" of gravity, any new theories that displace either of them will continue
>to have them as special cases, just as Newton's gravity was a special case of
>relativity.  As for proving either of them fundamentally incorrect, that's
>"impossible" as far as any sane man is concerned.  Hanging on to that last
>decimal place, and insisting that everyone respect it and kowtow to it whenever
>discussing your pet peeve in order to prove your mind is "open" merely proves,
>as another poster put, that your mind is open enough to have let your brain
>fall out.  Kindly take this to soc.religion where it belongs.

You know, it seems that we more or less agree on what we seem to be arguing
about. We agree that proving anything (correct or incorrect) is not possible
for anyone. The only thing we can know is that "it's worked so far..."

What we do seem to disagree on is why the hell we are posting in the first
place. I stated something which you apparently agree with, but you thought I
was espousing religion. Hence, you flame me, so I rebutt (sp?). You argue some
more, I argue some more, and everyone else gets rather tired of it.

So, my final position (which seems to agree with what you have said above):

Dinosaurs and humans *did not* co-exist, since we are lacking any proof
otherwise. If that proof ever surfaces, well, I guess I was wrong, and I can
accept that.

--
Scott Barker
barker@enel.ucalgary.ca

"Love sickness is like sea sickness... You think you are going to die, and
   everyone else thinks it's hilarious!!!"
   - Orson Welles (?)
Newsgroups: rec.arts.sf.science,rec.arts.sf.written
From: francis@dogwood.atl.ga.us (John Stracke)
Subject: Re: Something Nasty in the Human Genome
Organization: National Science Center Foundation
Date: Thu, 3 Sep 1992 13:36:58 GMT
	<1992Sep3.031844.21399@news.eng.convex.com>

In article <1992Sep3.031844.21399@news.eng.convex.com> cash@convex.com (Peter Cash) writes:

>Kind of intriguing...makes me think that information is encoded in the DNA
>in ways other than the direct code we know about. Hmmm...how about a
>fractal data compression algorithm? Maybe it's a picture of God?
>Directions for the next step in evolution? The Cosmic Self-Destruct
>Command? Guess I'm in one of those moods...

No, no.  It says, "If you can read this, you're too close." :-)

--
/===========================================================================\
|John (Francis) Stracke         |My opinions are my own.                    |
|Natl. Science Center Foundation|===========================================|
|Augusta, GA                    | I will not buy this .signature,           |
|francis@galois.nscf.org        |    it is scratched                        |
\===========================================================================/
(Formerly francis@dogwood.atl.ga.us,francis@zaphod.uchicago.edu)
-- 
/===========================================================================\
|John (Francis) Stracke         |My opinions are my own.                    |
|Natl. Science Center Foundation|===========================================|
|Augusta, GA                    | I will not buy this .signature,           |
From: janowsky@math.rutgers.edu (Steven Janowsky)
Newsgroups: rec.arts.sf.science
Subject: Re: Niven's teleportation & 2nd law of thermodynamics (was: Superconductors + the 2
Date: 3 Sep 92 17:17:23 GMT
Organization: Rutgers Univ., New Brunswick, N.J.

In article <FRANCIS.92Sep3094741@galois.dogwood.atl.ga.us> francis@dogwood.atl.ga.us (John Stracke) writes:

> >>    Any comment on this? Maybe the 2nd law of thermodynamics is
> >> supposed to be "less fundamental" or "less established" than the
> >> 1st by non-physicists?
> >
> >It is less fundemental in the sense that it is a statistical law.  Entropy
> >can go down in a system--its just unlikely.
> 
> Make that *extremely* unlikely.  Sufficiently unlikely that it
> probably has not occurred more than a handful of times in the history
> of the Universe to date.
> 
> Many physicists actually perceive entropy as the *most* fundamental of
> laws; I believe Hawking (?) has said that, if he were to come across
> an event that violated either the Second Law or some other (any
> other), he would keep the Second Law.  It's that powerful.

Utter crap.

The entire notion of entropy is not particularly clear for systems with
few particles.

If I take a box with 2 molecules in it then the `entropy' is going to
fluctuate all over the place, using any semi-reasonable definition.

Even in a large system it is easy to cook up initial conditions under
which entropy will decrease -- if eg we consider classical mechanics
then the evolution is reversible, after all.

SJ
Newsgroups: rec.arts.sf.science
From: ingles@rootbeer.engin.umich.edu (Ray Ingles)
Subject: Re: Something Nasty in the Human Genome
Date: Fri, 04 Sep 92 13:11:46 EDT
Organization: University of Michigan Engineering, Ann Arbor
Originator: ingles@rootbeer.engin.umich.edu


In article <kelso_j.715422933@kultarr>, kelso_j@cs.uwa.oz.au (J Kyle Kelso) writes:

[galactic genetic takeover-reproducing parasite idea deleted]

 I suppose, assuming a few things about the universality of
DNA and the great prevalence of life-bearing planets in the
galaxy, it might be technically feasible. I doubt it, but
we'll assume for the sake of the argument that it is.
 The main problem I see is explaining the origin of such
creatures. How could such a thing evolve? What are some
plausible intermediates between this and planet-bound life?
 On the other hand, you could posit them as designed beings,
perhaps a biotech counterpart to Fred Saberhagen's Berserkers.
This makes it more belieavable, but I'd want to know *why*
anmy race would build such a thing...

> J Kyle Kelso 

Sincerely,

Ray Ingles                  || The above opinions are probably
                            || not those of the University of
ingles@caen.engin.umich.edu || Michigan. Yet.
From: whheydt@pbhya.PacBell.COM (Wilson Heydt)
Newsgroups: rec.arts.sf.science
Subject: Re: Hydro energy storage systems
Date: 26 Aug 92 19:20:18 GMT
Article-I.D.: pbhya.1992Aug26.192018.13472
Organization: Pacific * Bell, San Ramon, CA

In article <1992Aug26.070643.4420@bb1t.monsanto.com>, bjgaed@bb1t.monsanto.com writes:
> It has been far too many years since I took thermo for me to continue
> to try to argue the point.
> 
> I had always heard the laws formulated thus:
> 
> 1)  You can't win. (energy cannot be created or destroyed 
> (classical).)
> 2)  You *can't* break even. (Entropy of a closed system tends toward a
> maximum.)
> 3)  You can't get out of the game. (You can't run part of your heat
> engine below absolute zero.)
> 
> To which I should probably add:
> 
> 4)  There is always someone more clever than you on the Net. 8{)  

I always heard the 4th law as:

4.  Everything costs more and takes longer.

But yours is a good one, too.

	--Hal
-- 
Hal Heydt                    |    "Boycott Time-Warner"
Analyst, Pacific*Bell        |         --J. Danforth Quayle
510-823-5447                 |    "... kill all the lawyers."
whheydt@pbhya.PacBell.COM    |         --William Shakespeare
Newsgroups: rec.arts.sf.science
Subject: Re: Laser weapons
From: ecmtwhk@ccu1.aukuni.ac.nz (Thomas Koenig)
Date: Thu, 3 Sep 1992 22:52:20 GMT
 <rwallace.715515667@unix1.tcd.ie><1992Sep3.135125.22354@cas.org> <cedYA5G00gpIB_gF0i@andrew.cmu.edu>
Organization: University of Auckland, New Zealand.

"Andrew C. Plotkin" <ap1i+@andrew.cmu.edu> writes:

>In article <rwallace.715515667@unix1.tcd.ie> rwallace@unix1.tcd.ie
>(russell wallace) writes:

>> >   Well, that's hardly necessary. You can do significant damage to a
>> >person by dropping just a kilojoule of energy onto a small spot over a
>> >short time interval. I believe flashlight batteries deliver more than
>>that much energy over their lifetimes.
>>
>>Not really; to raise the temperature of 1 litre of water (the main
>>constituent of the human body) by 10 degrees K (hardly enough to kill
>>someone), takes 42,000 joules of energy. 

>Which implies that if you can concentrate those 42000 joules on one
>cubic centimeter of flesh, it will go up 10000 degrees. Somewhat better 
>:-). A kilojoule dumped into that same cc will raise it 240 degrees,
>which is still burnt black and crispy.

And to evaporate one kg of water takes around 2.5e6 joules... You really
need lots of energy to burn through someone. I'd suggest this energy
could be more efficiently employed by driving a bullet, for example with
magnets. I seem to remember that the G-3, the very powerful Heckler -
Koch assault rifle (7.62x51 calibre), delivers around 200 J of energy to
its target, but its ammunition is generally considered to be too heavy.
Make the bullets smaller and throw them out at hypersonic speeds (driven
by electric magnets, for example) instead of building laser weapons.
-- 
Thomas Koenig, ecmtwhk@ccu1.aukuni.ac.nz, ib09@rz.uni-karlsruhe.de
The joy of engineering is to find a straight line on a double logarithmic
diagram.
Newsgroups: rec.arts.sf.science
From: sdr57@cas.org ()
Subject: Re: Laser weapons
Organization: Chemical Abstracts Service, Columbus, Ohio
Date: Wed, 2 Sep 1992 14:03:23 GMT

In article <1992Sep1.213233.7293@spss.com> markrose@spss.com (Mark Rosenfelder) writes:
>I'd like to throw some laser weapons into an sf story, but I find I don't
>know enough about lasers.
>
>Naturally, we're not talking about those wimpy supermarket lasers here--
>we want some lasers that can fry people.
>
>Some questions:
>Are these things even practical as hand weapons?

Currently, no. Lasers are used as target markers on conventional
hand weapons (pistols, etc.) - commercially available systems
produce a visible indication - a red dot - on a target which
indicates where the bullet will go. There are also military
systems which work in the infrared (IR) region (so the target doesn't
see the dot, but the shooter, equiped with IR goggles, does).
A laser hand weapon would depend on several advances in both power
supplies and the active media (the stuff which actually lases).

Laser weapons do exist, but they are usually either vehicle-mounted
or in fixed mounts - they are not small.

>How much energy do they use?

Depends on the type of laser (there are several types).
An ion laser can require 15 kW of power to produce a 1 W
beam.
A chemical laser, in which the active species is produced
by a chemical reaction, can require no power supply, just
tanks of reactants.
Power can be supplied by, among other things, nuclear reactors
(purpose-built), your friendly neighborhood electric company,
MHD generators, and previously charged capacitor banks.


>Do they make a noise when fired?

Yes. The noise made depends on several things, two of which are:

The type of laser: a discharge laser operating in pulse mode will
produce a sharp crack as the capacitors discharge, semiconductor or
continuous-wave helium-neon lasers produce a hum (from power supplies),
and a chemical laser can produce all kinds of noise from gas venting,
etc.

The power density (how much power is in a beam with a given cross section)
- at sufficiently high power densities, you can get heating or superheating
of atmospheric components - this produces rapid expansion - another crack.

(Of course, in space, no one can hear you lase)

>Does the frequency matter?  I.e., would it make more sense to generate
>  ultraviolet or gamma rays rather than visible light?

Frequency is determined by application. Before you use radiation
outside the visible range in an atmosphere, you may want to look
at the transmission characteristics for your frequency in that
atmosphere. (Of course, gamma goes through everything - I suggest,
however, that the energy requirements and optics for gamma ray
lasers make it unlikely such devices would ever be hand weapons).

******************************************************************************
Renegade academician. They're a dangerous breed when they go feral,
academics are...a chemist, too.
		    -(James P. Blaylock in "Lord Kelvin's Machine")

My organization hasn't agreed with any of my opinions so far, and
I doubt they'll start now.

Stanley "Ya nee speon" Roberts

Newsgroups: rec.arts.sf.science
From: u925599@postoffice.utas.edu.au (Chris Stapelberg)
Subject: Are you south african
Organization: University of Tasmania, Australia
Date: Tue, 1 Sep 1992 01:00:36 GMT

If you are please wrire to me or Just give me your
 Name and e-adress !
 regards, chris

Newsgroups: rec.arts.sf.science
From: neufeld@helios.physics.utoronto.ca (Christopher Neufeld)
Subject: Re: Niven's blunders (was:Superconductors + the 2nd law)
Organization: University of Toronto Physics/Astronomy/CITA
Date: Tue, 1 Sep 1992 20:46:48 GMT

In article <BCR.92Sep1214550@hpl3sn02.cern.ch> bcr@cernapo.cern.ch (Bill Riemers) writes:
>In article <la7dp6INN787@appserv.Eng.Sun.COM> fiddler@concertina.Eng.Sun.COM (steve hix) writes:
>
>>  If the flux is high enough, they are.
>>
>>  Apparently, if you're in a solar system whose star goes supernova (bad luck!),
>>  the neutrino flux will cook you before any other evidence of the explosion
>>  has time to get to you.
>>
>>  Sort of an extreme case, but...
>
>I need to see some detailed calculations to swollow that one.
>
   I'll jump in here with a foggy memory from the summer of 1987. You
remember, the year of the nearby supernova?
   Now, I was working as an undergraduate summer student at CERN that
summer, and the library had a scheme to winnow out interesting journal
articles for the hard-working physicists who don't have time to read
every issue from cover to cover. They presented teasers and factoids from
various articles in a little flyer with references for the interested
reader should he/she want to look up one of the stories in more detail.

   One week the leaflet included a segment on neutrino facts taken from
several different journal articles. Among the values presented were
statements to the effect that:

- The width of the Kamiokande peak puts an upper limit on the mass of the
electron neutrino, somewhere around a couple of dozen electron volts. No
surprises there.

- The supernova 1987A radiated 99% of the energy evolved in the collapse
as neutrinos. Of the remaining one percent, 0.99% was kinetic energy of
gas blown off, and 0.01% was radiant electromagnetic energy

- One person in three on the Earth experienced a neutrino interaction
event within their body due to the supernova.

- A person shielded from all other supernova effects, at a distance from
the explosion equal to the distance from our Sun to Jupiter, would be
killed by the neutrino flux.

>You would have to have a large enough flux to produce fission in a large
>fraction of your ship and body mass...
>
   No, that's not how it's likely to kill you. The neutrino can mediate
some up <-> down quark interactions, or produce neutral current
interactions, and both those will tend to result in highly energetic
electrons whipping around in your body. This is a form of ionizing
radiation, and gets you by the usual mechanisms. Induced radioactivity in
the nuclei won't be as important. I don't know off-hand the relative
cross-sections of the two mechanisms.


-- 
 Christopher Neufeld....Just a graduate student  | Confidence is the feeling
 neufeld@helios.physics.utoronto.ca    Ad astra  | you have before you
 utzoo.utoronto.ca!generic!cneufeld              | understand the situation.
 "Don't edit reality for the sake of simplicity" |
Newsgroups: rec.arts.sf.science
From: jbf@wts.com (Jens B. Fiederer)
Subject: Re: Dinosaurs and Dragons
Organization: Wegmans Transaction Services
Date: Wed, 26 Aug 1992 18:00:35 GMT

In article <1992Aug18.204851.15265@u.washington.edu> kellmer@u.washington.edu writes:
>This fire-breathing is purely Western European.  What it somes from, as well
>as the idea that dragons live in caves, and are great hoarders of treasure,
>is, in fact, the burial practices of Northern Europe, especially Scandanavia
>and the rest of the north.  In many of these places, early (bronze age to
>early Viking period) burials were often dug in the ground like this:

Fire-breathing is not only a quality of "Dragons" (the Europeans more
commonly called these beasts "Worms").  One of the Germanic heroes
(I believe he passed too close to the sun on his way to being born) would
breathe fire whenever he got angry -- I think it may have been Dietrich
of Bern.....
Newsgroups: rec.arts.sf.science
From: elf@halcyon.com (Elf Sternberg)
Subject: Re: Ringworlds
Originator: elf@halcyon.com
Reply-To: elf@halcyon.com (Elf Sternberg)
Organization: Pendor, UnLtd.
Date: Sat, 29 Aug 1992 06:17:37 GMT

In article <BCR.92Aug28230143@hpl3sn02.cern.ch>
     bcr@cernapo (Bill Riemers) writes:

>In article <BtpK2v.Aus@ux1.cso.uiuc.edu> gletty@ux1.cso.uiuc.edu (Bruce Gletty) >writes:

>>Both Ringworlds and Dyson Spheres still suffer from the instability
>>problem.  The star has no force acting on it to keep it in the center
>>of the system. I'm not sure if there exists a solution for either,
>>Niven kludged one up in Ringworld Engineers, but it seemed a little
>>hokey. Its probably easier for a ring than a sphere.

   Certainly easier for a ring than a sphere!  Niven's system works,
but one thing that always bothered me: Niven had TWO systems for
manipulating the relationship between the sun and the ring.  One was
the attitude jets around the rim of the ringworld.  This was the ONLY
system he had for his world that didn't destroy 20% of the ring.  These
jets would collect solar energy and distribute it in an impulsive
fashion, pushing the ring back to center.

   The other method used the ring as a giant magnet to create a HUGE
solar flare to knock the ring back into position.  This method always
bothered me for several reasons, not the least of which was it would
KILL 20% of the ring population.  If the 'knock' was powerful enough to
push the ring back where the jets weren't, why did the jets have to
power to stop the ring from sliding in the _other_ direction?  It also
seemed to that the HUGE (approx 200,000km) electricity networks he had
buried in the ring were more than adequate to generate _gentle_ EM
fields that, fired in a computer-controlled sequence, like the attitude
jets, would, with the magnetic field of the sun, be more than
sufficient to keep the ring in place.  This method has less moving
parts too!

>This may be a stupid idea, but why not just take advantage of the solar wind?
>As a side moves closer to the sun, that side covers a larger solid angle and
>has an increased force pushing it back out.

   It works for HUGE sails, where the mass/cu m. of the sail is
miniscule.  For ringworlds, the density of the ring is just way way too
high for this method to work.

>                                             Bill

          Elf  !!!
-- 
Elf Sternberg    __   |     I have looked into the abyss, and the abyss
elf@halcyon.com  \/   | has looked into me.  Neither liked what we saw.
elf@polari.online.com |                              - Brother Theodore
Newsgroups: rec.arts.sf.science
From: gapdrr@gsusgi2.gsu.edu (Daniel R T Rothman)
Subject: Re: Something Nasty in the Human Genome
Organization: Georgia State University
Date: Wed, 2 Sep 1992 15:12:36 GMT

kelso_j@cs.uwa.oz.au (J Kyle Kelso) writes:

>    The idea is this: all life forms in the galaxy have their genetic code
>"infected" by a kind of genetic parasite.  It's life cycle goes like:

 < well thought-out, detailed description of beastie lifestyle>

's been done. try Niven's "Wyrms". Must be a tight idea though, you came
up with almost EXACTLY the same thing Niven did.

daniel rothman
Newsgroups: rec.arts.sf.science
From: rwallace@unix1.tcd.ie (russell wallace)
Subject: Re: Laser weapons
Organization: Trinity College, Dublin
Date: Fri, 4 Sep 1992 10:55:10 GMT

In <1992Sep3.184558.4898@spss.com> markrose@spss.com (Mark Rosenfelder) writes:

>In article <1992Sep1.213233.7293@spss.com> I write:
>>I'd like to throw some laser weapons into an sf story, but I find I don't
>>know enough about lasers.  

>Many thanks to all who responded, both by post and by e-mail.  It's been
>fascinating reading, even though now I have to rewrite my story.  :)

>Guns with bullets seem to be pretty energy-efficient, but they're not
>very futuristic, are they?  Can anyone think of anything that's likely
>to replace them?

Well, have you seen Aliens? Remember the feel of gritty high-tech
realism, with the fact that they were using feasible weapons
contributing a large part of it? You can have interesting things like
caselesss ammunition, smart guns that help you aim at the target,
possibly even smart rounds that contain a tiny microprocessor and adjust
their aim very slightly in flight (thus turning a near-miss into a hit).
But it isn't likely that anything will actually *replace* guns in the
foreseeable future (i.e. not until you're getting into space-opera type
plots).

--
"To summarize the summary of the summary: people are a problem"
Russell Wallace, Trinity College, Dublin
rwallace@unix1.tcd.ie