HDTenEightyP/NetNews huggingface dataset:
From: francis@dogwood.atl.ga.us (John Stracke)
Subject: Re: Niven's teleportation & 2nd law of thermodynamics (was: Superconductors + the 2
Organization: National Science Center Foundation
Date: Thu, 3 Sep 1992 13:47:43 GMT
	<1992Sep2.204731.4669@msc.cornell.edu>

In article <1992Sep2.204731.4669@msc.cornell.edu> hillyard@msc.cornell.edu writes:

>From article <1992Sep2.114236.428@cine88.cineca.it>, by campo@sunthpi3.difi.unipi.it (Massimo Campostrini):
>[...]
>>    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.

--
/===========================================================================\
|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,           |
Newsgroups: rec.arts.sf.science
From: rwallace@unix1.tcd.ie (russell wallace)
Subject: Re: Laser weapons
Organization: Trinity College, Dublin
Date: Wed, 2 Sep 1992 09:02:50 GMT

In <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?  
>How much energy do they use?
>Do they make a noise when fired?
>Does the frequency matter?  I.e., would it make more sense to generate
>  ultraviolet or gamma rays rather than visible light?

Basically, lasers as we know them today are inherently useless as
weapons - they don't put out enough power.

To get enough power from an energy weapon, you want to tap it directly
from a nuclear reaction.

So the first practical energy weapon will probably be a fusion gun,
using a fusion reaction to produce energy, arranged so that the energy
is emitted from one end of the reactor. Whether the beam will primarily
consist of charged particles, infrared, visible light or X-rays I don't
know; it would depend on exactly how the device worked.

Note that this is *extremely* advanced technology, particularly if you
want fusion handguns (presumably they will become available as heavy
fixed-mount weapons before they become portable). Also, if you can build
such a weapon at all, it should be possible to make it pretty powerful
(after all, it can be thought of as a low-speed, straight-line
thermonuclear explosion :-))... maybe you could turn a city block into
slag with a gun you could fire with one hand. (Might be problems with
overheating though.) Also the operator might, at least with the more
primitive models, need radiation shielding.

The only other viable idea for an energy weapon I've heard of is the
X-ray laser powered by a nuclear bomb, suggested for the SDI project; a
weapon that requires a nuclear explosion at the firer's end probably
isn't what you're looking for though :-).

--
"To summarize the summary of the summary: people are a problem"
Russell Wallace, Trinity College, Dublin
rwallace@unix1.tcd.ie
From: wiml@milton.u.washington.edu (William Lewis)
Newsgroups: rec.arts.sf.science
Subject: Re: dragons were dinosaurs?
Date: 27 Aug 92 04:38:54 GMT
Organization: University of Washington, Seattle

In article <912@tdat.teradata.COM> swf@tdat.teradata.com (Stanley Friesen) writes:
>In article <auwen.714089675@starman> auwen@convex.com (John David Auwen) writes:
>|Is this where the concept of dragons and sea monsters came from?
>|
>So, no, at least not in the way you mean.
>
>Now there *is* a theory that these legends come from people finding *fossil*
>*skeletons*, and mistaking them for recent skeletons, and thus supposing the
>animal in question was to be found somewhere around.
>(This is certainly a popular explanation for the Amerindian myth of the
>Thunderbird).

  My favorite theory (which, as far as I know, I made up) is that
dinosaur legends are due to jetliners which flew through the
Bermuda Triangle and got transported back in time. Imagine (if you 
will) someone whose idea of high technology is tanning leather,
looking up and seeing a 747 thundering overhead looking for
a landing site. I'd think they'd be pretty impressed. When the
plane runs out of fuel, someone will find the crash site and the
charred bodies of the passengers, and start telliing people about
the enormous winged beast that breathes fire and eats people whole
(and wholesale). 
  The reason nobody lived through the crash to become immensely
powerful using bits of modern knowledge is that as soon as the DEA's
hidden transponder hadn't gotten a ping in long enough, it assumed
that the plane was up to no good and triggered the hidden explosive
in the turbines. Also, without regular transmissions from the
orbiting mind control satellites, most of the passengers went catatonic.
  Of course, this isn't to say that *some* passenger didn't escape
all this and change their name to Merlin or something. Would make a
good story...

-- 
email: wiml@u.washington.edu             |  Home:  Seattle, Washington   |
     (William Lewis)                     |  47 41' 15" N   122 42' 58" W | 
NeXTmail: wiml@ingalls.cs.washington.edu `-------------------------------'
        --*-- Member, Coalition to Preserve Semantic Vacuity --*--
Newsgroups: rec.arts.sf.science,rec.arts.sf.written
From: myboy@casbah.acns.nwu.edu (Lewis Murtaugh)
Subject: Re: Something Nasty in the Human Genome
Organization: Northwestern University, Evanston Illinois.
Distribution: na
Date: Fri, 4 Sep 1992 14:13:09 GMT

This is getting off the topic a bit, but one of my organic chemistry
instructors has a letter to Science (published a few years ago) posted on the
wall outside her office.  It seems some enterprising researchers searched the
database of all human genomic DNA sequences for the DNA sequence corresponding
to the amino acid sequence "ELVIS".  They found that the sequence they
searched for came up a few orders of magnitude more often than it would have
been expected to, randomly.

Then they rearranged the amino-acid "letters" to spell "LIVES", and found it
came up disappointingly few times.

--
Charles Murtaugh
From: fmonro@neumann.une.edu.au (F J Monro)
Newsgroups: rec.arts.sf.science
Subject: Re: Niven's blunders (was:Superconductors + the 2nd law)
Date: 29 Aug 92 15:12:23 GMT

ecmtwhk@ccu1.aukuni.ac.nz (Thomas Koenig) writes:

>Another thing - the notion that the Ringworld, by being built with its
>edge towards the galactic core, will offer its inhabitants safety when
>the shockwave from the explosion arrives (expressed towards the end in
>Ringworld Engineers by Louis) is ludicrous. The visible angle of the
>core explosion will be much larger than the angle of the opposite end of
>the Ringworld.

Thinking about it, I think one of his biggest "blunders" is his
assumption that human space will eventually have to be evacuated.

Why not buy the GP Hull, In "At the Core" Niven says it is for sale
(Amazingly cheap at 1 trillion stars..). Start making hull material
domes over your citys (think climate control, fusion reactor disaster
control, air raid defence), It also keeps radiation out. You'll need 
it over farms as well. with teleport booths you need never go outside.
GP domes need little maintenence. 

You have thousands of years to do it, eventually, every starship has
a GP hull, all the citys are protected. This would be expensive, but
not as expensive as evacuating a thousand+ worlds. As a backup, set 
up a colony in the magelanic clouds, you don't need the Hyperdrive2,
get say 1000 volunteers, equip them with the largest GP hull, and
1000 statis coffins, and the normal colonizing kit, also in statis.
Teach them all to pilot the ship, and have them fly it for one year
each. Alternativly, make a protector & get him to fly it.

As a further backup, scatter statis caches around Known Space which 
have very durable timing devices to turn them off after the radiation 
has past. Let these contain a colony kit & terestrial "Gene Bank" 
of the earth's bisphere (these can be living animals & plants). The 
Colonists terraform the empty worlds when they emerge. (of course
if the citys do survive, there may be no empty world around...).
To make shure that they do emerge, put some of the "arks" in prominent 
orbits around interesting celestial objects. The first aliens to evolve 
after the readiation will open them (only 2 or 3 billion years to wait.)
Also, make a contract with the outsiders to open some of them, should the 
timers fail (offer to statis some starseeds?). Also make some protectors,
send them off in hyperspace ships with orders to come back afterwards and
open the things. (or use protectors as your timers in the first place). 

What do you think (If you've read this far, you must be a Known Space Fanatic)?


-Che Monro			aka fmonro@neumann.une.edu.au
	"reverse the polarity of the neutron flow.."

Newsgroups: rec.arts.sf.science
From: alberti@mudhoney.micro.umn.edu (Albatross)
Subject: Donaldson's _Gap Cycle_: does this add up?
Organization: University of Minnesota, Minneapolis
Date: Wed, 26 Aug 1992 19:10:13 GMT

Having just finished the first two books in Donaldson's Gap cycle, I have a
couple of basic Sf/Science questions about what I read:

A the engine of a given ship is stated to be capable of accelerating the
ship to "50%" of lightspeed.  Care is taken to explain how, although it may
accelerate indefinitely, the engine will cease to significantly affect the
velocity of the ship when the ship has reached 50% of lightspeed.

Later, the same ship is accelerated by external forces (I'll remain vague
to avoid spoilers) to "90%" of lightspeed.  "Significant dopplering" of the
background starfield occurs.

This ship then _decelerates_ to "rest" (it docks with an object which it was
formerly approacing at 90% of lightspeed).

My first question is, does Donaldson have a clue?

My second question is simpler:  in several places in the novels ships
accelerate to significant portions of c.  They do so with levels of
acceleration which approach human tolerances for durations of between four and
about ten hours.  I suppose based on these descriptions one might expect
these accelerations to be between 3 and 8 G (?)

Now if I had one I'd look this up myself, but instead I'll ask:  is there
a table which might demonstrate whether these descriptions were credible?
In other words, something which would show...
  
  Accelleration/Time:   1 hour    2 hours   4 hours  8 hours  12 hours
            1 G   12,345 mi/s   100K mi/s 250K mi/s...
            2 G   45,678 mi/s   275K mi/s ....
            :        :            :

I'm curious as to how bad the science is going to be in the rest of these
books...
--
Bob Alberti: Computer & Information Services U of MN | aka: Albatross | Unitar-
E-mail     : alberti@boombox.micro.umn.edu           | Metropolis BBS | ian/
Disclaimer : My employer does not mean what I say.   | (612) 721-1870 | Univer-
Minnesota  : Where butter is a spice.                | BBSing as art. | salist!
From: swf@teradata.com (Stanley Friesen)
Newsgroups: rec.arts.sf.science
Subject: Re: dragons were dinosaurs?
Date: 26 Aug 92 16:35:50 GMT
Reply-To: swf@tdat.teradata.com (Stanley Friesen)
Organization: NCR Teradata Database Business Unit

In article <1992Aug20.144627.24952@news.acns.nwu.edu> myboy@casbah.acns.nwu.edu (Lewis Murtaugh) writes:
|In article <Bt92J2.1Gp@teleride.on.ca> stevew@teleride.on.ca (Stephen M. Webb) writes:
|>
|>There is no concrete evidence that any dinosaurs have been alive for the
|>past several hundered million years.  This isn't to say there haven't been
|>any, but a few hundred million years is a long time.
|
|The fossil record shows NO dinosaurs after the mass extinction that killed
|them off (I'm not sure how long ago that was, but it must have been around
|200-300 million years -- before any primates, let alone humans, existed).

Nit pick time.  The extinction event that wiped out the dinosaurs (and every
other vertebrate larger than about 100 kg) took place between 64 and 66
million years ago.  And while there were no primates of 'modern aspect',
there were a few species of 'primitive' primates present (I am talking about
the rather odd little beast, Purgatorius from the Hell Creek Formation of
Montana - guess where it gots its name?)

However, Purgatorius was a Plesiadapiform, which makes it only barely a
primate (in fact some scientists do not include Plesiadapiformes in the
order Primates, that is how different they were from any living primate).

Modern type primates, similar to galagos and tarsiers, first appeared about
10 to 15 million years later, in the Eocene.


|It may be that a statistically insignificant number of dinosaurs survived the
|great extinction, but they would be doomed genetically to extinction.  Any
|time a gene pool is reduced that far the species is in trouble -- that is why
|many scientists are worried that certain endangered species of tigers,
|elephants, etc. are doomed because their numbers are too small to ensure
|genetic diversity.

Quite true.  Even the most radical paleontologist, Dr Sloan, does not propose
the dinosaurs surviving the end of the Mesozoic by even as much as 1 million
years.  (His proposal comes out to something like 100,000 or so years).

|If enough dinosaurs did survive to ensure genetic diversity, where are they
|now?  Did primitive man kill them off?  Why aren't there any cave paintings of
|dinosaurs?

And believe us, a big bleeper like a brontosaur or a tyrannosaur would be
*noticed*, and made note of.  The larger dinosaurs were *not* exactly
what one would call inconspicuous.
-- 
sarima@teradata.com			(formerly tdatirv!sarima)
  or
Stanley.Friesen@ElSegundoCA.ncr.com
From: max@west.darkside.com (Erik Max Francis)
Newsgroups: rec.arts.sf.science
Subject: _Forge of God_ bullets?
Date: 1 Sep 92 05:02:37 GMT
Organization: The Dark Side of the Moon +1 408 245 SPAM

WARNING:  PROBABLE SPOILER


Just finished reading _Forge of God_ by Greg Bear (yeah, so I'm behind 
the times . . . just started taking the bus regularly; gives me plenty of 
time to catch up on my science-fiction reading).  Enjoyed it a great deal 
. . . but have some idle thinking.

The two bullets -- the neutronium and antineutronium chunks -- seem to 
make a good cosmic time bomb . . . but would it work?  It seems pretty 
evident that antineutronium would annihilate fairly fast, considering 
it's so dense . . . but Bear mentions (on p. 300 in a perspective) that 
the "antineutronium bullet would interact with the Earth's matter and 
create what's called an ambi-plasma, which would prevent the 
antineutronium from blowing up all at once."

Quite interesting . . . but what the hell is an ambi-plasma?  I've never 
heard of it.

Also:  I computed the total amount of energy required to completely 
dissociate a gravitational body.  For a spherical, uniformly-dense body, 
it's given by E = (9/15) G M^2/R, where M is the mass of the body and R 
the radius.  This comes to around 10^33 J for the Earth.  The total 
amount of mass converted in the two bullets would be something like "a 
hundred or two hundred million tons of matter" (p. 300).  That's an awful 
lot of matter to be annihilated, but it only comes to around 10^28 J of 
equivalent mass-energy.  That's about 100 000 too little energy to be 
accounted for the complete destruction of the Earth.

Anybody have any comments on this, specifically on the mechanism 
concerning the ambi-plasma?  All I can say about that, as a budding 
(ahem) hard science-fiction author:  I wish I'd thought of it first.

----------
Erik Max Francis   Omnia quia sunt, lumina sunt.  Coming soon:  UNIVERSE _ | _
USmail:  1070 Oakmont Dr. #1 San Jose CA 95117  ICBM:  37 20 N  121 53 W _>|<_
UUCP:  ..!apple!uuwest!max   Usenet:  max@west.darkside.com   464E4F5244   |
From: jc@crosfield.co.uk (jerry cullingford)
Newsgroups: rec.arts.sf.science
Subject: Re: Ringworlds
Date: 1 Sep 92 12:32:26 GMT
Organization: Crosfield Electronics, Hemel Hempstead, United Kingdom.

In article <2gsy8cq@rpi.edu> kasprj@rpi.edu writes:
"The mass deaths caused in 
"_The Ringworld Engineers_ come about as a result of using the system in a way
"unintended[5] by its designers.

" [2]: The system would also work in "reverse", if the jets at aphelion 
"fired _away_ from the sun when the radiation dropped _below_ a certain 
"level, but that wouldn't be as efficient.

So? why not do both?

" [4]: I just realized that you could "fool" a mechanical system into 
"firing when it wasn't supposed to by bombarding the detectors with 
"simulated solar radiation. A living protector wouldn't fall for this, 
"of course. Maybe a better system would be to link all the detectors 
"and have the thrust vary based on the differential between the closest
"and the farthest points. Anyhow, I think that the last surviving 
"protectors would have set up something reasonably foolproof if they'd
"had time.

Transmitters on the shadow squares? or do they need correction, too?

" [5]: But perhaps not unanticipated. The fact that the attitude jets 
"have the capacity to handle fuel intake at a level far above safe solar
"activity levels implies that the protectors designed for emergencies, 
"which seems unlike them. They prefer to slap together an improvement as
"the need arises. 

OTOH, it makes a handy weapon for uninvited invaders.. or just for keeping
rogue protectors in line :-)


-- 
+------------------------------------------------------------------+     |
| Jerry Cullingford  #include <std.disclaimer> +44 442 230000 x3868|   ,-|--
| jc@crosfield.co.uk (jc@cel.uucp) or jc@selune.demon.co.uk        |   \_|__
+-----(Work)---------------------------------(home)----------------+ \___/
From: jc@crosfield.co.uk (jerry cullingford)
Newsgroups: rec.arts.sf.science
Subject: Re: Laser weapons
Date: 3 Sep 92 12:55:48 GMT
Organization: Crosfield Electronics, Hemel Hempstead, United Kingdom.

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?

In reality, for frying people - probably not. At least not for continuous
or rechargeable units. Disposable, single/few shot ones may be a little better.

>How much energy do they use?

Well, you have to _deliver_ enough energy to fry your target, so you're
going to have to _use_ more than that, because your laser isn't going to be
100% efficient. And you want to pump that energy into your target fast..
AFAIK, most lasers today are pretty inefficient; to get ten or so _milliwatts_
out of an argon (blue/green) laser takes a fairly large PSU and a big fan
to keep the tube at a survivable temperature. So you might have to put tens or
hundreds of times more energy in than you get out. Solid state may be better,
but I don't think it's that much. So your laser is probably going to absorb
more power than your target.. and a hand held unit doesn't give you much to
spread it over.

If you want a multiple shot unit, you also have to avoid melting your optics
and/or your power source in the process.

(That's why I suspect they're not overly practical; I don't think you can
get the required energy density into normal batteries; maybe some vicious
chemical reaction would work for a single shot version..
 The other problem is mirrors; if they were common, a corner cube reflector
 would ruin the user's day :-) :-) )

>Do they make a noise when fired?

Maybe :-) It depends on whether your power supply makes a noise, how much
energy you lose into the atmosphere on route and suchlike. (and whether
you explosively vapourise your target :-) )

Of course, civilian weapons for hunting use might well be set up to make
a noise anyway (not too sporting if the target can't tell it's being shot at!)

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

Well, you want something that your target will absorb, and that isn't likely
to be absorbed by the atmosphere or reflected.. and you need to decide whether
you want to be able to (1) see that the thing is actually firing :-) and
(2) see where the beam hits (and is going, if there's enough suspended
particles in the atmosphere).

OTOH, people seem to be fairly used to laser weapons
(a bit like hyperdrive :-) ) so you can probably get away with them anyway :-)
-- 
+------------------------------------------------------------------+     |
| Jerry Cullingford  #include <std.disclaimer> +44 442 230000 x3868|   ,-|--
| jc@crosfield.co.uk (jc@cel.uucp) or jc@selune.demon.co.uk        |   \_|__
+-----(Work)---------------------------------(home)----------------+ \___/
From: dietz@cs.rochester.edu (Paul Dietz)
Newsgroups: rec.arts.sf.science
Subject: Re: Laser weapons
Date: 2 Sep 92 12:12:56 GMT
Organization: Computer Science Department University of Rochester

If one defines a "weapon" to be something that directly harms
the target, there is at least one kind of laser weapon that is
feasible today:  pulsed lasers designed to blind enemy soldiers.
Very short pulses will deposit energy on a very thin layer
of the target; in the eye, the retina can be damaged at fairly
modest energy levels.

Beam weapons that vaporize people or buildings are very
science-fictional, for a good reason:  all lasers are rather
inefficient (the very best, semiconductor lasers, convert only
1/2 of the electrical input to light), so you will be dissipating
more heat in the gun than in the target.

	Paul F. Dietz
	dietz@cs.rochester.edu
From: wixer!cactus.org!wixer!pro-smof.cts.com!rfletcher@cactus.org (Robert Fletcher)
Newsgroups: rec.arts.sf.science
Subject: Re: Hydro energy storage systems
Date: 29 Aug 1992 13:07:49 -0500
Organization: The SMOF-BBS: Science Fiction Online Since 1985 [512-467-7317]
NNTP-Posting-Host: cs.utexas.edu

  After about a year of toying with the idea of a home size
hydro-powerstation I have found out that it might not work well enought to
worth the effort. There must be a way to have a hydorgenerator for the home
owner.

----
ProLine:  rfletcher@pro-smof
Internet: rfletcher@pro-smof.cts.com
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