HDTenEightyP/NetNews huggingface dataset:
From: advax@reg.triumf.ca (A.Daviel)
Subject: Re: Niven's blunders (was: Superconductors + the 2nd law)
News-Software: VAX/VMS VNEWS 1.41    
Organization: TRIUMF: Tri-University Meson Facility
Date: Tue, 1 Sep 1992 22:32:00 GMT

In article <X880PB4w165w@west.darkside.com>, max@west.darkside.com (Erik Max Francis) writes...
>My understanding is that tides will kill him no matter what.  (He admits 
>this in another book:  "Alas and dammit, Shaeffer can't survive."  After 
>all, the ship comes within _one mile_ of the surface of the neutron star. 
>That's going to be a hell of a gravity gradient between his head and his 
>feet.
> 
>It is interesting how some astrogators in the future don't understand the 
>simplest astrophysical problems . . . :-)  Of course, it's all for the 
>sake of a story.

Protector-Brennan and Roy Truesdale went past the same star in a hyperbolic 
orbit somewhat earlier; I presume their orbit was further out. They cut the 
cable between the bits of ship, and went EVA during periastron (or is it 
apiastron; I get confused).

Andrew (another known space fan)
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: Fri, 28 Aug 1992 11:41:39 GMT

In article <15250@suns6.crosfield.co.uk>
     jc@crosfield.co.uk (jerry cullingford) writes:

>Benefits [of a ringworld]? _Lots_ of living space, and cheaper than a
>dyson sphere.

   Actually, I always thought that the major benefit of a Ringworld
when compared to a Dyson Sphere Classic (see Dyson's original works to
see what a true Dyson Sphere is) is that a Dyson Sphere requires a sort
of technology that we presently find incomprehensible (i.e. artificial
gravity) to make the interior surface livable.

   We don't even need Einstein to tell us why people can live on the
surface of a ringworld; Newton will do just fine.  Artificial Gravity
probably requires some kind of dependant power source and volatile
or dangerous hardware to continue operating.  Ringworlds (or, notably,
the Alderson Film Can design) require only brute force of the sort any
high school kid can understand.

            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
Organization: School of Computer Science, Carnegie Mellon, Pittsburgh, PA
Newsgroups: rec.arts.sf.science
Date: Thu,  3 Sep 1992 12:53:25 -0400 
From: "Andrew C. Plotkin" <ap1i+@andrew.cmu.edu>
Subject: Re: Laser weapons
	<1992Sep3.135125.22354@cas.org>

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.
Since it's a laser, it'll all be focussed on one spot; the only problem
is the rate of energy flow. If you can deliver those joules within one
second, you'll get a disabling wound. If it takes ten minutes, the
target will walk up to you (well, dodging back and forth a lot) and
knife you.

--Z

"And Aholibamah bare Jeush, and Jaalam, and Korah: these were the borogoves..."
From: daf31428@uxa.cso.uiuc.edu (David A. Fleming)
Newsgroups: rec.arts.sf.science
Subject: Re: Ringworlds
Date: 29 Aug 92 01:54:33 GMT
Organization: University of Illinois at Urbana

majcher@acsu.buffalo.edu (Salamander~) 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
>from a few of Elf Sternberg's Journal Entries, that is...)  Could
>someone take a few minutes and give me a _really_ fast rundown on
>exactly how one is supposedly constructed, what it looks like, and
>what the benefeits of living on one are?  (Or at least give me a
>pointer or two to where I could check it out...)

>Thanks,
>Marc


>-- 
>  majcher@acsu.buffalo.edu     *  The meek shall inherit the earth,   *
>  Marc Majcher@P.O. Box 156          and the wise keep moving on...
>     Amherst, NY  14226        *   The Earth is our Mother, but how   *
>    Voice: (716) 834-1648       many of us still live with our mother?

	Track down a copy of Niven's book, _A Hole in Space_.  There's a
chapter entitled "Bigger than Worlds" which should clear everything up.
					daf31428@uxa.cso.uiuc.edu
Newsgroups: rec.arts.sf.science
From: singley@helix.nih.gov (Erick D. Singley)
Subject: Re: Laser weapons
Organization: (National Institutes of Health, Bethesda, MD)
Date: Wed, 2 Sep 1992 14:00:01 GMT

>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?
Practical? Sure! Many SF writers have even used them as tool/weapons (spread
out wide for flashlight, remain narrow for cutting).  Energy depends on what you
want it do be able to do as a weapon.

What your universe will need that we don't at the moment is better/efficient
power.  Right now most of a laser you see in classroom demonstrations ('here
we see a laser melting through the target) is *power* and *cooling* (in the case
of gas lasers).  Lasing is a change in energy states.  I'm not sure how long
some of the crystals would need to be in order to fry a guy.

>Do they make a noise when fired?
Not by themselves; but your rechargeing unit (whatever high tech capaciter you
use) might if you want. ;-)

>Does the frequency matter?  I.e., would it make more sense to generate
>  ultraviolet or gamma rays rather than visible light?
The only way you are going to get gamma lasers now-a-days is to use a nuclear
explosion to pump it (See "Footfall") People say one can stop visible light
lasers by 'polish'/mirroring the armor- but lasers require special mirrors
deisgned for that wavelength (99.x%) to use in the first place.  Such mirrored
armour may reduce damage, but not stop entirily.  Still heating will take place.
Better than nothing I guess.  Higher energy sources (gamma) will 'punch'
through armour better (with the effect of spreading/spray!), but laser will
concentrate energy to 'burn' through.

Nuf for now.
From: jackc@vermont.mips.com (Jack Choquette)
Newsgroups: rec.arts.sf.science
Subject: Future Civilization Advances
Date: 2 Sep 92 18:29:32 GMT
Organization: MIPS Computer Systems, Inc.
NNTP-Posting-Host: vermont.mips.com


I've been playing the computer game called "Civilization", a great
game.  Part of the play is that you go through human history and
achieve various civilization advances, some of which are dependent on
previous advances.  For example, the civilization advance of Trade
requires the advances of currency and code of laws.  Each advance
allows you to do something.  For example, navigation allows you to
build sailing ships to sail the seas to explore the world and
transport items for trade or war.

This sparked an interest for me to do research in what science
fiction believes future civilization advances will be.  I'm interested
in finding out what people in this newsgroup feel will be the major
civilization advances in the near and far future.  What will be the
implications of this advance, and what will this advance require
before it can be developed.  Below are some possible categories and
some examples from history.  Feel free to go outside these categories.
	transportation:  sailing, railroads, flight
	weapons:  gunpowder, nuclear
	government:  Monarchy, Democracy, Communism
	religion/philosophy/education
	trade:  currency, trade caravans and routes  
	new sciences:  chemistry, physics.
	discoveries: electricity, magnetism

Either email me or post to this newsgroup.  I will post a summary of
replies if people are interested.  I would like to know of any books
or magazine articles where I could find such information.  Any
references to sf novels or short stories would also be very helpful.

Thanks for your help!

/jack
From: max@west.darkside.com (Erik Max Francis)
Newsgroups: rec.arts.sf.science
Subject: Re: Niven's blunders (was:Superconductors + the 2nd law)
Date: 29 Aug 92 19:12:38 GMT
Organization: The Dark Side of the Moon +1 408 245 SPAM

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

> If the ship is not perfectly in line with the centre of mass of the
> neutron star, there will be a torque resulting from the different
> gravitational attraction on the different parts of the ship (provided
> it is not a perfect sphere, but I seem to remember it was roughly
> cylindrical). That torque will presumably leave the ship spinning
> after it has left the immediate vicinity of the neutron star.

Tides are caused by a gravitational differential between two parts of the 
ship.  The ship in "Neutron Star," the _Skydiver,_ had a very significant 
profile -- it was by no means spherical.  (You can look on the cover of 
the eleventh printing (Sep 1981) and you'll see that the _Skydiver_ is 
about 12-15 times longer than it is wide.  It's roughly spherical, though 
it tapers at each end.  A large drive is stuck on the outside of the 
General Products hull.)

The periapsis of the _Skydiver_ was _one mile_ from the surface of the 
neutron star.  That's a hell of a close orbit.  Neutron stars are, of 
course, extremely dense objects (in fact, the densest that matter can 
theoretically get -- the density of the nucleus of an atom; the stuff 
that makes them up is called neutronium).  So even though the diameter of 
the neutron star is only a few kilometers, it masses as much as a few 
Suns.

The first thing that the neutron star will do is apply a torque to the 
ship, rotating it so that its axis points directly through the center of 
the neutron star.

Tides happen because your feet are being pulled much harder than your 
head.  This would tend to stretch you out, and would be quite 
uncomfortable.  I'm not sure the exact fields involved with this neutron 
star (no mass is given to my knowledge), and general relativity would 
come into effect, though I'm not familiar enough with Reimann geometries 
to handle it.  I could give a Newtonian approximation if anyone's 
interested.
> Anybody up to doing the calculations on that?


----------
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   |
Newsgroups: rec.arts.sf.science
From: jdnicoll@watyew.uwaterloo.ca (James Davis Nicoll)
Subject: Re: Ringworlds
Organization: University of Waterloo
Date: Sat, 29 Aug 1992 15:47:07 GMT

In article <1992Aug28.220054.585@enterprise.rdd.lmsc.lockheed.com> baylor@force.ssd.lmsc.lockheed.com writes:
>In article <1992Aug28.181923.27698@unixg.ubc.ca>, holland@geop.ubc.ca (Stephen Holland) writes:

>>There is a way to make a Dyson Sphere work with-out artificial gravity.  Just 
>>spin the sphere.  That way you get Earth-normal (or whatever) gravity near the
>>sphere's equator and a steadily decreasing gravity field as you move further
>>away from the equator.  At the poles you have no gravity, which migh be 
>>useful for the ball-bearing industry.
>>
>When you spin a dyson sphere, it may as well be a ringworld. The gravity
>and air will collect at the equator anyhow, and there's no way you'd
>have enough air to fill a significant fraction of a 1AU diameter sphere.
>Besides, given the vector of the centripetal acceleration, you'd have
>very steep hills at a very short distance off the equator.

	You could step the surface of the  sphere, so that you effectively
have a series of ringworlds of progressively smaller radius 'glued' together.
It would look a bit like a Japanese lantern.  

	The polar strips would  have to do something about the angle they 
got sunlight at, and  if the strips rotate uniformly, the smaller ones
might need lids to keep the air in, as the centrifugal effect will be 
low(er).

							James Nicoll
Newsgroups: rec.arts.sf.science
From: dani@netcom.com (Dani Zweig)
Subject: Re: Laser weapons
Date: Thu, 03 Sep 92 21:45:10 GMT
Organization: Netcom - Online Communication Services  (408 241-9760 guest) 

mvp@hsv3.lsil.com (Mike Van Pelt):
>He said that people who invoke mirrors as a defense against very high
>power lasers just don't understand this effect.

Do I take it we can dismiss the wearing of green cloaks as a defense
against green laser beams as another Nivenism?

-----
Dani Zweig
dani@netcom.com

   It was mentioned on CNN that the new prime number discovered
   recently is four times bigger then the previous record.
				-- John Blasik


Newsgroups: rec.arts.sf.science
From: blancha@seq.uncwil.edu (Chris Blanchard)
Subject: Re: Niven's blunders (was:Superconductors + the 2nd law)
Organization: Univ. of North Carolina @ Wilmington
Date: Tue, 1 Sep 1992 05:27:26 GMT

In article <78796@ut-emx.uucp> slug@ccwf.cc.utexas.edu (Glen Anthony Graham) writes:
>In article <8_ty6z#@rpi.edu> kasprj@rpi.edu writes:
>
>Um... if I recall correctly (and it has been a couple of years since I've read
>all the Niven books...), wasn't the "radiation" from the core explosion in the
>form of nutrinos or something like that?  Nutrinos have a nasty habit of being
>able to pass through planets and rocks without slowing down, so underground
>cities would not help at all.  
>
>Also, the GP hull was not impervious to whatever radiation the galactic 
>explosion was hurling at Known Space, but the Ringworld just happened to be
>completely impervious to this radiation.
> 
>As for leakage, with the core being some 20,000 lightyears away, that makes for
>an awfully small (apparant) source of radiation, so if the ring is aligned   
>along the radiation path, the opposite side would not really receive any 
>radiation.  I believe there was something mentioned about some leakage around
>the very edges of the Ringworld, but remember that you are dealing with a 
>lifing area that is 1 million miles wide.  No, I think that there would be
>no real problem of radiation on the Ringworld.  Neither did the Puppeteers  
>which is why they introduced the superconducting virus on the Ringworld- to
>destroy it's current civilization and make room for the Puppeteers themselves.
> 
>Glen Graham.
>slug@ccwf.cc.utexas.edu

Well not meaning to be rude but WRONG!! The GP hull was impervious to the
neutrinos. the scrith ie ring floor stopped, if I recall corectly, 30%. This 
is explained partially in the short story At the Core and of course Ringworld.
If the GP hull had not blocked 100% neutrinos Beowulf would have died. As the
outside readings were quiet HIGH.

-- 
-----------------------------------------------------------------------------
| Internet:                        |Chris Blanchard | Phone: (919) 452-9638 |
| blancha@seq.uncwil.edu           |-----------------------------------------
|                                  |   Think of it as evolution in action   |
From: baylor@force.ssd.lmsc.lockheed.com
Newsgroups: rec.arts.sf.science
Subject: Re: Laser weapons
Date: 2 Sep 92 19:22:55 GMT
Reply-To: baylor@force.ssd.lmsc.lockheed.com
Organization: LMSC, Sunnyvale, California

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?  
You're talking current technology? Probably not. I don't think
there'd be a large enough power source to be handheld, and if there 
were, the standard size components probably won't take the load.

>How much energy do they use?
Depends on how large a patch you want to fry at once.

>Do they make a noise when fired?
Little ones don't. Beyond that I don't know.

>Does the frequency matter?  I.e., would it make more sense to generate
>  ultraviolet or gamma rays rather than visible light?
Visible light has a BIG advantage. Rather than kill the enemy with
a super large power source, you can blind him with a small
one that is within the relm of current technology. There are warnings
accompanying most lasers about this effect. Something just off the 
visible spectrum (UV & IR) would work even better, since you might
get him without his noticing.

--Just shooting off my mouth.

RB
From: bjgaed@bb1t.monsanto.com
Newsgroups: rec.arts.sf.science
Subject: Re: Hydro energy storage systems
Date: 26 Aug 92 13:06:43 GMT
Organization: Monsanto Company, St. Louis, MO

>In article <78243@ut-emx.uucp>, dillard@ccwf.cc.utexas.edu (Alex Dillard) writes:
>> In article <hl71572@pro-smof.cts.com> wixer!cactus.org!wixer!pro-smof.cts.com
!rfletcher@cactus.org (Robert Fletcher) writes:
>>>
>>>  Is there or is there not a loss of energy when water is pumped up 
a hill
>>>in the day and the letting it run down at night.
>>

[Somewhat gauche stuff of mine deleted.]

>  No, the second law does say that you can break even.  'The change 
in entropy
>for all parts of the system is greater _or equal to_ zero'.

Sorry about that.  Give me three minutes for roughing the poster.

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{)  

-- 
--Electric Monk            (Bruce Gaede); 
                            e-mail: bjgaed@ccmail.monsanto.com

"...and then time started seriously to pass."
--Douglas Adams, _Dirk Gently's Holistic Detective Agency_
From: smith@ctron.com (Larry Smith)
Newsgroups: rec.arts.sf.science
Subject: Re: dragons were dinosaurs?
Date: 27 Aug 92 18:43:27 GMT
Reply-To: smith@ctron.com
Followup-To: soc.religion
Organization: Cabletron Systems, Inc.

In article <92Aug25.224337.28864@acs.ucalgary.ca>, iwsbarke@acs.ucalgary.ca (I W Scott Barker) writes:

in reply to my:
>> Heh, heh, heh.  By _your_ lights, _nothing_ can be proven.  But your lights,
>> dear boy, are quite broken.

>Care to explain why? Are you capable of proving anyrhing, beyond a shadow of a
>doubt, with no possibility of it ever changing?

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.

Larry Smith (smith@ctron.com)  No, I don't speak for Cabletron.  Need you ask?
-
How about we all do something reasonable?  I bet that'll confuse 'em!
From: jc@crosfield.co.uk (jerry cullingford)
Newsgroups: rec.arts.sf.science
Subject: Re: Ringworlds
Date: 27 Aug 92 12:46:06 GMT
Organization: Crosfield Electronics, Hemel Hempstead, United Kingdom.

In article <BtMFzD.IMs@acsu.buffalo.edu> majcher@acsu.buffalo.edu (Salamander~) 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
>from a few of Elf Sternberg's Journal Entries, that is...)  Could
>someone take a few minutes and give me a _really_ fast rundown on
>exactly how one is supposedly constructed, what it looks like, and
>what the benefeits of living on one are?  (Or at least give me a
>pointer or two to where I could check it out...)

Hmm.. Ok..

Basic starting idea: Dyson sphere

basically, a sphere enclosing the sun, thus being able to capture all
the radiated energy. If the radius is about that of the earth's orbit,
you get (1) the sort of sunlight we're used to :-) and (2) one hell of
a lot of living space.

One problem is how you keep things (like air and people) on the sphere.. so

Next Idea: Ringworld.

replace the sphere by a ring, with the sun in the centre.
Now you can spin the ring to provide fake gravity, on the inner face
of the ring. Stick tall :-) walls on the edges to keep the atmosphere in.

If you're used to day/night cycles, stick some opaque objects in a
closer orbit to the sun to provide eclipse style 'nights'.

Benefits? _Lots_ of living space, and cheaper than a dyson sphere.
Requirements? _Lots_ of excessively strong building material.



-- 
+------------------------------------------------------------------+     |
| Jerry Cullingford  #include <std.disclaimer> +44 442 230000 x3868|   ,-|--
| jc@crosfield.co.uk (jc@cel.uucp) or jc@selune.demon.co.uk        |   \_|__
+-----(Work)---------------------------------(home)----------------+ \___/
Newsgroups: rec.arts.sf.science