HDTenEightyP/NetNews huggingface dataset:
From: szabo@techbook.com (Nick Szabo)
Subject: Re: Costs of Transit Times (was Re: Wrecking a Planet)
Organization: TECHbooks --- Public Access UNIX --- (503) 220-0636
Date: Sun, 24 Jan 1993 02:08:14 GMT


Various points on water in space:

* The closest large-scale source of water is the Jupiter-family
  comets.  Over a dozen of these are already known; they have been 
  captured by Jupiter into the inner solar system and their orbits 
  resemble Earth-Jupiter transfer orbits.  The planets are usually 
  in the wrong position, of course, but there may be lucky days where 
  on could hitch a comet to Jupiter.  The delta-v to these comets is 
  8-10 km/s from high earth orbit, with several windows per decade.  
  Venus gravity assist could lower the return trip to 6 km/s to HEO.
* Type D & P asteroids probably have large ice deposits.  A few
  of these are as close as the inner asteroid belt, and if we
  get lucky we may discover earth-crossers with ice.  Those
  known now are 7+ km/s direct.
* If we can use the native comet volatiles as propellant, the 
  mass of equipment becomes proportional to the peak power output,
  not total energy expended.  A low-thrust native ice rocket
  can be orders of magnitude lighter, and significantly cheaper, 
  than a high-thrust system from Europa, Mars or Earth's surface.  
  I have designed a zero-tankage-factor ice rocket that delivers 
  10% of the ice as payload and expends the other 90% over the 8 km/s 
  trip from a Jupiter-family comet or belt asteroid to high earth 
  orbit.  The extraction equipment and solar-thermal-water rocket are 
  tiny and fairly simple.  Runs off of ice and the sun.  (Or alternately, 
  nuclear fission).  The system is so light, and automatically deployable, 
  it could probably be launched on current rockets.  
* Indeed, this is a prime candidate for near-term bootstrapping of space 
  industry, cheaper than manned lunar bases and Mars missions, and
  making such missions much cheaper and more effective.  10^4 tons 
  of organics, volatiles, silicates and perhaps even metals could be 
  placed in high earth orbit in a single 6-8 year mission, and processed
  with biotech and microchemical reactors (see my recent post on the latter 
  in sci.space).  Useful products include propellant, structures (eg
  kilometer-wide antenna dishes), shielding, microgravity process raw 
  materials, life support (air/food), etc.   Ice could also be shipped
  to the Moon, Mars orbit, asteroids, etc. for propellant or industrial 
  input at those sites.
* The comet system can return billions of tons of water to Earth orbit.
  I want to see the environmental impact statement of any system that
  proposes to launch billions of tons through Earth's atmosphere!

Nick Szabo					szabo@techbook.com
-- 
Nick Szabo					 szabo@techboook.com
From: sah@castle.ed.ac.uk (Juggler)
Newsgroups: rec.arts.sf.science
Subject: Re: Invading planets
Date: 25 Jan 93 10:53:13 GMT
Organization: Black Star

wolfone@ccwf.cc.utexas.edu (Nobody of Importance) writes:

>In article <1jqijdINN8c7@usenet.INS.CWRU.Edu> bp652@cleveland.Freenet.Edu (Gil W. Lau) writes:

>]If you take the analogy of invading a planet to invading a hostile nation,
>]I'd suppose you'd strike military targets from space, then when they're
>]weak, send down an invading force.

>I'd make sure the local navy was blown out of space or otherwise unable to
>interfere with landing ops. THEN I'd send strike teams down.

>]But now think of the *SCALE* of
>]such an operation!  We're talking millions upon millions of troops
>]here!  

The fundamental difference between invading a nation, and invading a
planet, is that a nation is protected by it's borders, whereas a planet
is vulnerable _absolutely_  anywhere - Assuming that jamming technology
advances on a par with communications technology, then all an invading
fleet has to do is isolate or destroy the planetary command HQ, and all
the defending armies are headless chickens. Presumably, it would follow
that any successful planetary defense would have to be massively
decentralised. 
-- 
S.A.Hovell,Dept. Electrical Engineering,University of Edinburgh,U.K.
(+31) 650-5655	 			          (Juggler@ed.ac.uk) 
-----					         	       -----
From: danb@zx.qsp.UUCP (Daniel Benbenisty)
Newsgroups: rec.arts.sf.science
Subject: Re: 20000 decibel
Date: 20 Jan 93 19:29:20 GMT
Organization: Quality Software Products, LA, CA

In article <1993Jan19.122923.15120@odin.diku.dk> klaus@diku.dk (Klaus Ole Kristiansen) writes:
>
>In one of the old Batman episodes, our hero is
>confronted by a tiger. He calls Alfred on the
>bat radio, and has him play a sound at 20000
>decibel through the radio. This frigtens off
>the tiger.  (Batman uses his bat earplugs, of
>course.)
>
>What would a 20000 decibel sound really do? I
>did not time it, but it played long enough for
>the tiger to growl, and walk slowly out of the
>room, say 30 seconds for the sake of argument.

Pretty funny - sounds like classic batman.  The screenwriter
probably meant to use a unit of frenquency (like Hz).

For one thing, "decibel" in itself is a relative unit of measurement.
"20,000 decibels" is literally equivalent to saying "10 to the power of 
2000" (10^2000).

On a scale that is used sometimes by sound engineers, where "0dB" is 
referenced to the sound level that a human can barely hear, this is pretty 
damn loud.

By comparison, sitting at a rock concert, will you may experience sounds
of around 100 dB or more, or 10^10 more sound energy reaching your ear than 
the minimum that you can hear.  20,000dB would be 10^1999 times THIS energy.  
I sure hope Batman had fresh batteries!

Unfortunately, I don't have an appropriate handbook here at work.  Does
anybody out there have energy levels for 0dB, 100dB, etc.?

I suspect that 20,000dB would absolutely dwarf what you would "hear"
if your ear was 6 inches from a 50 megaton nuke when it went off.

>How much energy does it take to evaporate the
>Earth? Where does the excess go?

Geez, what are you planning?  

>Klaus O K

>>>===Pan-Handle-Dan===>	danb@qsp.com
Daniel Benbenisty		Guitarist for EARWURM		
Newsgroups: rec.arts.sf.science
From: MLINDROOS@FINABO.ABO.FI (Marcus Lindroos INF)
Subject: 2001/2010 Rocket Engines - What are They?
Organization: Abo Akademi University, Finland
Date: Thu, 21 Jan 1993 10:29:43 GMT
X-News-Reader: VMS NEWS 1.24

Any idea what kind of engines the "Discovery" and "Alexei Leonov" of "2010 -
Odyssey Two" were using? Obviously, they have to be pretty fuel-efficient [=an
exhaust velocity of at least 25km/s] since neither craft seems to have much
room for fuel aboard. Ion engines seem to be out of the question but what about
a fusion-powered plasma motor? The visual appearance of the nozzles [=not
bell-shaped like those of the Space Shuttle or a nuclear engine] plus the 
fact that both vessels have clusters of small engines rather than three or 
four big ones all suggest that the exhaust jets produced by the engines 
contain little mass, but are being ejected at high velocities.
---
Does anyone know what the theoretical maximum exhaust velocity for an
"economical" fusion/plasma engine is, using standard propellants like methane,
water or hydrogen?  


MARCU$

--------------------------------------------------------------------------
. . . Fififinlandssvensk
     
Marcus Lindroos                             Internet:     mlindroos@abo.fi
Computer Science
Abo Akademi University
Finland
From: lizi@soda.berkeley.edu (Cosma Shalizi)
Newsgroups: rec.arts.sf.science
Subject: Re: Invading planets
Date: 24 Jan 1993 01:26:56 GMT
Organization: Campus Crusade for Cthulhu (Berkeley Tentacle)
NNTP-Posting-Host: soda.berkeley.edu

In article <dpn2.227.727824956@po.CWRU.Edu> dpn2@po.CWRU.Edu (Damien P. Neil) writes:
>Does anyone know of any good invasion books other than _Lucifer's Hammer_? 
>This thread has piqued my interest.
   For my money, the best is _still_ H. G. Wells, _The War of the Worlds_. Even
new it will cost you less than any of its successors <grin>. Besides, Wells
was the first (perhaps only?) invasion writer to appreciate the proper role
of microbial warfare - why bother dropping rocks when you can threaten
to rain down a fast-acting and highly infectious version of leprosy?
	Cosma Rohill Shalizi
	In Real Life: lizi@soda.berkeley.edu
	larval physicist
-- 
"I'd love to hold you/ I'd love to kiss you/ I ain't got time for that now."
-Talking Heads, "Life During Wartime"
"Death needs Time for what it kills to grow in."
-William S. Burroughs, "Ah Pook is Here"
Newsgroups: rec.arts.sf.science
From: cartin@cs.unca.edu (Dan Cartin)
Subject: Re: Interstellar War
Organization: University of North Carolina at Asheville
Date: Wed, 27 Jan 1993 20:47:56 GMT

In article <kkobayas.728116302@husc.harvard.edu> kkobayas@husc8.harvard.edu (Ken Kobayashi) writes:
>rwallace@unix1.tcd.ie (russell wallace) writes:
>
>>Surely the most efficient way to wage interstellar war would be to send
>>one von Neumann probe to a solar system near your target, have it make
>>a quintillion more probes, and have the whole quintillion (heavily
>>armed) probes attack your target.
>
>   Sounds good, but after the war's over, or even before that, the probes
>are going to mutate, keep reproducing, and spread out, invading other star
>systems (the probes has to be capable of interstellar flight correct?). 
>How do you prevent that?


	Actually, this was the premise behind both the Berserker series
  and the Star Trek episode "The Doomsday Machine," to name two off the
  top of my head. I guess one way to prevent it is, instead of telling
  the VN probes what to do, act as if they are a different race, and contract
  their mercenary services in return for something. But, then again,
  1) Who knows if they'd be willing? and 2) What would they want, since
  they can span the Galaxy and beyond for resources?

						-- Daniel	
Newsgroups: rec.arts.sf.science
From: dani@netcom.com (Dani Zweig)
Subject: Re: Industrial feudalism?
Organization: Netcom Online Communications Services (408-241-9760 login: guest)
Date: Tue, 26 Jan 1993 01:12:52 GMT

ig25@fg70.rz.uni-karlsruhe.de (Thomas Koenig):
>One key problem interfering with a society's success which has
>hereditary transfer of power ist that there is no easy way of getting
>rid of the duds, which education alone cannot do.  [...]

L. Peters makes the interesting, if deliberately provocative, case
in "The Peter Principle" that such societies are actually *better*
off in this respect, because of the limited opportunity for people
to find their levels of incompetence:  You don't get good sergeant
majors promoted to incompetent officers -- because they're not of
the officer class -- and you don't get brilliant generals who never
become generals because they didn't have what it took to be good
noncoms first.  Or the civil service equivalents.

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

   The inability of snakes to count is actually a refusal, on their part,
    to appreciate the Cardinal Number system. -- "Actual Facts"
Xref: sparky rec.arts.sf.science:4229 sci.physics:23270
From: alien@acheron.amigans.gen.nz (Ross Smith)
Newsgroups: rec.arts.sf.science,sci.physics
Subject: Re:  Davis Mechanics (was Re: John Woods Campbell)
Date: 22 Jan 93 15:03:18 GMT+12
Distribution: world
Organization: Muppet Labs

In article <1993Jan15.042749.15289@netcom.com> dani@netcom.com (Dani Zweig) writes:
>jbaez@riesz.mit.edu (John C. Baez):
>>>Yep.  The only things they take with them are mass, charge, and angular
>>>momentum.  :-)
>>
>>I am planning on leaving my mass, charge, and angular momentum to science.
>
>A worthy thought.  I guarantee that they will be equitably distributed, in
>strict accordance with the law.

I suggest you leave your baryon number too. Otherwise you may find yourself
strongly forced to comply with some conservative laws.

--
...... Ross Smith (Wanganui, NZ) ...... alien@acheron.amigans.gen.nz ......
"I blame you for the moonlit sky and the dream that died with the Eagle's flight
I blame you for the moonlit nights when I wonder why are the seas still dry
Don't blame me, sleeping satellite"                              (Tasmin Archer)
--
From: phydeaux@guru.med.cornell.edu (Dave Weingart)
Newsgroups: rec.arts.sf.science
Subject: Vinge's "Zones of Thought" in _A__Fire_Upon_The_Deep_
Date: 26 Jan 1993 20:36:39 GMT
Organization: CUMC
Distribution: world
NNTP-Posting-Host: guru.med.cornell.edu
Keywords: weird metaphysics

I admit, I'm only up to part II (about 200 pages into the book), so if
some of this is explained later in the book, please feel free to ignore
this.

The concept of regions of the galaxy where the rules of physics differ
is kind of bizarre to me (i.e., the Slow Zone where c is a limiting
factor, as opposed to the Beyond, where it's not (and of course, the
Transcend)).  Granting that it's a possibility, would it fit in with
the observable universe as we see it?  We're stuck in the Slow, down
below the Lower Beyond, at least currently (according to the "map" of
the zones)...how would that impact how we view the universe.

Forgive the rambling...I'm a tad punchy today.


-- 
73 de David Weingart  KB2CWF    In the event I am captured or killed, the
phydeaux@cumc.cornell.edu       Cornell University Medical College and the
phydeaux@guru.med.cornell.edu   Department of Academic Computing will disavow
phydeaux@src4src.linet.org      any knowledge of my opinions.
From: max@west.darkside.com (Erik Max Francis)
Newsgroups: rec.arts.sf.science
Subject: Re: Invading planets
Date: 24 Jan 93 20:50:26 GMT
Organization: The Dark Side of the Moon +1 408 245 SPAM

bp652@cleveland.Freenet.Edu (Gil W. Lau) writes:

> All right, all right!  I'm a Star Trek fan!  So sue me!  But if you
> can stun a city block, you can stun a planet.  Maybe not all at
> once, granted, but it's possible.

It's possible, but how useful is it?  In Star Trek, you only stay 
unconscious or stunned for a few hours.  That's not an awful lot of time 
to get a lot done on a planetary scale.

Besides . . . it's probably not a wise thing to bring up Star Trek in any 
technological discussion of the realities of space.


Erik Max Francis  -)(-  ..!apple!uuwest!max  -)(-  max@west.darkside.com   __
USMail: 1070 Oakmont Dr. #1; San Jose, CA  95117  ICBM: 37 20 N 121 53 W  /  \
Like strategic games of interstellar conquest? . . . Ask about UNIVERSE!  \__/
-)(- Omnia quia sunt, lumina sunt; all things that are, are lights. -)(-
Newsgroups: rec.arts.sf.science
From: szabo@techbook.com (Nick Szabo)
Subject: Re: Invading planets
Organization: TECHbooks --- Public Access UNIX --- (503) 220-0636
Date: Tue, 26 Jan 1993 21:30:12 GMT


>Now many may say that we will just "divert"
>a rock from the asteroid belt.  The energy required to do so will be
>simular to that expended by the rock reentry.  So, you are not
>accomplishing much.

A circular orbit belt is obviously a silly choice; the attacker would 
pick planet-crossers.  In that case, intercept velocity has nothing 
to do with the velocity change needed to achieve intercept.  Meteors and the 
occasional dinosaur-killer need no diversion at all; they're already on
an intercept course.  There are dozens of small asteroids passing 
within 1e6 km of Earth every week, which translates to c. 0.1 km/s 
delta-v to divert into intercept course a few months ahead of time.  
A typical intercept velocity is 20 km/s.  Very large asteroids (eg 
Toutatis, larger than the dinosaur-killer) require about 1 km/s 
for the same timeliness, since they are c. 1,000 times rarer than 
the small objects.

If there is ice on the object to be diverted or in a nearby orbit,
it can be easily processed into reaction mass for the diversion.
Alternatively, part of a metal asteroid might be oblated with nuclear 
explosives, or made into armatures for a mass driver.

The main problem with this method is that the strikes cannot be called
on demand; attack and strategy must be timed around the planetary
intercept time.

Superior to crude diversion of asteroid would be atmosphere-penetrating
javelins of heavy metal, such as depleted uranium that can be guided
against specific tarets.  Nukes are messier and more expensive to
manufacture, but specific-wavelength radiation bombs might be very
useful.

The specific invasion technique will depend on the objectives: do
we want to pacify the population?  Eradicate certain technological
capabilities it has?  Steal some resource they have?

Nick Szabo					szabo@techbook.com
-- 
Nick Szabo					 szabo@techboook.com
From: max@west.darkside.com (Erik Max Francis)
Newsgroups: rec.arts.sf.science
Subject: Re: 20000 decibel
Date: 21 Jan 93 08:04:40 GMT
Organization: The Dark Side of the Moon +1 408 245 SPAM

bs@tekig7.PEN.TEK.COM (Robert L Swarts) writes:

> Please note that a decibel is always a measure of relative power
> defined as ten times the logarithm to the base ten of the observed 
> power to a reference power. By appropriately choosing the reference
> power one can obtain any desired value of dB.
It's actuall the ratio of intensities, rather than the ratio of powers.  
I understand that the standard reference intensity, I0 = 1.0 x 10^-12 
W/m^2.


Erik Max Francis  -)(-  ..!apple!uuwest!max  -)(-  max@west.darkside.com   __
USMail: 1070 Oakmont Dr. #1; San Jose, CA  95117  ICBM: 37 20 N 121 53 W  /  \
Like strategic games of interstellar conquest? . . . Ask about UNIVERSE!  \__/
-)(- Omnia quia sunt, lumina sunt; all things that are, are lights. -)(-
From: alien@acheron.amigans.gen.nz (Ross Smith)
Newsgroups: rec.arts.sf.science
Subject: Re:  Wrecking an O'Neill (Was: Re: Wrecking a Planet)
Date: 22 Jan 93 15:07:22 GMT+12
Distribution: world
Organization: Muppet Labs

In article <MARTINC.93Jan16092228@grover.cs.unc.edu> martinc@grover.cs.unc.edu (Charles R. Martin) writes:
>In article <alien.02i0@acheron.amigans.gen.nz> alien@acheron.amigans.gen.nz (Ross Smith) writes:
>
>
>   >Would an attack from the Sun be invisible to radar? Does the Sun put out
>   >that much in the microwave spectrum?
>
>   No. Radar signals have been successfully bounced off the Sun from
>   Earth (from the Arecibo instrument, I think).
>
>That doesn't tell us anything about the signal-noise ratio of radar used
>on a target with the Sun in the beam behind the target.  But on the
>other hand some kind of keying in the radar emission should solve the
>problem anyway.

My point was that it tells us that the S/N ratio is low enough that a signal
from Earth can still be detected after bouncing off the Sun, even with
present-day technology.

--
...... Ross Smith (Wanganui, NZ) ...... alien@acheron.amigans.gen.nz ......
"I blame you for the moonlit sky and the dream that died with the Eagle's flight
I blame you for the moonlit nights when I wonder why are the seas still dry
Don't blame me, sleeping satellite"                              (Tasmin Archer)
--
From: dpn2@po.CWRU.Edu (Damien P. Neil)
Newsgroups: rec.arts.sf.science
Subject: Re: Invading planets
Date: Mon, 25 Jan 1993 03:49:32 GMT
Organization: Case Western Reserve University
NNTP-Posting-Host: b63519.student.cwru.edu

In article <1993Jan24.190517.13137@uumeme.chi.il.us> drac@uumeme.chi.il.us (Bruce Maynard) writes:
>Seems to me that, in order to accomplish a successful planetary takeover,
>one would first hammer down all detectable military capacity from orbit
>(assuming, of course, that any orbital defenses had already been neutralized),
>then inform the inhabitants that they had a choice: surrender & be cool about
>it or be subjected to a generalized bombardment (probably nuclear). Note that
>it would be quite desirabvle to present terms that the locals could probably
>live with... elsewise, one *could* gain a rep for genocide, and become a target
>by other spacefaring cultures. If handled well enuff, seems to me a takeover
>could be accomplished (and *maybe* even held) with minimal troops... say,
>between 1/2 mil & 2 mil...

This reminds me of a short story -- _Basic Right_, I think was the name. I 
don't remember the author. In it was an alien race that subjugates other 
races by coming in system and offering a "surrender or die" ultimatum. They 
use a planet-smasher on a nearby worthless moon to prove that they have 
the means to genocide the race they are invading. If the invaded species 
does not immediately and unconditionally surrender, they are destroyed. The 
deaths of any invaders are punished by killing several hundred subjects for 
each dead invader.

A direct and brutal method. I wonder if it would work?

An excellent story, BTW.
-----
Damien Neil   dpn2@po.cwru.edu    "Until somebody debugs reality, the best
Case Western Reserve University    I can do is a quick patch here and there."
CMPS/EEAP double majoring masochist               - Erik Green
From: rclark@lpl.arizona.edu (Richard Clark x4971)
Newsgroups: rec.arts.sf.science
Subject: Re: Invading planets
Date: 25 Jan 93 15:31:53 GMT
Organization: Lunar & Planetary Laboratory, Tucson AZ.

In article <1993Jan25.072613.23656@Princeton.EDU> jdunning@chagall.Princeton.EDU (John Alan Dunning) writes:
>In article <1jvpp8INNbol@uxa.ecn.bgu.edu> mgcbo@uxa.ecn.bgu.edu (Charles B. Owen) writes:
>>There is a real tendency in science fiction to always think of planets
>>as single entities, when our own planet does not bear this out.  If you
>>invaded Earth, who would you tell to surrender?  It is safe to assume
>>that other worlds will have hundreds, if not thousands, of governments.
>>I can't see how 1/2 mil to 2 mil troops could hope to handle them all.
>>You would have to take them one at a time and probably obliterate a few
>>holdouts.
>
>If the planet was not fighting as a single entity, I don't think it
>would have much of a chance against an invading force, especially one with
>superior technology.  Imagine if the Soviet Union were still a single
>entity and decided to make peace with alien invaders.  There's not
>much the rest of the world could do about it once the aliens had a
>terrestrial base and lots of resources.  Any planet with hundreds or
>thousands of governments which can't work together is going to be
>crushed.
>
>John


The Terran People's Front would have roots throughout the Free World
and extend into the nation of the Collaboraters where there would still be
Free Earth sympathizers. The Gaia Liberation Movement would also be a strong
rebel force and not totally in agreement with the TPF about goals. What
other groups would arise? Resistance and terrorist groups can be very
expensive to elliminate. Especially when they do not follow conventional
nationalist, ethnic, or ideological lines.

Compare the fates of the Indian civilizations of the Americas after the
arrival of Europeans. In Central and South America strong Indian empires
were quickly subjegated while in the US Indians had to be forced out of their
land one tribe at a time.

A strong centralized planetary defense might have more of a chance of
resisting the invasion in the first place but fragmented resistance can
make the occupation much more expensive.

Richard Clark
rclark@lpl.arizona.edu
From: bs@tekig7.PEN.TEK.COM (Robert L Swarts)
Newsgroups: rec.arts.sf.science
Subject: Re: 20000 decibel
Date: 21 Jan 93 20:16:02 GMT
Organization: Tektronix, Inc., Beaverton,  OR.

Erik,
I don't really want to start an argument, but if you will consult
The IEEE Standard Dictionary (amongst others) you will find that
a decibel is always a ratio of powers. Because acoustic power
depends on the sound intensity, the dB can be related to intensity.

bs
From: wiml@stein.u.washington.edu (William Lewis)
Newsgroups: rec.arts.sf.science
Subject: Re: 20000 decibel
Date: 26 Jan 1993 06:24:05 GMT
Organization: University of Washington, Seattle
NNTP-Posting-Host: stein.u.washington.edu

Just to throw some numbers at this, 20,000 decibels is equal to
10^2000 times the energy of 0 dB. 0 dB is 10^-12 W/m^2, so 20,000 dB
is 10^1988 W/m^2. Assuming a small bat-radio with a speaker 1 cm square,
and measuring the intensity at the source (more conventional measurements
add a few orders of magnitude) this is 10^1984 Watts. In one second,
this would amount to 10^1984 Joules of energy, or, um, the equivalent
of 10^1967 kilograms of matter converted directly into energy. 
I don't offhand know the rest mass of the Universe, but I wouldn't
be surprised to learn that it's a bit smaller than that.