Ringworlds

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Salamander~

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Aug 26, 1992, 10:52:24 PM8/26/92
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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


--
maj...@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?

jerry cullingford

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Aug 27, 1992, 8:46:06 AM8/27/92
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In article <BtMFz...@acsu.buffalo.edu> maj...@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.

References: _Ringworld_ and _Ringworld Engineers_ by Larry Niven.


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Olaf Titz

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Aug 27, 1992, 9:00:28 AM8/27/92
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In <BtMFz...@acsu.buffalo.edu> maj...@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_t...@iravcl.ira.uka.de -
uk...@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

Elf Sternberg

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Aug 28, 1992, 7:41:39 AM8/28/92
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In article <15...@suns6.crosfield.co.uk>
j...@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
e...@halcyon.com \/ | has looked into me. Neither liked what we saw.
e...@polari.online.com | - Brother Theodore

Stephen Holland

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Aug 28, 1992, 2:19:23 PM8/28/92
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In article 32...@nwnexus.WA.COM, e...@halcyon.com (Elf Sternberg) writes:
>In article <15...@suns6.crosfield.co.uk>
> j...@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.
>
> Elf !!!
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.

steve holland


Bruce Gletty

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Aug 28, 1992, 3:13:29 PM8/28/92
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hol...@geop.ubc.ca (Stephen Holland) 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.

Bill Riemers

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Aug 28, 1992, 6:01:43 PM8/28/92
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In article <BtpK2...@ux1.cso.uiuc.edu> gle...@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.

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.

Bill

David A. Fleming

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Aug 28, 1992, 9:54:33 PM8/28/92
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maj...@acsu.buffalo.edu (Salamander~) writes:

>Thanks,
>Marc

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.
daf3...@uxa.cso.uiuc.edu

A.Daviel

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Aug 28, 1992, 10:28:00 PM8/28/92
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In article <1992Aug28....@nwnexus.WA.COM>, e...@halcyon.com (Elf Sternberg) writes...

>In article <15...@suns6.crosfield.co.uk>
> j...@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.
>

In one of Niven's collections he writes about various ways of making Dyson
spheres, etc. I seem to remember that a real Dyson sphere isn't necessarily a
sphere at all; just a collection of hardware in various orbits that
collectively intercept 100% of the stellar radiation. So a large collection
of orbiting habitats would qualify. Niven talks about a spaghetti habitat -
actually, more like uncut macaroni - where people live on the inside of
incredibly long tubes which spin to provide artificial gravity. I forget what
stabilizes the tubes in solar orbit. He also proposes a discworld, where the
habitat consists of a thing like a gramophone record with a hole in the
middle. The star oscillates from side to side through the hole (I think it is
less massive than the disc. Due to the oscillation, this motion is stable.
Gravity is normal to the disc on both sides, due to the mass of the disc.

Andrew

bay...@force.ssd.lmsc.lockheed.com

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Aug 28, 1992, 6:00:54 PM8/28/92
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In article <1992Aug28.1...@unixg.ubc.ca>, hol...@geop.ubc.ca (Stephen Holland) writes:
>> Elf !!!
>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.

The only reason I can think of to close the ends, is for defense
(against space invaders, or maybe asteroids)

Trip

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Aug 28, 1992, 9:44:44 PM8/28/92
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e...@halcyon.com (Elf Sternberg) writes:

>In article <15...@suns6.crosfield.co.uk>
> j...@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.

No, it doesn't require gravity generators. You should have read about
two pages further.

For the unenlightened, I refer to the Alderson Double Dyson Sphere,
which uses an inner shell to hold the atmosphere in place. ("Bigger than
Worlds", Larry Niven. Page 122 in the Del Rey edition of _A Hole in
Space_.)

It may turn out that humans can't live without gravity, but modifying
humans is something we're starting to do now. By the time we can build
Dyson Spheres, it's not going to be difficult to modify humans to live
in microgravity.

Oh, and the original Dyson Sphere wasn't the solid shell so popularized
by miscellaneous SF writers. It was a shell of independent bodies
(O'Neill colonies, inflated asteroids, whatever). (I may be wrong on
this; does anyone have a solid reference?)

Trip | Never stay a minute too long
President, ECNG | Don't forget the best will go wrong
(tr...@cobalt.cco.caltech.edu) | Nobody's on nobody's side
| -_Chess_

Elf Sternberg

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Aug 29, 1992, 2:18:20 AM8/29/92
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In article <mwalker-28...@mwalker1.npd.provo.novell.com.>
mwa...@novell.com (Mel Walker) writes:

>In article <1992Aug28....@nwnexus.WA.COM>,
> e...@halcyon.com (Elf Sternberg) wrote:

>> 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.

>If we presently find "incomprehensible" the idea of artificial gravity, how
>can we say what it "probably" requires? Juuuuuuust asking.

A good question; certainly the more advanced a science becomes, the
more inscrutable the hardware becomes to handle it. I would argue that
I would trust a lever more than a laser to continue working. Since
nobody has yet "accidently" stumbled upon the technique of generating
an accelerative field, we can assume it takes technology we're not yet
familiar with.

"Dangerous" in the sense that, if an artifical gravity field fails
on an artificial world such as a Dyson Sphere, there's nothing to hold
the atmosphere down and everything near that particular emitter gets
blown into space.

I could just as easily say that it requires "magic" to make an
artificial gravity field. To a man of the 5th century, an internal
combustion engine certainly would have been magic! But to you and I,
it is nothing more than a self-destructive peice of hardware based on
well-known and -understood principles.

Elf Sternberg

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Aug 29, 1992, 2:17:37 AM8/29/92
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In article <BCR.92Au...@hpl3sn02.cern.ch>
bcr@cernapo (Bill Riemers) writes:

>In article <BtpK2...@ux1.cso.uiuc.edu> gle...@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

James Davis Nicoll

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Aug 29, 1992, 11:38:44 AM8/29/92
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In article <1992Aug28....@nwnexus.WA.COM> e...@halcyon.com (Elf Sternberg) writes:
>In article <15...@suns6.crosfield.co.uk>
> j...@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.

So live on the exterior of the sphere, where there is a
small attraction towards the primary, or hang habitats off solar
sails hovering on light pressure above the primary. Neither
requires artificial gravity. I am not sure how AG would help,
in the case of a hollow sphere's inner surface, as the problem
results from geometric concerns, not lack-of-mass.

Orbitsville was pretty silly on this point, as I recall.

James Nicoll

James Davis Nicoll

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Aug 29, 1992, 11:47:07 AM8/29/92
to

>>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

Jim Kasprzak

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Aug 29, 1992, 4:16:44 PM8/29/92
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In article <1992Aug29.0...@nwnexus.WA.COM>, e...@halcyon.com (Elf Sternberg) writes:
|> 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.

Not exactly. See below. I'm including your whole interpretation of it
because this seems to confuse a lot of people, including myself when I
first read the book. I'll try to clear it up.

|> 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!

Here's how the Ringworld Attitude Control System (a registered trademark of
Protector Engineering Services) is designed to function:

First, picture the Ringworld system as seen from "above": a circle with the
sun at the center. The ring drifts a little off center, and one side of it is
now closer to the sun.

Radiation detectors placed along the ring detect an increase of the solar
flux above acceptable levels.[1] Too much solar energy coming in means that
that section of ring is too close to the sun, so it's time to fire the
attitude jets.

The attitude jets scoop up the solar wind, ignite it in a fusion reaction,
and spit the exhaust back at the sun. This pushes the ring back towards
the heliocentric position.[2] If the ring drifts just a little off course,
the jets only have to apply gentle thrust, and there's no need to use the
magnetic grid. The jet kicks on as the solar flux exceeds a certain level,
increases thrust as the radiation increases, and cuts out as it drops back
down to safe levels.

Our picture of the Ringworld system now includes an arc of the ring where
jets are firing, the brightest ones at perihelion (closest to the sun), and
the dimmest at the spinward and antispinward extremes of the arc. As the
ring rotates, the jets antispinward of perihelion are firing up, the ones
spinward of perihelion are throttling down. As this process continues, the
ring is pushed closer to the proper position, so fewer of the jets reach
the threshold radiation level. The arc narrows, the thrust at perihelion
decreases, and when the ring is perfectly centered, no part of the ring is
receiving more energy than normal, so no jets are firing.[3,4]

Okay so far? That's just the system to correct for normal drift. Now
imagine something whacks the ring _way_ off-center. The attitude control
jets need more thrust to re-stabilize it in time to avert disaster; the
solar wind alone isn't providing enough fuel. This is where the superconductor
grid comes into play. The sun's magnetic field is manipulated to increase
flare activity, and thus solar wind output, on the side of the sun facing
the close section of the ring. This gives the attitude jets more fuel to
burn and allows the drift to be corrected before the sun's gravity makes
it even worse.

Now, what I've described is for a perfectly functional system, one with
the detection system and attitude jets all in place and working nominally.
Use of the system in this manner would _not_ cause mass deaths on the ring.
Protectors wouldn't design it that way.

However, in _The Ringworld Engineers_, the system is far from perfectly
functional. Only a small arc of the ring has any attitude jets on it - twenty percent of the circumference. Considering how far off-center the ring has
drifted already, this is nowhere near enough to push the ring back to its
normal position if the system operated within its safety constraints. So
the few jets that are working have to accept _much_ more fuel input, which
means much more flare activity. This is what will kill the inhabitants of
that section of the ring - the section with the attitude jets is getting
bombarded with solar activity every time it passes perihelion.

Note that nowhere is the solar wind itself used to push the ring. I don't
think the solar wind could generate anywhere near enough thrust by its
impact alone to make a difference unless you raised it to ludicrous levels -
something on the order of flinging huge chunks of sun at the ring.

In summary: there is only one attitude control system, and both the jets and
the magnetic grid are designed as parts of it. 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.

Notes:

[1]: Niven never mentions these detectors, but their existence is the
simplest way to assure that the system works. Note that these "detectors"
could be mechanical devices or living protectors; given what we know of
the Pak, I wouldn't be surprised if the original design had a childless
protector stationed at each ramjet.

[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.

[3]: Note that this system is self-correcting, since if the thrust
generated on one side pushes it too far and it drifts off-center in the
other direction, the jets on that side will start firing. Also, since
the Ringworld is naturally unstable, it will be very rare that no jets
at all are firing. Under normal conditions there should always be some
low-level corrections going on.

[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.

[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.


Michael Stoodt

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Aug 29, 1992, 4:13:04 PM8/29/92
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In <1992Aug29.0...@nwnexus.WA.COM> e...@halcyon.com (Elf Sternberg) writes:

> ... 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!

(Attempting to minimize spoilers:)

Under the assumptions that the designers of the Ringworld made, the
attitude jets would work just fine off the solar wind, and one would
never need to use the flare system to super-charge them. (The flare
system is a defense to destroy incoming rocks or spaceships (if they
weren't the designers' ships, they were by definition enemies).) But
the designers never expected to have 90%+ of their attitude jets
ripped off by another culture for use as interstellar ramjets (the
designers never expected to not be around, and never expected there to
be sentients on the Ringworld who didn't intuitively understand the
need for the attitude jets), so that by the time of _Ringworld
Engineers_, the only option was to combine the two systems (more jets
applied earlier would have kept the situation under control), killing
a large fraction of the Ringworld's population to save the rest.
--
Michael A Stoodt [MaS] sto...@cis.umassd.edu
"Will the last person to leave the planet please turn off the sun?"
- Mike Resnick

Thomas Koenig

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Aug 29, 1992, 11:39:16 PM8/29/92
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gle...@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.

A ring is indeed unstable; once its centre of mass is removed from that
of the sun, there is a resulting force to drive it further away.

Hollow, rigid spheres, however, are in indifferent equilibrum with
regard to anything inside, if you assume constant mass distribution.
There is no resulting force between the sphere and anything inside it.
MUCH easier as a control problem.
--
Thomas Koenig, ecm...@ccu1.aukuni.ac.nz, ib...@rz.uni-karlsruhe.de
The joy of engineering is to find a straight line on a double logarithmic
diagram.

Mike Beede

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Aug 30, 1992, 11:14:21 AM8/30/92
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bay...@force.ssd.lmsc.lockheed.com writes:

>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.

>The only reason I can think of to close the ends, is for defense
>(against space invaders, or maybe asteroids)

Isn't the idea of a Dyson Sphere to capture the entire energy
production of a star? I believe a ring may allow a not-insignificant
amount of Ye Olde Rays to escape.

As for ``steep very close to the equator'' -- isn't a couple million
miles wide enough? A rational culture advanced enough for cosmic
engineering will not have an ever-expanding population, since that
would _reduce_ the amount of energy available per person (not to
mention leading to eventual death and other such nasty things).

Mike


--
Mike Beede Secure Computing
be...@sctc.com 1210 W. County Rd E, Suite 100
------------------ Arden Hills, MN 55112
(612) 482-7420

T.F. Eccles

unread,
Aug 31, 1992, 3:50:50 AM8/31/92
to
gle...@ux1.cso.uiuc.edu (Bruce Gletty) writes:

>hol...@geop.ubc.ca (Stephen Holland) writes:

um..... wouldn't almost equal light pressure keep the Dyson Sphere stable...
Its just a thought....

Eccles

"Humans have mastered a power akin to that which drives the sun,
that of nuclear fission.... and they use it to boil water."

jerry cullingford

unread,
Sep 1, 1992, 8:32:26 AM9/1/92
to
In article <2gs...@rpi.edu> kas...@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 :-)

Alex Dillard

unread,
Sep 3, 1992, 7:23:06 PM9/3/92
to
In article <2gs...@rpi.edu> kas...@rpi.edu writes:
> Radiation detectors placed along the ring detect an increase of the solar
>flux above acceptable levels.[1] Too much solar energy coming in means that
>that section of ring is too close to the sun, so it's time to fire the
>attitude jets.
>
[excellent discussion of attitude jet control system deleted]

>
> [1]: Niven never mentions these detectors, but their existence is the
>simplest way to assure that the system works. Note that these "detectors"
>could be mechanical devices or living protectors; given what we know of
>the Pak, I wouldn't be surprised if the original design had a childless
>protector stationed at each ramjet.
>
> [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.

There is a problem with using radiation as the basis for determining distance
from the sun, solar radiation flux is neither constant nor uniform. Solar
flares, sunspots etc. (what else might effect this is beyond my knowledge, but
you get the idea) change the ammount of radiation coming out of various parts
of the sun. (btw, when I say 'sun' I mean the star around which the Ringworld
is built, not Sol) A much better system for finding the right position for the
Ringworld would be to measure the curvature of spacetime. If the curvature of
spacetime is greater than the average value, push that part of the ring away
from the sun. If the curvature is less, push toward. How do we measure the
curvature of spacetime? Simple, have an _extremely_ accurate clock at the
control station for each thruster. Each controller sends out a timing pulse to
it's neighbors. The controller compares it's clock with the times given to it
by it's neighbors, and if it sees that it is faster, it fires it's thruster away
from the sun, pushing it's segment of the Ringworld back down the curvature of
space-time around the sun. If it's clock is slow, it pushes away from the sun,
decreasing the curvature of space-time in it's vicinity and speeding up it's
clock.
A sampling of many of the neighbor clocks would help improve the space-time
curvature measurement, but would slow down the response time, as the controller
has to do more calcualtions to make the measurement. Looking at one neighbor
further away (say the tenth neighbor to each side) would make the accuracy
requirement for the clocks less stringent, but the timing of the signal path
would have to be more stable. I guess superconductor would be stable enough.
To initialize the system, some other form of heloicentricity would determine
that the Ringworld was spot-on centered, and then each controller would send a
timing pulse. The neighbors recieving the timing pulses would record the
difference between them, so that differences in signal path length or time would
be removed. The controller would then fire when the difference between it's
neighbor's timing pulses changed.
Well, now we have the control system, let's build it.

--
\ _
- o We were once so close to Heaven, Peter came out and gave us medals,
^ declaring us the nicest of the Damned. - They Might Be Giants
Alex dil...@doc.cc.utexas.edu

Erik Max Francis

unread,
Sep 17, 1992, 8:09:13 PM9/17/92
to
bay...@force.ssd.lmsc.lockheed.com writes:

> The only reason I can think of to close the ends, is for defense
> (against space invaders, or maybe asteroids)

Closing off the Ringworld into a Dyson sphere or other closed surface
only presents more surface area to hostile forces. And if you have a
full Dyson sphere with gravity generators and all, one failed generator
would make a nuclear war look like a sneeze.

Ringworlds are definitely the way to go. At least, they look a little
better. There's still nothing even remotely strong enough to use for
Ringworld foundation material . . .

----------
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: m...@west.darkside.com 464E4F5244 |

Erik Max Francis

unread,
Sep 17, 1992, 7:57:56 PM9/17/92
to
ad...@reg.triumf.ca (A.Daviel) writes:

> >In article <15...@suns6.crosfield.co.uk>
> > j...@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.
> >
>
> In one of Niven's collections he writes about various ways of making Dyson
> spheres, etc. I seem to remember that a real Dyson sphere isn't necessarily a
> sphere at all; just a collection of hardware in various orbits that
> collectively intercept 100% of the stellar radiation. So a large collection

Right. When science-fiction writers got their hands on the concept of
a Dyson sphere, they transformed it into a _solid_ sphere with a
habitable inner surface . . . though that isn't what Dyson was originally
talking about at all.

> of orbiting habitats would qualify. Niven talks about a spaghetti habitat -
> actually, more like uncut macaroni - where people live on the inside of
> incredibly long tubes which spin to provide artificial gravity. I forget what

The "cosmic macaroni" idea is by Pat Gunkel, and he calls it _topopolis._
Niven doesn't mention anything about stabilizing it in its orbit in
"Bigger Than Worlds" (_A Hole In Space,_ 1974 -- between _Ringworld_ and
_The Ringworld Engineers_); probably because it hadn't yet occurred to
him that such a structure (including the Ringworld) would be unstable in
the plane of its orbit.

Anyhow, Niven goes on to talk about the loops of spaghetti surrounding
one star; Gunkel calls this _aegagropilous topopolis._ Eventually the
the loops could be linked to other stars. "Eventually our _aegagropilous
galactotopopolis_ would look like all the stars in the heavens had been
embedded in hair" (p. 124).

> stabilizes the tubes in solar orbit. He also proposes a discworld, where the
> habitat consists of a thing like a gramophone record with a hole in the
> middle. The star oscillates from side to side through the hole (I think it is
> less massive than the disc. Due to the oscillation, this motion is stable.
> Gravity is normal to the disc on both sides, due to the mass of the disc.

This concept was brought up by Dan Alderson, and is called an Alderson
disc. The disc might be rather thick (a few thousand miles), and would
weigh more than the Sun, but you'd still need gravity generators to hold
the atmosphere and people down on either surface at one gee. Note if
you're standing on the surface, it's always either night, dawn, or dusk.
Niven points out that "the Disc would be a wonderful place to stage a
Gothic or a swords-and-sorcery novel. The atmosphere is right, and there
are real monsters. Consider: we can occupy only a part of the Disc the
right distance from the sun. We might as well share the Disc and the
cost of its construction with aliens from hotter or colder climes. . . .
Over the tens and thousands of years, mutations and adaptations would
migrate across the sparsely settled borders. If civilization should
fall, things could get eerie and interesting" (p. 124).

Nick Haines

unread,
Sep 18, 1992, 2:13:38 PM9/18/92
to
In article <3Xs0qB...@west.darkside.com> m...@west.darkside.com (Erik Max Francis) writes:

Closing off the Ringworld into a Dyson sphere or other closed surface
only presents more surface area to hostile forces. And if you have a
full Dyson sphere with gravity generators and all, one failed generator
would make a nuclear war look like a sneeze.

Assuming that your gravity generators are very large (i.e. provide
gravity for a large area). Since we don't have any such things, I'll
posit a gravity generator that provides gravity for a square
millimetre of Sphere. No problems if one of those fails: the `leakage'
from the neighbours will give you 0.9999 gravities while your
automated generator-replacing robots fix it.

Nick

Elf Sternberg

unread,
Sep 18, 1992, 2:29:35 PM9/18/92
to
In article <0es0qB...@west.darkside.com>

m...@west.darkside.com (Erik Max Francis) writes:

>ad...@reg.triumf.ca (A.Daviel) writes:

>This concept was brought up by Dan Alderson, and is called an Alderson
>disc. The disc might be rather thick (a few thousand miles), and would
>weigh more than the Sun, but you'd still need gravity generators to hold
>the atmosphere and people down on either surface at one gee.

Bzzzt. Max, you ain't reading that right.

Although I can't find the reference, Niven _does_ point out that,
except for edge effects at the 'hole' in the center at at the edge, the
gravity attracting you to the surface of the disk is (basic physics)
F= G*(m1*m2)/r^2, where r would be a function relating _your_ physical
description (and a trivial one, since compared to the disk you _are_ a
trivial mass), and the distance you were from the mass of the disk.
Basic calculus.

Now, put this all together, and we find that, for a disk of
sufficient density (and, btw, the standard density of Terra will work
just fine), since all of it's mass is "below" you, you could generate a
sufficient gravity field of 1G.

(In short, you would estimate gravity by the calculus of a series of
progressively larger inverted hemispheres, until increasing the size of
the hemisphere makes an increase in the gravitional pull trivial.
"Trivia" to be determined by the researcher. The fact that, at the
edges, you can't take solid hemispheres of matter 6x10^6m in radius
makes calculation of gravity at the edges trickier, requiring the
junction calculus of your hemisphere and the calculus of the cylinder
of the disk included in your hemisphere; remember that the volume not in
the junction of both hemisphere and that part cylinder you're
calculating over no mass in it, and would therefore not contribute to
your equation.)

Niven also stated that the best way to ensure a "Terran" environment
was to put walls, not unlike Ringworld walls, at the orbits of Venus
and Mars, to provide Man with a "Temperate Zone" where the temperature
would be comfortable for him. Inside the inner walls we'd put all our
power collection; Outside the outer zone we'd put our starports and
maybe some lounges for those really weird alien types.

The other aspect to an Alderson disk that Niven suggested was to
"bob the sun" up and down in the hole; this continual play (in harmonic
motion, no less) would provide a cyclic (l...o...n...g cyclic)
day/night period.

Alderson disks have the same troubles as ringworlds and Dyson
spheres; the calculus of a circle states that for every point in that
circle, the force of gravity generated by the circle on that point in
any given direction is precisely balanced by the force generated in the
other direction. Hell, I think Newton proved that. So the suns of
Alderson disks, like ringworlds and Dyson Spheres, have no reason to
stay in the center; there's literally no gravity working on them from
the body in question. Niven had a few cures for his ringworld, but the
Disk? It's so huge... any suggestions?

Elf !!!

Tom Weinstein

unread,
Sep 18, 1992, 6:18:47 PM9/18/92
to
In article <1992Sep18.1...@nwnexus.WA.COM>, e...@halcyon.com (Elf Sternberg) writes:

> Alderson disks have the same troubles as ringworlds and Dyson
> spheres; the calculus of a circle states that for every point in that
> circle, the force of gravity generated by the circle on that point in
> any given direction is precisely balanced by the force generated in the
> other direction. Hell, I think Newton proved that. So the suns of
> Alderson disks, like ringworlds and Dyson Spheres, have no reason to
> stay in the center; there's literally no gravity working on them from
> the body in question. Niven had a few cures for his ringworld, but the
> Disk? It's so huge... any suggestions?

> Elf !!!

You're wrong about this point. A ring is not just neutrally stable.
It's unstable. So if it drifts even slightly off center it will quickly
accelerate into the sun.


--
Love is a conveyor belt of | Tom Weinstein to...@orac.esd.sgi.com
warmth -- Jackie Chan | to...@bears.ucsb.edu

Matthew Bauder

unread,
Sep 24, 1992, 5:27:43 PM9/24/92
to
Okay. Possibly, these topics have been driven deep into the ground by past
discussions, but I missed them...so....

Most of the stuff I've read in _Analog_ or _IASFM_ are based somewhat with
the VR (virtual reality) or nanotech science. These scientific "themes", for
lack of a better word, seem to keep popping up.

Rather than discuss these topics all over again, my question to the net is:

What other futuristic science themes do you see coming this way?

I'm talking "very probable/possible" science. Not ringworlds, gravity
generators, or even FTL travel. I'm talking optical computing, upcoming
changes in scientific paradigms, etc.

What would be the impact of these changes on our society?

I imagine the editors of the SF mags are beginning to tire of VR and nanotech
stories. I'm wondering what's next. Any ideas?

David Smith

unread,
Sep 25, 1992, 3:11:18 PM9/25/92
to
In article <1992Sep24....@pool.info.sunyit.edu> om...@pool.info.sunyit.edu (Matthew Bauder) writes:
>I imagine the editors of the SF mags are beginning to tire of VR and nanotech
>stories. I'm wondering what's next. Any ideas?

Good VR and nanotech stories? The quality is starting to improve - not so
much "in your face - wow this is NANOTECHNOLOGY LOOKY LOOKY." "Steel Collar
Worker" in this month's Analog was a pretty good story that had both VR and
nanotechnology but as background, not the reason for writing the story.

--
David L. Smith
smi...@discos.com or davs...@nic.cerf.net

Steinn Sigurdsson

unread,
Sep 25, 1992, 10:52:57 AM9/25/92
to


Most of the stuff I've read in _Analog_ or _IASFM_ are based somewhat with
the VR (virtual reality) or nanotech science. These scientific "themes", for
lack of a better word, seem to keep popping up.

Rather than discuss these topics all over again, my question to the net is:

What other futuristic science themes do you see coming this way?

I'm talking "very probable/possible" science. Not ringworlds, gravity
generators, or even FTL travel. I'm talking optical computing, upcoming
changes in scientific paradigms, etc.

Well, there's a real cute paper out on possible fundamental
problems with reconciling QM and GR (Preskill, J. 1992),
hints that QM may really have to be fundamentally refomulated
- the Proteus Manifest by Sheffield is a more accessible
SF kinda loosely based on the same general concept.

What would be the impact of these changes on our society?

Absolutely no idea. Could be drastic - could be negligible,
but it's probably the best clue to a paradigm shift in the
mainstream literature - I'm discounting the flaky crap that
recularly floods the sci.groups...

S Ye cannae change the laws of physics, S
S the laws of physics, the laws of physics. S
S Ye cannae change the laws of physics, S
S the laws of physics, Cap'n! - Star Trekkin' S


* Steinn Sigurdsson Lick Observatory *
* ste...@lick.ucsc.edu "standard disclaimer" *
* Just because there's a reason *
* Doesn't mean it's understood Specials, 1979 *

Bruce Scott

unread,
Sep 26, 1992, 7:19:13 PM9/26/92
to
Steinn, could you give a more complete reference for

"Well, there's a real cute paper out on possible fundamental
problems with reconciling QM and GR (Preskill, J. 1992)"

maybe want to post it on sci.astro as well.

Gruss,
Dr Bruce Scott The deadliest bullshit is
Max-Planck-Institut fuer Plasmaphysik odorless and transparent
bds at spl6n1.aug.ipp-garching.mpg.de -- W Gibson
--
The opinions expressed are not necessarily those of the University of
North Carolina at Chapel Hill, the Campus Office for Information
Technology, or the Experimental Bulletin Board Service.
internet: bbs.oit.unc.edu or 152.2.22.80

Steinn Sigurdsson

unread,
Sep 26, 1992, 4:40:59 PM9/26/92
to

Steinn, could you give a more complete reference for

"Well, there's a real cute paper out on possible fundamental
problems with reconciling QM and GR (Preskill, J. 1992)"

maybe want to post it on sci.astro as well.

It's paper 9209058 on the hep-th server, I would not
post it under any circumstances, the paper is copyright and
not postable. I would also ask that no-one consider posting
any of the papers on the TeX mail servers (unless of course
you're the author), there are very serious copyright issues at
stake.

| Steinn Sigurdsson |I saw two shooting stars last night |
| Lick Observatory |I wished on them but they were only satellites |
| ste...@lick.ucsc.edu |Is it wrong to wish on space hardware? |
| "standard disclaimer" |I wish, I wish, I wish you'd care - B.B. 1983 |

Bruce Scott

unread,
Sep 27, 1992, 1:09:30 PM9/27/92
to
ste...@topaz.ucsc.edu (Steinn Sigurdsson) writes:

>Bruce...@bbs.oit.unc.edu (Bruce Scott) writes:
>
> maybe want to post it on sci.astro as well.
>
>It's paper 9209058 on the hep-th server, I would not
>post it under any circumstances, the paper is copyright and
>not postable. I would also ask that no-one consider posting
>any of the papers on the TeX mail servers (unless of course
>you're the author), there are very serious copyright issues at
>stake.

Was I really this vague? I agree absolutely; maybe you should realise
that from the average size of my posts. I meant post the *reference*.
I thank you for having done so.

Let me add my voice to Steinn's: DO NOT post whole papers.

Lewis Murtaugh

unread,
Sep 28, 1992, 11:40:48 AM9/28/92
to
In a word -- biotechnology.

The Human Genome Project is chugging along, gaining speed as advances come
down the pike. There will be payoffs. At first just new drugs and new
diagnostic tools, then (mark my word) the eugenics debate will reappear as it
becomes easier to plot unborn children's genetic history. Eventually
something bad will result from this.

Beyond that, it may become possible to *alter* your child's gene's in utero,
fixing bad alleles, etc. Then people might start adding entirely new genes,
and developing better vectors (e.g. viruses that "turn off" after a certain
number of rounds of reproduction) that allow them to alter their own genes, at
any stage in their lives.

New crops, new livestock, new medicines, new bacteria (some productive and
useful, some pathogenic).

Biotech will be much bigger than either VR or nanotech (which is basically a
joke and will continue to be for long after we're dead).

--
Charles Murtaugh

Jonathan Burns

unread,
Sep 28, 1992, 6:56:28 AM9/28/92
to

> Most of the stuff I've read in _Analog_ or _IASFM_ are based somewhat with
> the VR (virtual reality) or nanotech science. These scientific "themes", for
> lack of a better word, seem to keep popping up.

> What other futuristic science themes do you see coming this way?

Brain stuff.

I always liked the bit in Vernor Vinge's _True Names_, when Debbie/
Erythrina is discovered to be an acute woman of 80 years age. She
suffers from frequent memory lapses, _but her computer keeps a cache
of her short-term memory_, and kick-starts her attention.

What may be coming in:

(1) Detailed knowledge of the hormonal dynamics of the brain. Memory
print chemistry, regulating the natural print agents (endorphins?)
and counterfeiting their functions. Discovery of the proximate causes
of sleep, and whether our wayward sleep cycles are harmful. Lucid
dream agents? Control of addictions? New addictions?

(2) A wealth of metaphors coming into neurological theory from neural
network research. Is attention subject to entropy? Is recall subject
to traffic jams? Given that eidetic memory is possible, what usually
prevents it? Accurate diagnosis of dislexia, digraphia?

(3) Specific controllers for brain regions. Is it true that the
reticular activating formation is The switch in hypnosis? Can we
hallucinate on command, and can the hallucinations be directed?
What is free will in neural terms, and can it be invoked?

(4) Mapping of the attractors in behaviour. Are we addicted to being
who we are? Would it do us any good to disrupt the attractors?
Can we change gender?

(5) Can we regress, to past episodes? Can we do what the psychotherapists
hoped, revive traumas and reevaluate them from a mature viewpoint? Can
we invoke the mature viewpoint?

(6) Biofeedback and psychosomatics are low-key at present. But the brain
remains a potent regulator of bodily functions, including healing,
weight, muscle formation.

(7) If us, then why not other high mammals? Can gorillas speak?
Can dogs drive cars? Whales dig astronomy?

Lotta damn weird stuff.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Jonathan Burns | He'd buy turtles, and afix jewels to their backs.
bu...@latcs1.lat.oz.au| Then he'd sit up smoking hashish, and watch the
Computer Science Dept | turtles crawl around on his Persian rugs. We should
La Trobe University | all go home and do this. - Terence McKenna
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

guru

unread,
Sep 30, 1992, 10:29:38 AM9/30/92
to
In article <1992Sep28.1...@news.acns.nwu.edu> my...@casbah.acns.nwu.edu (Lewis Murtaugh) writes:
>
>The Human Genome Project is chugging along, gaining speed as advances come
>down the pike. There will be payoffs. At first just new drugs and new
>diagnostic tools, then (mark my word) the eugenics debate will reappear as it
>becomes easier to plot unborn children's genetic history. Eventually
>something bad will result from this.

guru sez:
I thought the HGP had run into hot water because the main guys behind
it had fallen out out some petty matter, as scientists tend to do.

Sorry, I can't recall any names, but I was only half-paying attention.

Whatever does come out of it, I'd hate to be caught up trying to
decide for real what should be done with the knowledge.

Still, as a thought-experiment, I'd prefer to see a "minimum action"
policy taken up, whereby genetic disorders are removed from the genome.
Interestingly, this would only need to be done for a relatively short
period of time, since only a few generations would be needed before
the disorder was wiped out. Of course, that's when new mutations crop
up...

As soon as you start getting involved in "selecting" for specific
properties, you hit very shaky ground, and the argument between those
who do and don't want to will big the biggest and bloodiest ever seen,
IMHO.

Just my half-baked thoughts on the matter.
--
/~~~) / / /~~~) / /
(___/ (___/ / (___/ These mind-expanding drugs have given me so much
/ imagination, I'm hallucinating grey vividly....
(___/ mei...@cch.cov.ac.uk Victor Lewis-Smith

Thomas B MacIukenas

unread,
Oct 4, 1992, 3:25:56 PM10/4/92
to
mei...@cch.coventry.ac.uk (guru) writes:

>guru sez:
> I thought the HGP had run into hot water because the main guys behind
> it had fallen out out some petty matter, as scientists tend to do.

Don't worry, there are plenty other researchers working on the HGP (Human
Genome Project).

> Whatever does come out of it, I'd hate to be caught up trying to
> decide for real what should be done with the knowledge.

Just to keep everything in perspective, I'd like to point out that we
do have plenty of time to think about it. You see, the HGP researchers
are not trying to figure out what all the genes do, they're just trying
to list all the base-pair sequences. In other words, when they're done,
all they'll have is a sequence of letters. They won't have any idea
what any of them do.

In order to discover the functions of each gene, they will have to
individually sequence the genomes of millions of humans, cross-referencing
the data with every personal characteristic you could think of. That will
take decades. Plus, since the genomes of all humans are identical in
something like 98% of the base pairs, the researchers will also have to
sequence the genomes of all kinds of other organisms for comparison.

So, you see, there is plenty of time to figure out what to do with
the knowledge. (Of course, there is no guarantee that we will spend
that time actually thinking about it. My guess is we won't, and won't
we all be surprised when the time comes for making decisions and we
have no idea what to do? :^( )

> [....]


> As soon as you start getting involved in "selecting" for specific
> properties, you hit very shaky ground, and the argument between those
> who do and don't want to will big the biggest and bloodiest ever seen,
> IMHO.

I totally agree.
--
___-Tom_Maciukenas_(tbmg...@uxa.cso.uiuc.edu)______________________________

"S.E.T.E.C. : Special Extra-Terrestrial Earthling Counter"
"A turnip cures Elvis = Universal Studios" -- from "Sneakers"

Urban F

unread,
Oct 3, 1992, 12:59:16 PM10/3/92
to
mei...@cch.coventry.ac.uk (guru) sez:
>
> Still, as a thought-experiment, I'd prefer to see a "minimum action"
> policy taken up, whereby genetic disorders are removed from the genome.

Be sure to archive them! Some of them may actually have some
beneficial properties.

> Interestingly, this would only need to be done for a relatively short
> period of time, since only a few generations would be needed before
> the disorder was wiped out.

Only if you screen everyone. And with us beeing 5+ billion and
increasing, an enormous task indeed.

My "minimum action" would involve introduction of a set of genes
that provide immunity to some very common diseases, or maybe let
us digest food more efficiently. It is sad that people suffer from
genetic diseases, but in numbers they are relatively few.
--
Urban Fredriksson u...@icl.se (n.g.u.fredri...@oasis.icl.co.uk)
Knowledge is power: Read books!

Juggler

unread,
Oct 8, 1992, 6:15:12 AM10/8/92
to
u...@icl.se (Urban F) writes:

>My "minimum action" would involve introduction of a set of genes
>that provide immunity to some very common diseases, or maybe let
>us digest food more efficiently. It is sad that people suffer from
>genetic diseases, but in numbers they are relatively few.

As the average lifespan of humans increases, more and more
genetic "diseases" are being discovered. Many of these (such as sickle
cell anaemia) have evolved in order to prolong short term life
expectancy. Ultimately, we are genetically designed to die, because
almost *all* of our genes are imperfect. Even if we could wipe out all
the defects that are currently considered to be genetic deseases, I
reckon that medical science is going to continue improving, and
processes that are at the moment considered as natural aging will in
the future be treated as genetic defects resulting in eventual death.
This will only stop if (more probable) we reach a technological limit
beyond which we cannot advance, or (inconceivable in the short or
medium term) we eventually wipe out all such "defects" and are
effectively immortal - albeit not invulnerable!

TTFN,
Simon.


--
S.A.Hovell,Electrical Engineering dept,University of Edinburgh,U.K.
(+31) 650-5655 (Jug...@castle.ed.ac.uk)
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