Why havent the Pak killed the Kzinti?

  > > of course I guess you could spend a hundred years spinning it up with
free
  > > energy from the sun . .
  > >
 > Could it be built already spinning? If the Ringworld rotational speed is a
 > stable orbit, then the construction equipment and materials could just
build
 > already moving.
 >

if I were building it I would start with all the masses at orbital speed and
with a central truss. Once you hade the keel/central truss in place you
hang identical moduals on them extending port and starboard. Every so far
you put an additional secondary support truss port and starboard until you
are half a million miles from the central truss, where you put the rim
walls. Finally you feed stored fuel to the attitude jets all pivoted
spinward as far as they will go, the bussard collectors on them won't work
until you have accellerated half way to final speed but the fusors work fine
if you give them fuel directly.


 > Was it built in pieces, then connected together? Was a central tether put
in
 > order, and expanded from there? Was it built in hyperspace, then just
 > appeared in place when the switch was thrown?

Could not have dropped out of hyperspace, it is way to close to its sun for
that option.

Allen W.<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Why havent the Pak killed the Kzinti? 

David Lesher wrote:
 > I'd go with the Outsiders making RW far before the Pak. First off,
 > you'd need their reactionless drive system to spin it up.

Not at all. Since each part of it is orbiting the sun at the same speed
that a planet in that orbit would, it has to have been built "spun up".
In fact, once you have moved each part to its proper location, orbital
mechanics would keep each one approximately in that orbit (though not
rotated/oriented the right way) until the builders go through and start
fastening the parts together.

It's once you've assembled a part-structure substantially bigger than a
planet that you begin to need thrusters to keep it from rotating out of
place (and to correct for the small perturbations resulting from the
pull of gravity from other parts of the uncompleted Ringworld). I'm
assuming its total mass is small compared to that of the sun.

And it's only after you've assembled the whole thing _and_ turned off
the thrusters that it needs to have the tensile strength of unobtainium.<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Why havent the Pak killed the Kzinti? 

<< From: John David Galt jdg.RemoveThis@diogenes.sacramento.ca.us >>


<< I'm
assuming its total mass is small compared to that of the sun. >>

About the mass of Jupiter.
 >> Stay informed about: Why havent the Pak killed the Kzinti? 

Hello,

According to The Ringworld Engineers, it would take several thousand years
to spin up the Ringworld to 770 miles/second,
just using energy from the sun. Louis Wu speculates that the Engineers used
up several Jupiter-sized masses powering
the project. Of course, I don't think it is told for certain just how it
was done.

Dale

"David Lesher" <wb8foz DeleteThis @panix.com> wrote in message
news:cav56l$2lr$1@reader2.panix.com...
 > Mark Landin <mark.landin DeleteThis @tdwilliamson.com> writes:
 >
   > >>I'd go with the Outsiders making RW far before the Pak. First off,
   > >>you'd need their reactionless drive system to spin it up.
 >
  > >Why couldn't you spin it up with the attitude jets?
 >
 > Let's see. We know the total mass, I think.
 > We also know the rotational rate.
 >
 > Anyone care to figure out the total energy required?
 > {I suspect it is non-trivial....}
 >
 > --
 > A host is a host from coast to coast.................wb8foz DeleteThis @nrk.com
 > & no one will talk to a host that's close........[v].(301) 56-LINUX
 > Unless the host (that isn't close).........................pob 1433
 > is busy, hung or dead....................................20915-1433<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Why havent the Pak killed the Kzinti? 

On Wed, 30 Jun 2004 16:53:06 -0700, John David Galt
<jdg.TakeThisOut@diogenes.sacramento.ca.us> wrote:

 >David Lesher wrote:
  >> I'd go with the Outsiders making RW far before the Pak. First off,
  >> you'd need their reactionless drive system to spin it up.
 >
 >Not at all. Since each part of it is orbiting the sun at the same speed
 >that a planet in that orbit would, it has to have been built "spun up".
 >In fact, once you have moved each part to its proper location, orbital
 >mechanics would keep each one approximately in that orbit (though not
 >rotated/oriented the right way) until the builders go through and start
 >fastening the parts together.

Yes, but the ringworld rotates much faster than the orbital velocity
required for an object orbiting at it's radius. IIRC it needs to do in
order to simulate gravity on it's inner side, and keep the air in. So
it would need to be spun up, after construction.

I think it says somewhere that the ring is approximately the same
distance from it's star as the Earth is from our sun i.e. 93 million
miles, which equates to an orbital speed of about 18 1/2 miles/s,
rather than the ringworld's 770miles/s.<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Why havent the Pak killed the Kzinti? 

"Darren J Longhorn" <me RemoveThis @privacy.net> wrote in message
news:t0j7e0d2hi3ud3c7vt8b479e8br3b23blc@4ax.com...
 > On Wed, 30 Jun 2004 16:53:06 -0700, John David Galt
 > <jdg RemoveThis @diogenes.sacramento.ca.us> wrote:
 >
  > >David Lesher wrote:
   > >> I'd go with the Outsiders making RW far before the Pak. First off,
   > >> you'd need their reactionless drive system to spin it up.
  > >
  > >Not at all. Since each part of it is orbiting the sun at the same speed
  > >that a planet in that orbit would, it has to have been built "spun up".
  > >In fact, once you have moved each part to its proper location, orbital
  > >mechanics would keep each one approximately in that orbit (though not
  > >rotated/oriented the right way) until the builders go through and start
  > >fastening the parts together.
 >
 > Yes, but the ringworld rotates much faster than the orbital velocity
 > required for an object orbiting at it's radius. IIRC it needs to do in
 > order to simulate gravity on it's inner side, and keep the air in. So
 > it would need to be spun up, after construction.
 >
 > I think it says somewhere that the ring is approximately the same
 > distance from it's star as the Earth is from our sun i.e. 93 million
 > miles, which equates to an orbital speed of about 18 1/2 miles/s,
 > rather than the ringworld's 770miles/s.
 >
Could pieces have been built at a larger orbit (where the giants are being
torn apart) where 770 miles/second is more feasible -- (what is the orbital
speed of Jupiter anyway?) -- then spiraled in for final assembly without
decelerating? They could even be accelerated along the way in from the outer
planets. (Assuming one mother of a reaction drive facing sideways to bend it
into that final orbit.) Only the center "wire" of the RW would need to be
spun up, while the floor plates would already be at that speed when they
arrived. Of course, the construction crew would need new underwear after
each delivery...
--
Zamboni<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Why havent the Pak killed the Kzinti? 

"Zamboni" <zamboni.TakeThisOut@nospam.com> writes:
 >Could pieces have been built at a larger orbit (where the giants are being
 >torn apart) where 770 miles/second is more feasible -- (what is the orbital
 >speed of Jupiter anyway?)

There is no distant orbit around a normal sun where 770 mi/sec is feasible.
Orbital velocities get SLOWER as you move farther away. IIRC, Jupiter's
orbital velocity is in the mid-teens.

 >-- then spiraled in for final assembly without
 >decelerating? They could even be accelerated along the way in from the outer
 >planets.

It would be unimaginably harrowing to maneuver objects moving at 770 mi/sec
while you are trying to bolt them together into a structure. Why not just
spend the couple thousand years spinning it up - after all, the ringworld
has been populated for a very, very long time - long enough for
homo sapiens to speciate. The builders, Pak or otherwise, obviously weren't
working on a short timescale.

 >arrived. Of course, the construction crew would need new underwear after
 >each delivery...

Heh. Exactly. *
--
* PV something like badgers--something like lizards--and something
like corkscrews.<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Why havent the Pak killed the Kzinti? 

"Darren J Longhorn" <me DeleteThis @privacy.net> wrote in message
news:t0j7e0d2hi3ud3c7vt8b479e8br3b23blc@4ax.com...
 > On Wed, 30 Jun 2004 16:53:06 -0700, John David Galt
 > <jdg DeleteThis @diogenes.sacramento.ca.us> wrote:
 >
  > >David Lesher wrote:
   > >> I'd go with the Outsiders making RW far before the Pak. First off,
   > >> you'd need their reactionless drive system to spin it up.
  > >
  > >Not at all. Since each part of it is orbiting the sun at the same speed
  > >that a planet in that orbit would, it has to have been built "spun up".
  > >In fact, once you have moved each part to its proper location, orbital
  > >mechanics would keep each one approximately in that orbit (though not
  > >rotated/oriented the right way) until the builders go through and start
  > >fastening the parts together.
 >
 > Yes, but the ringworld rotates much faster than the orbital velocity
 > required for an object orbiting at it's radius. IIRC it needs to do in
 > order to simulate gravity on it's inner side, and keep the air in. So
 > it would need to be spun up, after construction.
 >
 > I think it says somewhere that the ring is approximately the same
 > distance from it's star as the Earth is from our sun i.e. 93 million
 > miles, which equates to an orbital speed of about 18 1/2 miles/s,
 > rather than the ringworld's 770miles/s.
 >
 >
Unless their star is cooler it ough to overheat. Wait a minute didn't they
have shades or something?<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Why havent the Pak killed the Kzinti? 

"Eric S. Harris" <eric_harris_76 DeleteThis @mindspring.com> wrote in message
news:F13uc.15915$be.9140@newsread2.news.pas.earthlink.net...
 > bertschnik DeleteThis @aol.com (BertSchnik) wrote in
 > news:20040125150001.28443.00000676@mb-m01.aol.com:
 >
  > >
  > >
  > > Why havent the Pak made the Kzinti race extinct? Last we saw in
  > > Protector,
  > > Roy Truesdale had recruited an army and was going to have Home on " a
  > > war footing".
  > >
 >
 > See this 2000 thread for my thoughts on the matter
 >
 >
<a style='text-decoration: underline;' href="http://groups.google.com/groups?hl=en&lr=&ie=UTF-8&oe=utf-8&safe=off&th=c617b6055686be32&seekm=3A33BB77%40MailAndNews.com#link1" target="_blank">http://groups.google.com/groups?hl=en&lr=&ie=UTF-8&oe=utf-8&safe=off&t...617b605</a>
 >
 > --
 > -Hk
 >
reasonible enough. I don't think that once these beings started to defend
the human race they would stop. If you can't save your kid you can save your
niece.<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Why havent the Pak killed the Kzinti? 

JRS: In article <10e8u0vc7nf48ae.TakeThisOut@news.supernews.com>, seen in
news:alt.books.larry-niven, Paul Vader <pv+usenet@pobox.com> posted at
Thu, 1 Jul 2004 20:46:23 :
 >"Zamboni" <zamboni.TakeThisOut@nospam.com> writes:
  >>Could pieces have been built at a larger orbit (where the giants are being
  >>torn apart) where 770 miles/second is more feasible -- (what is the orbital
  >>speed of Jupiter anyway?)
 >
 >There is no distant orbit around a normal sun where 770 mi/sec is feasible.
 >Orbital velocities get SLOWER as you move farther away. IIRC, Jupiter's
 >orbital velocity is in the mid-teens.

It is about 13 km/s. Near mid-teens, except in the USA.

--
© John Stockton, Surrey, UK. ?@merlyn.demon.co.uk Turnpike v4.00 MIME. ©
Web <URL:http://www.merlyn.demon.co.uk/> - FAQqish topics, acronyms & links;
some Astro stuff via astro.htm, gravity0.htm; quotes.htm; pascal.htm; &c, &c.
No Encoding. Quotes before replies. Snip well. Write clearly. Don't Mail News.<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Why havent the Pak killed the Kzinti? 

There is only one way it could have been built I think.

The energy requirements for construction and for roatating it up to
speed are so huge that it cannot have been built with materials from the
pre-existing planetary system (Niven says this in N-Space, I think).

So... the material was teleported in from another system. And ... this
is the clever bit ... if that other system had a substantial relative
difference in momentum, then, because KS teleportation conserves
momentum, the matter would arrive with oodles of surplus energy - enough
to spein up the ring.

Whatdya think?

Zamboni wrote:
 > "ANIM8Rfsk" <anim8rfsk DeleteThis @aol.comNOSPAM> wrote in message
 > news:20040618153824.05640.00000225@mb-m14.aol.com...
 >
  >><< From: David Lesher wb8foz DeleteThis @panix.com >>
  >>
  >>
  >><< Let's see. We know the total mass, I think. >>
  >>
  >>Pretty much the same as Jupiter.
  >>
  >>
  >><< Anyone care to figure out the total energy required?
  >>{I suspect it is non-trivial....} >>
  >>
  >>of course I guess you could spend a hundred years spinning it up with free
  >>energy from the sun . .
  >>
 >
 > Could it be built already spinning? If the Ringworld rotational speed is a
 > stable orbit, then the construction equipment and materials could just build
 > already moving.
 >
 > Was it built in pieces, then connected together? Was a central tether put in
 > order, and expanded from there? Was it built in hyperspace, then just
 > appeared in place when the switch was thrown?
 > --
 > Zamboni.
 >
 ><!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Why havent the Pak killed the Kzinti? 

<< From: Julian Treadwell julian.t.TakeThisOut@ihug.co.nz >>


<< So... the material was teleported in from another system. >>

This assumes that the Pak had intersystem teleportation technology (something
we've never seen in Known Space) and lost it after finishing construction.
 >> Stay informed about: Why havent the Pak killed the Kzinti? 

Julian Treadwell <julian.t.TakeThisOut@ihug.co.nz> writes:
 >So... the material was teleported in from another system. And ... this

Where did you get that idea? There's no evidence that anyone in Known
Space, Pak included, have any form of long-distance teleportation
technology. Why would the Pak be travelling around in Bussard Ramjets in
normal space if they had something like that?

 >is the clever bit ... if that other system had a substantial relative
 >difference in momentum, then, because KS teleportation conserves
 >momentum, the matter would arrive with oodles of surplus energy - enough
 >to spein up the ring.

We've been over that - it's too wacky to contemplate. You can't build a
structure while the parts are spinning at 770 miles per second. *
--
* PV something like badgers--something like lizards--and something
like corkscrews.<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: Why havent the Pak killed the Kzinti?