From: eripe.dk@gmail.com   
      
   On Friday, March 17, 2017 at 3:11:33 PM UTC+7, Greg Goss wrote:   
   > In one of the Ringworld novels, Either Louis or someone explaining to   
   > Louis points out the truly humungeous amount of hydrogen that would   
   > have been consumed spinning up the artifact.   
   >   
   > Bussard Ramjets are canon in this series, and were used by the   
   > builders of the Ringworld.  So you have a humungeous supply of   
   > hydrogen in the solar wind.   
   >   
   > You've got the rudiments of a transport system along one rim wall.   
   > OK, you build a fleet of bussard ramjet locomotives, and use the   
   > transport system to bring them up to Bussard speed.  After a while,   
   > you're using much of the "linear" accelerator's applied force to   
   > circularize the "orbit" of each locomotive.  Once you ignite the   
   > ramjet using solar wind, the locomotive can now pull on each transport   
   > system impeller rather than be pushed by it.  We've got   
   > superconductors, so the brief exposure to fusion heat in the impeller   
   > ring can be bled away without having to stutter the drive, as was my   
   > first idea.   
   >   
   > Once you're done, you discard all but a few hundred of these   
   > locomotives, remount the rest as attitude jets, and you're in action.   
   >   
   > Why are we talking about burning up a planet in a world where Bussard   
   > engines work?  You have to accelerate much of that planetload of fuel   
   > as deadweight to use in the later portion of the spin-up, in and echo   
   > of the classic rocket equation (but in angular momentum and energy   
   > rather than linear)   
   > --   
   > We are geeks.  Resistance is voltage over current.   
      
   You would gain a lot of energy too, by moving a Jupiter mass closer to the   
   sun. Jupiter is at 5 AU, but suppose the builders picked a planetary system   
   with one further away.   
      
   Than again, they might have a number of black hole drives, doing straight mc^2   
   energy conversion, and then you don't really have to worry about such things   
   as having enough power. After its spun up, you send the black holes away to   
   explode.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)