Not necessarily. The center of mass needs to be at geosynchronous orbit, and the easiest way to manage that is to put a large mass just beyond geosynchronous distance, and minimize the mass of the cable. If the cable extends out too far, I think Keplerian shear (just a fancy way to say that stuff farther from the planet orbits slower) starts to cause problems.
Thanks people, I’d remembered something about balancing but obviously it’s the mass not the length.
I think it was a Kurt Vonnegut story that had a democracy where the President was selected from the population by random lottery. The only way to get disqualified from the lottery was to actually want to be President. The country worked best, apparently, when the draftee was carried into office kicking and screaming.
During various presidential elections, I have thought fondly of this idea. Then I watch an episode of Jerry Springer, and my opinion changes back.
Hijack: I understand how extending a space elevator beyond geo-synchronous orbit can cancel the vertical forces on it, but how do you deal with the massive moment about its center of gravity that results?
Yes, but unless I’m misremembering the book, the beanstalk in Red Mars broke below the center point. Everything below that point fell, everything above it was flung off into solar orbit.
One of Arthur C. Clarke’s novels uses that idea as a throw-away. The other ways to get disqualified are to be above or below certain ages, or to commit a crime. There’s a nice little tidbit about the current president having considered that last one.
This sounds like Overdrawn at the Memory Bank, the Public TV movie that ended up as MST3K fodder.
Actually, I’m pretty sure the beanstalk extended past the geosynchronous point, but not as far again as the distance between the geosynch point. There was an asteroid/station “ballast” at the end. The beanstalk wasn’t destroyed in mid-length, but at the point where the stalk connected to the asteroid.
I thought it was really cool that when the connection was destroyed, the asteroids’s motion caused it to be flung off away from Mars. There were people onboard, and they had to rig up some kind of system to eventually decelerate the station and return to the inner solar system. But this took them a year or two to do.
John Varley wrote the original story Overdrawn at the Memory Bank in 1976. Of the PBS production, he wrote “I don’t think it was entirely successful, but I enjoyed it as it was the first of my works to be dramatized,” in the introduction to the story in his book The John Varley Reader: Thirty Years of Short Fiction.
Ah, Danke.
I loved Vernor Vinge’s concept of an galaxy-spanning Internet where races who have little or no prospect of communicating with each other face to face even with FTL because of the vast distances involved, were nonetheless able to chat with one another in real-time. The functioned as a sort of Greek chorus to the action of the story and added a great deal of dramatic power to “A Fire Upon The Deep.”
Also, Iain Banks’ concept of a “knife missile.” It’s basically a small, self-propelled AI of slightly greater than human intelligence which can move extremely fast and slice holes in people in a split second. It’s self-directed and intelligent. Basically, you + a knife missile vs. any modern army = one dead army. The soldiers die one at a time, but they die so fast it makes no different, and the knife missile can be very selective in picking out targets, being sentient and all.
Gaah, that was almost exactly my latest “really great idea for a sci-fi short story” I knew someone must have beaten me to it, if you think about it there is really no need for two sufficently advanced spacefaring societys to contact each other physically at all as long as they have ftl communication.
I really think Iain Banks is the master of this sort of stuff, all the technology in his books is so usefully and sensibly exploited. And let us not forget the Lazy Gun (although it isn’t exactly mentioned as a casual aside).