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artificial gravity

Posted by Carmen J. Nappo on 07/04/2016

I've just finished EON. Very imaginative work. However, imagination and reality often do not mix. For example, centrifugal force is not similar to gravitational force. The two forces are similar in effect when a mass is in contact with a rotating structure, i.e. the Stone. However; if I were on the Stone's wall and jumped upward, I would not fall back to the wall. Instead, I would continue moving upward. Because of this, an atmosphere could not exist inside the Stone. Of course, coming some some 20 years after the publication of EON, my comments are somewhat moot. Still, I think that in science fiction the known science should be true. For example, it is not critical what the value of Plank's constant is, as long as there is a Plank's constant. But all-in-all, it's a great read.

Re: artificial gravity

Posted by Bill Goodwin on 07/23/2016

Sorry to nit-pick, but you would indeed "fall" back to the wall of a rotating habitat after jumping upward (or toward the axis). When your feet leave the inner surface, you retain the momentum you had at that moment, which was directed tangentially in the spin-ward direction. Add the upward motion of your jump and you're in a slantwise trajectory...but remember that the surface "underneath" you keeps rotating while you're in the air. If the habitat is big enough, your jumping-off point will be right there to meet you when that trajectory brings your feet back into contact with the outer shell. At smaller sizes walking and jumping become difficult, but you don't lose the centrifugal effect, and the atmosphere is fine. If you want to float away toward the axis, your best bet is to run very fast in the anti-spinward direction. THAT will cancel out the gravity, and you'll be on your own.

Re: artificial gravity

Posted by A Culture Mind on 01/05/2017

Yeah, didn't you ever spin marbles in a bucket or bowl - and then 'jump' them a little, wherein they return to their trajectory around the inside of the container - unless your force exceeded the acceleration inside, wherein like Bill says they'd escape. But one g rotation is a LOT to exceed. It's called escape velocity, yo.

Re: artificial gravity

Posted by Bence on 11/28/2017

Hi, I'm in the middle of the book EON right now (russians invading), so please dont spoil me, but I have a question quite relating for this topic, that I don't understand (maybe because I am not native English). So when Russians reached first Chamber while attacking the Stone, they are floating (flying) through that chamber in their suits. Are they not under the effect of the 'artificial gravity'? And why they can't put off their suits, like they need oxigen from the suit? Did the Americans open the first chamber to push air out to the space? Thank you in advance!

Re: artificial gravity

Posted by Greg Bear on 12/07/2017

Inside the Stone, there is no artificial gravity... just the centrifugal force of the Thistledown's rotation, which they don't feel unless they contact the walls or the already-rotating atmosphere. The axis is mostly free-fall. Definitely interesting to try to visualize! As for atmosphere, the rotated atmosphere of the stone is well below the axis, and "clings" to the chamber walls, though there would be some leakage over time. There is no breathable atmosphere inside the bore holes or along the axis.

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