cipher@mmm.UUCP (Andre Guirard) (07/22/86)
On a planet with higher gravity than Earth, all else being equal,
things would tend to be shorter and thicker than on Earth. The
problem: name one thing that under higher gravity would tend to be
taller and thinner than on Earth.
E-mail me your responses and I'll post the results in a couple of weeks.
--
(___) Andre Guirard
|_ _| La Diablo kiu Strabas
( v ) ihnp4!mmm!cipher
\-/
Vcipher@mmm.UUCP (Andre Guirard) (08/01/86)
This is the promised posting of the results of my question, what things would tend to be taller and thinner under higher gravity? I received several different answers. I discussed them with a physicist at the University of Minnesota to decide which were correct. From mlf@genrad: tornadoes. From jacob@renoir.berkeley.edu (Jacob Butch): clouds. Says the expert: Clouds, tornadoes and other atmospheric phenomena would tend to be compressed under higher gravity. From dopey@ihlpl: a helium balloon. I thought this was a good answer, but the expert says the shape of a helium balloon would not change noticeably. The air outside and the gas inside would have the same pressure relative to each other regardless of amount of gravity. From melissa@TRILLIAN.ARPA and jcs@hocad: stalactites, icicles. Length of icicles, quoth the raven, is determined by atmospheric conditions rather than gravity. Stalactites are a possibility, but on reflection I think they would _not_ be longer because (a) cave ceilings would be lower and (b) water would run off of them faster, leaving less time for minerals to deposit. In any case, the problem asked for what would be _taller_, and stalactites and icicles don't have "tallness," onlt length. From ado@sie and fulton@emory: Waterfalls (and other falling things) I don't need the raven for this one. The height of waterfalls and similar phenomena is determined by the height of what they fall from. Features of the landscape would tend to be lower under higher gravity. From herb@uwvax (Benington Herb): Pendulums. It's hard to say, because pendulums are man-made, but to get the same frequency under higher gravity you need a shorter pendulum. My own answer: a flame. I figured that since a flame is spherical under zero-gee, that the greater the gravity the taller it would get. The raven expresses serious doubts about this idea, and says in his opinion it would be the same height. In fact, the raven says he can't think of _anything_ that would be taller and thinner under higher gravity. If anyone can think of something, or can refute the raven on some point, I'd be happy to hear of it. -- ===+=== Andre Guirard /@ @\ ihnp4!mmm!cipher /_____\ ( @ @ ) My mission: to explore strange new words. \ _ / To seek out and utilize new applications. `-' To shovel snow that snow plows have shoved before.
tim@ism780c.UUCP (Tim Smith) (08/05/86)
In article <1033@mmm.UUCP> cipher@mmm.UUCP (Andre Guirard) writes: > >In fact, the raven says he can't think of _anything_ that would be >taller and thinner under higher gravity. If anyone can think of >something, or can refute the raven on some point, I'd be happy to hear >of it. Visitors from another planet. -- "I keep pitching 'em and you keep missing 'em" Tim Smith USENET: sdcrdcf!ism780c!tim || ima!ism780!tim Compuserve: 72257,3706 Delphi || GEnie: mnementh
lwall@sdcrdcf.UUCP (Larry Wall) (08/07/86)
In article <1033@mmm.UUCP> cipher@mmm.UUCP (Andre Guirard) writes: >>In fact, the raven says he can't think of _anything_ that would be >>taller and thinner under higher gravity. If anyone can think of >>something, or can refute the raven on some point, I'd be happy to hear >>of it. In article <3093@ism780c.UUCP> tim@ism780c.UUCP (Tim Smith) writes: >Visitors from another planet. Only when dangling from a tree limb. A spring would serve as well. Or anything else that stretches when it hangs. Also, I think the raven is wrong about things that are buoyant, such as balloons and flames. The higher gravity would induce a bigger gradient of pressure from the top of something to the bottom, causing more vertical force. I'm not sure how this would affect the shape of the balloon envelope proper, but the cables would certainly stretch more. The higher air pressure might well collapse the balloon partially, like a stratospheric helium balloon looks at sea level. The flame should rise faster, creating a lower pressure due to the venturi effect, resulting in a narrower flame. Atomic mushroom clouds might be taller and skinnier for the same reason, and also because the initial fireball would be smaller and hotter in a denser atmosphere. Buoyant but cohesive objects will also have greater tidal effects. This might tend to stretch out the shape of the balloon envelope, if ever so slightly. Thinking a bit more about the flame in 0 g being round--surely you believe that the transition from a round flame at 0 g to a long flame at 1 g is continuous? I doubt there's some amount of gravity at which the flame suddenly springs from being round to being long (catastrophe theory notwithstanding). Given this presumption, is there any reason to suppose the the transition from round to long flame stops at 1 g? Maybe the length of a flame peaks or plateaus out at 2g. Here are some other, rather esoteric, candidates: * An arch of a given mass, cross section, and lateral force. * A rocket of a given mass with a given amount of drag, due to denser air. * A valley, whether carved by water or ice (presuming the rock is strong enough to support steep sides), because it is carved faster at the bottom in proportion to the weathering of stone on the sides, which is more related to the annual freeze/thaw cycle. * Certain trajectories, optimized for certain things, AND taking into account air resistance. I'm not sure about this, but how about something like a minimum energy trajectory necessary to put a cannonball over a cube. The increased air resistance would tend to truncate the flight, so the minimum energy trajectory might involve blasting it higher and letting it drop straight down the other side, a shape more approximating a right triangle than a parabola. I don't have the math, and could be all wet. A rough sketch: . . . . . . . . ._________. ._________. . | | . . | |. (NB: Dot spacing does . | | . . | |. NOT represent speed.) . | | . . | |. . |_______| . . |_______|. Thin Air Thick Air (Note when I say minimum energy trajectory, I don't mean that the energy would be the same on both planets. It would obviously take more energy to get over the cube on the planet with higher gravity.) Enought of this. Anybody want to give me a ride to such a planet so I can check it out? Larry Wall {allegra,burdvax,cbosgd,hplabs,ihnp4,sdcsvax}!sdcrdcf!lwall
rickheit@ulowell.UUCP (Erich W Rickheit) (08/08/86)
In article <2939@sdcrdcf.UUCP> lwall@sdcrdcf.UUCP (Larry Wall) writes: >In article <1033@mmm.UUCP> cipher@mmm.UUCP (Andre Guirard) writes: >>>In fact, the raven says he can't think of _anything_ that would be >>>taller and thinner under higher gravity. If anyone can think of >>>something, or can refute the raven on some point, I'd be happy to hear >>>of it. > > >Thinking a bit more about the flame in 0 g being round--surely you believe >that the transition from a round flame at 0 g to a long flame at 1 g is >continuous? I doubt there's some amount of gravity at which the flame suddenly >springs from being round to being long (catastrophe theory notwithstanding). >Given this presumption, is there any reason to suppose the the transition >from round to long flame stops at 1 g? Maybe the length of a flame peaks or >plateaus out at 2g. > Consider: a flame (net not included :-) is glowing hot gas from a combustion. Under 0g (free fall) it will of course tend to be spherical, if the gases do not actually diffuse outward.(In actuality, things like candles in free fall do not form spheres, but collapse into a glowing ember at the top of the wick) The height of the flame depends on the relative density of the gases and of the surrounding atmosphere. The less relatively dense the glowing gases are, the taller and narrower your flame will be. Does gravity effect the atmosphere in the same way it effects the hot gases? I certainly hope so. -- a lesser Power of Darkness This is indeed an opinion; whose fault it is, I don't know. UUCP: ...wanginst!ulowell!rickheit USnail: Erich Rickheit 85 Gershom Ave, #2 Lowell, MA 01854 Phone: (617) 453-1753
king@kestrel.UUCP (08/11/86)
From: cipher@mmm.UUCP (Andre Guirard) Newsgroups: net.puzzle,net.sci Date: 1 Aug 86 14:33:40 GMT Reply-To: cipher@mmm.UUCP (Andre Guirard) This is the promised posting of the results of my question, what things would tend to be taller and thinner under higher gravity? I received several different answers. I discussed them with a physicist at the University of Minnesota to decide which were correct. I missed the original posting, but I have a response. Spacecraft would be taller and thinner. They would be thinner because they would accomodate the artifacts and later bodies of physically smaller owners, because tradeoffs between miniaturization and fuel would more favor miniaturization, and because they would have thicker air to punch through. They would be taller because they would have to be built in more stages, and because the fuel requirement per kilogram, being exponential in the delta-v (in turn proportional to the surface gravity times the size of the planet) grows much faster than the payload shrinks.
brunner@sdsioa.UUCP (Rob Brunner) (08/12/86)
>In fact, the raven says he can't think of _anything_ that would be >taller and thinner under higher gravity. If anyone can think of >something, or can refute the raven on some point, I'd be happy to hear >of it. How about womens' ears (whazzat??). Or anything with something hanging for that matter. Earrings tend to pull down on the ears... with higher G they would stretch the suckers out, wouldn't they? 8-) As for thinner: it seems anything with a T type shape would be thinner, yes? The Big G would pull down on the outsides of the T and make whatever it is thinner. (remember your circles) In some sort of extreme context: something in the general set-up of: | would tend to become: | / \ | | / \ | | A B A B In some sense, the gravity between A and B would cause this distorted shape and thus if each /, \, or | has the same length, whatever it is is now taller. (circles again :-)) Does any of this make any sense, or is my keyboard just foaming at the mouth? -- Rob Brunner email: Scripps Institution of Oceanography brunner@sdsioa.UUCP Mail Code A-010, UC San Diego sdsioa!brunner@sdcsvax San Diego, CA 92093 {backbone}!sdcsvax!sdsioa!brunner Phone: (619) 534-2040 (work) (619) 452-7656 (home)
mcb@styx.UUCP (Michael C. Berch) (08/13/86)
> This is the promised posting of the results of my question, what things > would tend to be taller and thinner under higher gravity? I'm not sure what the thrust of the original question is. The question could either mean A. "What actual earthly objects, if taken to a planet of higher gravity, would become taller and thinner?" -or- B. "What objects are likely to {grow,be designed} to be taller and thinner on a planet with higher gravity than Earth?" In case "A" essentially anything that is suspended from above and has some sort of elasticity would be thinner, and, I suppose, "taller". Michael C. Berch ARPA: mcb@lll-tis-b.ARPA UUCP: {ihnp4,dual,sun}!lll-lcc!styx!mcb