rick@iddic.UUCP (Rick Coates) (06/17/85)
Here are a couple of discrepancies (one large, one small) that I have run across lately: Dune: Stillsuits wouldn't work. As I read it, the idea behind a stillsuit is that it allows cooling by evaporation while trapping the moisture. Thermodynamics does not allow this. Any cooling action gained by the evaporation inside the suit would be offset by the condensation process. The net result would be a steam box that would be hot on a cold day with any insolation at all. Ringworld: After the Liar had been zapped by the ringworld meteor defense and was falling towards the ringworld, why didn't they use the flycycles to change their orbit? Obviously they had considerable thrust since a single one could move a large building about, and they had four while still in the ship. It wouldn't take a tremendous thrust to allow them to miss, given the distance they were traveling. I haven't seen these recently, so please excuse me if these have been beaten to death all ready. Rick Coates ...!tektronix!iddic!rick
joel@peora.UUCP (Joel Upchurch) (06/19/85)
> Here are a couple of discrepancies (one large, one small) that I have > run across lately: > > Ringworld: > > After the Liar had been zapped by the ringworld meteor defense and was > falling towards the ringworld, why didn't they use the flycycles to change > their orbit? Obviously they had considerable thrust since a single one > could move a large building about, and they had four while still in the > ship. It wouldn't take a tremendous thrust to allow them to miss, given > the distance they were traveling. > As I recall flycycles worked by using a replusion effect against the scrith, and would therefore be useless until they were very close to the ringworld.
john@hp-pcd.UUCP (john) (06/19/85)
<<< Regarding Ringworld, I seem to recall that the flycycles worked by repulsion from the surface. That would work if you were close enough to the plane of the surface but would be ineffective out in space. John Eaton !hplabs!hp-pcd!john
landauer@drivax.UUCP (Doug Landauer) (06/19/85)
> Stillsuits wouldn't work. As I read it, the idea behind a stillsuit is > that it allows cooling by evaporation while trapping the moisture. > > Rick Coates > ...!tektronix!iddic!rick > Organization: Tektronix, Beaverton OR No, there is no need for cooling on Arrakis. Nowhere is it mentioned that Arrakis is a particularly hot planet, just a very very dry one. The whole idea behind stillsuits is *water conservation*. Of course, residents of northern Oregon may not be familiar with the meaning of that phrase. :-) -- -- Doug Landauer -- ...[ ihnp4 | mot | ucscc | amdahl ] !drivax!landauer
msj@gitpyr.UUCP (Mike St. Johns) (06/19/85)
In article <2039@iddic.UUCP> rick@iddic.UUCP (Rick Coates) writes: >Here are a couple of discrepancies (one large, one small) that I have >run across lately: > >Dune: > >Stillsuits wouldn't work. As I read it, the idea behind a stillsuit is >that it allows cooling by evaporation while trapping the moisture. >Thermodynamics does not allow this. Any cooling action gained by the >evaporation inside the suit would be offset by the condensation process. > >The net result would be a steam box that would be hot on a cold day with >any insolation at all. > > Sorry to disabuse you, but all Thermodynamics says is that you can't get something for nothing. If you recall, the description of the stillsuit includes some form of "pump" which operates as the wearer walks. This provides the necessary "work" to circulate fluid. A refrigerator works well just by circulating fluid. I haven't done any calculations, but on the surface a stillsuit should be feasible. Mike -- Mike St. Johns Georgia Insitute of Technology, Atlanta Georgia, 30332 ...!{akgua,allegra,amd,hplabs,ihnp4,seismo,ut-ngp}!gatech!gitpyr!msj StJohns@MIT-Multics.ARPA (404) 982-0035
rick@iddic.UUCP (Rick Coates) (06/20/85)
>As I recall flycycles worked by using a replusion effect against the >scrith, and would therefore be useless until they were very close to >the ringworld. No, Nessus had no way of knowing what the characteristics of the ringworld floor material was. I believe that specific mention was made that they used reactionless thrusters. The floating cities used electomagnetic repulsion and as I remember the lander from Ringworld Engineers used this effect. Still looking for a reasonable explanation . . . keep those cards and letters coming. . . Rick Coates ...!tektronix!iddic!rick
guzman@ttidcb.UUCP (Marc Guzman) (06/21/85)
In article <483@gitpyr.UUCP> msj@gitpyr.UUCP (Mike St. Johns) writes: >In article <2039@iddic.UUCP> rick@iddic.UUCP (Rick Coates) writes: >>Here are a couple of discrepancies (one large, one small) that I have >>run across lately: >> >>Dune: >> >>Stillsuits wouldn't work. As I read it, the idea behind a stillsuit is >>that it allows cooling by evaporation while trapping the moisture. >>Thermodynamics does not allow this. Any cooling action gained by the >>evaporation inside the suit would be offset by the condensation process. >> >>The net result would be a steam box that would be hot on a cold day with >>any insolation at all. >> >> > >Sorry to disabuse you, but all Thermodynamics says is that you can't get >something for nothing. If you recall, the description of the stillsuit >includes some form of "pump" which operates as the wearer walks. This >provides the necessary "work" to circulate fluid. A refrigerator works well >just by circulating fluid. I haven't done any calculations, but on the >surface a stillsuit should be feasible. Mike >-- I too, felt that stillsuits would not work, and having read _Dune_ a long time ago I don't remember what powered them. But, if the above description is accurate, then the stillsuits definately can't work. The "engines" for the "pump" are obviously human muscles which will generate heat. And because, as we all know "... 2) You can't break even ...", the wearer will produce more heat than they can remove; resulting in "friedman" (boiled might be more accurate). Marc
throopw@rtp47.UUCP (Wayne Throop) (06/22/85)
Heavens! Marc Guzman has proven that space capsules cannot possibly be cooled to livable temperatures! I always thought those pictures from space must be faked! :-) For those who tuned in late: >>> Rick Coates >>>Stillsuits wouldn't work. [...] it allows cooling by evaporation >>>while trapping the moisture. Thermodynamics does not allow this. >> Mike St. Johns >>Sorry to disabuse you, but all Thermodynamics says is that you can't get >>something for nothing. [...] the stillsuit includes some form of >>"pump" which operates as the wearer walks. > Marc Guzman >[...] stillsuits definately can't work. The "engines" >for the "pump" are obviously human muscles which will generate heat. >And because, as we all know "... 2) You can't break even ...", the wearer >will produce more heat than they can remove; Now then, substitute "spaceship" for "stillsuit" and "fuel cells" for "human muscles", and we see that clearly NASA must have been pulling the wool over our eyes. :-) There is more than one way to skin a cat, and more than one way to get rid of heat. The stillsuit is wildly improbable, given current materials science, but more improbable yet is the "ornithopter". Neither, however, are "impossible" in the sense that they violate physical laws. As a peripheral issue, if one is going to pick nits this small, why isn't FTL travel pointed out as a much larger "discrepancy"? -- Wayne Throop at Data General, RTP, NC <the-known-world>!mcnc!rti-sel!rtp47!throopw
msj@gitpyr.UUCP (Mike St. Johns) (06/24/85)
In article <389@ttidcb.UUCP> guzman@ttidcb.UUCP (Marc Guzman) writes: >In article <483@gitpyr.UUCP> msj@gitpyr.UUCP (Mike St. Johns) writes: >>In article <2039@iddic.UUCP> rick@iddic.UUCP (Rick Coates) writes: >>>Here are a couple of discrepancies (one large, one small) that I have >>>run across lately: >>> >>>Dune: >>> >>>Stillsuits wouldn't work. As I read it, the idea behind a stillsuit is >>>that it allows cooling by evaporation while trapping the moisture. >>>Thermodynamics does not allow this. Any cooling action gained by the >>>evaporation inside the suit would be offset by the condensation process. >>> >>>The net result would be a steam box that would be hot on a cold day with >>>any insolation at all. >>> >>> >> >>Sorry to disabuse you, but all Thermodynamics says is that you can't get >>something for nothing. If you recall, the description of the stillsuit >>includes some form of "pump" which operates as the wearer walks. This >>provides the necessary "work" to circulate fluid. A refrigerator works well >>just by circulating fluid. I haven't done any calculations, but on the >>surface a stillsuit should be feasible. Mike >>-- > >I too, felt that stillsuits would not work, and having read _Dune_ a long >time ago I don't remember what powered them. But, if the above description >is accurate, then the stillsuits definately can't work. The "engines" for >the "pump" are obviously human muscles which will generate heat. >And because, as we all know "... 2) You can't break even ...", the wearer >will produce more heat than they can remove; resulting in "friedman" >(boiled might be more accurate). > > Marc (Sorry for including the whole thing, but its still relevant) So you are claiming that fanning yourself on a warm day produces no cooling and actually results in a rise in body temperature? I.e. you would be cooler if you did nothing? Mike -- Mike St. Johns Georgia Insitute of Technology, Atlanta Georgia, 30332 ...!{akgua,allegra,amd,hplabs,ihnp4,seismo,ut-ngp}!gatech!gitpyr!msj StJohns@MIT-Multics.ARPA (404) 982-0035
louie@umd5.UUCP (06/24/85)
In article <2053@iddic.UUCP> rick@iddic.UUCP (Rick Coates) writes: >>As I recall flycycles worked by using a replusion effect against the >>scrith, and would therefore be useless until they were very close to >>the ringworld. > >No, Nessus had no way of knowing what the characteristics of the ringworld >floor material was. I believe that specific mention was made that they used >reactionless thrusters. >The floating cities used electomagnetic repulsion and as I remember the lander >from Ringworld Engineers used this effect. > >Still looking for a reasonable explanation . . . keep those cards and >letters coming. . . > >Rick Coates > Well, actually the puppeteers *did* know quite a bit about Ringworld. They were the ones who caused the superconductor "blight" on Ringworld. Perhaps the flycycles were not used because there wasn't enough delta-V? -- Louis A. Mamakos WA3YMH University of Maryland, Computer Science Center Internet: louie@umd5.arpa UUCP: {seismo!umcp-cs, ihnp4!rlgvax}!cvl!umd5!louie
friesen@psivax.UUCP (Stanley Friesen) (06/25/85)
>> Stillsuits wouldn't work. As I read it, the idea behind a stillsuit is >> that it allows cooling by evaporation while trapping the moisture. >> >> Rick Coates >> ...!tektronix!iddic!rick >> Organization: Tektronix, Beaverton OR Actually, the thing to remember here is that stillsuits are based to a large extent on the actual desert suits of nomadic Arabs, you know, those all-over wrap-up robes they wear. Since the Arabs find these robes so useful, it seems reasonable that the stillsuits would work. So, the question becomes, what do these robes do for Arabs and how do they accomplish it? Then we can try to determine if the stillsuit would perform the same function or not, and if it would do it better. -- Sarima (Stanley Friesen) {trwrb|allegra|cbosgd|hplabs|ihnp4|aero!uscvax!akgua}!sdcrdcf!psivax!friesen or {ttdica|quad1|bellcore|scgvaxd}!psivax!friesen
js2j@mhuxt.UUCP (sonntag) (06/25/85)
> >>Stillsuits wouldn't work. As I read it, the idea behind a stillsuit is > >>that it allows cooling by evaporation while trapping the moisture. > >>Thermodynamics does not allow this. Any cooling action gained by the > >>evaporation inside the suit would be offset by the condensation process. > >> > >>The net result would be a steam box that would be hot on a cold day with > >>any insolation at all. > > > >Sorry to disabuse you, but all Thermodynamics says is that you can't get > >something for nothing. If you recall, the description of the stillsuit > >includes some form of "pump" which operates as the wearer walks. This > >provides the necessary "work" to circulate fluid. A refrigerator works well > >just by circulating fluid. I haven't done any calculations, but on the > >surface a stillsuit should be feasible. Mike > >-- > > I too, felt that stillsuits would not work, and having read _Dune_ a long > time ago I don't remember what powered them. But, if the above description > is accurate, then the stillsuits definately can't work. The "engines" for > the "pump" are obviously human muscles which will generate heat. > And because, as we all know "... 2) You can't break even ...", the wearer > will produce more heat than they can remove; resulting in "friedman" > (boiled might be more accurate). Can some thermodynamics whiz in net.physics clear this up? The stillsuit uses work provided by muscles to move heat from the interior of the suit (which would have to be a little less than 37 celcius) to the exterior of the suit, which could be around 45-65 celcius, I guess. The question is, could this work, in principal? It seems as though it depends on the efficiency of human muscles and the efficiency of the heat pump and the efficiency of the external radiator. Obviously, if human muscles were 100% efficient (ie, they change chemical to kinetic energy with no loss), then this could work, regardless of the objections of the last person quoted above. -- Jeff Sonntag ihnp4!mhuxt!js2j "Well I've been burned before, and I know the score, so you won't hear me complain. Are you willing to risk it all, or is your love in vain?"-Dylan
rick@iddic.UUCP (Rick Coates) (06/26/85)
I want to comment about some comments about the Dune discrepancy that I brought up earlier. One person said that the temperature of Dune was not necessarily high. Well, I don't have any references, but I don't think that Dune was a chilly place during the day. If it were, being a desert, the nights would be extremely cold. I would think that in describing a desert world an author would mention if it were that cold. The other explanation is that stillsuits were much more high tech than I believe they were. The suggestion is active cooling with refrigeration. I again don't have any references for this ... does anybody else? Rick Coates ...!tektronix!iddic!rick
rick@iddic.UUCP (Rick Coates) (06/26/85)
The reason that faster-than-light is acceptable is that it is explained, and has rules. This includes reactionless thrusters, for example. The explanation that Niven gives in his 'Known Space' series is that the technology was sold to us (humanity). One of the tenets of 'speculative fiction' is to assume new technology or even laws of physics, and consider how this would affect people. There was no explanation for stillsuits and I was just curious. I believe that a good sci-fi book that uses techology or science that is not part of our current knowledge should establish, and follow, some rules and limitations, not just do whatever that author feels like doing. Larry Niven discussed this in some essay in one of his collections, I don't remember the name. Rick Coates ...!tektronix!iddic!rick
nessus@mit-eddie.UUCP (Doug Alan) (06/29/85)
> From: rick@iddic.UUCP (Rick Coates) > The reason that faster-than-light is acceptable is that it is explained, and > has rules. The use of faster-than-light travel in almost all SF is pretty assinine, because almost no SF story considers the full effect that a faster-than-drive would have on the world that is described in the story. According to Special Relativity, faster-than-light travel is exactly equivalent to traveling backwards in time: there is no difference. (This is similar to the way in which Special Relativity equates mass and energy as being exactly the same thing.) Thus, if faster-than-light travel is possible, time travel is possible, and thus causality is violated. But how many SF stories that have faster-than-light travel, consider these extremely important ramifications? It is pretty silly that SF stories use faster-than-light travel, because almost any story that does use it could be easily rewritten to use parallel universes instead, without these problems. "You'll see... you'll find one in every car!" Doug Alan nessus@mit-eddie.UUCP (or ARPA)
friedman@h-sc1.UUCP (dawn friedman) (06/30/85)
> Can some thermodynamics whiz in net.physics clear this up? The stillsuit > uses work provided by muscles to move heat from the interior of the suit (which > would have to be a little less than 37 celcius) to the exterior of the suit, > which could be around 45-65 celcius, I guess. The question is, could this > work, in principal? It seems as though it depends on the efficiency of > human muscles and the efficiency of the heat pump and the efficiency of the > external radiator. Obviously, if human muscles were 100% efficient (ie, > they change chemical to kinetic energy with no loss), then this could > work, regardless of the objections of the last person quoted above. Gah. I had hopes of staying out of this one, but can no longer retain my objectivity. What I want to do is separate the entropy question from the energy question, if this is possible. Is anyone still saying that you simply can't move heat from a colder object to a hotter object? This is the entropy part of it. You CAN, but it's not spontaneous: you have to put work into it. So it isn't going to work the way that was suggested earlier, that is, by evaporation balanced by condensation. (Unbalanced evaporation will cool you nicely and leave you a raisin; but if you evaporate the water within the stillsuit AND recondense it WITHIN the stillsuit, the stillsuit-bounded system remains at the same temperature; that was the point being made earlier.) So what was the cooling mechanism proposed in place of evaporation? After all, wasn't saving water the main point of the stillsuit? I'm quite willing to believe in a human-powered refrigerator suit; but I want to hear a proposal for a cooling mechanism. The two tablespoons of water or whatever minute quantity Kynes mentioned is not going to cool anything larger than a sandrat. dsf (Dina)
hes@ecsvax.UUCP (Henry Schaffer) (06/30/85)
I thought that the Dune stillsuit was a water *reclaimation* device, not a cooling device. --henry
throopw@rtp47.UUCP (Wayne Throop) (07/01/85)
> > Can some thermodynamics whiz in net.physics clear this up? > > After all, wasn't saving water the main point of the stillsuit? > I'm quite willing to believe in a human-powered refrigerator suit; > but I want to hear a proposal for a cooling mechanism. The two > tablespoons of water or whatever minute quantity Kynes mentioned is > not going to cool anything larger than a sandrat. > > dsf (Dina) Here is a model to work with, using convection cooling to cool the stillsuit, and evaporative cooling to cool the inhabitant. Consider these layers, working from the wearer out: 1 wearer 2 layer that lets water out, but insulates heat very well, and also prevents the water from getting back in. 3 water & humid air reservoir 4 layer that prevents water from escaping, but is a thermal conductor. 5 the outside environment The "human muscle power" here is used only to pump various substances around in the water & humid air reservoir for convenience (this is more like what Dune says they are used for). Layer 1 is cooled by evaporation. The heat from the evaporate is deposited in layer 3, which is in turn cooled by convection. Layer 3 is the hotest, layer 5 the next hotest, and layer 1 the least hotest :-). The key to making it work is the "magic" properties of layer 2. It allows water to pass one-way, and is a terrific thermal insulator. It may be that in order to have the properties I state, some energy would have to be expended... I'm not sure on this point. Someone has already mentioned the present-day desert-dweller's basic uniform, which covers essentially the entire body. My understanding of how it works is that it is layers 1-thru-3 from above. That is, the interior is cooled by evaporation, the evaporate is allowed to escape through porous clothing, and the clothing insulates against the now higher exterior temperatures. Without the added properties of layer 2 and layer 4, the "stillsuit prototype" used by current desert-dwellers must allow the water to escape. So: are the "magic" properties of layer 2 theoretically possible? If they are impossible in a simple sense, can it be done "with mirrors", that is, by clever (but minimal) expenditure of energy? If layer 2 could be made to work, it seems to me that stillsuits would work just fine. -- Wayne Throop at Data General, RTP, NC <the-known-world>!mcnc!rti-sel!rtp47!throopw
joel@peora.UUCP (Joel Upchurch) (07/01/85)
> The use of faster-than-light travel in almost all SF is pretty assinine, > because almost no SF story considers the full effect that a > faster-than-drive would have on the world that is described in the > story. According to Special Relativity, faster-than-light travel is > exactly equivalent to traveling backwards in time: there is no > difference. (This is similar to the way in which Special Relativity > equates mass and energy as being exactly the same thing.) Thus, if > faster-than-light travel is possible, time travel is possible, and thus > causality is violated. But how many SF stories that have > faster-than-light travel, consider these extremely important > ramifications? > > Doug Alan > nessus@mit-eddie.UUCP (or ARPA) Actually Heinlein used exactly that premise in 'Time Enough for Love', but most 'FTL' drives in SF don't literally assume you can go faster than light. They use 'warp drives' through 'Hyperspace', which is usually defined to be an alternate universe of some sort which has a one-to-one mapping onto our universe, but is much smaller. There are many variations on this theme, of course. So there is no violation of Relativity.
franka@mmintl.UUCP (Frank Adams) (07/01/85)
In article <4577@mit-eddie.UUCP> nessus@mit-eddie.UUCP (Doug Alan) writes: > According to Special Relativity, faster-than-light travel is >exactly equivalent to traveling backwards in time: there is no >difference. Stories assuming ftl travel generally (implicitly) assume that special relativity is wrong, that there is a preferred frame of reference, which approximates our own here on Earth. Admittedly, most do this because the author does not understand special relativity, BUT it is a consistent assumption -- just not very likely.
mangoe@umcp-cs.UUCP (Charley Wingate) (07/04/85)
In article <82@rtp47.UUCP> throopw@rtp47.UUCP (Wayne Throop) writes: >Here is a model to work with, using convection cooling to cool the >stillsuit, and evaporative cooling to cool the inhabitant. Consider >these layers, working from the wearer out: > > 1 wearer > 2 layer that lets water out, but insulates heat very well, > and also prevents the water from getting back in. > 3 water & humid air reservoir > 4 layer that prevents water from escaping, but is a > thermal conductor. > 5 the outside environment > >The "human muscle power" here is used only to pump various substances >around in the water & humid air reservoir for convenience (this is more >like what Dune says they are used for). Layer 1 is cooled by >evaporation. The heat from the evaporate is deposited in layer 3, which >is in turn cooled by convection. Layer 3 is the hotest, layer 5 the >next hotest, and layer 1 the least hotest :-). > >The key to making it work is the "magic" properties of layer 2. It >allows water to pass one-way, and is a terrific thermal insulator. It >may be that in order to have the properties I state, some energy would >have to be expended... I'm not sure on this. Here's the problem: a packet of dry air picks up water from (1), and also heat (since (1) is supposedly cooler than (3)). We let it sit there until it reaches some sort of equilibrium (assuming it can only pick up a particular quantity of water). Now we take it to layer (3), where it has to get rid of the water. To do this, it has to get rid of some heat, which it must dump in layer (5). The important question is: how much heat? The answer: not as much as it started out with. Therefore the vapor pressure in (3) has to grow, or (4) has to be refrigerated. If we take the first possibility, eventually this pressure must rise high enough to prevent the flow of water from (1) to (3). In addition, there is a net flow of heat INWARD; when the water vapor cannot flow, heat is still being produced in (1), and thus there is no cooling. You can't cool a device in a hotter environment without disposing of the heat in some manner other than radiation or convection, or without some sort of refrigeration. The problem with the stillsuits is that they explicitly forbid the former, and that the energy supplied for refrigeration is insufficient. Charley Wingate
gdmr@cstvax.UUCP (George D M Ross) (07/05/85)
Sweating is a means of cooling down. If you sweat into a stillsuit then the suit has to get rid of the heat somehow, otherwise you will become rather uncomfortable.... -- George D M Ross, Dept. of Computer Science, Univ. of Edinburgh Phone: +44 31-667 1081 x2730 UUCP: <UK>!ukc!cstvax!gdmr JANET: gdmr@UK.AC.ed.cstvax
JAFFE@RUTGERS.ARPA (07/08/85)
From: peora!joel (Joel Upchurch) > The use of faster-than-light travel in almost all SF is pretty assinine, > because almost no SF story considers the full effect that a > faster-than-drive would have on the world that is described in the > story. According to Special Relativity, faster-than-light travel is > exactly equivalent to traveling backwards in time: there is no > difference. (This is similar to the way in which Special Relativity > equates mass and energy as being exactly the same thing.) Thus, if > faster-than-light travel is possible, time travel is possible, and thus > causality is violated. But how many SF stories that have > faster-than-light travel, consider these extremely important > ramifications? > > Doug Alan > nessus@mit-eddie.UUCP (or ARPA) Actually Heinlein used exactly that premise in 'Time Enough for Love', but most 'FTL' drives in SF don't literally assume you can go faster than light. They use 'warp drives' through 'Hyperspace', which is usually defined to be an alternate universe of some sort which has a one-to-one mapping onto our universe, but is much smaller. There are many variations on this theme, of course. So there is no violation of Relativity.
JAFFE@RUTGERS.ARPA (07/08/85)
From: cstvax!gdmr (George D M Ross) Sweating is a means of cooling down. If you sweat into a stillsuit then the suit has to get rid of the heat somehow, otherwise you will become rather uncomfortable.... -- George D M Ross, Dept. of Computer Science, Univ. of Edinburgh Phone: +44 31-667 1081 x2730 UUCP: <UK>!ukc!cstvax!gdmr JANET: gdmr@UK.AC.ed.cstvax
hollombe@ttidcc.UUCP (The Polymath) (07/09/85)
In article <82@rtp47.UUCP> throopw@rtp47.UUCP (Wayne Throop) writes: >So: are the "magic" properties of layer 2 theoretically possible? If >they are impossible in a simple sense, can it be done "with mirrors", >that is, by clever (but minimal) expenditure of energy? If layer 2 >could be made to work, it seems to me that stillsuits would work just >fine. This probably doesn't fulfill all the requirements, but it's a present-day start. Damart Corporation's Thermawear products are made of a cloth with some of the required properties. It's an excellent heat insulator, and body heat drives moisture through it and away from the skin. The only missing property is the one-way permeability to water. Heat will drive water through it in either direction, as I found out the hard way by standing next to a radiant heater after coming in from a rain storm. (The embarrassing result is left as an exercise ... etc. (-: ). If one adds cooling fins to the stillsuit and a stiff desert breeze it may be possible to get rid of the heat. Another possibility is a mechanism for storing the heat energy until night or a cooler environment arrives (human body energy output is about 600 btu/hour, I think). Heating up dehydrated fecal matter before dumping it would be a partial help, though probably not enough heat could be got rid of solely in that manner. --- -_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_- The Polymath (aka: Jerry Hollombe) Citicorp TTI Common Sense is what tells you that a ten 3100 Ocean Park Blvd. pound weight falls ten times as fast as a Santa Monica, CA 90405 one pound weight. (213) 450-9111, ext. 2483 {philabs,randvax,trwrb,vortex}!ttidca!ttidcc!hollombe
Purtill.SIPB@MIT-MULTICS.ARPA (07/10/85)
From: Mark Purtill <Purtill@MIT-MULTICS.ARPA> <Fnord> >thus causality is violated. But how many SF stories that have >faster-than-light travel, consider these extremely important >ramifications? Well, STAR TREK did. There were at least two episodes wherein the Warp Drives (plus extraneous things like black holes) where used for time travel. >It is pretty silly that SF stories use faster-than-light travel, >because almost any story that does use it could be easily rewritten >to use parallel universes instead, without these problems. See Larry Niven's _All_The_Myriad_Ways_ for why he (and I) hate the standard parallel universe concept (cross-time). If it really bugs you, just go thru all ftl books and replace "spaceship" with "parallel universe machine." Mark ^.-.^ Purtill at MIT-MULTICS.ARPA **Insert favorite disclaimer here** ((")) 2-032 MIT Cambrige MA 02139
Alfke.PASA@Xerox.ARPA (07/10/85)
From: Peter Alfke <Alfke.pasa@Xerox.ARPA> Doug Alan writes: >The use of faster-than-light travel in almost all SF is pretty >assinine, because almost no SF story considers the full effect that >a faster-than-drive would have on the world that is described in the >story. According to Special Relativity, faster-than-light travel is >exactly equivalent to traveling backwards in time: there is no >difference. Actually, according to Special Relativity, faster-than-light travel is just plain impossible. All the sqrt(v^2 / c^2) terms turn imaginary . . . Any story in which ftl works is tacitly assuming that something new has superceded Relativity in the same manner as Relativity superceded Newtonian mechanics. That, or the author just doesn't care about all the physical ramifications; he/she just needs ftl to tell the story. (Either approach is equally valid in my book.) --Peter Alfke alfke.pasa@xerox