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Past Through Tomorrow by Robert A. Heinlein
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2,256174,362 (4.03)25
Possible future worlds are explored in this collection of short pieces.
Recently added bydrjmallen, kschweiss, UncleSamZ, private library, scottshjefte1, alaman13, Alexander_Holik



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(Original Review, 1980-10-13)

People have complained about roads as conveyor belts as represented in Heinlein's THE ROADS MUST ROLL as being an inefficient means of transportation because of a number of reasons, some of those being energy efficiency and the problems of handicapped people using them. Instead of building them as a single conveyor belt, how about building them as a variable speed conveyor belt (by this I mean a conveyor belt that at different locations on it can have different speeds). This can be done by building them as a number of small conveyor belts, each of them having its own speed and controls. This immediately eliminates the problem of expending lots of energy dragging the whole road behind you. I don't know if the energy needed to drag lots of little roads is less than that of dragging one big road. Anyone with more knowledge care to speculate? These smaller belts could be sensor controlled, operating only when there is a chance that someone is close enough to use them. This could be done by stopping any belts with people too far away to use them, and when people get somewhat close start speeding the belts up to a waiting speed, and if people are very close speed the belt up to its normal running speed. This should save a lot of energy at nighttime or for places such as the middle of Kansas with very small people to area ratios.

An analogous construct to on-ramps on freeways could be developed by creating on-belts which would gradually speed the rider up to the speed of the lane that he was entering. If this was done gradually enough, the rider should not even notice it and handicapped people in wheelchairs should have no problems using it. This would preclude needing the agility to ride the walkways that was demonstrated in Asimov's THE CAVES OF STEEL. Off-ramps could be done the same way but on- and off-ramps could only be unidirectional (come to think of it, they already are on freeways.) This setup of multiple belts might preclude on-line steakhouses. Seats could be done as portable affairs, picked up upon entrance to the roadway and dropped off on leaving it. Balance however might be a problem with non-fixed chairs. An interesting thought just occurred to me. What if you rode a bicycle on one of these roads? Think of the speed-up that would give you.

Another advantage of a multiple belt roadway is that it is a simple matter to curve the path of belts to get a curved road without needing a special material. One safeguard necessary for one of these roads is for the situation (a la tRMR) of one belt somewhere in the middle stopping. Belts leading to that belt should have a gradual slowdown so that passengers don't go flying because of accumulated momentum. Belts leading away from that belt should gradually speed up so that the passengers are brought back up to standard cruising speed. This feature would also have the effect of stopping any problems such as those that arose in tRMR.

The question then becomes "HOW MUCH energy is lost to friction, compared to the energy costs of acceleration?" (I have heard that fairly effective regenerative braking systems (i.e., brakes which slow the vehicle by acting as generators, converting kinetic energy into electromotive energy) are available, but I have no figures for their net efficiency.)

With regard to wheelchairs, it seems to me that motorized models can already go fast enough to make a smooth transition --- and un-motorized ones (admittedly rolled by people in good condition) have in the past few years been beating the best times on foot for the Boston Marathon. A bigger problem would be people on crutches (my guess is that a large fraction of these are temporary rather than permanent, but that would mostly affect the social (as opposed to technical) factors of the problem); a short, parallel, accelerating belt would help these onto the slowest conveyor but after that there'd be problems.

Guess what: the SAME conveyor can be moving at different speeds at the same time. All that is required are elastic links. Consider that the requirement for equilibrium is simply that the speed in LINKS-PER-SECOND be the same for every point on the conveyor. Thus, if we want to go twice as fast over one section of conveyor, we simply double the length of the links! Of course this implies that objects such as chairs, freight pallets, steak joints, etc., can only be fastened down at one end. I've seen this phenomenon employed somewhere or other; it may have been in a baggage-handling system.

Note that the closest current technology to "rolling roads" is railroads, and that they are more efficient than cars and trucks. If you could get theoretical mechanical optimality, the rolling road would be more efficient than any vehicle that has to start and stop. A good way to get on and off is to have the road mesh with the edge of a, say, 1000 foot radius circular platform turning at 1 rpm. You come down onto the middle of the platform and move out to the edge, where you have a minute to step over the invisible line (the road goes around the loop, and disengages near where it engaged).

a) My personal favorite for short-range personal transportation would be a jet-belt or antigrav equivalent. I commute 8 miles and one would be ideal for this. Build another one into my suitcase and I'll be all set to hop over to the nearest RR (rolling road).

b) I am given to understand that the most dangerous activity commonly engaged in is bicycle riding (on streets where there are cars). Now danger of death or maiming may add spice to your commuting, but my last two bikes were stolen, so I don't do it anymore.

Given that the main objection to "rolling Roads" is all the excess road that has to be transported, how about roads that are stationary of themselves, but move the object to be transported? I can think of several ways -- a road of numerous computer-controlled electromagnets and a steel cart to sit in, for instance -- the cart could be moved from one side of the road to the other, adjusted for other carts, and sent down off-ramps, with the only power expended going entirely toward transportation of the cart. That would involve a hell of a lot of wiring, though.

Or how about a liquid approach? A standing wave, like, a flexible surface under the cart, rows of plastic tubes beneath and them connected to hydraulic pumps -- the cart would "surf" a continuous "wave" generated beneath it, and could either be steered by the front wheels or guided by wave variation. Again, you wouldn't have to move a lot of excess road, but I’m not sure whether it's all that efficient. Just playing with ideas...

First, both of the stories Weinreb mentions ("The Roads Must Roll" and THE CAVES OF STEEL) show extensive provisions for seating on the strips. Asimov specifically mentions that being seated on the strips is the prerogative of higher (job) classifications, while there is a chain of steakhouses on the rolling roads. Unfortunately, neither of them considers the problems of getting a material tough enough for the job and flexible enough that it can be brought around in a loop rather than simply brought under for the return trip the way an ordinary conveyor belt is. (It could be argued that such a reversal is not necessary in Asimov's design; the seats could collapse like the steps of an escalator --- but that would make a mess of one of Heinlein's steakhouses, to say nothing of requiring twice as much material (from internal evidence Heinlein's road runs in a dog bone layout).

Also, tRMR is not the story of a mechanical failure, although mechanical failures are mentioned in the story; he specifically states that when shutdown of all of the driving rollers in one of the twelve sectors caused excess tension on the belt, safety interlocks caused the belt to come to a smooth stop (although he does note the absence of an obvious safety device to force the speed of any belt to approximate that of its immediate neighbors). tRMR is the story of a management failure, which is a horse of a different color (which has been proved to be impossible by means of the pejorative calculus (- )).

[2018 EDIT: Still no conveyor belts in 2018; just the crappy escalators; I remember thinking at the time conveyor belts would be just a matter of time. Now I’m not so sure…I won’t see it in my lifetime. Maybe my children will.]

[2018 EDIT: This review was written at the time as I was running my own personal BBS server. Much of the language of this and other reviews written in 1980 reflect a very particular kind of language: what I call now in retrospect a “BBS language”.] ( )
  antao | Nov 9, 2018 |
This is an anthology of Heinlein short stories. Most were written between 1939 and 1949 and they are rather dated by modern standards. The earlier stories are rather simple in plot and the emphasis on "how it works" is salient. Several are still interesting, however, and some hints of future developments are discernable. My favorite is "The Menace From Earth," which story focuses on an intellectually precocious teenage girl living in Luna City and her thoughts and feelings about her “best friend” who is spending far too much time as a guide for an attractive older woman visiting from Earth. I love Heinlein’s idea that the combination of low gravity and a strong up-draft will permit humans to do aerial acrobatics (i.e., glide and fly) on the moon. ( )
  Tatoosh | Sep 2, 2018 |
(see copy 1) Read on original publication.
  librisissimo | Jul 27, 2018 |
Read this on publication, as part of my subscription to SF Book Club for a few years. Have read the individual stories other times, and most recently the ones that are also contained in "The Green Hills of Earth" collection.

I wanted to check and see if I still liked them - most of them I did. Some more than others, but opinions of individual stories haven't changed much, if any; quality is variable; 3.5 is an average.

FWIW, I prefer the "old" Heinlein to his flights of fancy in the later years after he started living in the Lazarus Long subdivision.

BTW, "Requiem" was written before "The Man Who Sold the Moon" - I have always thought both were on the top of Heinlein's works, and that opinion holds. I believe that "Requiem" may be my all-time favorite story, for the gritty pathos, and perhaps an autobiographical element from a man who knew he would never go to the moon himself.

"If THis Goes On --" it was a surprise to me that it was written in 1941, as I have been wont to associate the preachiness and inconsistent character traits with his later writings; maybe they just didn't come into play (or into focus) in his shorter works. My opinion of Vast Conspiracies, in any genre by any author, is that it's awfully hard to hide the massive infrastructure and personnel they require without totalitarian government control.
Smaller HQs maybe (see "hidden training camps" on the internet, your choice of White Supremacist or Muslim Jihadist).
However, as is also typical of Heinlein, the story is full of useful data if you DO want to run a Vast Conspiracy, with advice and predictions that could be directed at either the USSR (bogeyman at the time) or USA Continental Congress (positive connotations here).

p. 445 - "tyled" - meaning what? Secured?
p. 469 - the Heinlein Creed: Win first, argue later. ( )
  librisissimo | Jul 26, 2018 |

Heinlein's mammoth future history: 21 stories published as a collection in 1967, though in fact all but two originally came out between 1939 and 1949, outlining the future development of humanity through the coming centuries.

Heinlein misses a lot of things - notably the rise of information technology; his 23rd century spaceships are still running with slide rules. Some of these are a bit too sentimental, some based on concepts that don't really resonate today, and the last, "Methuselah's Children", is pretty weak - 100,000 people surviving on a spaceship built for a much smaller number??? But the idea of framing a future history based on technological advance rather than, say, the mysticism of Olaf Stapedon remains engaging. In particular, the theocratic America of If This Goes On- is rather closer to the bone now than it was in the 1940s. The whole collection is one of those taproot texts of the genre that remains well worth reading. ( )
  nwhyte | Nov 18, 2017 |
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Author nameRoleType of authorWork?Status
Heinlein, Robert A.primary authorall editionsconfirmed
Hundertmarck, RosemarieTranslatorsecondary authorsome editionsconfirmed
Knight, DamonIntroductionsecondary authorsome editionsconfirmed
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The Chairman rapped loudly for order.
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(Click to show. Warning: May contain spoilers.)
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Book description
Collects these stories:
"The Roads Must Roll"
"Blowups Happen"
"The Man Who Sold the Moon"
"Delilah and the Space-Rigger"
"Space Jockey"
"The Long Watch"
"Gentlemen, Be Seated"
"The Black Pits of Luna"
"'It's Great to Be Back!'"
"'-- We Also Walk Dogs"
"Ordeal in Space"
"The Green Hills of Earth"
"Logic of Empire"
"The Menace of Earth"
"'If This Goes On --'"
"Methuselah's Children"
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