Friday, 8 April 2016


"'Any [kzinti Swift Hunters] that remain in service will certainly be phased out as hyperdrive comes in, because it makes them as obsolete as windjammers.'" (Man-Kzin Wars III, p. 220)

The change from slower-than-light to faster-than-light in space must be like the change from sail to steam at sea. Future histories feature this change from STL to FTL. Poul Anderson's Technic History began with FTL interstellar exploration but Anderson later added an earlier story of interplanetary exploration by light sail ships. In his earlier Psychotechnic History, the STL period involves interplanetary travel and an interstellar generation ship. Heinlein's Future history had introduced the generation ship idea and showed the start of FTL travel.

In Larry Niven's Known Space future history, the transition from STL to FTL is an important part of the history. In Poul Anderson's Known Space/Man-Kzin Wars story, "Inconstant Star," an interstellar expedition departed from Alpha Centauri thirty years ago and never returned. It would have taken ten years to cross five light years and the crew, kzinti with one man, Peter Nordbo, would have been in stasis. Now an FTL ship with Peter's daughter, Tyra, in the crew will investigate. For Tyra, those thirty years are "...the dark backward and abysm of time..." (see here) but the FTL ship will cross five light years in almost no time.

"'...what are we trying on this voyage but to probe the past and learn what happened long ago?'" (p. 222)


David Birr said...

"The change from slower-than-light to faster-than-light in space must be like the change from sail to steam at sea."
Actually, I have to quibble with this as an analogy. Steamships, especially the early ones, aren't always faster than well-handled sail; the big advantage of steam is STEADY movement, without having to wait for favorable winds. As for its disadvantages, consider this extensive quote from an essay by William R. Forstchen:

"One of the single largest disadvantages of the transition from wind to steam was that the distance ships could cruise had been drastically curtailed. The ability to hoist sail and arrive three months later in the Pacific without ever sighting land was now gone. No modern warship could sustain itself much beyond two or three weeks at moderate cruising speeds, and two or three days of high-speed maneuvers would not just empty the coal bunkers but so rattle the reciprocating engines that a ship had to have overseas bases for repairs and recoaling."

Sean M. Brooks said...

Hi, David!

I'm very ignorant of these matters, but why then did steam powered ships displace most wind driven ships by the late 19th century? I do know you said the chief advantage of steam power was "STEADY movement, without having to wait for favorable winds." But your quote from Forstchen's article would seem to contradict this.


Paul Shackley said...

Thank you. Very instructive.

David Birr said...

Wind-driven ships could be stuck in harbor for weeks or even MONTHS at a time waiting for the winds to be right for sailing. Or, worse, the winds could become unfavorable or die away entirely while at sea: "becalmed."

A steamship didn't need to wait -- as long as it didn't get caught in too strong a storm or hit a reef, something like that, it could just chug across the ocean. But the steamship HAD to go to a place where it could refuel -- OR carry a lot more fuel and less cargo than its owners wished. And, of course, the ability to maneuver without taking account of the wind was a critical advantage for warships in battle.

I SHOULD have added to my first comment, but didn't think the comparison through soon enough, that the difference between STL and FTL seems to me more like that between early ships which had to travel in short, single-day voyages and "hug the coast," so to speak, beaching each night to sleep ashore; and later vessels, fully ocean-capable, which could, as said in Forstchen's article, spend three months without sight of shore in the ordinary course of things. (A significant part of that difference was improved navigational techniques letting a captain set a fairly straight course across large stretches of open water.)

Sean M. Brooks said...

Hi, David!

Many thanks for your explanation on how and why steam powered ships so quickly displaced wind driven ships (despite some serious disadvantages in the former). I really should have worked it out for myself, things like steam ships not needing to depend so much on winds or avoiding getting becalmed.

I like the analogy you made comparing FTL travel to ships being able to go on truly long voyages out of sight of land to earlier ships needing to "hug" the coast.

Thanks! Sean