I am only just taking on board the limitations on communication by hyperdrive oscillations. These oscillations are instantaneously detectable at about a light year but, for most of that distance, they can be modulated only into an on-off code. Voice transmission is possible only within a few thousand kilometres and pictures require even closer proximity. Ship to ship, Grand Duchess Sandra and a Baburite representative communicate by sound alone.
This seems plausible. Technology has its limits and these sound like the sorts of limits that faster than light communication might have if it were possible in the first place. Less plausible, I think, is the instantaneous interstellar communication in Poul Anderson's later For Love And Glory.
Ursula Le Guin's future history has an instantaneous communicator called the ansible but the master of faster than light (FTL) communication is James Blish:
the ultraphone, FTL but not instantaneous;
the CircumContinuum (CirCon) radio in A Case Of Conscience, instantaneous;
the Dirac transmitter in Cities In Flight, instantaneous;
the Dirac transmitter in "Beep"/The Quincunx Of Time, receiving messages not only from the present but also from the past and future.
9 comments:
It also serves plot purposes. Instantaneous communication would make the Technic history very different.
Kaor, Paul!
I think Anderson's speculations, even assuming something like a FTL hyperdrive, about the limitations likely to be seen in interstellar communications, are plausible. Albeit, we do see Edwin Cairncross, a later Duke of Hermes, wondering in A STONE IN HEAVEN, if it might be possible to communicate FTL using hyperdrive relays spaced at intervals of a bit less than a light year.
In Technic known space interstellar communication was done via couriers and mail carried by hyperdrive ships which needed days, weeks, or months to reach their destinations. Sort of like what the situation was like in the 19th century or earlier, before transoceanic cables for telegraphy became practical.
Ad astra! Sean
In Pournelle's Codominium series, he has messages going my starship jumping through series of Alderson points.
He missed a likely use of the technology. L.M. Bujold in her SF had radio or lasers beaming messages between space stations at each wormhole on busy routes so that every time a starship passed through a wormhole it would take accumulated messages through, resulting in messages travelling at lightspeed through solar systems then jumping to the next solar system. This results in messages travelling faster than any individual starship.
Jim: that would work, but it only speeds things up a bit. In the Technic universe, the speed of spaceships is limited.
Kaor, to Both!
And I like the Alderson drive of Pournelle's Co-Dominium timeline. It's almost as seemingly plausible as the Technic hyperdrive.
Ad astra! Sean
Assuming the Technic Civilization version of FTL, messages carried on starships is the fastest way, with the possible exception of an *expensive* series of hyperdrive pulse relays.
Given something like the Alderson Drive or Wormhole Jumps, the fastest way to send messages would be to have radio or laser beams between stations at Alderson points & message shuttles that jump through the Alderson connection every so often. Whether the interstellar community considers it worth the expense would depend on the capital cost of such shuttles and the expense of each jump, as well as how much message traffic there is along any given route.
Kaor, Jim!
What you suggested might be worth the cost in cases of top priority, urgent emergency messages.
Ad astra! Sean
If you have put it in for the high priority messages, you might as well use it to send as many lower priority messages as the system can handle as well.
Kaor, Jim!
I can agree with that, if the persons sending these low priority messages are wiling to pay the costs for doing that, instead of using cheaper but slower means of sending mail.
Ad astra! Sean
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