Keeping in Touch

Some practical problems for a federation of planets. Published by Pan Books 1981. Cover photography by Michael Freeman.

It is theoretically possible that travel between the stars at close to light speed may happen one day.  And because of the time dilation effect which is a consequence of Einstein’s theory of relativity, the journey time for those travelling may not be a serious problem.  Journeys may be over fairly quickly.

Some science fiction stories have focused on how dramatic this might be.  The classic is probably Poul Anderson’s 1970 novel Tau Zero, where travellers move so fast that they reach the end of the universe, and beyond, within a relatively short timespan.  Ursula K Le Guin’s 1990 short tale The Shobies’ Story gives quite a different perspective on very short journey times between stars.

So travel to Alpha Centauri, four light years distant, might be achieved in a matter of days.  Castor (in our constellation of Gemini), around fifty light years away, in perhaps a few weeks.  Not long to wait before reaching a colony on another world orbiting a distant star.  But, of course, that’s not the case for anyone left back on Earth, or waiting for you at your destination.  They’ll still be waiting fifty years or so for you to reach Castor.  Time dilation only applies to those on board the spacecraft.

Add to that the problem that I talked about in an earlier Odyssey post, The Lonely Universe: Do You Hear What I Hear? – there is a severe restriction that the speed of light imposes on any attempt to communicate across interstellar distances.  Unless something like Le Guin’s fictitious “ansible”, which permits instantaneous messages across the light years, was somehow technologically feasible, then colonies will always be limited to talking to one another no faster than the speed of light.  It won’t be much quicker than word-of-mouth in a galaxy of near light-speed space travel.

And all this imposes some serious constraints.  In our imaginary colony in the Castor star system, the colonial society will have advanced fifty years by the time the new arrivals turn up – considerable by the standards of a progressive civilization these days, and probably even more so in future.  Imagine some guys from fifty years ago, or thereabouts, suddenly arriving on our doorstep today.  Those of us who were active both then and now like to think we still contribute to society, but only because we’ve lived through those intervening years and have (hopefully) gained experience in the process.  Someone with just the knowledge and experience of fifty years ago could be seriously out-of-date.

If we imagine ourselves to be those Castorian colonists, we would no doubt welcome these people from our past (because we’re friendly types) and listen with interest to their historical anecdotes.  But, unless they have specific talents which are in short supply in our more advanced society, or can provide manual labour if required, their value to us will be, quite frankly, limited.  Perhaps they may supply a wider basis for the gene pool if numbers are restricted – in other words, as breeding stock.

All of which suggests that there are no great prospects for a truly interstellar civilization – perhaps just a few local stars trading and communicating at journey times of no more than a few years.  In Extraterrestrial Civilizations, his 1979 analysis of the potential for other intelligent species to exist in our Galaxy, Isaac Asimov imagines space settlements becoming increasingly isolated from their home world and developing their own cultures, each with its own independent existence.

He suggests that astronauts returning home, or one might suppose reaching distant colonies, several generations after their departure would experience a profound “future shock”.  The same would apply in cases of suspended animation during long space flights.  Both they and the people they are visiting will be strangers to one another and, more than likely, of limited interest or value to each other.  The idea of a far-flung federation of planets, or even a galactic empire, seems unlikely.

Richard Hayes, Assistant Editor (Odyssey

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