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Book review: ‘A Traveler’s Guide to the Stars’ by Les Johnson

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The real-life challenges faced by the still largely hypothetical dream of interstellar travel.

The idea of a guide book to the Universe is not new. At different times it has been tried by the likes of Stanislaw Lem (‘The Star Diaries’) and Douglas Adams (‘The Hitchhiker’s Guide to the Galaxy’). It is the American writer and physicist Les Johnson, however, who with ‘A Traveler’s Guide to the Stars’ (Princeton University Press, £22, ISBN 9780691212371) adds solid scientific and engineering foundations to that so far nebulous, utterly fictitious, and, in the case of The Hitchhiker’s Guide, humorous, concept, which, incidentally, Johnson does not reject. On the contrary, he uses a quote from Douglas Adams as an epigraph to one of his opening chapters: “Space is big. You won’t believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it’s a long way down the road to the chemist’s, but that’s peanuts to space.”

I’ve reproduced that beautifully tongue-in-cheek quote in full because, to me, it neatly sums up the main message of Johnson’s deeply scientific, yet very readable and accessible ‘Traveler’s Guide’ – the need to break the persistent stereotypes about interstellar travel by outlining the serious technological and engineering challenges that we have to overcome before successfully colonising some super-remote extrasolar planets. Not that Johnson lacks the imagination of Adams and other writers of fiction, but his fantasies rest on science, literally the proper ‘rocket science’ – not a euphemism for some incomprehensible esoteric nonsense.

His description of a typical starship of the future can serve as a good example of an exciting, and yet scientifically valid, mixture of fantasy and reality: “Any ship that will carry people to the stars... will have... such attributes as Earth: similar gravity; breathable air; drinkable water, places to live, work, eat, socialize, and play; and all the systems necessary to keep the crew alive for the duration of the journey. As you might imagine, taken together, these requirements lead toward an exceptionally large vehicle.”

And, yes, thanks to Johnson’s highly engaging literary manner, magnified by his scientific competence and credibility, we can easily imagine it all.

As for the real-life challenges faced by the still largely hypothetical interstellar travel, they, as I have grasped from this trailblazing book, boil down to first distance, second propulsion, and third motivation. The latter means finding “a valid reason for exploring space, including space beyond our meagre solar system... to learn more about the universe, what’s out there, and how it works.”

“If you want to touch the infinite, go outside on a cloudless night and look at the stars,” writes Johnson in the chapter ‘The Universe Awaits’. “To touch the infinite” – there cannot be a more far-reaching motivation.

That was Johnson the writer speaking. Johnson the physicist, however, notes that, with the nearest exoplanet, Proxima Centauri, being about 4.2 light years away from us, it would take us years to complete the journey, but it will be much shorter, if we travel with the speed of light, which makes this whole calculation pretty meaningless. It will sound slightly less meaningless, if we consider using nuclear power for propulsion. But even that currently Utopian scenario would only work within the solar system, for “there is simply not enough energy released in [nuclear] fission... to allow for practical interstellar travel.” Johnson believes – quite reasonably – that any space trip that takes thousands of years or more is impractical.

What’s the solution then? Well, there’s none at the moment (otherwise, we’d already be roaming all over the Universe), but the future bodes well for intergalactic travel, and it is here that fantasy and dreams come into the picture. “Going to the stars will not happen unless people have a vision to make it happen, and science fiction may be as important to making it a reality as the development of all the systems and technologies described in this book,” concludes Johnson.

Myself an incorrigible dreamer, I do believe that the time will come when a ‘Baedeker Handbook for the Intergalactic Traveller’ becomes reality rather than just a clever joke. Les Johnson’s superb ‘Traveller’s Guide to the Stars’ has made this belief of mine considerably stronger.

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