This week I thought I would go slightly retro and take a look back at some classic 1970s hard science fiction with Poul Anderson’s Tau Zero. This is the story of the stricken interstellar colony ship Leonora Christie, which suffers damage to its deceleration systems, forcing the ship to continually accelerate using its relativistic “Bussard Drive.” The crew experience delirious disparity between the years on-board the ship, and the eons of time passing beyond the whickering electromagnetic force shields of their lonely vessel.

A veteran of the genre since 1947, Poul Anderson demonstrates with this novel just why he was so lauded as a science fiction writer. The ideas and premise of the novel are a fascinating thought experiment, extrapolated through a lean and tightly-plotted 189 pages. The novel’s science could be daunting perhaps to a novice, but I do enjoy reading sci-fi which has done its homework. Anderson avoids breaking Einstein’s theory of relativity, going into exhaustive detail to ensure the novel maintains a rock solid air of plausibility.

The only real cheat is the Bussard engine’s ability to avoid near infinite mass at significant fractions of c. Physics has moved on in some areas covered by the book (particularly at the thrilling climax), but that shouldn’t matter in the slightest. Tau Zero feels in a way like a Jules Verne novel for the twentieth century. A fantastical voyage that, whilst it may prove to be errant in certain details, remains remarkably prescient and grounded in solid science of the time.

However, as with the best science fiction, this novel is not just a stolid technician’s manual on intergalactic flight, but a conversation on monumental ideas. These include the end of the universe, the responsibility of the Leonora to avoid harming developing life, on the existentialism of outliving all of human civilisation in a matter of a year. It also asks if it is right for the crew to reproduce, and potentially doom their offspring to a curtailed life in a steel prison for the rest of their life, like living corpses watching the universe flourish and blossom and perish around them.

Anderson’s prose is at its most beautiful when depicting the sublime enormity of the universe outside the ship, conjuring up surreal images of a vastly accelerated universe from the point of view of the colonists. Red shifting galaxies, the whirl of lurid colours when the Bussard ramjet drives through nebulae to refuel. The juxtaposition between the mundane and the extraordinary is a key recurring motif, exemplified in this wonderful line towards the climax:

"The baby's first cry responded to the noise of inward-falling worlds."

That’s just magic.

I won’t go into a full examination of the novel, as I wish to keep this review relatively short and spoiler-free if possible, but it is dense with meaning waiting to be unpacked in a closer reading of the text.

With such a vast scope of cosmic import, the novel does not really have the space to really develop its characters, who feel a little unnatural, more ideas and mouthpieces of philosophical musings than real, living characters. In part I think this is a structural issue. To keep the story thundering along at a brisk pace, there are numerous jumps in on-board time, months and even years. We simply don’t get enough time with them for my liking. Each time we return to the ship, the characters feel like they are compelled by authorial fiat to impart lengthy expeditionary dialogue to explain what they have been doing since we last saw them.

This feels particularly redundant when we consider this is a crew of about fifty people living in close confines. This is not helped by the main protagonists, Lindgren and Reymont (whose main character trait is his inscrutable stoicism), both putting on an air of aloof detachment as a ploy to keep order on-board the ship. Beyond some impotent wrath and low level discontent, any conflict within the ship remains muted in favour of the cosmic ballet unfolding outside, and the crew’s attempts to survive it.

Even with these reservations, Tau Zero remains an excellent piece of work. Anderson’s ideas about the effect of relativistic travel on the human psyche, only touched upon here, tap into the zeitgeist of his contemporaries, most notably in The Forever War by Joe Haldeman. That novel depicts the disorientating experience of fighting an interstellar war, and was written just four years after Tau Zero. The depiction of the relativistic flight of Alastair Reynolds’ light-huggers in Revelation Space owe a lot to Leonora Christie, in particular the strange view of the stars distorted into clusters fore and aft of the ship as major red shift makes itself known.

In the end, I like Tau Zero for its ideas and the lasting effect they’ve had on the sci-fi which followed it, and for the courage of its author to plunge headlong into a narrative as huge as a voyage to the end of the universe, and actually do it justice. This is a very hard science fiction, so is not everyone’s cup of tea, but personally I would highly recommend this mature and ferociously clever book.