Writing about favourites is always hard. Not — at least for me — because it’s hard to be critical, but because it’s too easy. Writing about something I really like, I often feel somewhat self-conscious, and try to compensate by pointing out all the flaws before anyone does. And when we’re talking about a writer like Stephen Baxter — who started publishing just as I reached the golden age of twelve, who I keep thinking I should try to write about in some vaguely substantive way, and who remains one of my favourite writers — it has to be admitted that there are flaws to be pointed out. Baxter stories are full of passages such as this, from “Last Contact” (in The Solaris Book of New Science Fiction, ed George Mann). Caitlin is visiting her mother, Maureen; at this point, on the second page of the story, all we know about the larger situation is that Caitlin is about to deliver news about something called the “Big Rip”:

It was just a scrap of lawn really, with a quite nicely stocked border, behind a cottage that was a little more than a hundred years old, in this village on the outskirts of Oxford. “It’s the first time I’ve seen this properly.”

“Well, it’s the first bright day we’ve had. My first spring here.” They walked around the lawn. “It’s not bad. It’s been let to run to seed a bit by Mrs Murdoch. Who was another lonely old widow,” Maureen said.

“You mustn’t think like that.”

“Well, it’s true. This little house is fine for someone on their own, like me, or her. I suppose I’d pass it on to somebody else in the same boat, when I’m done.”

Caitlin was silent at that, silent at the mention of the future.

It’s that last phrase — “silent at the mention of the future” — that grates, a clumsy intrusion into Caitlin’s thoughts. And it seems both unnecessary — we don’t yet know for certain that we’re reading an end-of-the-world story, but we could have made an informed guess without that sort of nudge — and premature. Why not build up the atmosphere of unease just a bit longer?

Baxter’s writing is never going to be lauded as beautiful, exactly (although more often than not he has a good eye for description), and I think this sort of infelicity is part of the reason why — the sort of thing that, even if entirely intentional, looks like it would have been caught and removed if there’d been one more draft. Of course, there are compensations, most commonly the sort of cosmological vistas that almost nobody else is writing right now. Which is why I was so glad to read, and so dazzled by, “The Siege of Earth”. It’s been over year since I read a really mind-expanding Stephen Baxter story — Transcendent, the third of the three novels that make up what is probably Baxter’s most consistently impressive (if somewhat unfortunately named) sequence of novels to date, Destiny’s Children. “A Siege of Earth” is another pure hit of no-apologies, no-compromises science fiction.

It’s the closing story — and the only original story — in Resplendent, a (very) loosely linked collection of short stories which was published as “volume four” of Destiny’s Children. All four books are set in Baxter’s well-established Xeelee universe, a future history in which godlike and eternally-offscreen aliens deliver as thorough a kicking to the idea of a manifest destiny for humanity as you could wish for. Moreover, all four track the fate of humanity over evolutionary timescales, but in truth most of the stories in Resplendent add little to arguments already made in the novels. In particular, many of them read as pendants to the second Destiny’s Children novel, Exultant. Some of the stories explicate events referenced in the novel — as part of a Grand Tour of the solar system, for instance, Exultant’s protagonists visit the site of “Reality Dust”; you don’t need to know that, but if you do the scene in the novel acquires an additional resonance. Most of the stories are also set in roughly the same period as the novel — give or take ten thousand years, and on the scale Baxter’s working to you can give or take ten thousand years quite easily — and share a predominantly militaristic tone. “The Siege of Earth”, though, is a leap forward from the rest of the book, more elegiac in tone, and set almost four times further in the future than its nearest neighbour, “Between Worlds” (AD 27,152). Admittedly this may seem rather inadequate by the standards of something like “The Baryonic Lords”, which capped Baxter’s previous Xeelee collection, Vacuum Diagrams, and which takes place more than four times further into the future again; but it’s still deep enough into time for the solar system to be virtually unrecognisable, and well past the events of Transcendent, noted in Resplendent‘s timeline as “the high water-mark of human destiny”.

Most of Baxter’s Xeelee stories have a specific date attached to them, but the date of “The Siege of Earth” is tidier than most: 1,000,000 AD. Such an ostentatious declaration of futurity can’t be accidental, and nor, surely, are the associations raised by the oh-so-familiar image in the story’s opening line: “The canal cut a perfect line across the flat Martian landscape, arrowing straight for the crimson rim of sun at the horizon.” Not for the last time, the writing trades openly on a presumed familiarity with earlier sfnal visions to gain emotional power. (With a commendably broad scope of reference; one character even says, in so many words, that “Earth got used up”, albeit to an extent far beyond that implied in Firefly.) The three paragraphs immediately following that opening sentence establish the tone of the story more firmly:

Walking along the canal’s bank, Symat was struck by the sheer scale on which people had reshaped the landscape for a purpose — in this case to carry water from Mars’s perpetually warm side to the cold. Of course the whole world was engineered, but terraforming a world was beyond Symat’s imagination, whereas a canal was not.

His mother had always said he had the instincts of an engineer. But it wasn’t likely he would ever get to be an engineer, for this wasn’t an age when people built things. A million years after the first human footsteps had been planted in its ancient soil, Mars was growing silent once more.

Symat was fourteen years old, however, and that was exactly how old the world was to him. And he was unhappy for much more immediate reasons than man’s cosmic destiny. He stumbled on, alone.

Plainspoken these may be, but they achieve an impressive amount nonetheless, taking us with satisfying economy through several different understandings of what the story is going to be about. Depending on the reader, the “Of course” in the first of the above paragraphs is either a slight jolt (how casually such grand work is mentioned!) or an expression of trust (yeah, you know what Mars is going to be like in 1,000,000 AD). The next paragraph swiftly punctures any hopes we might have been harbouring that this is a time of human prosperity: Mars is “growing silent”. But we’re not given time to fully absorb the implications of that, either, because the next paragraph focuses the story down onto Symat, the boy-engineer, and his much more mundane unhappiness. He has, in fact, run away from home.

The first part of the story continues Symat’s exploration of Mars, gradually unpacking some of the other implications of those opening paragraphs. Through his eyes, we start to see a solar system not just engineered (Mars no longer rotates) but prematurely aged (the sun has swollen into a red giant before its time, and has already swallowed Mercury and Venus). The towns and cities through which Symat passes are magnificent but empty. He encounters some other children, and befriends one in particular, a girl called Mela. But none of them are true humans; they’re Virtuals, holographic projections of Mars’s own artificial mind (which is in turn part of a galactic-scale assembly known as the Conclave), created as surrogates by a human race so broken it seems to have forsaken the future altogether. This turns out to be more of a literal truth than we might expect; in fact, it’s another iteration of evolutionary destiny, probably the grimmest anywhere in Destiny’s Children. The forces shaping human development in Coalescent, Exultant, and Transcendent were (loosely) family, war, and religion: here it is ultimate defeat that provides a selection pressure. The humans of “The Siege of Earth” live between the might of the Xeelee on one hand, humanity having become enough of an annoyance that they merit being dealt with permanently, and the inevitability of the sun’s death on the other. “The trap of history”, we are told, “closing in Symat’s lifetime.”

“The Scourge has been continuing now for three hundred thousand years. To the Xeelee the Scourge is a conscious project. To humans it has become our environment.” Mela’s voice was neutral, her words not quite her own, Symat thought. “A steady force applied to a population for long enough becomes a selection pressure. In such an environment those able psychologically to accept the reality of inevitable defeat will prosper. And that is why you are prepared to walk trustingly into the booths, even without knowing what lies beyond. Your ancestors have learned to accept similar bolt-holes without question, far back into your history. You’ve been preadapted to accept the booths for ten thousand generations! Perhaps even that was part of the grand design of the Scourge.”

As evolutionary theory this may not be entirely convincing, even with godlike aliens to help the process along, but it’s a powerful starting point for a story. Of course the reason Symat is the protagonist of the story, it transpires, is that he’s different. He has, as his mother says, the instincts of an engineer, the engineer’s urge to investigate, find out, solve; which is a shorthand way of saying he has the instincts of someone from our own time, that he is someone we can safely identify with in this alien deep time. The very last thing Symat wants to do is walk into a “transfer booth” of uncertain origin, even if it does ostensibly lead to a pocket universe that might be a sanctuary for humanity. (And others: one of the story’s multiple grace notes establishes that booths have also been provided for the solar system’s other indigenous intelligences, such as those identified in Baxter’s 1993 story “The Sun-People”. Another sidebar notes that Saturn’s moon Titan, now warmed by the sun, is finally blooming into life, an idea Baxter spent more time on in his 1996 novel Titan.)

In pursuit of an alternative ending, Symat and Mela embark on their own Tour of the solar system. Revelations come thick and fast, producing repeated shocks of perspective in Symat, and the cumulative effect is powerful, even if some of the surprises are easily enough anticipated by readers familiar with the shape of the Xeelee timeline. There are still some immortals (described, perhaps too cutely, as “Ascendents”) trying to save humanity from the transfer booths. The plan involves saving the Earth, over the course of millennia — although given the state of it, you’d be forgiven for wondering why they’re bothering. The Earth Symat imagines, our Earth, is a “story-book vision”. In reality, “The mountains were worn down”, and “the air seemed thin, supporting only wispy traces of cloud. And though a few cities still glittered, the ground of Earth shone brick red, the red of Mars, of rust and lifelessness.” The ecology is even more radically reconfigured than this suggests, imported alien species gone wild having developed a new balance with the native flora and fauna. Even the gravity has been reduced. It is through such dramatic aftereffects, rather than direct effects, that Baxter most effectively conveys the scope and power of the forces which have worked on the solar system over time.

There is an extent to which a good-sized chunk of Baxter’s recent sf, and certainly a story like “The Siege of Earth”, can be read as grappling with the challenge of personalising cosmic-scale events. Primo Levi’s recent story notwithstanding, a date like “1,000,000 AD” is not meaningless — quite the opposite. Such a great vista of time, so effortlessly stated, is invested with an almost overpowering amount of meaning. The challenge, for a writer, is to draw that meaning out, and shape it into something resembling a readable story. “The Siege of Earth” is arguably not entirely successful, if you object to being told things by fiction: it contains great gobs of backstory to explain the mighty ruins that Symat finds around him, such as the changed Earth noted above, either exposited by other characters, or by the omniscient narrator. What makes it work, I think, is the impersonal tone with which such information — and the story as a whole — is delivered, the casual mentions of immense projects, and the contrast between that tone and Symat’s emotional, excitable reactions.

Ultimately, as you may already suspect, the story’s resolution involves a choice made by Symat that only Symat can make (in flat contradiction of an earlier assertion by Mela that “every important choice was made long ago”). The setup is a black inversion of the robots-poison-Earth dilemma in Asimov’s Robots and Empire: here, the Ascendents know how to save Earth, but like the robots they need to have their solution authorised, and to do that they have to get around a restrictive definition of “human” that prevents them enacting their solution. So, R. Giskard invented the Zeroth Law; and Luru Parz, first Ascendent, spent several millennia selectively breeding herself a throwback human to fool an ancient machine. The whole situation is so extensively and coldly rigged — not to mention fail-safed, since if things don’t go the way Luru wants, she’ll just start again from scratch; she has time, after all — that the only response left to the reader is a kind of bleak awe.

I don’t know of any contemporary writers as skilled at evoking this sort of vertigo of perspective as Baxter, from the cold immensity of Ring to the dizzying well of futurity in Time to the epic sweep of Evolution. Like the vast emptiness that suffuses “The Siege of Earth”, it’s something that can’t be trivialised, can’t be reduced to something within normal human experience by refiguring it as a metaphor; it simply is. It’s the sort of choice that results, Baxter seems to be saying, when you look the universe as it really is in the eye and don’t blink. It’s also a choice that kills Symat. The story, however, lives on: in the last few pages, it becomes apparent that Luru Parz’s vision of an “Old Earth” is one that Baxter has already started exploring. A sequence of stories beginning with “PeriAndry’s Quest” (2004) has explored a world encased in a pit of spacetime that isolates it from the universe outside, where time runs faster the higher you climb — an extraordinarly resonant setting for all sorts of stories. Symat’s choice is where “The Siege of Earth” ends, where Resplendent ends, where Destiny’s Children ends; but not where the story ends. We’re only in 1,000,000 AD, after all. There’s plenty of time left on the clock yet.