The great game, when writing hard-sf blockbusters, is to extract the maximum possible mileage or lightyearage from actual, defensible, speculative science. Thus the fearfully knowledgeable Stephen Baxter makes a point of listing his sources for Time in a brief appendix, and after thus legitimizing virtually all this story's bizarre technological bogglements, demurely adds: "The rest is fiction."
Time begins in deceptively familiar near-future Dream Of Space territory, as a dreaming entrepreneur who's a bit of a naughty boy – and is thus subtly named Malenfant – schemes to exploit the wealth of the asteroids. He plans to make his Big Dumb Boosters succeed where the clogging bureaucracy of NASA failed, by eliminating such frills as excessive quality testing, safety precautions, and astronauts. Instead, a small but genetically enhanced intelligent squid will pilot the BDB that should instal a self-building autofactory on the chosen asteroid. On several occasions, engaging squid-viewpoint scenes steal the show from mere humans. Never act alongside children or animals.
The first indication that the asteroid mission will go somewhere entirely different is also the point where the science feels dodgiest – even though it has been seriously advanced, as noted in that appendix. Malenfant is nobbled by the visionary Taine, who trots out that hotly disputed probabilistic argument that the human race very likely won't exist all that much longer because – and I don't believe I oversimplify – as the projected species lifetime extends, the less probable it is that any given individual like you or I could exist so startlingly early in the sequence. Yet, astonishingly, we do! So because we're here now, and irrespective of the fact that any future containing humanity requires someone to be here now, extinction is coming sooner rather than later. I was relieved to learn (by personal enquiry) that Baxter himself doesn't take the argument seriously, still less the wisely unexplained quantification of our remaining span by Taine's think-tank Eschatology Inc.: 200 years. All's fair in love and science fiction.
Further developments now go swimmingly. Thanks to these warnings of doom, Malenfant's organization tunes up to listen for a Feynman Radio transmission from the future, which puts the finger on a particular odd asteroid – Earth's "second Moon", Cruithne. Sure enough, after complications of politics, the illegality of the launch, and a certain amount of scandal because the star squid pilot got pregnant before her mission, the far side of Cruithne proves to house that favourite Baxter artifact: a glowing wormhole lined with exotic matter.
Passing over incidental difficulties (expanding intelligent squid colony on Cruithne, attempted NASA clampdown on Malenfant's even more illicit launch of self and colleagues to investigate, punitive police expedition sent in pursuit, etc), this is where Baxter tries in earnest to outdo the deep-future vision of The Time Machine. His own The Time Ships had a slightly different agenda. Here, in successive wormhole jumps into ever more distant futures, we see the ultimate possibilities of human mastery of the universe, expanding on Freeman Dyson's most daring scenarios. A heavy charge of that old sense of wonder builds up as the cosmological slide-show displays the harnessing of stars and then of whole galaxies, of cunning black-hole manipulation when all else is dark, of subtle computational and information-theoretic possibilities of life beyond mere mass and energy, all the way to that final entropic flatline. So much for doomsday being only 200 years away from the 2010 opening scenes!
But.
Baxter's surprising position in Time is that this best of all possible options, this total human control of what can be achieved under the known laws of physics ... is not good enough. The future itself is dissatisfied with the future, and as in The Time Ships its people have plans to reshape time along new, improved lines.
The mechanisms of change are irresistibly reminiscent of Childhood's End, with future influences having led to the emergence of super-gifted children who are feared and persecuted to an extent which one would like to believe couldn't happen, but which is all too arguable from historical example. There's even a ready-made hate word: they are "Blues", tuned to and obsessed with the glowing blue circle of that time gate on Cruithne. One group of these kids develops some astounding super-science and takes delivery of a blob of quark matter from the future. (Later we see this gift being despatched from upstream in time, just as Taine eventually sends the Feynman Radio transmission which he and Malenfant puzzled over; Baxter is very tidy about some though not all of his causal loops.)
With this wildcard tool in their hands, and despite the best efforts of the paranoid US military – not excluding the nuclear option – the young Blue geniuses are ready to fast-forward to Eschatology Inc.'s approximate doomsday date and fulfil the prophecy. They duly brew up a "beneficent" cataclysm on a scale that dwarfs mere squibs like supernovae or colliding black holes. Childhood's End meets A Clash of Cymbals. It's all suitably staggering, with thoughtful and moving touches interspersed. One of the best of these is a final glimpse of those spacegoing squid, who during humanity's last 200 years have colonized the entire asteroid belt, mined Jupiter for fusion fuel, and are now accelerating away from the solar system at relativistic speed, followed by a wavefront they can never quite outrun.
And there amid the final wreckage of the universe stands Stephen Baxter, his noble brow illumined by the glare of snuffed-out galaxies, grinning manically at having run his storyline into this enormous full stop in the first volume of what is to be the "Manifold" trilogy. Whatever next?
Time uses far-out physics as a playground and makes a game of assembling its patchwork of technologies from speculative scraps which don't always fit together without considerable stretching – e.g. Feynman Radio, at least if it's to carry actual information, doesn't sit well with the relativistic paradigm invoked elsewhere. The sheer fun and technogeeky exuberance of this apparatus is nicely counterpointed by greater and more plausible attention to character than Baxter was known for in earlier work. People feel, bleed, worry and generally matter. But the squid still steal the show.