TIMELIKE INFINITY by Stephen Baxter

This is the next in the Xeelee Sequence, a sprawling series of hard science fiction space opera novels, novellas, and short stories  which spans billions of years of fictional history, centering on humanity’s future expansion into the universe, its cosmos-spanning war with an enigmatic and supremely powerful Type IV alien civilization called the Xeelee, and the Xeelee’s own war with dark matter entities called Photino Birds. The series features many other species and civilizations that play a prominent role, including the Squeem (a species of group mind aquatics), the Qax (beings whose biology is based on the complex interactions of convection cells), and the Silver Ghosts (symbiotic organisms encased in reflective shells). Several stories in the Sequence also deal with humans and posthumans living in extreme conditions, such as at the heart of a neutron star (Flux), in a separate universe with considerably stronger gravity (Raft), and within eusocial hive societies(Coalescent) .  The Xeelee Sequence is notable for its treatment of ideas stemming from the fringe of theoretical physics and futurology, such as exotic-matter physics, naked singularities, closed timelike curves, multiple universes, hyperadvanced computing and artificial intelligence, faster-than-light travel, and the upper echelons of the Kardashev scale.

Whew. This is a series with a lot of hard science matters, terms and ideas involved and tossed around like confetti. The first is Raft,  which you can read about here.  Raft is not so riddled with quantum physics stuff, so is not too hard to understand.  But Timelike Infinity really tests your knowledge base of (and possibly even your tolerance for) all those quantum science ideas and terminology.  Although Raft was the first written and published,(1992)  and Timelike Infinity the second (1992),  Baxter recommends if you are now just starting the journey, that you read Timelike Infinity third, and Raft sixth in the series as it finally was constructed.   But he also says that he feels each book or story or novella should be a stand alone, and able to be read in any order, just as time is not linear.  Neat idea.

OK, to the story line.  This is not a sequence to Raft.  Raft is set in AD 104,858.  Timelike Infinity is set  in 5407 AD, so it actually predates the events in Raft.

The human race has been conquered by the Qax, a truly alien turbulent-liquid form of life.  OK; what does that mean?  It means that the turbulence of a liquid IS the lifeform.  They travel in what is essentially a giant aquarium in which the liquid is constantly in motion, and communicate through some kind of voice simulator.  They now rule over the few star systems of human space – adopting processes from human history to effectively oppress the resentful race. Humans have encountered a few other races, including the astoundingly advanced Xeelee, and been conquered once before – by the Squeem – but successfully recovered.

In this book, we are introduced to the ambassador for the humans to the Qax, and they watch as a wormhole begins to form, and then they see the firing of particles which preceeds a ship from …. the past?  The future?   Meanwhile, a group of young people have built a ship with a hyperspace drive secretly under the earth in what we today would call England.  Right under Stonehenge, as a matter of fact.  They manage to take off right under the nose of the Qax, assuming the Qax have a nose,  into the wormhole and travel back 1,500 years in time.  They call themselves the Friends.

The Friends believe that quantum wave-functions do not collapse like the Copenhagen interpretation holds, nor that each collapse actually buds off separate universes (like the quantum multiverse hypothesis holds) but rather that the universe is a participatory universe: the entire universe exists as a single massive quantum superposition, and that at the end of time (in the open universe of the Xeelee Sequence, time and space are unbounded, or more precisely, bounded only at the Cauchy boundaries of “Time-like infinity” and “Space-like infinity”), when intelligent life has collected all information (compare the Final anthropic principle and the Omega Point), and transformed into an “Ultimate Observer”, who will make the “Final observation”, the observation which collapses all the possible entangled wave-functions generated since the beginning of the universe.

This is a deep and complex book, involving a LOT of physics, philosophy and a complicated universe of various time periods.  There is a lot about black holes and singularities, a great deal of which tests my layman’s knowledge.  But I did enjoy this:

If you had a black hole in your kitchen you could just throw in the waste and see it compressed to invisibility in a fraction of a second, releasing floods of usable short-wavelength radiation.    Of course you’d have to find some way of keeping the singularity from eating the Moon.

Then there is the matter of exotic matter.  (See what I did there?)

Exotic matter is mass/energy that is compressed to singularity densities, almost, so that the superforce emerges to bind it together — and then allowed to cool and expand so that the superforced breaks open in a controllable manner, to give us the negative-energy characteristics we want.

How far could we take this?  I’d anticipate the manufacture of singularities themselves, on the scale of a few tons up to maybe, asteroid masses.

See what I mean?  It has a number of plot threads for different people/groups of people and different time periods.  It is a lot of fun to read, and it really exercises your brain trying to keep it all organized in your head.   I looked up timelike infinity, and it basically is a kind of measurement for singularities, because you know, your tapemeasure is just not going to cut it.