Conference noted::sf

1038.0. "Stephen Baxter" by TECRUS::REDFORD () Wed Jan 01 1992 21:09

"Raft"
Stephen Baxter
(c) 1991, first US publication Jan 1992, ROC (paperback)

A good first novel with an interesting physics premise but somewhat
flat characters.  The protagonist, Rees, grows up on the Belt, a chain
of habitats in orbit around the iron core of a dead star.  The people
of the Belt make their livings by mining the surface of the star for
iron.  Other stars are continually falling around the Belt on their
way into the Core.  People remember a time when the sky above the Belt
was blue, but lately it's all turned a disturbing red.

As you can guess, this universe is very different from ours.  A bad
hyperspace jump has taken humans into a universe where the
gravitational constant, G, is a billion times greater than in ours. 
That means that a ball of gas only a hundred yards across can ignite
into fusion.  The entire galaxy is only a few thousand miles across,
and interstellar gas is dense enough to breathe.   People feel
literally attracted to each other, that is, to each other's mass.  

But now the galaxy seems to be dying.  Fewer and fewer stars are
forming on its fringes as the supply of hydrogen runs out.  Rees grows
up ignorant, but he knows what the important questions are, and knows
that the only place to learn the answers is on the Raft, a giant 
platform in interstellar space that is the center of human
civilization.  He stows away on a cargo ship (made of a native,
helicopter-like tree) and goes to the Raft to learn the nature of his
world.  He gets to see every part of it, from the naval hierarchy of
the Raft with its simmering proletariat, to the ghastly Bone worlds,
the ethereal whale creatures, and even the Core itself, where black
holes take the place of subatomic particles to form a strange,
gravitic matter.

There are a lot of echos of Niven's "The Integral Trees" here, but the
premise seems more interesting.  No one knows why G has the value it
does, or rather, why gravity is so weak in relation to the other
forces.  Some theorize that it has had all values in all possible
universes, but our particular value happened to permit the evolution
of creatures who can measure it.  A fascinating account of this can be
found in "The Accidental Universe" by P.C.W Davies, a physics
professor at the University of Newcastle-upon-Tyne.  He lists 13
constants in all that account for the features of our world:

- the gravitational constant, 
- the charge of the proton, 
- the mass of the proton, 
- the mass of the electron, 
- Planck's constant, 
- the speed of light, 
- the weak force constant,
- the strong force constant,
- the Hubble constant (which governs the expansion of the universe),
- the cosmological constant (which is an odd variant of general
relativity and may be exactly zero), 
- the cosmic ratio of photons to protons, 
- the permitivity of free space, 
- Boltzmann's constant

If the ratios between certain of them were at all different, then
structures such as stars and atoms could not exist.

I'm sure Baxter had this in mind when he decided to vary G.  The nice
thing about G is that it doesn't affect the basic chemistry
needed for us to live.  It's also nice in that it so accelerates
astronomical processes that a person can watch the birth and death of
a star within his or her own lifetime, and a culture can see the
birth and death of a galaxy.

So the physics here is intriguing, and its extrapolation is well
done.  The only complaint I have about the science is that the native
ecology didn't seem diverse enough.  There were only a couple of
kinds of plants and animals, and the environment seems hospitable
enough for many more.  

The dramatic aspects of the story are weaker, but tolerable.  The
characters are rather one-dimensional: the wide-eyed student Rees, the
sullen and vindictive Gover, the gruff but honest tree-driver Pallis,
and the absent-minded professor Hollerbach.  I could also have done
without some of the violent confrontations.   Exploring this world has
plenty to hold a reader's interest; no blood needs to be added for
spice.

/jlr