Did you mean to suggest that the speed is related to how strong electromagnets (E: not magnets) are?
I suspect you'd enjoy reading The Clockwork Rocket, where speed of light in vacuum is frequency-dependent.
I didn't read much of Baxter (I recall Voyage/Titan/Moonseed). Is there a point in time when his writing changed, or is it that it was always like that to some extent?
(In case I caused confusion, the two books I mentioned are by Greg Egan and not Baxter. The society described in Clockwork Rocket does contain various malicious parties, but it IMO shows an optimistic view of how society can change.)
@robryk Much of his writing is on the "humans only survive a nasty universe by being quite fascist" theme, and is also very "here's humans trying to escape that bullshit". The Xeelee novels in particular (strong WW2 themes, one is basically a rewrite of Dambusters).
Not for a moment saying he's a fascist, doesn't read like that to me, but definitely the writing of somebody who recognises the long term fascist options for humanity. And it's depressing.
@robryk Titan, even alongside all of Clarke and Asimov, is one of my favourites. Just the realism of it, spaceflight as plumbing.
@robryk I love that kind of hard SF, play with the fundamental variables, see what happens 😎
Sadly, Stephen Baxter has turned out to be all to right with "and you get rogue billionaires with rockets, fascist human cultures and child soldiers in the process"