Greg Egan

Yatima, an Orphan Mind of the Konishi Polisi is an excellent example of a Synthetic Intelligence as a main character. Ve's alien but you don't really notice cause the writing is so good.

The remaining fields — where no changes to the seed had yet been tested, and no predictions could be made — were classified as indeterminate. Here, the one tried code, the known landmark, was shown as grey against white: a mountain peak protruding through a band of clouds which concealed everything to the east or west of it. No more detail could be resolved from afar; whatever lay beneath the clouds could only be discovered firsthand.

Whenever the conceptory created an orphan, it set all the benignly mutable trait fields to valid codes chosen at random, since there were no parents to mimic or please. Then it selected a thousand indeterminate fields, and treated them in much the same fashion: throwing a thousand quantum dice to choose a random path through terra incognita. Every orphan was an explorer, sent to map uncharted territory.

And every orphan was the uncharted territory itself

http://gregegan.customer.netspace.net.au/DIASPORA/01/Orphanogenesis.html

Greg Egan renewed my faith in Science Fiction. I just finished reading Diaspora, and I am now a fan. It's an incredibly well thought out extrapolation of the future of the human race, much less phantasmagorical and much more grounded in science than pretty much every other SF I know of, while still going off into mind-bending tangents.

I think the most common critique of his work might be about the occasional digressions on physics. It's undeniable that they make the book a bit dense, but in fact, he appears to have restrained himself to keep it readable and entertaining, instead publishing the actual hairy details on his website:

http://gregegan.customer.netspace.net.au/DIASPORA/DIASPORA.html#CONTENTS

PS: I'd like to thank HN for making me discover this author. Now I'm keeping with the tradition!

Just posting a follow-up comment to say that the interactive simulation is really the highlight of this set of pages. I was expecting a trivial demo widget, along the lines of the animated GIFs in the article, but it's actually a full 3D rigid-body simulation.

Playing around with blocks and ramps in a browser does a great job of taking the mathematical analysis given in the article, and making it at least somewhat intuitively understandable. But on the other hand, it doesn't exactly make a convincing case that a world built according to these rules could ever be stable!

http://gregegan.customer.netspace.net.au/DICHRONAUTS/02/Interactive.html

I'd ditto the question ;)

Semi-recent thread with some interesting-looking suggestions, not sure of 'hard' scifi label though: http://www.reddit.com/r/printSF/comments/1eyt3b/is_there_any_sf_book_that_gets_orbital_mechanics/

I'd recommend other books by Greg Egan, though. Permutation City (http://en.wikipedia.org/wiki/Permutation_City) is particularly interesting and makes some very interesting conjectures dealing with computation, cognition, 'quantum ontology', etc. Character development is somewhat poor, but eh! (there's also a FAQ on the author's website: http://gregegan.customer.netspace.net.au/PERMUTATION/FAQ/FAQ.html)

For those who think that nanotechnology is too mundane, what about machines made from nucleons?

https://en.wikipedia.org/wiki/Femtotechnology

Greg Egan speculates on femtotechnology in some of his sci-fi, mostly as insanely fast computers. (I mean, jeez, it takes SO MUCH TIME for an electron to whirl around the nucleus of an atom... it's so much faster when your computer is the nucleus.)

An excerpt from a Egan short story: http://gregegan.customer.netspace.net.au/SCHILD/00/SchildExcerpt.html

More on femtocomputing: http://hplusmagazine.com/2011/11/01/femtocomputing/

This is like asking whether god exists. Until there is some evidence one way or the other, it is pointless to consider the question seriously. Though it's worth noting that the total ignorance implied by the lack of evidence about the purpose of the universe implies that any specific speculation on the question is almost certainly incorrect.

Fun to think about, though. Have you read Greg Egan's Permutation City or Diaspora?

http://gregegan.customer.netspace.net.au/PERMUTATION/Permutation.html

http://gregegan.customer.netspace.net.au/DIASPORA/DIASPORA.html