SF book series. Main character is a lunar miner who finds an alien intelligence. First book stopping asteroid sent to destroy Earth

Question

In the first book the main character is recruited (?) in a mission to save Earth by an alien AI with immense powers. He absconds with two robots, initially with no personalities, but radically enhanced by the AI. He steals a ship which is modified by the AI for extreme speed in order to intercept an asteroid targeting Earth, sent by an enemy which destroys entire civilizations. In a later book they come to a galactic mega city in space, and also descend into a sentient star to remove "dark matter" placed to destroy it. I started the series but lost the books.

I read the books at least 6 years ago. I lost the books during a move. I can't remember the cover art. I was into the third (or 4th?) book of the series. I'm not sure if that was the last one at the time. The last book ended with the main characters at the mega space station (a habitat with thousands of species). At that point he is surprised to find out his girlfriend from Earth may be there (since as far as he knows he is the only contact with the civilization). There is the main plot point of a an immensely powerful and secretive enemy seemingly bent on wiping out civilizations.

Answer 1

This is Neptune Crossing, the first book of The Chaos Chronicles by Jeffrey Carver (continuing in Strange Attractors, The Infinite Sea, Sunborn, and a seeming "side series," the "Out of Time Sequence" consisting (to date) of The Reefs of Time and Crucible of Time, likely with more to come).

I've read only the first of these. The protagonist encounters an alien intelligence, not an AI, which comes in two parts: one that communicates with him, and the other that gets things done (for instance, adjusting fusion engines to provide many times the thrust on a fraction of the fuel). A memorable point in the book was "Einy Steiny Pool", a game crossing billiards with orbital mechanics, which provides the inspiration for the quarx (the alien communicator) to be able to save Earth (not from an asteroid, but from a comet not yet known to human astronomers, on course to center-punch Earth and create another Chicxulub event) -- yes, by the protagonist stealing a ship and flying it directly into the comet's nucleus -- at which point, the other alien part is able to use the energy of that collision and the resulting destruction of the comet to "translate" the ship (or perhaps just the protagonist, I don't recall) to a destination in the heart of galactic civilization.