I read a sci-fi novel whilst on a teaching assignment in Guernsey in 2014.
I regret only skimming the book because I was so busy and would like to read it fully now that I am retired. Here's what I remember.
It starts in the present, pretty much. The Moon and Mars have been terra-formed and settled. Some humans choose to have genetically enhanced brains which makes them super intelligent and they eventually master inter-dimensional travel and plan to set up home in some other dimension having become disillusioned with our world. For some reason this threatens our existence (can't remember why). There are no aliens as such, just branches of humanity that have been adapted to living on other planets, thus some have become virtual aliens.
I recall a lot of reference to the Einstein-Rosen bridge. The heroine of the story lives many lifetimes, taking up to 30 year time-outs to marry and live normal lives with normal humans with normal life spans. (I think she is a mathematician) the medics also conquer, more or less, old age. Near the beginning of the story she sets up some kind of school for potential enhancement candidates.
If anybody can give me this title I will be so grateful as I want to read this properly and enjoy every line.
The cover was predominently red and it was a thick book -- I would guess 500 pages or more. My best guess is that it was written post 2000. It may have the word "millennium" or "500" in the title but that could just be my brain playing tricks.
The author, whoever he/she may be, was IMHO a gifted story teller and not a newcomer to the genre.