Practically stars are mostly burned out in another 50 billion years and radioisotopes that produce a heat gradient will also be mostly decayed by then. Eventually good tidal energy situations like https://en.wikipedia.org/wiki/Tidal_heating_of_Io will end as well since this kind of situation changes the orbits. So energy for life and usable thermal gradients will disappear even if entropy will continue to increase fo…
I've had plans for a sci-fi book I plan to never write that takes place in the ultra far future. The chapters' numbers would be the time dilation scale in a base 10 logarithm. The book would be made up of a series of short stories told from the point of view of a "time coast guard" rescuing idiots who refuse to time dilate from their creaking space hulks. A later (set?) of chapters might just be in the 90+ scale; at…
Sounds like Stephen Baxter's cup of tea. Hell, the detective could even be Reid Malenfant himself (maybe a cameo for Sheena 5 in a later book in the series?)
Then again, if there was an ultradeep-time Saturn's Children book, I'll place the preorder so fast it'll be blueshifted.