Epic space sci-fi! Human beings in the future lives hundreds of thousands of years, discover a spaceship as old as the universe and the size of Jupiter. Live in it for ages. Discover a planet at its core that they'd completely failed to notice for ages. They have plot twists and a big fight or two. There is a Dark Secret associated with the core. The fact that people who live so long appear somewhat less risk averse than someone with an expectation of three score and ten is irritating, and the Epic Scale begins to annoy after a while. Altogether, a fairly long and tedious book, although the occasional twist did keep me reading.