A few years ago, I picked up a book called Starquake by Robert L Forward, a physicist. I started reading it, and was amazed at how well the man knows his physics. However I should start with its prequel, Dragons Egg. Dragons Egg is about a neutron star that spirals into our solar system. Since it is such a rare event, humans create a spacecraft and have some gravity compensation masses that keep them alive against tidal forces. The interesting part of the whole story is not about the humans, but about what is on the star. The star has many chemical reactions in a short time, eventually, this creates life that lives extremely fast. The life forms, called Cheela, live so fast that one human sleeps through the equivalent of the rise and fall of the Roman Empire. I don't want to spoil the story line for anyone, but I have to say, if your a "hard" Sci-Fi fan, or even if you aren't and want to read something a little bit "out there", I definitely recommend it.