So I've just finished reading this mammoth tome... 870 odd pages... and having invested so much reading energy into it I thought it was deserving of a thread all of its own. Where to begin... 2/3rd of the book are excellent... 5/5 superb. From the opening lines where the sheer ambition of the novel is laid out ''The Moon blew up with our warning or apparent reason'' to the detail and [presumed] accuracy of the unfolding events. The descriptions of the desperate race to expand the International Space Station as the two year life span of life on Earth ticks away... the different mad cap schemes to extend humanities time beyond the extinction level event unleashed. However, IMO the book stumbled at the final 3rd. Not catastrophically so, but it was struggling... skipping 5000 years ahead was always going to be risky and having to invest in new characters was a struggle because at the same time the writer was introducing all new technology and social structures. As a result the book got bogged down in detailed explanations of new tech or skimmed over the history of the previous 5000 years. Personally I think it could have been a series... a duology to open the series and then have the impact into the future explored. How the disaster altered the human race and changed forever the idea of a shared future. I also found it unrealistic that in 5000 years the orbital humans never seem to have considered altering [terraforming] other planets in the solar system. If they can slam comets into the sterile Earth and then seed the oceans with atmosphere producing bacteria, then certainly they could repeat the exercise on Mars or Venus. So 4/5 for me... excellent main body of the novel but the ending feels rushed and lacks narrative coherence for me.