Somewhere out there, many light-years from earth, two vast and exorbitantly randy black holes are grinding and osculating in an unrestrained and unashamedly public similitude of passion. We know this because the energy created by this unsavoury event sends gravitational shockwaves through space, with the result that, a few billion or so years later, the last quivers of those exhausted tsunamis make two tiny mirrors on the surface of our planet tremble. We hear about it on the news and it makes us wonder; it might even make us shift uneasily on our seats. But at the same time it's oddly calming to be reminded that even the most outrageously distant cosmic cataclysms have their neat, human-sized, parochial outcomes, demonstrating once again that distance and nearness are just two sides of...