Sixty-six million years ago another day dawned over a Cretaceous earth. Life was carrying on as normal, but everything was about to change because heading towards the planet at an astounding speed was a ten-mile wide object. The impact of this object left a crater, traces of which can still be detected and managed to obliterate the dinosaurs and 75% of all the other species on the planet. The few that survived evolved into the huge variety that we have today and provided an opportunity for the mammal to thrive. It is now thought that this was not one of those, one in several million chance events, rather an effect of our solar system interacting with the wider universe and the gravitational influence of dark matter.
Randell has some interesting theories about dark matter, the pervasiveness of it in the universe and how the gravitational influence of dark matter causes disturbances in our galaxy and solar system. It is a substance that we know is there, but at present, we have no idea where it is, what it is or how to detect it. Quite elusive stuff, especially given how much of it there is out there. Randell writes with clarity on a difficult subject, although it is occasionally incomprehensible; but that is as much because I am fairly rusty at physics, rather than her explanations. She is well qualified to talk about this being Professor of theoretical particle physics and cosmology at Harvard, but this is one book that might be beyond the general science reader, even though they should probably give it a go.