It is safe to say that I grew up reading Paul Davies; my first real introduction to physical sciences such as astronomy and physic was the television series 'Cosmos'; that inspired me to purchase the companion text, which further inspired me to join the Astronomy Book Club two dozen years ago. One of the first books offered, and the first book I received from them, was Paul Davies' 'Other Worlds' -- from then on, I was hooked. I have nearly a dozen books by Paul Davies, all on topics of theoretical physics, astrophysics and cosmology -- he is consistently readable, entertaining and educating with the same style that compels the reader to want more (which he then provides).
It was not surprising to me to see his name on the Science Masters Series. The series has basic introductions to many of the key issues in science today -- evolution, origins of life, cognitive science, time, computer science, and more. Each volume is relatively short -- 'The Last Three Minutes' has a mere 150 pages of text that is not too dense, sparing technically and mathematically without losing much conceptually.
The issue of the end of the universe is one of the 'hot spots' of astrophysics and cosmology, and so there are elements of this book that are already a bit out of date, despite being less than a decade old. However, given the speculative nature of many 'discoveries' in this field, it is impossible to say if anything is truly out of date or false at the present time.
Davies explores the end of the universe by setting the stage -- drawing from current thinking about the origins of the universe, in fact one of the options for conjecture, in a closed universe system, would be that the last three minutes would resemble quite closely the first three minutes. Davies looks at the various processes -- stellar evolution and decay, gravitational issues, overall radiation depletion, energy-fuel consumption -- and draws these together for the various theories about the end of the universe.
Davies shows the ideas of the closed/collapsing universe (a view not widely held today) and of the infinitely expanding universe (the current reigning theory), giving ideas about the variables required to tip the scales in one direction or the other. Even with an infinitely expanding universe, however, all is not necessarily well with the world -- the universe runs the risk (in the future so distant there is no realistic way of expressing it in terms of time we know) of becoming a dark, deep freeze with no activity left, and all matter becoming inert and inactive in every respect.
Davies speculates on what this means for the survival of humanity and human history -- how can information be preserved? How can our species go on in the face of this? Such speculation is pure conjecture; the time distances are so far removed that nothing we devise will likely come close to resembling an actual answer to this. However, it is interesting as a mental exercise, and leads the reader hopefully to further reading.
