After the jump, my review and excerpts.
This is a difficult book to pigeonhole. It deals with a seemingly simple concept ("nothing") and asks what we mean by it. We use the word all the time, but hardly ever give it any thought. Barrow goes back in history to tell us what the great thinkers meant by it in all its aspects, from ancient Greek philosophers to early Christians to modern scientists.
Barrow covers it from all angles, starting thousands of years ago with the invention of the number zero in mathematics. This part of the book is easy to follow and may mislead readers about the depths they are getting themselves into.
Barrow quickly turns his attention to the real meat of his book -- the concept of the vacuum. Thinking about vacuums or empty space has vacillated over the centuries. Once thought heretical to divine perfection, later accepted as self-evident in a Newtonian world, still later thought inconsistent with phenomena like light waves, the vacuum is now beginning to be recognized as a realm of unimaginable busy activity at the quantum level.
Much of the book (the last half or more) is pretty complicated, as relativity, quantum theory, modern cosmology, etc., unavoidably must be. Barrow delves into all the latest theories about quantum vacuums, the Big Bang, dark energy, multiverses, and grand theories of everything. This part of the book will almost certainly lose all but professional physicists. But readers who persevere will never think of "empty" space between the stars as "empty" ever again.
It's the review of the history of science as it deals with our emerging understanding of vacuums, outer space, and the size and history of the universe that is the most valuable part of the book. Science is shown to be a process of problem solving (observation, hypotheses, experiments, and theories) through the work of scientists like Newton (gravity), Einstein (gravity reimagined), Torricelli (barometer), and Michelson (speed of light). The process continues to this day. Anyone who thinks the "Big Bang" is the last word on the origin of the universe (or thinks the Bible is, God forbid) needs to read this book.
"The Indian system of counting is probably the most successful intellectual innovation ever devised by human beings."
"Aristotle had denied the possibility that the world (or anything else) could be created from Nothing. The original Aristotelian scenario of an eternal, uncreated Universe had the drawback of clashing with Christian doctrine and so the more appealing alternative was a version in which the world had been created from a pre-existing void containing nothing."
"Newton clung to the Stoic picture of a finite world surrounded by an infinite void space. He could imagine an empty space but not the absence of space itself."
"Torricelli’s simple experiment led eventually to the acceptance of the radical idea that the Earth was cocooned in an atmosphere that thinned out as one ascended from the Earth’s surface and was eventually reduced to an empty expanse that we have come to call simply ‘space’ or, if we keep going a bit further, ‘outer space’."
"In the middle of the nineteenth century, it was the accepted view of almost all scientists that space was filled with a ubiquitous ethereal fluid. There was no vacuum."
"Einstein’s theory is remarkable in that it describes an infinite collection of possible universes of all shapes and sizes according to the distribution and nature of the matter you care to put into them. One of the simplest solutions of Einstein’s equations, which does contain matter, and expands at the same rate in every direction and at every place, gives an extremely accurate description of the behaviour of our observed Universe."
"What these beautiful experiments show is that there really is a base level of electromagnetic oscillation in space after everything removable has been removed."
"The quantum vacuum can be viewed as a sea composed of all the elementary particles and their antiparticles continually appearing and disappearing."
"We have already seen one spectacular example that appears to evade the need for a beginning. The self-reproducing eternal inflationary universe almost certainly has no beginning. It can be continued indefinitely into the past."
"Overall, the Universe is likely to be in a steady state, but populated by many little inflating bubbles, each spawning a never-ending sequence of ‘baby universes’."