Our cosmic habitat

It's some two years between Our Cosmic Habitat and Sir Martin Rees' explanation why the universe is the way it is, thanks to Just Six Numbers. Six physical constants express our universe--a universe big enough and long-lived enough to engender consciousness. If the numbers were other than they are, we wouldn't be around to know about it. Our Cosmic Habitat is a smoother read, as Rees works his explanations inwards, from the physical world towards the numbers at its heart. But Rees offers more than a revamped description. The clue to the book's real value lies in the title. Our universe is a habitat. If you want to understand how a habitat works, you have to sweep away the trivia and the accidents, the merely local conditions, and uncover the underlying rules. And it isn't easy. Could it be that those six numbers could be very slightly different, and still give rise to a conscious universe? If, as Rees speculates, there may be many universes, spawning other universes, all the time, then maybe those six numbers of his merely reflect the rough conditions necessary for the existence of a world such as ours. If he is right, this has massive implications for the kinds of answers physics can at present offer. Sweating over the precise relations between these difficult numbers in the hope of uncovering a "unified theory" will turn out to be as futile as trying to predict the precise arrangement of a snowflake, a column of tap water, the whirl of a thumbprint. But this, it seems, is the perennial peril of science. One moment you're attaining an objective vision of underlying processes. The next, you're asking the equivalent of why, of all the bars in all the world, she had to walk into yours... --Simon Ings