Stephen Hawking reckons a complete theory of the cosmos may yet be attainable.

IT’S a staggering idea, perhaps akin to the ultimate free lunch. The prospect of receiving not merely something but indeed everything for nothing sounds too good to be true.

Although it stands to reason that most objects — from teacups to such celestial exotica as stars, nebulae or black holes — cannot simply appear out of naught, it seems that an entire universe can. That’s right: absolutely everything may arise from absolutely nothing, including no blueprint for laws determining how such a formidable feat comes to pass.

This is not late-night pub talk or New Age fantasy but serious physics from no less a scientific authority than Stephen Hawking.

“Spontaneous creation is the reason there is something rather than nothing, why the universe exists, why we exist,” write Hawking and co-author Leonard Mlodinow, a US-based physicist and science writer. So bold are they that the duo conclude: “It is not necessary to invoke God to light the blue touch paper and set the universe going.”

Although Hawking once intimated that the search to understand the cosmos might never end, he appears to have had second thoughts. Something called M-theory, he now contends, is the only candidate for what the famous Cambridge University physicist describes as “a complete theory” of the universe, which he apparently believes may lie within reach.

(By “theory”, incidentally, physicists invariably refer to not a capricious notion but a rigorously testable mathematical model.)

“If it is finite — and this has yet to be proved — it will be a model of a universe that creates itself. We must be part of this universe, because there is no other consistent model.” Ever confident, Hawking omits the words “as yet”.

So what is this breathtakingly audacious, “creator-not-required” M-theory? And how might it explain the everything-from-nothing origins of our mind-numbingly vast universe, including hundreds of billions of galaxies, most brimming with hundreds of billions of stars, and probably planets galore.

To fully grasp the answers to both questions requires a careful reading of this intriguing book, which, though only 181 pages long, requires full attention.

In a nutshell, M-theory — it’s not clear what the “M” stands for but possibly Mystery or even Mlodinow, perhaps — is a fundamental model of physics invoking no less than 11 dimensions. It’s an extension of string theory in which particles, usually conceived of as tiny blobs of frozen energy, or even points, are held to be one-dimensional wiggling strings with length but neither height nor width, as such.

“Infinitely thin pieces of string,” is how the authors string readers along. Only a few of the multiple dimensions are experienced, we are told, because others are curled in imperceptibly on themselves.

By explaining how time formed a dimension of space for a fleeting fraction of a second after the big bang, the authors skilfully dispense with the irksome question of what happened before the universe’s birth, which apparently arose from a quantum fluctuation. This is not unnatural: such fluctuations occur all the time in the supposed vacuum of space and so constitute an integral part of Mother Nature.

The book offers a tantalising smorgasbord of scientific fact and conjecture, touching on topics as arcane but riveting as supersymmetry (don’t ask), wave-particle duality and imaginary time. It also advances a compelling argument for model-dependent realism — the highly controversial idea that there is no one version of reality.

In this context, it’s explained how the basic laws of nature need not have been set in place by a deity but could have evolved from a much larger multiverse — a multitude of universes, perhaps of infinite number, each with its own parameters and dimensions. In this sense, there was not one unique big bang but many, each yielding separate, possibly bizarre, universes with no access to one another.

The macrocosm in which we reside happens to be one where, by felicitous accident rather than design, the laws were just right — like Goldilocks’s porridge — for life as splendid as we know it.

As experimental techniques improve, M-theory may one day become testable, though exactly how requires a super-stretch of the imagination. After all, we have no door to other worlds to discover what laws they might possess.

Even if our universe were merely the remarkable out-working of a humble quantum fluctuation, the nagging question remains: whence came the laws that gave rise to the cosmic blip in the first place? The long-sought theory of everything, it seems to me, is as elusive as ever.

Peter Spinks’s Wizards of Oz is published by Allen & Unwin. He writes a weekly online column about science for Education Age.

http://www.smh.com.au/entertainment/books/the-grand-design-20110106-19h86.html

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Excellent response by William Lane Craig: http://www.reasonablefaith.org/site/News2?page=NewsArticle&id=8415