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A New Dawn for Cosmology

An interview with James Gardner
by Carter Phipps

Why is the universe so life-friendly? It is a question that has haunted and fascinated physicists for years. Presenting his unique vision of cosmic coincidences, superhuman intelligence, and baby universes, science writer James Gardner spins a celestial tale, arguing that human life may be a crucial and necessary step in the evolving architecture of our amazing cosmos.

WHAT IS ENLIGHTENMENT: It seems like every day we learn something new about the universe, with incredible pictures of distant stars, strange nebulae, or colliding galaxies that dazzle astronomers. If we take a bird's-eye view on the subject of cosmology, what do you feel is being revealed about the universe we live in?

JAMES GARDNER: There are two important things going on right now in the field of cosmology. The first is a growing sophistication in observational technology. This era will be viewed in retrospect as the dawn of precision cosmology—incredible new instruments are showing us a level of detail that was inconceivable a couple of decades ago. We are learning what the universe looks like, how it evolved, and what patterns have driven its evolution. Practically every day, there is a new instrument coming on-line that essentially constitutes a better set of eyes for the human race as it looks back in time and out in space.

The second related development is ironically in almost the opposite direction. The clearer that our picture of the universe is becoming, the more mysterious it is growing. In particular, we now know with a high degree of certainty that in the “cosmic budget”—what actually makes up the cosmos—the largest entry by far, constituting over fifty percent of the stuff in the cosmos, is neither ordinary matter nor ordinary energy nor even dark matter. It's a mysterious force called “dark energy,” which is a kind of antigravity, variously termed “cosmological constant” or “quintessence.” It's the force that appears at the very largest scale to be propelling the universe outward. Dark energy is the generic name for it. No one has a clue as to what it is. It's literally antigravity, a force similar to what Einstein, before the advent of the Big Bang theory, put into his equations as the “cosmological constant” and then later bemoaned as the biggest blunder of his career. In fact, it turned out to be perhaps his greatest insight.

WIE: Would this also potentially be the force that gave birth to the Big Bang?

Gardner: Yes; it might be a scaled-down version of the force that propelled the Big Bang. So that's one huge mystery. Another has to do with the most successful theoretical attempt to unify general relativity and quantum mechanics and arrive at a “theory of everything,” which is called “M-theory,” formerly known as string theory. It postulates that all the subatomic particles are different modes of vibration of tiny one-dimensional strings of energy. In order to be mathematically consistent, M-theory requires there to be one dimension of time but ten dimensions of space, because you need that many dimensions to encode the information that is worked into the characteristics of fundamental particles.

Physicists had hopes that M-theory would yield a single solution, in line with the standard model of particle physics. But instead, a great surprise has happened. The number of solutions allowed by M-theory, which essentially corresponds to different types of universes with different kinds of subatomic particles and physical constants, is literally astronomical. It's measured not in the millions, billions, or trillions, but in googols or googolplexes. A googol is ten to the hundredth power. And a googolplex is ten to a googol power. Those numbers far exceed the number of subatomic particles in our particular universe. That's how big they are.

WIE: So the only way that the mathematics of string theory can begin to work is if you suddenly allow for this incredible infusion of all these dimensions and potential universes beyond ours?

Gardner: Yes. There are all of these potential solutions to the mathematics, and none of the solutions appear to be mathematically favored, let alone dictated. Do you remember Einstein's famous question as to whether God had any choice in designing the laws of physics? The answer, under this interpretation of string theory, is that He had an enormous range of choices, literally an astronomical degree of choice. Our most advanced and sophisticated cosmological science seems to be telling us that the physical creation of the cosmos could have turned out in any number of ways that would have yielded a universe very different from the one we inhabit.

Now, that gets to the next point: Why did our particular universe, out of odds of perhaps a googolplex to one, have the cards shuffled in just such a way—as a result of a presumably random process—that they happened to yield a life-friendly cosmos? Nothing in the fundamental principles of M-theory would indicate that there was any mathematical predisposition for things to come out so strangely well tuned. And the physical laws and constants of this universe are, in fact, extraordinarily well tuned for life. In physics, attempts to explain this mystery are classified as different variations of what is called the “anthropic principle.”

There are four primary versions of the anthropic principle. First, the weak anthropic principle says that since we inhabit this particular cosmos, it must necessarily be life-friendly, or else we would not be here to observe it. Some physicists have said that the weak anthropic principle is really little more than a tautology, and I agree. It hardly deserves to be called a principle.

The second is the strong anthropic principle. It says that the laws and constants of physics actually encode within them the emergence of life and intelligence. This is an almost quasi-religious notion that few scientists subscribe to. And there are two others that are interesting. One is called the participatory anthropic principle, which was first articulated by John Wheeler at Princeton. Using the strange properties of quantum mechanics, it asserts that the very act of observing the universe summons it into existence and gives it the structure and the properties that we observe. And then there is a fourth anthropic principle that John Barrow and Frank Tipler have articulated. It's called the final anthropic principle, and it advances the claim that once life has arisen anywhere in this or any other universe, its sophistication and pervasiveness will expand inexorably and exponentially until life's domain is conterminous with the boundaries of the cosmos itself.

So those are the four versions of the anthropic principle. Now the fact that the universe appears to be exquisitely fine-tuned in just such a way as to render it life-friendly is really not very controversial anymore. The set of coincidences is just too stunning to escape the notice of any but the most diehard dogmatic opponents of the term “anthropic”—the “A-word.” But the explanations for this phenomenon vary dramatically.

I happen to think that this utterly mysterious phenomenon poses the biggest of the big questions currently outstanding in all of science. It is certainly the deepest question in cosmology: Why is the universe life-friendly?

The two most popular attempts by cosmologists to account for the bio-friendly quality of the universe both involve enlisting the weak version of the anthropic principle. One approach is favored by people such as the famous physicist Steven Weinberg. It says that the Big Bang didn't just happen once. There are countless “big bangs” going off all the time in inaccessible regions that we simply cannot perceive. It is called “eternal chaotic inflation,” and it's really the consensus view now.

WIE: So there are “big bangs” going off everywhere, and our universe is just one of hundreds of millions or so?

Gardner: Yes, hundreds of millions of googols of them. Under this view, generating a life-friendly cosmos is simply a matter of randomly reshuffling the fundamental parameters and values of physics a sufficient number of times until a particular big bang yields that result—until, against odds of a googolplex to one, a permutation just happens to be bio-friendly. It's kind of like assuming that if you wait long enough, a Boeing 747 will assemble itself out of the dust in the asteroid belt. Yes, it could happen. Nothing in the laws of physics says it can't, but it's not what I would call a parsimonious hypothesis. To be blunt, in my view, it's just giving up. It's just throwing in the towel. It represents a failure to recognize that just as the appearance of a seemingly well-tuned natural world constituted a vital set of clues for Darwin to follow, so, too, does the appearance of a seemingly well-tuned cosmos constitute a vital set of clues that should be pursued.

The second common explanation—and this is the one favored by Stephen Hawking—basically says that the origin, and evolution, of the universe is a quantum phenomenon and that every possible quantum state of the cosmos exists simultaneously. But we're limited to those quantum states in which human beings can exist. It's really a very close cousin of the weak anthropic principle. It essentially asserts that we'll never be able to observe any branch of the quantum wave function other than the one that we inhabit. They're unobservable, and of course, we inhabit a life-friendly branch because otherwise we wouldn't be here to observe it. It's another kind of tautological non-explanation in my view.

Both of these approaches violate what's called the “mediocrity principle,” which is a statistically based rule of thumb that says that without extraordinary evidence to the contrary, our universe should be assumed to be relatively typical. The Weinberg approach, in particular, flouts that principle. His approach takes refuge in a brute, unfathomable mystery—the conjectured lucky role of the dice. It declines to probe seriously into the possibility of the existence of a naturalistic (as opposed to supernatural) cosmic evolutionary process that could yield a life-friendly set of physical laws and constants.

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