The Meaning of Life According to Physics


The Universe in a Nutshell

    by Stephen Hawking

Hyperspace

    by Michio Kaku

A fascinating look at our universe, including time travel, black holes, and multiple dimensions.

            reviewed by Theresa Welsh

If you're interested in the Big Questions of life, you cannot ignore physics. It is the branch of science that investigates the "stuff" of the universe and tells us what our physical world is made of, both in a micro sense (quantum mechanics) and macro sense (cosmology). I've just finished reading two books that provide fascinating speculation about this still-mysterious subject.

Newton, Einstein, and Hawking
Physics has come a long way since Newton told us about gravity and Einstein told us about relativity. But it has a long way to go to truly explain the universe. Stephen Hawking, in The Universe in a Nutshell, does a great job of telling us what he knows about it. As holder of the same chair at Cambridge University once occupied by Issac Newton, Hawking is probably the greatest living authority on cosmology. Although he deals with a subject that is conceptually difficult, the wonderful illustrations and his lucid manner of writing make this book accessible to all who have ever looked up in the sky and wondered about our universe. Hawking has a delightful sense of humor, reminding us, for example, that when Newton had his university "chair," it was not electrically operated (Hawking is confined to a wheel chair). He includes pictures of himself as he appeared in a Star Trek: Next Generation episode playing poker with Newton and Einstein . I remember that episode as one of my favorite; Hawking looked like he was having such a good time. Hawking clearly loves his subject and wants all of us, even us math dummies, to share some of his knowledge and insights. The book represents a huge and successful effort at making a difficult subject interesting and understandable.

Wormholes to Other Worlds
While Hawking tells us the black holes in our universe may connect to other universes, he is not optimistic that they can be used for time travel or entry to other worlds. By contrast, Michio Kaku takes us on more fantastic speculative journeys through time and space in his book, Hyperspace, written before Hawking's book. Kaku's book, like Hawking's, is highly readable. He gives us a good background on the many theories that came after Einstein, including Einstein's own effort to unify the micro world of quantum mechanics with his own sweeping pronouncements about relativity. His famous equation (E=MC2) was a beautiful explanation he identified as "marble" but the ugliness of quantum theory he called "wood." Quantum physics just kept turning up more strange particles and resulted in the clumsy theory called the Standard Model which has satisfied almost no one, certainly not Einstein. He died without unifying the two.

Other physicists have taken up the cause, and some possible theories have emerged. Kaku tells us Einstein's effort at uniting micro and macro finds its most plausible fulfillment in a theory of hyperspace. In short, if we postulate that the universe has ten dimensions, we can bring together wood and marble. He recounts previous interest in extra dimensions, going back over a century to a popular book called The Flatlanders. By creating a world that exists in two dimensions and characters who could not imagine a three-dimensional world, the author of this fictional work provided some insight into our own inability to visualize more dimensions. Back in the latter part of the Nineteenth Century, scientists had introduced the concept of the "Fourth Dimension" and it had fired the popular imagination.  Many decided it was where ghosts and even God lived. Victorian England was fascinated with the occult and the idea of a mysterious Fourth Dimension appealed to many. Then Einstein came along and told us the Fourth Dimension is time.

Stalking Extra Domensions
It's now accepted that space and time go together to form space-time, so the former Fourth Dimension had to become the Fifth Dimension. But could there be even more dimensions than four? Kaluza-Klein theory postulated that light was vibrations from the Fifth Dimension. It also showed that if the universe has N dimensions, the clumsy collection of quantum particles take on a symmetry that would have pleased Enistein in his search for "marble." The only problem was that no one could figure out the value of N. In the 1980s, other physicists extended Kaluza-Klein to form the superstring theory, which does give a value for N: exactly ten dimensions.

How could these other dimensions exist without our knowing it? One answer is that they are curled up and are very small. It is difficult to get your mind around such a concept, and Kaku gives some analogies that help, but extra dimensions must be proven with mathematics. Science usually requires more than mathematical proofs; generally it demands experiments that prove a theory, and it seems an impossibility to do any experiments that would show us the extra dimensions. Is this where science and faith intersect? Will people come to believe in a ten-dimensional universe based on the symmetry of the mathematics? (I'm lost here. I don't understand math well enough to form any judgement. Can't the math look good but still be wrong?)

Cross Over the Bridge
While Hawking thinks black holes connect multiple universes, Kaku speculates that they connect multiple dimensions. Kaku also shows how time travel might be possible, but it would require such an expenditure of energy that we have no chance of doing it until our knowledge and technology advance enormously beyond the present. It would require us to pass through a black hole over the Einstein-Rosen bridge (the connection between our universe and another universe or dimension). And where would we be? What wonders would await us on the other side? Hawking is so sure time travel can't happen that he has a standing bet with physicist Kip Thorne. We'll have to wait for our knowledge to expand before we can truly know if it is possible to move backward in time. The prospect for moving forward in time appears dim. (Remember what Yoda says in Star Wars: "Always in motion is the future.")

While our inability to harness the needed energy to cross the bridge might be a discouraging thought, Kaku points out that knowledge grows exponentially. The more we know, the more we can know. Assuming there is not a built-in booby trap that dooms civilizations to periodic collapse, we would eventually acquire the knowledge to use the power of our sun, then the power of our galaxie and maybe even the power of the universe. But if such a thing is possible, where are the other civilizations that have done this? Through our SETI searches, we have found no energy signatures of such a civilization. Could it be that all societies destroy themselves before they attain such knowledge, or have all the civilizations of such advanced knowledge already died out or moved to new universes? There are billions of years and billions of galaxies that could contain such a civilization; could be that's just too much space-time for a successful search.

Learning From Captain Kirk
Both Hawking and Kaku are big science fiction fans. Kaku says science has done a poor job of explaining itself to the average person and that most of us have learned more from science fiction than we have from scientists. Both authors refer to Star Treck technology and discuss the possible accuracy of some of what's in popular books and movies. The "warp drive" that powered the Enterprise is an apt description of how we might actually travel to other star systems. By warping space-time, we bring distant locations closer, in the same way as crunching up a sheet of paper brings points on the paper together. Kaku even deals with the touchy subject of science and religion and does not rule out an intelligent first cause. He says the God of Order makes sense to him, but he says most people cling to the God of Miracles, whose feats are outside of science. He says the evidence for the Big Bang is very strong, but we don't know what caused the Big Bang. We should be able to figure out, eventually, whether the universe will end in the Big Crunch, or whether all matter will just drift apart in an endless expansion.

I recommend both of these books to Seekers. If you're on a journey to find truth, you must consider what these scientists have to say. Both have written books anyone can read, and both consider not just what science has revealed, but what it might mean.

Buy The Universe in a Nutshell at Amazon.com
Buy Hyperspace at Amazon.com.



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