Book review: The Grand Design (Part 2 of 4: The basic ideas)

In part 1 of this review, I argued that the lack of a unified theory of gravity and quantum mechanics is what has stymied scientists in their attempt to understand the origins of our universe and even what came ‘before’, assuming that the question even makes sense. M-theory and the no boundary condition is what Hawking proposes as the candidate for a unified theory that can address the physics of the early universe.

M-theory is not an elegant theory expressed in a single equation (like Newton’s law of gravity) or even a few equations (like Maxwell’s equations of electromagnetism) but instead consists of a patchwork of theories, each with its domain of application, and overlapping with other theories so that the whole space of nature is covered. Hawking argues that this patchwork feature may not be due to our lack of imagination or inventiveness but intrinsic to the nature of the laws of science.
[Read more…]

Book review: The Grand Design (Part 1 of 4: The nature of the problem)

This new book by Stephen Hawking and Leonard Mlodinow has generated some publicity and so I thought I’d check it out. The first part of my review will explain the basic questions that are being addressed by the book, the second will describe the physics behind the solutions that the authors propose, the third part will provide some of the more basic physics background that lies behind those ideas, and the last part will discuss the religious implications of the book, which have received the most attention, and some of my own reactions.

I should warn readers that cosmology and general relativity are not my fields of study, although I am a theoretical physicist and thus familiar with the basic theories of modern physics. So my knowledge of the book’s subject matter is likely to be not that much greater than that of an informed layperson. If you want a really authoritative reaction, you will need to ask your friendly neighborhood cosmologist or read reviews by them such as the one by Sean Carroll in the Wall Street Journal.

The book seeks to address three questions: Why is there something rather than nothing? Why do we exist? Why this particular set of laws and not some other? These are, of course, big questions that have long been the province of philosophers and theologians. But modern science has wrestled such questions away from them and made them into empirical questions to be addressed the same way that science addresses any questions about the physical world, making purely philosophical and theological speculations about them superfluous. Needless to say, philosophers and theologians are not happy about this development and are trying to assert that they still have a contribution to make and it is this that largely constitutes the modern science-religion debate.

To begin, we live in a universe that has three space dimensions and one time dimension, which we think of as distinct from the space dimensions. We are comfortable with the idea that there is no ‘beginning’ to space but with the conventional big bang theory there is the sense that there is a beginning to time, which naturally raises the question of what existed before that time or what triggered the start of the universe.

One answer could well be that the universe began as a quantum fluctuation and that there was no such thing as time before the universe began. The laws of science came into being with the universe and there is no mystery of why they happened to be such as to produce life like ours because if they hadn’t been, we would not be here to ponder such questions. The laws had to take some form and the very fact of our existence means that that laws happened to be such as to produce us. Such as answer is sufficient for many people.

But the authors seek answers that go beyond that, hence the book.

At present, our understanding of the physical world is spanned by theories of gravity, quantum mechanics, electromagnetism, and the weak and strong nuclear forces, each successfully working in a specific domain of application. There has been some success in straddling the boundaries of the domains, especially those areas in which quantum mechanics, electromagnetism and the strong and weak nuclear forces overlap.

Gravity has been the tough nut, the outlier, resisting strongly all attempts at combining it with other theories, and its unification with quantum mechanics has been the major challenge. Gravity is important in dealing with massive objects like planets, stars, and galaxies, while quantum mechanics deals with the very small. We use the theories of gravity to explain the large-scale structure of the universe and quantum mechanics to explain the sub-atomic world. For most things, the two domains do not overlap. But the unification of gravity and quantum mechanics becomes important in dealing with cosmological questions because when we speak of the beginning of the universe, we are talking about the entire universe being compressed into a tiny region of space and so we need a theory that combines the two domains if we are to make sense of that early state.

The main difficulty that has stumped scientists for so long is that space and time are not distinct but are intertwined due to the warping of space by gravity. At low speeds and in the presence of weak gravitational fields, the mixing is so slight as to be not noticeable which is why we perceive them as independent. The highly successful theory of quantum mechanics was developed for use in space that is ‘flat’, i.e., not warped by gravitational effects. But when we are dealing with the origins of the universe at very early times, the density of matter is extremely high. Consequently the gravitational fields are so large and the warping of space so great that the laws of physics, which were developed for use in flat spaces, appear to break down, depriving us of the only tools we have to study the world. As a result, we could not say what happened at times very close to zero or before. This has been a big barrier to progress.

The search for a quantum theory of gravity was the search for a theory that would work even under conditions of the extreme curvature of space that constituted the beginning of our universe. The original hope of Einstein and his successors in the search for such a unified theory was that it would be simple and elegant. But many have failed in this search and that goal has proved to be frustratingly elusive.

This book outlines a solution to this problem that is currently in vogue among cosmologists. It is based on what is known as M-theory and the ‘no boundary’ condition. The book lays this out in chapter 5, which is the heart of the book. (No one seems to know who coined the name M-theory or even what M stands for. I suspect that it was tossed out casually at a physics conference and became adopted by word of mouth.)

Next: M-theory and the no boundary condition.

Back to the future

Blog reader Norm sent me this link to something called “The first annual conference on geocentrism” to be held in South Bend, Indiana near the University of Notre Dame. It has the title Galileo Was Wrong: The Church Was Right.

My first reaction was that this was an Onion-type spoof but it seems to be legit.

Of course, the choice of any point in space to be the origin of the frame of reference is purely arbitrary. Which frame one chooses depends on one’s purpose. For purely practical purposes such as navigation, choosing the Earth to be at rest makes sense. The heliocentric model is the best choice for describing the motions of the planets, and the center of a galaxy is most convenient to describe the motions of stars in the galaxy.

The church was wrong in insisting that the geocentric model was the only choice and it was Galileo’s assertion that there were alternatives to it that disturbed them. All this has been well known for some time and so the point of this conference completely mystifies me. Are the organizers really suggesting that there is only one allowed frame of reference and that its origin is at the Earth?

The Mystery of the She-Pope

A young Catholic woman dresses up as a man and joins the priesthood (not hard, given that the robes they wear), goes to Rome, and ends up as the pope. She then gets pregnant and delivers the child on a public street during a procession in which she is wearing the full papal regalia. The bystanding worshippers, outraged by the revelation of her deception, kill her and bury her by the roadside. This is the story in a new German film called Die Papstin.

Far fetched? Perhaps, except that the film is based on events that might have actually happened. The September/October issue of The New Humanist has an article by Sally Feldman (not available online) that looks at the story of ‘Pope Joan’ who supposedly lived in the ninth century. The catch is that even though there are about 500 reports on this episode written from early medieval times to the 17th century, there are no contemporaneous records of what happened during her time, which has rightly called the Dark Ages, and the powerful Catholic Church would have had every reason to expunge any mention of such an embarrassing episode.

The article points out that this story has been investigated by many people and even though unproved is quite widely known and believed. In the course of investigating it, Peter Stanford, the former editor of the Catholic Herald discovered a chair that was used in papal elections in medieval times that had an odd key-shaped hole cut in the seat. According to accounts, before the election of a new pope could be confirmed, the would-be pope was required to sit in it and then the youngest deacon present would have to reach up through the hole and confirm the pope’s ‘eligibility’, if you catch my drift. Such a precaution might well have been the result of the Pope Joan episode.

Dean Baker on solving the budget deficit problem

I just returned from a talk by Dean Baker, co-director of the Center for Economic and Policy Research, and he said that there is no crisis in social security and the real crisis is the rapid rise in health care costs that, if unchecked, could raise the budget deficits from their current value of around 10% of GDP to disastrous levels of 30%, 40%, and even 50% in the next few decades. But our policy makers, instead of addressing this issue head-on, are instead deflecting attention to other things.

If our per capita health care costs could be made the same as Canada and the UK, the current budget deficits would become surpluses even if we did absolutely nothing else, such as raising taxes or cutting costs in other areas. It is that simple.

This is pretty much what I have been saying for some time, but Baker has studied this issue in great depth for many years and so has way more facts at his fingertips. He is one of the foremost authorities on social security, Medicare, and the budget. You can follow him on his blog.