Tag Archives: cosmogeny

Book Review: Cycles of Time by Roger Penrose

This is a very interesting read on Penrose’s new hypothesis: conformal cyclic cosmology. Before he gets to this in the third part of the book, he first needs to give the reader the background to his thinking. To that end, the first part of the book looks at the Second Law of Thermodymanics, which plays a pivotal role in this work. So if you don’t yet have any idea what this is, I would recommend a little preliminary reading before tackling Cycles of Time.

If you are not familiar with Penrose’s writings, then this perhaps is not the best starting point. He jumps straight into the Second Law and doesn’t shy away from the necessary maths. For a science graduate, this is relatively easy reading, though those without a formal background in maths or physics may struggle, although Penrose’s styles of diagrams are immensely helpful. One thing that is helpful is that even if you haven’t grasped all the detail in a given section (and I certainly didn’t) then that doesn’t mean you cannot grasp any of the later concepts.

No one could ever accuse Penrose of patronising his audience, and though many topics will be familiar to scientists, Penrose’s particular style always stretches you and makes you think in a slightly different way; so that which you thought you knew quite well suddenly has a few extra question marks posed against it. One thing that is very praiseworthy in this book is Penrose’s modesty and his clearly laying out of what is well evidenced scientific consensus and what is his own minority view, as well as pointing out the drawbacks in his own theory. This style contrasts greatly with the brash optimism that Hawking & Mlodinow put forward in their book, The Grand Design, published within a few weeks of Cycles of Time. The fact that Penrose does this raises some interesting questions. For example, he does state that in order for his hypothesis to be correct, we would have abandon many well-established theories, such as the invariability of rest-masses of fundamental particles.

I could not claim to have fully understand all the nuances and detail of this book at the first, but that does not diminish my enjoyment of it or my ability to get the overall gist of it. I will be re-reading this book, going over each line in more detail in order to get the complete picture.

Book review: The Grand Design by Stephen Hawking & Leonard Mlodinow

The inside cover of the book states that it is

“A succinct, startling and lavishly illustrated guide to discoveries that are altering our understanding and threatening some of our most cherished belief systems, The Grand Design is a book that will inform – and provoke – like no other.”

Well, it is most certainly succinct, well illustrated and thought provoking. Indeed, the book is perhaps a little too succinct. It is certainly very short, and it doesn’t take long to read. The writing style is very clear, though some of the humour does have the feeling of having been inserted periodically as an afterthought, to maintain some levity in the book.

The book is a mixture of bold statements about the current state of theoretical research and an overview of historical developments in physics over the last hundred years (with some going further back than that). One of the weak points of the book is that it lacks references. This makes it very difficult to distinguish what is widely-accepted, evidenced scientific theory and what is optimistic speculation. At one point in the book, the authors state: “M-theory is the only candidate for a complete theory of the universe.” I would certainly take issue with that, given that it is certainly not a universally accepted opinion. Any reader wanting to gain an alternative opinion on some of the bold assertions made about M-theory would do well to read Lee Smolin’s The Trouble With Physics.

Probably the most interesting claim in the book comes at the start, with the declaration that “Philosophy is dead.” This claim is never convincingly argued, and in fact the authors go on to employ certain philosophical ideas in pursuit of their goals. The entire argument of the book hinges on the acceptance of “model-dependent realism.” After a little research, it seems that this is an original term although the authors do a good job of defining it. Here, however, rhetoric has been used as a substitute for reason. There is plenty for room on this debate and so it seems that if philosophy ever had been dead, which I see no evidence of it ever having been, then this book jolts some life back into it.

There is one enormous “If” hanging over the book, which is not dealt with in sufficient detail. That is the question of experimental verifiability. M-theory is spoken of as the underlying principle behind the various string theories. Yet even these have not been confirmed by experiment. At one point, the authors state that their claims can be verified by experiment but they do nothing other than state it as though it were plain fact. No justification is given, nor experiments suggested.

It certainly well worth reading, but if anyone who has not studied the issues discussed were to read it in isolation, then they would likely end up with a highly skewed view of physics. This is a good book, worth reading, but it could have been so much better.

An evening with Stephen Hawking

I heard some time ago that Prof Hawking was in the process of writing a new book, and had kept an eye on when it would be released. Shortly before I pre-ordered it, a friend pointed out that he would be presenting a public lecture at the Royal Albert Hall. This public lecture included a copy of the book, so I was quite happy to wait for a month and a half after publication for it.

Just prior to the release, the book was afforded a huge dose of publicity, by the interpretation of some in the media relating to theological claims in the book. Since the extracts were being published in the Times, and this is hidden behind a Murdoch-dictated paywall, I had to rely on scant quotes from it as cited by the BBC, Guardian and Independent.

The headlines were saying that Hawking had declared that God didn’t exist, although the quotes belied this position, as they instead seemed to indicate merely that God was not necessary for the creation of the universe. Over the course of a few days, the book picked up loads of free advertising with atheists and theists taking shots at one another. A lot of words were used (most of which have been heard before ad nauseam) yet very little was actually said. Another thing that was picked up, and was potentially the more interesting claim, was that “philosophy is dead.” More on this later.

Even though the above 3 named news outlets tend to be the most objective and fair minded, they still managed to quite sensationalist in the matter. So I decided it would be better to hear what he had to say himself, and to read the full text of what he had written. I have not yet read the book, so I can only comment on his lecture.

It was nice to see a venue as large as the Royal Albert Hall full of people wanting a public lecture on science, although the sight of the ticket touts outside was something I hadn’t expected. I am used to them for gigs, but not for lectures. Once I’d taken my seat, I was soon asked to take a photo of a group of rather excitable postgrads who were in the box behind me. Before long, we were ready to start, with Prof Jim Al-Khalili giving a very well-spoken introduction.

It was interesting, and really quite telling, that his opening gambit was to address the issue that had been the cause of the heightened publicity surrounding the publication of the new book. He stated that Prof Hawking was not here to discuss the existence or non existence of God, and he also refuted the claims that Hawking said God did not exist. He then put forth what Hawking’s view was. He said that “God” was the name we give to the reason we are here. And in Hawking’s opinion that reason is physics.

So really, there did not appear to have been a significant change from the pantheistic view Hawking had earlier propounded in A Brief History of Time. Although I thought this quite clear, it did strike me as odd the Prof Al-Khalili felt this needed saying at the start. Why couldn’t Prof Hawking address this during the lecture? It did seem another instance of words being put in Hawking’s mouth, although at least these ones did seem to chime with the evidence.

After just a few minutes, Prof Hawking was brought onto the stage. It took a couple of minutes for his assistant to hook up the microphone to his computer but eventually we were treated to a “Can you hear me” in that familiar, mechanised American voice. The Albert Hall is not the ideal venue for that kind of voice to be projected, and in many places throughout the evening it was quite difficult to make out what the professor was saying. On other occasions, there were prolonged pauses while the professor was inputting his speech into his computer. At times, this made a few people uncomfortable, but it was not a significant distraction.

To help his talk, there was a large screen up behind him which showed graphics of various degrees of helpfulness.

The first half an hour of the talk was spent covering a lot of Stephen’s earlier life. The screen showed various locations important to his life, although the accuracy of the map certainly left something to be desired. Oxford appeared to be just north of Cheltenham , London was magically moved on top of Reading and Cambridge was now parked on top of Peterborough!

He revealed that as a boy he was very interested in train sets, and was keen to understand how they worked. His philosophy was that understanding led to a feeling of control. I felt it was an interesting point to note, as it may help to understand his thinking about his own motor neurone disease, although he didn’t mention it explicitly in this context. Later on, he said that if we understand the universe, then we are the lords of it.

As a child, he spent some time living on the island of Majorca with his mother and sisters, whom he considered cleverer than he was. Though he didn’t learn to read until late on, he did learn and the key text he was given as an example of good English was the King James translation of the Bible. There was a problem with this, however. An analysis of the first word of each sentence in the first couple of books revealed that “And” was most commonly used. If the pie chart that went up on the screen was to be believed, then it accounts for the start of around a third of all of these sentences.

From there he moved on to his time as an undergraduate at Oxford. In those days, those who worked for their degrees were looked down upon. There weren’t exams every year, only the finals counted. Even for those, you were expected to pass on the basis of your brilliance alone. It was only when he was diagnosed with motor neurone disease that he realised the value of work and how much he wanted to do in the time he had left alive, given that he was only expected to live for a few more years.

Since he did very little work, he was on the border between a first and second class degree, and had to go through a viva process. During this he was asked what he intended to do with his degree. His answer was that he intended to go into research, with the condition that if he got a 2:1 he would stay in Oxford, and if he got a first he would go to Cambridge. After a short pause, he said, “I got a first!”

At this point, he gave away something that I feel showed why he is a physicist and not a mathematician. He said that though he could follow equations, he never got a feel for gravity. My own experience of mathematicians and physicists is that mathematicians get an instinctive feel for equations and then see what the final result looks like in a physical manner, whereas the physicists tend to think through the mechanics of what happens in the observable universe and then try and work out what the equations are that fit this model.

Throughout the talk, Hawking made references to those people he came across and worked with. This was quite a long and distinguished list. However, of them all, two names stood out for me as being spoken of with particular affection. This may be influenced by my own filter of how I regard them, but those two people were Dennis Sciama, Hawking’s PhD supervisor, and Roger Penrose, a mathematical physicist with whom Hawking did a lot of work on black holes.

Getting slightly more technical on some of the work he did, he began to talk about Wheeler Feynman Electrodynamics. I confess, this is not something I recall ever having come across before. He summarised like this. [“The light that is emitted from a lightbulb is dependent upon all the energy in the universe.”] I paraphrase as I didn’t write down the precise wording. It was related to the idea that the inertia of an object is due to all of the other mass in the universe. Now while this may seem quite an odd concept, if you imagine a universe with only 3 massive objects in it, then the situation becomes fairly clear and the idea of light simply uses the mass-energy equivalence of general relativity. At least I think so! I may have gotten hold of the wrong end of the stick.

The talk moved on to some hand-wavy arguments (not literally, of course) about black holes. In particular how they are formed. This was something I never really studied at university; my particular focus was on finding solutions of the Einstein equation. So I was quite happy to learn a little about the theory of how black holes can be formed. The focus was on a star collapsing and whether or not that star needed to be perfectly spherical in order to form a black hole. There had been a theory proposed that indicated that unless there was a perfect sphere, the star would “bounce” back and not entirely collapse in on itself. This certainly seemed a problem, given that no star ever observed has been a perfect sphere.

However, Penrose later showed that minor deviations from perfection could still lead to the total gravitational collapse of a star and result in a singularity. From here, the natural progression was to talk about cosmic censorship, the notion that “nature abhors a naked singularity.” Whenever I have come across this before, it always struck me as a bit axiomatic. Other than the fact that it makes some equations possible to solve, there is no evidential basis for it. Hawking confirmed that my suspicions were correct. I still think the idea is probably true, given that it agrees with working theories and sounds quite reasonable, though the fact that it has not been confirmed by experiment leaves it open to revision.

The professor then had a brief discussion on black hole entropy, although I’m not sure he defined it particularly well for a lay audience. He put up on screen the only equation of the evening, being the formula for black hole entropy that he developed with Jacob Bekenstein, along with the idea of information loss. The analogy he used was taking an encylopaedia and challenging someone to find some information in it, only before you give him the books, you burn them and presenting only the ashes. The idea is that information which goes into a black hole is not lost; it is just very hard to read. That said, I think the analogy is more flawed than the theory.

Some of what followed was a brief recap of A Brief History of Time, covering ideas of inflation theory and imaginary time. Both of these are neat ideas that help to sort out some mathematical problems, although their actual validity is something I’ve yet to be convinced about. But this wasn’t the forum for those particular discussions.

Finally, Hawking moved onto the outline and purpose for his new book, The Grand Design. In short, its scope is to look at the “big questions.” As noble and worthwhile a task as this is, it did seem to me from looking on Amazon that a book of less than 250 pages would be able to cover this in sufficient detail to make a good case. But the book is yet to come. I shall read it shortly (am currently half way through Kafka’s The Trial) and write a review thereafter.

Then we got round to a point I mentioned earlier: the statement that “Philosophy is dead.” This was stated as a matter of fact. The reason given was that philosophy had not kept up with physics and that now the sciences are the leaders in thought. If this is true, I wondered if this event was the funeral and if The Grand Design was the death certificate. The trouble with the idea is that it doesn’t seem to have been noticed until the last couple of months. I have a distinct feeling that the fate of this statement may befall the same as Friedrich Nietzsche’s declaration that “God is dead,” which proved to be unfounded and untrue. There is also the view that this is a deliberate hyperbole, which is not meant to be taken seriously. A possible indicator of this was the laugh that the statement evoked from the audience. Nonetheless, I am sure I shall have more to say on the matter after reading the book, where I hope this point is expanded on and not left as a pithy aphorism.

Professor Hawking then embarked on what I thought was a quite remarkable little exercise, where he presented a highly deterministic view of the universe. Now I was of the opinion that quantum mechanics, and the Heisenberg Uncertainty Principle in particular, had signalled the end of determinism in physics. Maybe the old clockwork is back, eh?

Then he came back slightly to his views on theology. Following on from determinism, he gave his opinion on the nature of the laws of nature (sorry for using the same word with two different meanings in the same sentence – limitations of my English & all that). For an elongated, entertaining and informative book on this topic, I cannot highly recommend enough The Character of Physical Law by Richard Feynman. Hawking didn’t have enough time to go into depth on this subject, though he did say that “A law is a law, with no exceptions or miracles. Gods and demons cannot intervene.” So here we have, though somewhat indirectly, Hawking’s definition of a miracle: something that contradicts the laws of nature. While I know some people who would agree with this, I know more who think that the definition is that a miracle is something extremely unlikely to happen, right on the borders of possibility.

However, Hawking did hint at one of the most important questions on the physics/philosophy border: where do our physical laws come from? His answer: M-theory. Now we get to the crux of the argument. I’m well aware of the issues faced when trying to explain anything beyond basic quantum mechanics to a lay audience, particularly in a short space of time (no pun intended). There was a diagram put up on the screen showing how M-theory is related to the 5 major string theories, although he never explained what they were or what differentiated them. His analogy was to use a patchwork map of the world, where the patch is correct in some areas, but cannot be used for the entire surface of the globe. However, where two patches overlap, they are in agreement. I’d like to see the workings behind how this analogy stretches to the overlaps between different string theories. The problem with it, is that doesn’t tell you if you actually have all the pieces.

From my present understanding of M-theory, the term “theory” is a bit strong and not really warranted. It is an hypothesis of a theory that may exist, but no formulation of it yet exists. I know a lot of work is being done on it, though it is yet to make a convincing case for itself. At times, the fervour of belief in M-theory is more befitting a cult than that of a community of scientists. For an excellent critique on this, please read The Trouble With Physics by Lee Smolin.

One hypothesis in particular that has had a noticeable rise in popularity over the last 10 years or so is that of the multiverse. Hawking gave a little explanation of this which was very good. The idea goes like this: Our universe is just one of many. And by ‘many’ we means googolplexes of the things. The idea (in the M-theory framework) is that the laws of physics we see in our universe are the way they ‘just because they are.’ The fine-tuning elements of the constants of nature has long been a puzzle for a physicists and a boon for proponents of a teleological argument for the existence of God. If the multiverse hypothesis is true, however, then it wipes away that line of the teleological argument for good. Every different universe has a different set of laws of physics. However there are supposed to be more fundamental laws of M-Theory that govern what particular laws arise in each given universe. The problem with this, though, is that we have no idea what these more fundamental laws might look like. Hawking didn’t admit this is his talk. He only got so far as uttering the phrase “if confirmed by observation…” which is just about the biggest IF hanging over all theoretical attempts at finding a Theory of Everything. I hope his book is a little more sober.

The evening finished with 3 selected questions.

Q1: Is a black hole a sphere?
A1: Yes, if it’s non-rotating, but it will be squashed slightly if it is rotating. [Bit of a bland question, I thought. Should be obvious]

Q2: Do we see the same galaxies over and over again but at different ages.
A2: It might be possible for light to come right around the universe, but it’s not old enough for light to have travelled that far. So while it is theoretically possible, it is presently impractical.

Q3: Will we ever know and understand all of physics
A3: I hope not

Overall, it was a greatly enjoyable, informative and thought-provoking evening. I look forward to reading the book.