Dialogue Concerning the Two Chief World Systems – Galileo Galilei

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The final, and longest, book in my August reading marathon of important scientific works is also definitely the oldest and arguably the most significant in the leap of understanding passed on to those members of the public able to read a copy. Published originally in 1632 in Italian so that it was more accessible to the general public than it would have been if written in Latin it was immediately seen as an attack on the Catholic church as it presented as valid the then heretical Copernican system of the Sun at the centre of the Solar System rather than everything rotating around the Earth as taught by Aristotle and Ptolemy and adopted as clearly correct by the church as Earth should be the centre of Gods handiwork. Galileo was duly tried by the Inquisition and sentenced to life imprisonment at home and the book remained on the Catholic church’s list of banned works for over 200 years until 1835.

It is styled as a conversation over four days between three characters, Salviati is the instigator of the meetings and is clearly a Copernican, Simplicio is an adherent to Aristotelian and Ptolemaic systems and Sagredo is there initially to play devils advocate putting questions to both of the others but towards the end is obviously swayed by Salviati. Both Salviati and Sagredo are based on real people with those names who had been friends of Galileo but had both died many years before publication so could not be implicated by their names being used, whilst Simplicio appears to have got his name from the Italian word semplice which means simple minded. The choice of this name for the character backing the Ptolemaic system was also not lost on the Inquisition. Galileo was well aware that he was pushing at boundaries and originally got permission from the church to write a book about tides which grew into the final work covering far more than his original proposal, but even the characters acknowledge that this is potentially dangerous territory.

We are arguing for our own amusement, and are not obligated to any such strictness as one would be who was methodically treating a subject for professional reasons, with the intention of publishing it … it should be almost as if we had met to tell stories, so that it is permitted for me to relate anything which hearing yours may call to mind.

This edition was published by The Folio Society in 2013 using a translation originally done by Stillman Drake in 1953. It includes a modern introduction by Dava Sobel along with a foreword by Albert Einstein, which presumably dates back to the first publication of this translation. I did struggle a little with the verbose nature of the translation which whilst it may reflect Galileo’s original did also mean that I several times had to reread a sentence to make sure I followed the text correctly. This is not helpful when I was also trying to appreciate the leaps being made by Galileo whilst reminding myself that this was written decades before Newton formulated the Theory of Gravity so Galileo was truly groundbreaking in his explanations. His theoretically neutral but definitively pro-Copernican text starts from first principles with balls rolling down a slope to end up with not only the Earth rotating each 24 hours but also orbiting the Sun each year with the angle of the Earth’s axis also included to explain the equinoxes.

That is not to say that everything is correct as we would understand the cosmos now, Galileo has astronomical distances far too small, although much exceeding that of his contemporaries. A good example of this is the section of detailed calculations surrounding the two supernova that had been observed in the last few decades before he wrote the book. He is rightly dismissive of a book which aimed to prove that that these occurred within the orbit of the Moon so as to not disturb the changeless firmament which does so by carefully choosing between astronomical measurements of the period so as to find ones with sufficient error to support the authors position. However Galileo makes the same error in his selection by dismissing not only these examples but also any that would imply the nova occurred at an infinite distance from Earth which using the methods explained would actually have been the correct solution. Instead Galileo had decided that the stars were roughly six to eight times as far away as Saturn (then the furthest known planet) although some “could be two or three times further than that” to explain relative brightness and apparent size. He duly provides many pages of calculations regarding the sample set he has chosen, which are clearly there just to demolish the book and author he dislikes. Other ‘scientific’ books and papers from his time are likewise introduced and their methodology and reasoning torn apart. Galileo clearly wanted to leave no stone un-turned in his defence of Copernicus.

In the final section Galileo covers the subject that he originally stated was to be the main topic of the work, that is the tides and what causes them. Fortunately this makes up a tiny proportion of the whole book as sadly this is another area where he is in error by effectively ascribing them to the rotation of the Earth and the consequential ‘sloshing’ of the waters in the seas. The examples of mistakes given above are entirely understandable given the groundbreaking nature of the book and although I feel the translation could have been better this is still a book I thoroughly enjoyed as the insights presented by Galileo are not only good examples for today but give an understanding of the reasoning of the time and the turmoil between science and the Catholic church that would hold back scientific advances within its sphere of influence for decades if not centuries to come.

Galileo finally received an apology for his treatment at the hands of the church on the 31st October 1991 from Pope John Paul II over three hundred and fifty years too late.

The Elegant Universe – Brian Greene

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I bought this book in the July 2020 Folio Society sale specifically for this August science marathon which I have just realised I am reading in order of length. After the relatively short ‘The Double Helix’ last week I jump to the 432 pages of this volume, next weeks is a similar length and the final book to tackle is over 550 pages. If you are a regular reader of my blog you will know that I do a reading marathon each August, previously I have read multiple books each week but this year I have decided to tackle major scientific works at the rate of one a week when normally I would have interleaved them with shorter and easier works. So what is the importance of ‘The Elegant Universe? Well it was originally published in 1999 and is one of the first books to attempt to summarise the issues between Einstein’s relativity theories and quantum mechanics and then go on to explain a possible solution to their inconsistencies using String Theory to a readership that is not composed solely of physicists. The book was nominated for the Pulitzer Prize so definitely qualifies for my requirement to be a significant science work for this months readings and represents theoretical physics as I have previously read and reviewed the logical book for this subject namely Einstein’s own book on Relativity.

After a couple of brief introductions, one written in 2017 especially for this new edition, and a brief summary of the current understanding of elementary particles which makes up section one of the book Professor Greene dives straight in with two chapters on the General and Special Theories of Relativity, how these moved us on from the Newtonian Laws of Motion and the odd effects that are predicted by Einsteins equations. After this is a chapter giving a good introduction to Quantum Mechanics, which is a surprisingly easy read given the counter intuitive behaviours of forces and particles at this level of magnification. These are followed by a chapter entitled The Need for a New Theory where he looks specifically at the contradictions between Relativity and Quantum Mechanics and the problems that are faced by physicists trying to unite the two in the search for the Theory of Everything. These four chapters make up the second section of the book and cover ground I was already familiar with however I have not read up on String Theory so from here on the theoretical physics was all new.

 

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The chapters get ever more complicated  as they try to explain the various aspects of String Theory, which by its very nature as the search for The Theory of Everything has to stretch from atomic level to cosmology. Professor Greene is very good at using analogies to express complex thoughts in a way the reader can approach them. For those who are fans of the Star Trek spin-off Deep Space Nine you will be pleased to find that String Theory allows for wormholes to exist. Spoiler alert – they probably don’t but at least there is some physics behind the idea as shown on the page spread above.

One potentially good way that the entire book is written is the ability of the reader to take it at their own pace and also to decide how deep they want to go. This is done by use of an extensive notes section at the back of the book which moves more complex discussions of points raised along with most of the mathematics out of the main body of the text. Now for me this became increasingly annoying as I had to keep two bookmarks to track where I was up to and to make skipping to the notes section easier but it does make the main text simpler to follow for the more lay reader who after all is probably the target audience.

Am I convinced by String Theory after finishing the book? The answer is probably no, there are far too many places where the solution to problems within the theory appear to be solved by the ‘with one giant leap our hero escapes’ methodology favoured by Flash Gordon short films from the 1930’s. Be it the ‘convenient’ choice of three holes in the six dimensions curved around a string so that the known three families of particles are predicted by approximate mathematical formulas. Or the super-symmetrical particles which are a cornerstone of most string theories (of which there are five versions which also doesn’t seem like a solid foundation) not being found as expected by the Large Hadron Collider so the assumptions of which they are based being changed so they ‘couldn’t have been discovered with current technology’ there are too many holes being papered over. Even assuming that the mathematics is finally worked out, and there is almost forty years of people trying, the idea that a mathematical model is also the physical construct is dubious to say the least and there is no need for the actual physical basis of the universe to match the mathematical representation for a theory to be valid in predicting motion and inter-reaction but String Theorists insist that this is the case.

Twenty years on from the book being written even those heavily involved in the physics back then are starting to have doubts about some of what is suggested. The most obvious candidate is super-symmetry. This is seen as one of the most important signatures that String Theory is correct and is number one on the list of things that ‘will prove or disprove the theory’ included in the book but few physicists now believe it is true as can be judged by this extract of a Royal Institution lecture by Dan Hooper, Head of the Theoretical Astrophysics Group at the Fermi National Accelerator Laboratory in the USA. Maybe String Theory will unravel, maybe it will be adapted to match experimental reality, who knows, but it is an fascinating subject and needs to be tackled to understand the fundamental basis of reality.

Read the book, it’s difficult, even with the solid background in Relativity and Quantum Mechanics that I have, but worth it. It will challenge your understanding of these subjects and that can only be a good thing, physics and mathematics rely on constantly pushing the boundaries and at least at the moment String Theory is the only game in town that attempts to mesh the Quantum Mechanics and what is happening at the smallest boundaries with Relativity and the physics of huge distances. It might be right, it might be wrong, but it will certainly push the boundaries of scientific endeavour for many years to come.

Relativity – Albert Einstein

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If you are going to read a book about relativity then why not go for the man who created the theories, after all as Einstein says himself in his preface…

The present book is intended, as far as possible, to give an exact insight into the theory of relativity for those readers who, from a general scientific and philosophical point of view, are interested in the theory, but are not conversant with the mathematical apparatus of theoretical physics. The work presumes a standard of education corresponding to that of a university matriculation and despite the shortness of the book, a fair amount of patience and force of will on the part of the reader.

Consider yourself warned.

The edition I have was published by The Folio Society in 2004 and has an introduction by Emeritus Rouse Ball Professor of Mathematics at Oxford University Roger Penrose.  Einstein originally wrote the book in 1916, just a year after he published his main paper on his General Theory of Relativity and eleven years after he had formulated his Special Theory of Relativity. Originally in German the translation is by Robert W. Lawson and he does an excellent job especially considering the complexities of the subject. Put simply the two theories deal with different things, the special theory is concerned with resolving issues between the laws of electromagnetism (specifically Maxwell’s equations) and those of motion as described in Newtonian mechanics, this becomes especially problematic as speeds approach the speed of light and time ceases to behave the way you would expect it to. The general theory on the other hand deals with gravitation and the forces between bodies caused by this. This is where the concept of warped space-time comes into place and the highly satisfying rubber sheet model which can easily demonstrate the basics of the idea and has become largely familiar to most students over the last century. It should be noted for anyone who watches the video is that the reason that the objects ultimately collide is due to friction between the balls and sheet, without that elliptical orbits would continue as we are familiar with planetary motion so this can only ever be a rough approximation of space-time curvature.

There are two ways of approaching an explanation of the theories of relativity, one book which I read several years ago does it very successfully and that is Why Does E=mc²? (And Why Should We Care?) by Professors Brian Cox and Jeff Forshaw which takes eight chapters and roughly 250 pages (depending on the edition) to cover the subject including the derivation of E=mc². Yes there is quite a lot of mathematics but there is also a large number of diagrams and descriptions in simpler terms in order to expand the readers understanding over a extended period and a short appendix in later editions to add more detail to a section that readers had queried. Einstein takes the other approach, with thirty two chapters over 132 pages (in this edition) so you approach quite complex theories and mathematics in small bite size chunks and you can reread the short chapters until you have grasped the concept being covered. There are also five appendices in a further fifty four pages which go into significantly more detail of the mathematical models and theories underpinning the two theories which are not needed by the casual reader but are there largely for completeness. In his introduction Penrose explains that part of the calculations done by Einstein in the book are no longer done that way as expressing time with a fourth dimensional axis based on imaginary numbers is seen as an unnecessary complexity when it can be done by clocks instead. This negates the need for one of the appendices which deals with Minkowski’s four dimensional space model using the square root of -1, other than as an example of Einstein’s thinking at the time.

There is no denying that some of the chapters can be difficult to get your head around the first time of reading, especially if like me you haven’t done theoretical physics at this level for over thirty five years, but it definitely worth the effort as Einstein gradually takes you through the maths. Starting with Euclidean Geometry (the first chapter which also looks at the concept of ‘truth’ for a mathematical axiom) and then pushing your understanding through relative movement of co-ordinate systems until you hit the Lorentz Transformation less than thirty pages later which gives you the basics needed to understand relativity by comparisons of motion within relative co-ordinates systems.

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With the introduction of Gaussian co-ordinates later on we can finally approach non-Euclidean geometry, which combined with Minkowski’s four dimensional space leads to the mathematics behind the general theory and warped space-time, which for now is how we understand gravity. The book is complex, but not unreasonably so, and the short sharp sections work as a way for the reader to grasp the overall concept in practical chunks. A century on this work still underpins our understanding of the cosmos and reading this book or the one by professors Cox and Forshaw, whichever you get on best with, is a good way to exercise the brain.

Of course there is still a lot of work to go before physics hits its ultimate goal of ‘the theory of everything’. Relativity is very good at explaining the very large but when you hit the realms of the very small quantum mechanics is just plain strange to the layman and even Einstein for a long time refused to believe most of the concepts behind that branch of physics. I do have a very good book on that subject as well which I will look at later this year.