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By
Roger Penrose

- Little Secrets
- Chosen Ones
- The New Husband
- Afterlife
- The Missing Sister
- The Southern Book Club's Guide to Slaying Vampires
- The Book of Longings
- Hidden Valley Road: Inside the Mind of an American Family
- The Sweeney Sisters
- Death in Her Hands
- Chosen Ones
- The Southern Book Club's Guide to Slaying Vampires
- A Bad Day for Sunshine
- Conjure Women
- If I Had Your Face

Theme: Avant by
Kaira

Es justo lo que se describe, se adapta a lo que necesito y cumple su funci n Estoy muy satisfecho con la compra.

This is a very powerful if complicated book It does not appear to be written to the lay audience but to the author s peers and those who aspire to be his peers graduate students in mathematics, physics, and cosmology Dr Penrose tells us at the outset that he will decouple the complicated mathematics from the text and place it in appendices which are heavily referenced and linked throughout the text But even this concession is about a reasonable pace for the text and all the subject matter covered rather than to save people like me the math There remains plenty of math in the text itself, something a physicist might call mathematical summarizations.Each chapter is long and covers a wealth of issues related to the chapter s focus Chapter one Fashion focuses on string theory, chapter two, Faith on quantum mechanics, and chapter three Fantasy on cosmology The majority of the text is a deep analysis of various phenomena associated with each of these areas highlighting both that which should be taken seriously in any explanation of the real physics of the universe, and that which is problematic to that endeavor These are detailed analyses indeed and if I was lucky I understood about 20% of what Penrose was trying to get across in these details.Of the first three chapters, the cosmology chapter is the easiest to understand perhaps because it is the most observation ally oriented of the three broad disciplines covered Quantum mechanics chapter two is only indirectly observational and string theory chapter one has no observational basis whatsoever making Penrose s explication of them each going backwards from 3 to 1 progressively difficult In chapter four, Penrose gets into twistor theory first applied to quantum mechanics and then to cosmology where twistor theory s math is supportive of conforming cyclic cosmology, Penrose s hypothesis about how big bangs come about and why their entropy is so low There is again plenty of summary math here but as with the first three chapters, Penrose manages to convey what problems he is trying to solve and the limitations of even his own solution.Given its detail perhaps this book and its themes will not be ignored by the physics and cosmology communities at whom it appears directly aimed Those of us who follow these things from the outside, if you do not have an insider s grasp of the math, will just have to content ourselves with parts of the text that address the author s concerns in between the development of the math supporting his arguments.Before ending I want to say something explicitly about the kindle version of this book All too often technical books are converted to kindle format without being subsequently checked Even if they are checked, problems that crop up in converted diagrams, equations, and formulas are not addressed What was easy to read on the printed page converts on the kindle to a difficult to see shade of grey, or becomes very small Sometimes these problems even extend to the text In some typefaces, for example, certain letter combinations like fl are misread by the converter as a single letter, say k and so words like conflict come out as conkict throughout the text In this book, attention has obviously been paid to these issues Not only is every section almost every paragraph cross referenced into themes referenced in the other chapters and appendices, but every equation and diagram is easily readable Even equations in the end notes come out very read ably This might be the most heavily cross referenced book I have ever read and following the links works very smoothly in the Kindle edition My thanks goes out to the technical production team for this book They all did an excellent job of producing a quality Kindle text

Roger Penrose is now 85 and this book may be the final presentation of his worldview Although he talks about the layman as his audience, potential readers should recall The Road to Reality In reviews of that tome, retired maths professors and physics PhDs lined up to recount at which chapter they hit the limits of their knowledge and had to give up.This volume is not so different.In a nutshell 1 Penrose dislikes String Theory because its extra dimensions admit too many functional degrees of freedom basically the number of possible field configurations It is not explained clearly why the super explosion in the functional freedom space size is problematic, although he does make a related point that he believes that the six curled up dimensions are actually unstable and should collapse.Perhaps it s obvious.2 Quantum Theory is seen as a partial or incomplete theory in particular, Penrose thinks that its linearity will be violated in an improved theory He believes that the reason we don t observe Schr dinger s cat spatial superpositions is due to the gravitational effects of superposition he takes spatial delocalisation to have a real gravitational effect, aligning with his ontological realism for the quantum state Specifically, the gravitational self energy due to the superposition generates energy uncertainty, equivalent to time uncertainty, hence superposed stationary states collapse into a position eigenstate very quickly As he explains it, the maths behind this is pretty advanced, requiring general relativity.3 Cosmologically, Penrose is not a fan of inflation, basing his criticisms on the 2nd Law and entropy His criticisms have force suggesting that inflation retains support faute de mieux.What does Penrose himself suggest as alternatives He thinks twistor theory a framework featuring emergent space time continues to have promise, and believes that a particular kind of bouncing, recurrent universe traversing through repeated big bangs can explain the extraordinarily low entropy 13.8 billion years ago.I think it s good for physics that he wrote this book, but absent a huge background in general relativity, complex analysis, twistor theory, quantum field theory and tensor analysis it s difficult to assess the merits of his arguments.

I have read quite a few of Penrose s popular books you know that you are in the company of an amazing mind, with great depth I have a B.Sc in physics, but obviously he is writing about pretty advanced concepts, above my level, and he doesn t dumb it down, in my humble opinion Basically, he examines the fundamental underlying principles of string theory and quantum mechanics, and finds some of them wanting, particularly the high dimensionality aspects Thus, the title i.e he thinks some of modern day physics resembles fashion, faith and fantasy, than verifiable science Lots of GR here, too, since he was a major contributor to this and many other math physics areas Anyone interested in this issue might also try The Trouble with Physics, by Lee Smolin.Though he writes at an advanced level about difficult topics, he is a very good writer I would give it a 5, but that would imply that I understood everything in the book extremely well, which would be misleading Though I doubt that many people in the world could make that claim, anyway.