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Review:The Fabric of the Cosmos: The story of theoretical physics

June 6th, 2010 | by Digvijay Lamba |

In summary this is the easiest to understand book ever written on Cosmology and Theoretical Physics.

When I first read A Brief History of Time by Stephen Hawkings, it was a great book, but as you progress through it you start to lose deeper understanding of what you are reading. The complex concepts take over and even if you work at figuring each paragraph out, the big picture slowly slips by.

“The Fabric of the Cosmos” doesn’t have that problem. Really, this is THE book to read if you are interested in understanding the mysteries of Quantum Physics, Relativity, and the beginning of the Universe. For the first time I have a coherent story in my mind that goes from Relativity of Time to Multiple Universes, from Inflationary Big Bang to Quantum Entanglement. Everything just makes sense the way Brian Greene tells it.

Wikipedia does a great job of describing the book: The Fabric of the Cosmos: Space, Time and the Texture of Reality but I am going to take a different tack and list, in order, the key questions the book discusses.

Q1: Is space real? What makes water in a rotating bucket change shape?

After a great introduction to classical physics, relativity and cosmology he considers the question why does water in a rotating bucket change shape? The answer is because it is rotating “relative” to the rest of us. The question is would it happen if there was nothing in the universe but the bucket? What does the bucket then be relative to? Is there an absolute frame of reference?

This is a great question that leads to the central topic of relativity. Why can we “feel” acceleration but not “feel” constant velocity. You can close your eyes, and you’ll still “feel” if you change speed or direction. Why? The age old question is explained in the book as studied by Einstein, Mach and Leibniz. Special relativity is explained here.

Now the author does a great job separating out special relativity from general relativity.  General relativity extended special relativity to discuss the relative motion of reference frames which were accelerating in reference to each other. Quantum physics is introduced and explained in a very simple way.

Q2: Does time flow? And if so does time have a direction?

A good description of how different observers in different reference frames will see different amounts of time lapse between two events is given. He discusses how time exists just as space and has relative speeds.

But does it have a direction? Does time always move forward? He notes that none of the laws of physics would break if time reversed its direction except the second law of thermodynamics which says entropy (Chaos) in a system always increases. After a good introduction to the different concepts involved, he describes why the fact that we “feel” time flows is just an artifact of the fact that our universe had very low entropy when it started. We are the product of a very highly ordered early universe. In THIS universe entropy is increasing and in our experience that is the direction of time. Quantum impacts on time are also discussed.

Q3: Why is our universe so uniform? How did stars billions of miles away know to be the same?

The concept of symmetry is introduced and what it means to theories of physics. How an early high entropy universe came into being is discussed. Probably the easiest explanation of the Higgs Field and how breaking of symmetry can explain the early universe is given. Inflationary Cosmology is introduced.

Inflation explains why our universe is so uniform. We are living in a small bubble that inflated rapidly and are a very very small part of a very very large universe. Inflation makes several predictions including the cosmic background radiation that have been tested out. The expansion happened because the breaking of symmetry of the Higgs Field.

Q4: Why are there such a large variety of elementary particles?

String theory is now introduced. It is one of the easiest explanations of string theory anywhere.

Planck Length is explained as the fundamental size of the universe. How far String Theory has progressed and its success at explaining all the different fundamental particles as different vibration patterns on fundamental strings is discussed. Insights into M-Theory, a version of string theory where elementary particles are flat branes instead of strings, are given.

The author also explains how the multiple dimensions pointed to by the string theory might exist and how we may experimentally test them some day. These concepts are at the very edge of research today and the book has good explanation of where we are.

Q5: Why do theories bring up such a strange universe?

The book explains how we are highly tuned by evolution into seeing a reality that our senses need to see in order to survive. And how there is concrete and indisputable proof that reality is really very different from what we can imagine.

The scale of space and time, the complexity of the very nature of space and time, and how close we are to revealing the next great mysteries is what makes this book such a revelation. The last 50 years have been an absolute revolution in cosmology and the book does a great job of explaining why.

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Tags: Astronomy, Big History, Cosmology, Inflation, Physics, Relativity, String Theory, Technology, Theoretical Physics