Showing posts with label Physics. Show all posts
Showing posts with label Physics. Show all posts
Wednesday, 31 July 2013
I have read this book once, but feel that it is a book that requires more than one reading. It is not an easy book, although it is also an introductory book and does explain all concepts. There is no requirement to have a degree in science, or even much understanding of mathematics.
I think the problem is that the world of particle physics is complex and confusing. It is very different from our normal view of the world and it seems harder to rely on the sort of analogies that are common in cosmology. A Big Bang seems easier to visualise than virtual particles.
The book details the sheer difficulty in particle physics, and that several decades passed between the Higg Boson being postulated(by lots of people not just Higgs) and discovery. Billions of euros and vast amount of data have had to be gathered. The author leaves it up to the reader to determine if this is a good use of resources, and indeed argues it is a pure search for truth rather than relying on the usual arguments for spin off benefits.
I did take away some things from this book. It offers an introduction to the Standard Model of particle physics. The standard model looks like:-
Quarks make up the nucleus of atoms. Leptons are not subject to the strong force and are most important in electrons which give atoms their chemical properties.
The Higgs Boson is important because it explains why some of the particles have mass. It seems this is not the source of mass in the universe, as this is caused by other interactions within atoms(as energy is mass and the energy of particles reacting leads to mass). The other role is breaking symmetry, but I must confess on first reading of this book I do not really understand this.
I liked this book a lot, it is readable and has advanced my understanding of a complex area. I am left wondering if there are other introductory books on particle physics that might allow me to approach it from another angle and so develop a further understanding. Or perhaps Brian Cox will do a television series.
Monday, 29 July 2013
This book looks at time; why time seems to flow in one direction? Why can we not remember the future?
This is a more complex puzzle than it appears as the laws of physics are all reversable, they all work if you run them backwards - provided you make certain other changes. For example you could reverse time with the earth rotating around the sun, but you would need to also reverse the direction and angular momentum.
The author explains how the tendency of entropy to increase differentiates the future from the past. The future is more "chaotic". He does this by explaining statistical mechanics in a reality easy to explain way.
After this he asks why the Big Bang, the start of the universe, was such an ordered state and how we found ourselves to be here. The short answer is nobody knows so there is much speculation and he dips into quantum physics, black holes, whether we could build a time machine and multiple universes. The book becomes more speculative as it goes on.
The author ends with a model that involves our universe being a sort of bubble universe that broke away, it emerged as a flux in a larger empty space with just periodic fluctations(something called a De Sitter space which is basically empty space with just virtual particles popping in and out of existence). I read a similiar theory in Roger Penroses Cycles of Time, but I found that book far harder to read.
This is a good book, especially the first half. The author avoids the use of mathematics to describe his theories and so is forced to use analogies in the Stephen Hawkins style. I am sure this means leaving out some of the depth as analogies are rarely perfect. But most of us lack the ability to perform the mathematics, so this is probably a wise step especially when it comes to book sales. I found the second half grew a little more speculative, but it is a book I have read on more than one occasion. It seems a bit more advanced than other books that endless recount twin astronauts travelling at different speeds. And the range of material is quite vast.
This is a more complex puzzle than it appears as the laws of physics are all reversable, they all work if you run them backwards - provided you make certain other changes. For example you could reverse time with the earth rotating around the sun, but you would need to also reverse the direction and angular momentum.
The author explains how the tendency of entropy to increase differentiates the future from the past. The future is more "chaotic". He does this by explaining statistical mechanics in a reality easy to explain way.
After this he asks why the Big Bang, the start of the universe, was such an ordered state and how we found ourselves to be here. The short answer is nobody knows so there is much speculation and he dips into quantum physics, black holes, whether we could build a time machine and multiple universes. The book becomes more speculative as it goes on.
The author ends with a model that involves our universe being a sort of bubble universe that broke away, it emerged as a flux in a larger empty space with just periodic fluctations(something called a De Sitter space which is basically empty space with just virtual particles popping in and out of existence). I read a similiar theory in Roger Penroses Cycles of Time, but I found that book far harder to read.
This is a good book, especially the first half. The author avoids the use of mathematics to describe his theories and so is forced to use analogies in the Stephen Hawkins style. I am sure this means leaving out some of the depth as analogies are rarely perfect. But most of us lack the ability to perform the mathematics, so this is probably a wise step especially when it comes to book sales. I found the second half grew a little more speculative, but it is a book I have read on more than one occasion. It seems a bit more advanced than other books that endless recount twin astronauts travelling at different speeds. And the range of material is quite vast.
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