5 comments about The End of Certainty.

1. If you want a simple, elegant, responsible, well-informed book on the origin of the macroscopic arrow of time and on how time-revesibility at the microscopic level resolves many of the quantum paradoxes, read Physics Prof. Victor Stenger's "Timeless Reality". You will get much more out of it.



2. I did buy this book some time ago and then I was fascinated. I studied the basis of his theory, but unfortunately, Prigogine passed away recently, before I can discuss with he some topics in more detail.

   The greater part of the book is written in a natural style, but some sections are highly mathematical even for the majority of scientists! This mathematical presentation has a curious explaining. There are several version of Prigogine's theory, but the first versions had been "abandoned", and then Prigogine details the new approach: "Star-unitary theory for LPS outside of Hilbert space".

   An earlier reviewer said that the book provides a solution to three of the most important problems in science: (1) Time's arrow. (2) The measurement problem in QM. (3) The existence of freewill. Precisely, I am working in those and other questions, and I do not believe that claim was completely correct (and perhaps Prigogine believed the same, because in his last communication, said me "The questions that you ask are very difficult."). In my opinion, the novel theory is conflictive both in mathematical and physical details, but I consider that, at least, the aim of the School is correct one. Irreversibility and uncertainty are two fundamental features of our universe. I see that orthodox physics (including particle physics and the so-called String-M theory) is incorrect and/or inapplicable. I believe that, whereas other "popular" books (The Quark and The Jaguar, The Elegant Universe, etc.) should be "relics" in 21st century physics, Prigogine's book will be then a basic work.

   The contributions of Prigogine's physics to the understanding in other disciplines, as chemistry, are not clear. In fact, I believe that the impact of recent Prigogine's ideas into fundamental chemistry has been "insignificant", because his revolutionaries ideas in physics are an outcome of their previous chemical investigations (Nobel Prize for Chemistry). For example, in his complex spectral theory, energy is an imaginary quantity, and this is in direct conflict with standard quantum theory postulates. However, in theoretical chemistry, one always defines a transition state by means of an imaginary frequency. As said Prigogine in a recent Solvay conference, "all of Chemistry deals with irreversible processes". I cannot say the same of physics.

   The book is very good one, but I disagree in one point. When one writes a scientific paper for publication in a specialized journal (as Physical Review), one can write about everything. Referees and other scientist can either accept or reject your work in scientific grounds. When one writes a popular book for non-expertises, one must be the most "neutral" possible. If this is not possible, one must to "alert" to the reader. This book is not neutral and, in some restricted sense, shows several theories and ideas as been of broad acceptance or current use in science. Of course, this overemphasizes the scientific status of the so-called Brussels School and minimizes the importance of other interesting points of view. In my opinion, this is not a correct attitude. For example, the "diagrammatic" method developed by Brussels School in the 60's (and illustrated in the book) is broadly not used by scientific community. See, for example, "Nonequilibrium Statistical Mechanics" by Robert Zwanzig for a view in more standard formalisms. In addition, I also must say that some previous Prigogine's ideas in dissipative structures, kinetic potentials, etc. are not standard, and other, as the "universal" criterion of evolution (following production of entropy), was experimentally shown to be false. Of course, other contributions of called Brussels School are simply impressive, for example the extension of scattering theory of particle physics to more general situations of chemical kinetics. Effectively, you have read fine, orthodox S-matrix of "fundamental" physics can be derived as an idealized asymptotic version valid for typical accelerator experiments! I am sorry, but I must said that Chemistry is not applied QED.

   Conclusion: The book describes an excellent philosophical view in a "new" physics, and for this reason it may be a central piece on your collection. Nevertheless, I consider that the scientific way proposed is a little conflictive and some mathematics may be modified!




3. Reading this "popular science" book, written by one of the greatest contemporary chemical physicists, was both difficult and satisfying. To avoid a fit of sycophancy, let's just say that I wish I had it when taking my postgrad Statistical Mechanics class. The only negative thing I can cay about this book is that the discussion is somewhat eclectic; it often oscillates between almost trivial philosophy and very high-level, cutting-edge science. It is not clear what the reader is expected to know before starting on this book. That said, if you can work your way through it, you will likely come out with a new understanding of non-equilibrium statistical mechanics and the physics of complex systems.



4. by the late Nobel Laureate on the controversial issue of time's arrow. It's not clear he succeeded but his passion was never missing. He has consistently held in his books that nature is probabilistic even though his explanation of the 2nd law of thermodynamics, that entropy can only hold constant or increase in an isolated system, has evolved. (For instance in acceding to Frank Tipler that gravity breaks invariance.) Much of his motivation seems to have been in sorting out why Boltzman and Gibbs failed to satisfy the science community that their statistical physics explained the 2nd law, due to reversible classical equations and Poincare recurrences. However in order to make his probabilistic argument he may have created a loophole. He points to the Langevin equation as an irreversible equation with noise (friction) and he says Poincare should have connected nonintegrability with irreversibility and most dynamics are nonintegrable. However everyone agrees some (simple) systems are reversible (pendulums etc) so how can all of nature be stochastic? Maybe because the noise terms tend to but never go to zero? However in addressing the arrow of time he suggests gravity which is ignored in thermodynamics as are all interactions; but this explanation is also used by others in deterministic models. So it may never be provable who is right; but if his loophole is real I think there may be a simpler explanation.
   
   Statistical entropy in all of it's variations is an excellent inference tool but it is about an observer's measurements and not underlying properties of the system being measured (frequentist approaches come close but usually have to extrapolate). In this case Poincare recurrence maybe non-physical, a mere statistical fluctuation with no actuality. (Prigogine says it is false because he introduces new microscopic dynamics, I'm just saying it may not arise in reality but only through statistical assumptions which depend on observer uncertainty.) I agree with the explanation at the website secondlaw.com that the thermodynamic explanation of entropy is fundamental as it is a measure of energy diffusion, and not randomness or uncertainty as the tool of statistical entropy would imply. In this way the 2 approaches are not contradictory; the statistical is merely a measurement tool for observers while the thermodynamic is real dynamics requiring no observers (ice melts, water crystalizes etc long before man was around). The current argument in wikipedia that statistical entropy is considered more fundamental because the others can be derived from it is silly; there are many types of subjective entropy measures, the basic frequentist vs Bayesian approaches, there is volume entropy such as for measuring expanding gases, configurational entropy such as for crystals etc; however there is only one thermodynamic entropy, Clausius's dS = <>q/T (for reversible systems; calculations change of course with potential variables of volume, pressure and temperature). If anything this should be viewed as fundamental as it is a direct measurement of the physical movement of heat. One should not confuse information theory and measurement techniques with real underlying dynamics. When some authors say 'entropy is not a property of a system, it is a property of our description of the system' they are referring to statistical entropy measures and not real thermodynamics. As Prigogine says 'irreversability is not just in our minds', that it applies to nonintegral systems identified by Poincare but not the connection. The very same wikipedia current description, possibly by a different author, accedes the point: "The problem with linking thermodynamic entropy to information entropy is that in information entropy the entire body of thermodynamics which deals with the physical nature of entropy is missing...information entropy gives only part of the description of thermodynamic entropy. Some, authors, like Tom Schneider, argue for dropping the word entropy for the H function of information theory and using Shannon's other term 'uncertianty' instead."
   
   
   If Boltzman had accepted that his equation was not fundamental but an inference tool then most of the debates would likely not have arisen, including Prigogine's criticism of an excellent tool that did not deserve to be criticized on that basis. However what he has done is to show mathematically how irreversibility can apply at the microscopic level for nonintegral systems (in agreement with macroscopics) due to non-local persistent interactions but has to be measured statistically at the level of ensembles and not individual trajectories. This is quite a feat even if controversial. Nevertheless the standard entropy calculations apply for equilibrium systems and the arrow of time is still mysterious though possibly linked to gravity as he says. It would have been nice to see some discussion of entropy of non-equilibrium systems for which there is no universal agreement. For instance it is said that 'the rate of change of entropy with time for a nonequilibrium stochastic process is always positive.' [B.C. Bag; the following references are also available on the net with a simple author search.] This might suggest he already solved the problem and gravity is not required? But-
   
   R. Metzler et. al. say 'Prigogine introduced novel microscopic laws which are irreversible with time. One reason for this ongoing discussion is the absence of rigorous mathematical proofs of irreversible properties in the thermodynamic limit...ensemble averages do not give a basic explanation of irreversible properties, since they contain an average over infinitely many trajectories. Ergodic theory does not help either, since it needs time averages over infinitely many trajectories...In this model we introduce a model with deterministic time reversible dynamics which can be analysed in detail...The Poincare return time is known exactly...' However this takes us back to the usual complaints about statistical fluctuations. [Is there a real arrow of time if everything is eventually reversible?]
   
   Castagnino and Lombardi have developed an interesting approach to the question of the arrow of time. [Clearly Prigogine failed by his own admission and his gravity conjecture!] 'In fact time reversal invariant equations can have irreversible solutions. [e.g. the pendulum is time-reversal invariant...however the trajectories...are irreversible...]...The traditional local approach owes its origin to the attempts to reduce thermodynamics to statistical mechanics...[however] only by means of global considerations can all decaying processes be coordinated. This means that the global arrow of time plays the role of the background scenario where we can meaningfully speak of the temporal direction of irreversible processes, and this scenario cannot be built up by means of local theories that only describe phenomena confined in small regions of spacetime...the geometrical approach to the problem of the arrow of time has conceptual priority over the entropic approach, since the geometrical properties of the universe are more basic than its thermodynamic properties.'
   
   Obviously the debate continues. While Prigogine may not have solved the arrow of time, his work on correlations is important as these are assumed away in classical physics but they are critical to life!



5. This is one of the best books which I have ever read in my life.

5 comments about About Time: Einstein's Unfinished Revolution.

1. About Time discusses twentieth century developments in theoretical physics and their impact on our notion of time. Davies is a well known and prolific Australian science writer. I offer the following thoughts for potential readers.
   
   Aimed at the general reader the book does not require a detailed knowledge of physics or mathematics. In light of the counter intuitive nature of modern theoretical physics, however, the uninitiated reader may require a little effort to get the gist of this intriguing but esoteric topic. Given the broad scope of material addressed in the text the time spent on each issue is relatively limited.
   
   I concur with previous reviewers that the book is generally quite readable - Davies' technique of using a hypothetical skeptic as a means to highlight certain issues may strike some as awkward (that was my impression). From an overall stylistic perspective, however, Davies has improved significantly from his earlier efforts and become a solid writer.
   
   The author does a nice job of discussing relativity and some of its implications. For instance, his handling of the twins paradox is among the best I have come across. I agree with Davies that there is solid empirical evidence to support time dilation - his transition from this to a tenseless view of time, however, seems premature - or at least insufficiently argued. Indeed, many of Davies assumptions regarding the nature of time, though interesting, will likely not be convincing to those who do not hold his narrow verificationist view of knowledge.
   
   I found the latter part of the book that discusses highly speculative issues such as time travel to be of limited value. At this point much of the thought in this area, though wonderful to ponder, is largely unstructured and untestable - more science fiction than science. Probably the two biggest challenges facing About Time, however, is it dating (a lot has happened in the interim) and the increased competition in this genre of writing.
   
   Overall, it is not a bad book. There are, however, better options available to readers interested in this subject matter - Greene, Singh and Ferris are authors worth looking at.



2. After eight years in the waiting the CERN Hadron collider is set to resume testing in 2007. In so doing it will -- according to noted physicist Ed Witten -- have an opportunity to test some of the more gross predictions of cosmic string theory and in so doing perhaps re write notions of space and time itself.
   
   That being said, Professor Davies book is up to his usually high standards of scholarship and communication in discussing that most pivtol of topics: time.
   
   From recounting speculations of ancient philosophers such as Augustine to telling the modern story of how we are better understanding time to his own speculations, Davies does a wonderful job of briefly recounting the material and making it accessible to the layman.
   
   Well worth reading, but definately keep your eyes peeled for events at CERN.



3. This over-simplistic physics account which holds that universal time and entropy are reversible and that Poincare's recurrence theorem disproves the 2nd law of entropy increase in isolated systems (and Boltzman's statistical mechanics) ignores the fact that physics equations are idealizations and that mathematical equations are tautoligies that do not define direction or cause. These arguments generally ignore real world effects such as friction, noise, chaos (e.g. the 'many body' problem for gravity) and non-linear effects and correlations etc.
   
   For instance the wikipedia description of Poincare's recurrence theorem points out that environmental noise and chaos alone can break the idealization. In addition chaos can cause entropy increase in both time directions (e.g. P. Cipriani). Various authors (with articles on the net) have pointed out that for non-adiabatic processes, 'the natural evolution of entropy is towards larger values because the natural state of matter is at a positive temperature' (M. Campisi), and only in adiabatic classical mechanics are energy and entropy both conserved and time reversible (e.g. Silverberg and Widom). In addition 'One of the basic postulates of the classical statistical physics is an assumption that the particle's interaction range is considered to be small compared with the system size. If this condition does not hold the internal and free energies, entropy etc are no more additive physical quantities... the Boltzman relationship between the entropy and the statistical weight is not any longer valid. The non-extensive systems are common in physics- gravitational forces, Coulomb forces in globally charged systems, wave-particle interactions, magnets with dipolar interactions etc.' (Apostolov et al, April, 2007).
   
   Essentially all of Davies' book is concerned with the idealizations and so most of the paradoxes he describes are not real and he has not updated the debate since Boltzman from the early 20th century. His analysis of the 'twin paradox' from Einstein's early relativity of the same era is also dated (even though his book is a century later!). This paradox about the twins each measuring each other's clocks with telescopes appearing slower to the other when one takes a fast spaceship into space and yet one returning younger is readily dismissed by Davies as the effect of the traveller's acceleration, is in fact not fully accepted. For instance S. Kak's recent article succinctly describes the actual situation:
   
   "There exist many different 'resolutions' to the paradox [which] are not in consonance with each other. The slowing down of all clocks and processes - including atomic vibrations - on the travelling twin cannot be laid on the periods of accleration and turning around during the journey, since they can, in principle, be made as small as one desires... Einstein's own 'resolution' in 1918 (13 years after Davies says he reolved it!) which was an attempt to counter the criticism related to the paradox until that time, used the gravitational time dilation of the theory of general relativity to explain the asymmetrical time dilation of the travelling twin. This explanation is generally considered wrong and is different from the other 'resolutions...In this article we present a new principle for the identification of inertial frames in a matter-filled universe [assumed away in the other idealizations!] that allows us to easily resolve the twins paradox. The principle implies that the identification of a frame as being inertial depends on whether the universe has spatial isotropy with respect to it. This is equivalent to determining the motion of objects against the background of distant stars."
   
   One might describe this solution as 'Machian', whose central principle was that a particle's mass was determined by all of the other particles in the universe. There has been some evolution of this (Mach's general) theory which has gained some popularity and some authors have shown how it can be adapted to conform to any gravitational theory including Einstein's relativity. There are also some good books on this subject for sale on Amazon.
   
   So once again when one does away with the idealizations and enters some reality into the models one can resolve many of the so-called paradoxes.



4. This, as the title states, is a book about time; all the possible aspects of time, from that of the Greek philosophers, through Newton's idea of time, to Einstein's relativistic view of time and beyond. The book is a blend of philosophy, physics and physiology, but heaviest on the physics aspects of time. Everyone thinks that they know what time is, but on closer examination it is not so clear what time actually is. Is it an illusion or just the interval between events? Does it flow, or is it only perceived to do so? Does time always run forward, or can it run backwards? What is imaginary time, or quantum time? Did time start at the instant of the big bang? What does time look like in a black hole? How does the brain perceive time?
   
   To the ancient Greeks time was a mystery, to Newton time was absolute and to Einstein it is relative to the observer. All these are subjects (and much more) that are discussed in the book; discussed in a very literate and highly entertaining manner. This is not, however, a physics text, although much of it is concerned with the physics of time. There are no equations and only the results of relativity theory, quantum mechanics and cosmology are discussed, not the details. Nonetheless, it brings time to life (to use the sort of analogy that is discussed in the book) in a way that the details of a physics text cannot. I highly recommend this book to students and to anyone who wants their perception of the most basic aspect of consciousness challenged. Read this book and you will never perceive time in quite the same way again.



5. I liked this book. When I read the first pages, I thought that I had chosen the wrong book, but afterwards everything changed. Here you can find a light and clear review of many aspects of time.
   
   It is not perfect, and some times it is not clear what the author means with "time reversal", etc, even if he tries to explain it several times. The theory about the proximity of Doomsday is also quite weak.
   
   In spite of this, you find a clear view of time as it is currently known by science. I have not found many new ideas, but in general they are well structured and consolidates what you have read separately in many other books. Apart from that, it has good rhythm, and it is easy to read and understand.

5 comments about The End of Time: The Next Revolution in Physics.

1. I found this book rambling, difficult to understand, and not particularly well written. The main thesis that all that exists is NOW (see the other reviews for more detail) was not proven in the book and, as far as I can see, cannot be proven empirically (mathematical proof without experimental proof is not adequate). In my opinion this book's theories belong to the realm of science fiction. If you want to let your imagination roam, anything is possible. Maybe everything is an illusion. Maybe I am the only thing that exists in the universe. Maybe there are all sorts of simultaneous universes that are constantly breaking in on each other. Etcetera. If I tried hard enough, I could probably support each of these ideas with concepts from quantum mechanics and the theory of relativity.
   
   I don't think it's unusual for theoretical physics to cross the line from science to conjecture: This book is in that tradition.



2. Barbour's thesis is that time is an illusion, and doesn't really exist. According to Barbour, the universe is a timeless thing existing in configuration space; it doesn't "move through time," but rather exists as an infinitely dimensioned manifold (my word, not his, and I may not have accurately captured his meaning) in configuration space, where each point on the manifold represents the universe in a unique configuration.
   
   Many of the key concepts in this timeless universe were developed by earlier scientists, particularly Mach. Indeed, one of the benefits of reading this book is the many historical highlights and anecdotes provided by the author. Even if you don't subscribe to his timeless universe hypothesis, the books background material in Newtonian dynamics, special and general relativity, and quantum mechanics makes it worth reading.
   
   The first part of the book lays out general concepts, including the notion of configuration space. I particularly liked Barbour's method of using three points (a "universe" with just three points) as a metaphor for the timeless universe he imagines. In this simplified three-point universe one can define a history as just a path through configuration space - thus eliminating the need for a time variable (at least as far as describing a history is concerned, anyway).
   
   One of the traps in both reading and writing this book is that the concept of time is so permanently ingrained into our minds that it seems impossible to discuss the issue without recourse to phraseology pregnant with the very thing (time) that Barbour says doesn't exist. His wording is literally dripping with time-impregnated words as he describes a timeless world. He understands, even apologizes for the problem - but it persists and was a source of distraction and confusion for me throughout the book.
   
   I think the author does a better job of showing how to eliminate time (or at least think in terms of a timeless universe) within the context of Newtonian dynamics, than in a relativistic and quantum universe. The explanations from an Newtonian point of view are pretty straight forward, but as he progresses through special and general relativity, and on to quantum dynamics, the picture - and figures - become more sparse and (it seems) more dependent on speculation.
   
   At an intuitive and philosophical level I find myself largely in agreement with Barbour. There's something weird about time. It doesn't quite fit. I've often caught myself toying with the notion that it's an illusion. On the other hand, we can measure it, and all our measurements seem to be consistent. It's hard to see how we can measure a second so precisely if it's just an illusion.
   
   On another level I'm almost inclined to think the whole thing is based on semantics. After all, if someone told me that pain is an illusion - that it's really just electrical impulses transmitted to my brain - I'd reply that that's an explanation of what pain is, not an argument that it doesn't exist. Similarly, the universe may exist in timeless configuration space, but my consciousness certainly doesn't. Maybe what we mistook for the universe (and us) moving through time is really just us - our consciousness - moving through configuration space. We mistake our travel through configuration space as movement through time the same way someone floating down a river might mistakenly think the trees are moving past them, and they are just standing still. In fact, I wonder if that might be a characteristic of consciousness - something that moves through configuration space - and perhaps the "laws" of the universe look the way they do because our consciousness is constrained, by virtue of its existence, to travel through configuration space along histories (paths in configuration space) that have certain characteristics (increasing entropy, for example).
   
   That's just speculation, of course, but that's what a lot of Barbour's book is, too; a lot of speculation. Not that that's particularly bad, it's just that, in the end, there's nothing really testable here to evaluate.



3. This book, which is flawed & a bit messy, is a fascinating mind-game about what happens if we nix Time or rather Time directionality. We get time-stop-photography wave-function "manifolds", eigenstates, machine-thought, reductio ad absurdum. Humans see at 70 frames/second, so, no chance of us handling light-speed + quantum, unless we get implants.
   I like Barbour's Platonia analogy of "quantum stasis" (P.305). Also his Zen-like Gaussian "becoming-ness". Time is a self-referential human artifice (Leibnitz). To explain Barbour's dogmatic idea of illusion, he posits that the stasis-Platonia is 'fixed' like the 3D turntable of Manhattan in Lauryn Hill's 'Everything is everything". Except the turntable is quantum-flux static. There can be no real Alpha point or Omega point, so one assumes the Big Bang was an illusion. Quantum particles do not obey distance or time & are 5th dimensional. In reality, all 'snapshots' are synchronous. Hence, we and all things that ever were, are alive and dead at the same time in the ETERNAL NOW. Just with "Platonian" separations.
   Heisenberg's dE * dt > h means time is subordinated to energy flow. How we "see" a movie (film strip) is because of the film strip's movement (energy) creating a forward sequence. Time-v-energy is determined by E = mc2 so that the 'now' of different objects is different. One needs a grasp of Mach's principles here.
   If absolute time is DEAD, it means revising all previous metaphysics.
   Also "time travel" becomes a whole different prospect, & curious questions then arise. I don't think Barbour has anything like the total picture, but he's dipping into a Pandora's Box of quantum weirdness. An open mind is categorically required for this stuff.



4. I find many of the reviews useful and well considered but there are a number where it is obvious that the reviewer either didn't read the book or didn't understand it.
   
   Today there are two major schools of physics; quantum theory and relativity. In quantum mechanics space and time must exist on their own. One example is the neutrino. In the standard model (see en.wikipedia.org/wiki/Standard_model) there are the electron, muon and tau neutrinos. For years physicists have tried to study the sun by the neutrinos it emits but there were way fewer than predicted. Last year that problem finally got resolved by the discovery that neutrinos act much more like waves than expected. They change from electron to muon to tau depending on the phase of the wave instead of staying electron as theory predicted. To do this space and time must exist separate from the neutrinos.
   
   In General Relativity time and space dimensions only exist as metrics--that is to the extent that they measure relationships between things; be the things sub atomic particles or galaxies. They have no independent existence.
   
   This dichotomy is why when physicists try to unify quantum mechanics and general relativity they come with silliness like particles traveling backward in time from the edge of the universe. (This to try to reconcile Stephen Hawking's application of quantum mechanics to black holes and finding that they radiate mass to eliminate spin and to decrease their mass.)
   
   The author takes on the one real remaining problem with time and that is time asymmetry. IMHO the explanation he gives is a valid one although conceptually difficult and not again IMHO complete. I could wish that Feynman had addressed the topic as he had a excellent talent for getting complex concepts across. But he refused to have his views on time attributed to him or have them published. Considering the beating Fred Hoyle took over "Symmetric Electrodynamics in Arrow of time Cosmology" he was probably right.
   
   Overall this is an interesting book and a good read although hard going conceptually. Luckily the math is simple trig.



5. I would like to know in person Julian Barbour. His narrative is very good, and he definetively motivates the interested reader. However, my impression is that he took good care of the first chapters of "The end of time", whereas the last part of the book dedicated to quantum gravity and DeWitt equation was written quite fast and without care.
   The beginner get confused. And if you are a physicist, or engineer with some knowledge of modern physics, you cannot grasp the essence. It is too qualitative.
   It would be interesting if any of these guys that claim to understand relativity and field theory target a book to a regular exact science professional.
   Nevertheless, I recommend the book to the reader interested in physics; it is motivating.

5 comments about Time Travel in Einstein's Universe: The Physical Possibilities of Travel Through Time.

1. Summary: Interesting read but when Gott left time travel physics to discuss statistics and probability theory the book became bland like author was padding his essential [time travel, nature of the universe, beginnings, etc & TOE-chasing] published papers with his other non-essential statistical theory work.



2. Gott explores the current possibilities for actual time travel in light of current physics and quantum mechanics. He summarizes the history of quantum physics, as providing insights into the concepts of time, and possibility of wormholes and other perturbations of Spacetime that might allow time travel. He reports on various experiments and lines of enquiry by various physicists, like Kip Thorne, who have investigated time and practical factors in time relationships and travel into the future or past. The concepts of relativity and war speed (speed of light) come into view here. Gott correlates various areas of current enquiry, including a rich survey of contributions science fiction has made to actually enquiry in quantum physics.)



3. I searched extensively for a book that would explain current theories of time and the implications thereof that could be understood by a non-mathematical mind and one not trained in physics, and it was extraordinarily difficult. I ended up choosing this book, which is probably as close as one will get to what I was hoping for. The first and last chapters are actually the most accessible and interesting, the first being an overview of many fictional accounts of time travel (both movies and books) and the last a treatise on future prediction and probability, which I found most interesting and consoling. The chapters inbetween were the denser material in which the author discusses whether or not time travel to the past or the future could work and, inevitably, it deals with the theory of relativity, wormholes, black holes, etc. and how all that would function, all of which is confusing for a layperson like me. Nevertheless, this is, as I mentioned, the closest thing to a non-scientific explanation of what are at base purely mathematical constructs. It does get one thinking philosophically about what "time" is and about time travel in general. For example, if one can travel to the future, doesn't that imply that the future already "exists" as a "place" which one can visit? Mindbending reading and worth it for that reason alone.



4. "The moving finger writes and then moves on, nor all your piety can lure it back to retrace a line nor your tears wash out a word of it."
   
   John Donne
   
   Perhaps if Donne had written his immortal words AFTER having read this book, he MAY HAVE SAID "...unless of course, you have your Richard Gott time machine handy."
   
   And like many other serviceable entries in the time machine genre of scientific speculation (like Paul Davies "How to Build a Time Machine"), Gott uses plain simple English with great illustrations to explain the three traditional theories of how time travel could be accomplished as well using the idea of time travel itself to speculate on the origins of the universe.
   
   As to the three potential theories, Gott makes some good points:
   
   1) Kurt Godel's suggestion that IF this were a rotating static universe, then time travel would be possible simply by going far enough into the future. Significantly, Godel was friends with Einstein over the course of the last fifteen years of Einstein's life. So, while Godel knew both Einstein and Einstein's physics, unfortunately his theory doesn't comport with physical observations that our universe is not rotating is expanding and not static as his theory would require. However, his theory does show that Einstein's physics do allow time travel, just not in the way Godel suggested.
   
   2) The Tipler rotating cylinder...Proposed by Frank Tipler, if you could create and infinitely long cylinder in space and rotate it, one could travel along the access of rotation to move forward or backward in time. Unfortunately, to put it mildly, Tipler's cylinder is a tad bit beyond our current financial resources. (Just over a "few" billion, Congress nixed the Supercolliding Superconductor back in 1993 so they probably would be less excited about this project!).
   
   3) Wormholes. The specialty of Star Trek lore wormholes were discussed at length in the Kip Thorne book "Black Holes and Time Warps." And although Thorne was the idea man beyond how Carl Sagan got Jody Foster to the middle of our galaxy in the movie "Contact," for his part Thorne is not optimistic that Black Holes could stay open to actually transport materials beyond a Planck length. In other words, modern string theory talks about basic building blocks of reality -- strings -- that are in size to a neutron as a neutron would be to our solar system. Even on weight watchers, the astronauts ("chrononauts") would have tough going.
   
   Still the same, Gott noted that even though available for only subatomic transmissions, time travel could still explain how our universe was created.
   
   SPOILER ALERT: IF YOU WANT TO HEAR THE GUY WHO INVENTED IT TO EXPLAIN STOP READING NOW.
   
   But if you're willing to let me do it, here goes:
   
   As noted, time travel -- even backwards -- can work at subatomic levels. The technical jargon is cosmic foam and apparently it happens all the time. To create the universe all that would need to happen is for a sufficiently compacted amount of matter to travel back in time so that it could become the Big Bang.
   
   So in other words, depending on how you denominate it, time may be going now, about to begin somewhere or already be thirteen point seven billion years old.
   
   Even if you read my explanation, read Gott's. He's a great accessible writer who has written perhaps the very best book on this issue.



5. According in pages 68 and 69. Astra must think Eartha 11.8 years instead of 10 years if her departure from alpha centauri is thought to be 8.2 years. I think the best replacement is Astra thinks that he departure from Alpha is simulaneous with Earhta on Earth 6.4 years from the start.

No comments about Nature's Clocks: How Scientists Measure the Age of Almost Everything.

5 comments about The Secret Pulse of Time: Making Sense of Life's Scarcest Commodity.

1. THE SECRET PULSE OF TIME: MAKING SENSE OF LIFE'S SCARCEST COMMODITY explores many time-related issues, from why some folks are morning people and others function best nights, why time either races or crawls, and other perceptions of time, memory, and efficiency. Stefan Klein is one of Europe's leading science journalists and writers, so his scientific perspective on the nature and function of time in society and in personal life makes for excellent, authoritative reading for not only college-level science and psychology collections, but for general-interest libraries who will find it lively enough for easy circulation and lay reader interest.
   
   Diane C. Donovan
   California Bookwatch



2. About: A primer on everything you wanted to know about time and how humans use and perceive it.
   
   Some things I thought were cool:
   
   Time flies when we're having fun because we don't pay attention to time cues
   Every cell in our body has its own "clock"
   City dwellers move, speak and react faster than country folk
   Humans are very poor judges of long lengths of time
   After 200mg of caffeine, people judge time durations as 50% shorter than usual
   Racers start with a shot because we react more quickly to sound than light
   Humans are very, very poor at multitasking as our brains are not adept at switching gears
   Taught time management techniques normally don't stick for a long time
   
   Pros: Very interesting and makes difficult concepts mostly easy to follow. Highlights include spatial hearing, why folks are night owls or morning people, how time is related to stress, memory and attention.
   
   Cons: Dense. A few topics can get confusing.
   
   Grade: B+



3. Like his book on happiness, I have first-hand, life-long account of this topic yet found most of the information new and fascinating. There are three sections. The first on the mental perception of time - biorhythms, attention, memory, etc. The second on the sociological aspects - time wasters, stress, time management. The third and smallest section on the abstract notion - invention of the clock, Einstein's disproof of absolute time. He ends with 6 recommendations for you to better enjoy your time. Overall very informative and practical.



4. This book is rich in information on the way human beings experience Time. There is a repetition of much well- known and common-sensical material( When you enjoy it flies, when you are in anxious waiting- it stands still) But there is a buttressing of such information with interesting anecdotal and experimental evidence. I especially enjoyed the small section in which Klein talks about 'flow' the concept popularized by Mikhaly Csikszentmihalyi. This refers to the focused, concentrated state- of- mind in which tasks have the exact right level of difficulty- neither too easy or too hard. In this situation mind and perception are we feel in our control and our complete attention in the present means past and future do not disturb us. This state of mind comes when we are engaged in a certain activity.
   Klein also explains why the rich despite their ability to delegate all kinds of life tasks to helpers of various kinds feel more pressed for time than most others. The answer is that they have many more options. They are more in Toffler's Future Shock pressured all the time by the many good things than they can give their time to and get.
   In his concluding section Klein mentions six areas in which it might be possible for us to improve our lives in relation to 'time'. These involve in some way moving away from the tyranny of the clock and imposing both at the personal and global level better ways of integrating our own circadian rhythms and mechanisms of human perception of thought.
   He speaks about the importance of reducing stress, of living in harmony with our own body rhythms, achieving balance and relaxation, having a more conscious perception of the present, actively shaping available time and not simply being passive victims of circumstance.
   All these involve using our freedom to use our time more wisely.Efforts of concentration, of honing our powers of perception, of learning to truly take time out and relax, In arguing for a new culture of time Klein says we cannot escape the clock and calendar but need not be obsessed with them. In effect he tells us to follow the advice of Thoreau and 'walk to the sound of our own drummer' to find the personal rhythm of our life which is right for us.



5. I'm closing in on finishing this book, and I have to say that its got it's pros and cons. Many of the pros have already been mentioned here. My personal opinion is that the material is very interesting, and that it can be applied to your life as you read it, which makes the pages turn quickly.
   
   On the downside, this is one of the most poorly edited books I've ever read. Grammatical errors are everywhere, including spelling, punctuation, and tense. I suppose this is more a complaint towards the editors, but it made for some very distracting reads. Some of the authors examples, in addition, felt trivial or poorly thought out. An example: "No matter what lies behind us, we throw a big party when we reach the age of fifty. After another ten or fifteen years at the most, we retire, even if our health would easily allow us to remain on the job." It's nit picky, I know, but the "at most" type writing is everywhere. Generalizations stated as facts left and right.
   
   Now that my rant is over, I want to again stress the fact that the topics covered are very interesting, and that the author covers them in ways that make them understandable. I recommend reading it for anyone interested in the subject of time, but don't go in expecting to read top-notch writing.

5 comments about Galactic Alignment: The Transformation of Consciousness According to Mayan, Egyptian, and Vedic Traditions.

1. Clearly John Jenkins is extremely knowledgeable on his subject. The depth of detail in this book is quite amazing and is written concisely.
   
   For me however, I found the detail a little too much. I couldn't help but think this kind of academic, intellectual inquiry was some attempt to justify the validity of the Mayan Calendar. It seems a distinct possibility to me that one could get lost in the detail of all this and miss the very essence of the Mayan Calendar. The point, in my mind at least, it is to turn inside to the intuitive Self, which is arising so obviously in these turbulent yet exciting years.
   
   I can understand how an academic person would enjoy the deep analysis and mass of information, but a more "heart" directed person may find it all a bit heavy and drawn out.
   
   I suppose the one thing I would simply suggest is that if you are a "heart" type of person, as I am, then maybe this isn't the book for you. As a matter of interest, I found Carl Calleman's books easier and more direct.
   
   And in case you're wondering, I find the whole 2011 versus 2012 debate a little moot. That will show up soon enough. It isn't now. Be here now, in touch with your SELF. Practice that vigilantly, and the rest will follow perfectly naturally. Just like it's supposed to.



2. This book was interesting and a decent read. Jenkins brought a lot if info together and didn't go overboard on the religious rhetoric. I found it to be a good comparison of interesting facts brought together with some interesting opinions with nothing forced on the reader. You are left to make your own conclusions.



3. The book was delivered as was said. The Author brings out a lot of interesting information but is a little long winded at certain points. At times he seems to forget that not all of the readers of his book have his background in the things he writes about. Overall the book was a good deal.



4. Actualy that book is very informative, especially where it touches on the Vedic tradition and the work of Rene Guenon.
   
   Magical Christianity, Revised Edition: The Power of Symbols for Spiritual Renewal with a CD of Guided Meditations



5. i thought this book was really informative giving lots of accumulated info that he has gained from over the years, researching, etc..condensed into a meaningful whole as it relates to 2012. He gave information that i wasn't aware of, so, I HAVE to continue to research FURTHER AND SO INTERESTING, THAT I WOULD BE INTERESTED IN BUYING MORE OF HIS BOOKS TO READ.

5 comments about Bones, Rocks and Stars: The Science of When Things Happened.

1. How does dating affect authenticity in identifying relics and linking historical facts? Eleven chapters each focus on a famous dating controversy, examining the procedures of dating, common methods used to date everything from tree rings to astronomical bodies, and common problems which involve dating. Discrepancies in evidence, forgeries, and misinterpretations are all covered in BONES, ROCKS AND STARS: THE SCIENCE OF WHEN THINGS HAPPENED, an essential pick for college-level collections strong in scientific inquiry.
   
   Diane C. Donovan
   California Bookwatch



2. Turney's book is a great easily read science book explaining how we know when historic and prehistoric events occurred. Each chapter stands alone on its own merits, describing how we know one particular fact, or how one particular measurement system works...but tie together to show how a multitude of different measures can describe events as recent as the 1300s and as distant as dinosaur extinctions 65 million years ago.
   
   This book is great reading for the layman interested in how science works and how scientists can be confident about the chronology and timing of events deep in our past.
   
   The only criticism is that it left me wanting more...I would have devoured a book twice as long!



3. In this series of evocative essays, Turney explains how our continually changing concept and use of time affects how we view the world and ourselves. Using a sprightly prose style, he opens with a description of various calendar systems developed by the ancients. It was difficult for them to reconcile the irregularities of lunar month, solar year and constantly changing heavens. Egypt, Babylon and Rome all struggled to maintain some control over the calendar. Many forms of adjustment were implemented but precision was difficult, if not impossible. The device of the "Leap Year" to adjust for the lack of precision was the best humans could do until the invention of the atomic clock.
   
   The atom, with many versions and intricacies, has proven an effective tool in time-keeping. From measuring split seconds to granting us some insight on circumstances billions of years ago, "atomic clocks" in their various forms have provided many solutions to long unresolved problems. Turney's chapter on the Shroud of Turin is but one example of a practical application. Its status as a forgery went undetected for centuries until radiometric measurements revealed its true age.
   
   A grander sweep of time, yet one with significant implications for today's world are the chapters on the eruption of Santorini in the Mediterranean and what led to the Ice Ages. Thera has been described as the cause of the elimination of the Minoan Empire. Based on Crete four thousand years ago, the Minoans operated an intricate network of trade routes in the region and were a highly sophisticated and successful people. Yet, they disappeared almost instantly around thirty-five hundred years ago. The author examines the evidence that Santorini might have been responsible. Further back in time, he reviews another threat to society in the form of invasive glaciers. Atoms play a role even in ice as accumulations of oxygen isotopes tell the story of climate change events. Even though some of those shifts rely on Earth's orbit and tilt relative to the sun, their signature rests with those oxygen atoms.
   
   Human societies have their own fluctuations, as Turney notes in other chapters. The dating of hominid fossils has contributed a great deal in deriving both the time and place of our origins. Rocks surrounding bones tell us when the fossils lived, and tiny grains of pollen indicate the type of environment they lived in. One of the enigmas of science is why there is but one species of upright-walking ape remaining - us. There have been competitors for living space, most notably the Neanderthals. But at least one other species co-habited the planet with us. The "Hobbit" fossil found on an Indonesian island resided there only 18 thousand years ago, as Turney's own dating research revealed. The possibility that there may be remnant populations yet to be found raises compelling questions.
   
   Turney's book may seem light-hearted at first glance, but it rests on serious work by dedicated workers. Dating the rocks was a difficult science in the 18th and 19th Centuries, but technology has provided astonishing new insights on our world. There's much to be learned and the author's effective presentation makes this book a stimulating introduction to this field. [stephen a. haines - Ottawa, Canada]



4. In eleven thrilling chapters, the author discusses various methods by which items and events from the (extremely distant to not-so-distant) past can be dated. The limitations and uncertainties associated with each method are also touched upon. Each chapter presents a different topic, all real-life cases and some of which the author has actively participated in. The author has been very successful in conveying to the reader the methods by which science works and the excitement involved in scientific discovery. The writing style is clear, friendly, authoritative and very accessible. In fact, as a physicist, I probably would have explained the physics of a few things a bit differently and given more details; but then, this may have been at a cost - a loss in momentum and excitement for the general reader. So, clearly, this is a book that can be enjoyed by anyone, especially those interested in the scientific method.



5. After the first two chapters, this book get really interesting. The first two chapters are about how the different calendars used throughout history are synchronized and whether King Arthur actually existed. Not much science there.
   
   But once we get into science (as opposed to history) things get interesting. For example, the chapter on the Shroud of Turin was great and the way tree rings can be used to date things is fascinating.
   
   Unfortunately, there is very little science here. Instead, this book talks about the stories surrounding various scientific controversies.
   
   I was much more interested in learning about the technical details of things like potassium argon dating, thermoluminesence, and electron spin resonance. But I wasn't gonna get that. Here's the disclaimer from the author when he starts talking about isotopes: "Unfortunately, to understand the [age of the Earth], it's going to be necessary to cross to the other side. I'll try and keep [references to isotopes] to the absolute minimum."
   
   Unfortunately? "The Other Side"? Jimminy Cricket! I learned about isotopes in seventh grade, for crying out loud. I wish someone would write about science as if I actually made it through high school. I want to know about why these methods work, their limitations and when they should be used.
   
   
   And I think I have the right to be disappointed. The book is subtitled: The Science of When Things Happened." Overall, though, it is quite interesting.

5 comments about Time Traveler: A Scientist's Personal Mission to Make Time Travel a Reality.

1. "The moving finger writes and having writ moves on, nor all your piety can lure it back nor your tears wash out a word of it." Jon Donne.
   
   If Prof. Ron Mallett has his way, the words of Jon Donne will be a quaint aphorism that people used to say. The reason Mallett says this is because he believes that the time barrier can be broken and that -- someday -- people will have the technology to travel into the past.
   
   Almost immediately on announcing his speculations, Mallett became the topic of intense media interest including a Learning Channel special and great media coverage. And this is rightly so because the back story of Mallett's motivation -- so ably told in this book -- is itself so compelling.
   
   In 1955, while still a child, Ron Mallett lost his father who died of heart failure at the age of 33. Loving his Dad as intensely as he did, Mallett began to dream of breaking the time barrier to rejoin his father just to tell him "I love you."
   
   Just as everyone can easily connect with Mallett's motivation, mostly everyone will find themselves somewhat befuddled by the science behind Mallett's speculations. This isn't because he doesn't do a good job of explaining himself, but rather simply because scientific explanations typically tend to tax comprehension.
   
   That being said, his theory is an ingenious one: that just as gravity can used to distort time, so can concentrated light. In this way, Mallett must now consider it the sweetest serendipity that he worked in the private sector with lasers for a formative part of his early career. In this way, he became immediately acquianted with the very device he intends to employ in his time travel device.
   
   The typical time travel scenerios that have been set out involve a radical twisting of space. If we were bugs living on a sheet of Christmas wrapping paper, our travel from one end of the sheet to the other would be greatly speeded if we could somehow get the paper from the ends to connect with each other. And indeed, this is what the tradition theories of time travel all propose: that somehow -- whether it's through cosmic strings as speculated by J Richard Gott or black holes as speculated by Kip Thorne -- a force so great is created that space is litterally forced to warp back on itself.
   
   Unfortunately, at the end of the day, Mallett's theories will probably face the same fate at those of Gott and Thorne respecting time travel by people into the past...failure. However, having opened by quoting Donne, it's perhaps best to close by quoting Theodore Roosevelt who said:
   
   "Pity not those who have failed but those who live in that grey twilight that knows neither success nor failure."
   
   By dint of genius, Mallett -- ultimately successful or not -- has irrevocably taken himself out of that "grey twilight" and us with him...if only in our hearts and imaginations.



2. I enjoyed the auto-biography and the quantom physics lessons along the way. I wish more was said about the more recent events concerning the time travel experiments. I felt hungry for more information on the whole subject and was left wanting more.
   
   This was an easy read and I enjoyed reading non-the-less...



3. I heard Dr. Mallett on NPR and ordered the book right away. While some aspects of this book are less than satisfying (Dr. Mallett alternates between hubris and humility in an odd fashion at times....), the emotional quest that set the author on the path of theoretical physics cannot be anything other than deeply affecting. While his personal accounts were sometimes just not quite authentic or unfeigned to me (hey, he's not perfect!), what truly shines in this book is Dr. Mallett's love of science, of math, and his gift for explaining some of the very complex aspects of relativity theory. In this respect, I heartily recommend the book and would hope that he would write further for the general public on the subject. As a PhD chemist myself, I am very appreciative of the gift of teaching with which he is endowed, a rarity among great researchers. His explanations to a general science audience are almost as powerful as those of Feynman. Dr. Mallett's commitment to his lifelong work, his dogged pursuit of any and all tools (mathematical and instrumental) to achieve that goal stand as a shining example. His story should be required reading for minority youth interested in the sciences, engineering, or just seemingly forging ahead in academia. Any flaws in the book are dwarfed by his true artistry in theoretical physics.



4. My son is thoroughly enjoying this book -- he loves learning about astronomy and time travel!



5. Spike Lee has acquired the film rights to this story (spring 2008). "Lee, who will co-write the script for the film and direct it, says he is 'elated to have acquired the rights to a fantastic story on many levels, but also a father-and-son saga of loss and love.'" (University of Connecticut Advance, June 23, 2008)

5 comments about The Mayan Code: Time Acceleration and Awakening the World Mind.

1. This is a fascinating study of the Mayan calendar or time keeping system and it's relationship to the history of the planet earth and other time keeping systems. The author notes comparisons to India and Egypt and other ancient civilizations and points out how evolution speeded up at many places on the planet at the same time.
   Since I am still in the middle of the book, I can't explain more, but I am glued and often rereading sections to absorb all the information. She also inspires me to read her other books which are referenced often in this work.



2. Several reviews have criticized this book for lack of technical depth, yet the author clearly states that this was not her intention and directs you to Calleman's work for this material. You don't hand a child a copy of Webster's Unabridged and say "Here, learn to read & write!" Those who don't really care about the more technical nuances and those who are perhaps not patient enough to wade through all of the "nitty gritty" will appreciate this presentation. Although simpler than others, it still contains much useful material about the Mayan calendar, a buzzword often used and seldom fully understood. I am not the least bit sorry I bought and read this book, though I will agree it could have used a little less frequent mention of her previous work. If you enjoyed "The Mystery of the Crystal Skulls" - buy this book.



3. There are some decent bits about the mechanics of the calendar. However, the author spends more time puking out her political opinions than she does on the subject matter. This book was a major disappointment, as I had to weed through the soapbox-style tirades to find the information on the Mayan calendar and 2012. On the whole, this book was a total waste of time.



4. This book is impossible to read, makes no sense, and basically reads like the ramblings of a lunatic.
   Don't bother with this.



5. This book is a key in understanding not only of our history as humans, but also earth and our galaxy. The Mayan Code is here put together with an astrologers view and reading of the planetary energies surrounding us.
   The upcoming events need millions of readers with comprehensive understanding and why 2011 is so important for our "junk DNA" to lighten up again.
   Highly recommended for the open mind reader!