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THE LATEST PROFITEER IN EINSTEINIANA
http://www.wired.com/wiredscience/2010/02/what-is-time/
"Sean Carroll is a theoretical physicist at Caltech where he focuses on theories of cosmology, field theory and gravitation by studying the evolution of the universe. Carroll's latest book, From Eternity to He The Quest for the Ultimate Theory of Time, is an attempt to bring his theory of time and the universe to physicists and nonphysicists alike. (...) Sean Carroll: I'm trying to understand how time works. And that's a huge question that has lots of different aspects to it. A lot of them go back to Einstein and spacetime and how we measure time using clocks. But the particular aspect of time that I'm interested in is the arrow of time: the fact that the past is different from the future. We remember the past but we don't remember the future. There are irreversible processes. There are things that happen, like you turn an egg into an omelet, but you can't turn an omelet into an egg. And we sort of understand that halfway. The arrow of time is based on ideas that go back to Ludwig Boltzmann, an Austrian physicist in the 1870s. He figured out this thing called entropy. Entropy is just a measure of how disorderly things are. And it tends to grow. That's the second law of thermodynamics: Entropy goes up with time, things become more disorderly. So, if you neatly stack papers on your desk, and you walk away, you're not surprised they turn into a mess. You'd be very surprised if a mess turned into neatly stacked papers. That's entropy and the arrow of time. Entropy goes up as it becomes messier." Unlike Brian Greene who is still procrusteanizing his mind into conformity with Einstein's time-is-an-illusion idiocy, Seal Carroll seems to have taken notice of what clever John Norton teaches: http://www.salem-news.com/articles/j...dj_6-22-09.php "For those of us who believe in physics, this separation between past, present and future is only an illusion, however tenacious" - Albert Einstein http://www.geekitude.com/gl/public_h...50422141509987 Brian Greene: "I certainly got very used to the idea of relativity, and therefore I can go into that frame of mind without it seeming like an effort. But I feel and think about the world as being organized into past, present and future. I feel that the only moment in time that's really real is this moment right now. And I feel [that what happened a few moments ago] is gone, and the future is yet to be. It still feels right to me. But I know in my mind intellectually that's wrong. Relativity establishes that that picture of the universe is wrong, and if I work hard, I can force myself to recognize the fallacy in my view or thinking; but intuitively it's still what I feel. So it's a daily struggle to keep in mind how the world works, and juxtapose that with experience that [I get] a thousand, even million times a day from ordinary comings and goings." http://www.newscientist.com/article/...erse-tick.html "General relativity knits together space, time and gravity. Confounding all common sense, how time passes in Einstein's universe depends on what you are doing and where you are. Clocks run faster when the pull of gravity is weaker, so if you live up a skyscraper you age ever so slightly faster than you would if you lived on the ground floor, where Earth's gravitational tug is stronger. "General relativity completely changed our understanding of time," says Carlo Rovelli, a theoretical physicist at the University of the Mediterranean in Marseille, France.....It is still not clear who is right, says John Norton, a philosopher based at the University of Pittsburgh, Pennsylvania. Norton is hesitant to express it, but his instinct - and the consensus in physics - seems to be that space and time exist on their own. The trouble with this idea, though, is that it doesn't sit well with relativity, which describes space-time as a malleable fabric whose geometry can be changed by the gravity of stars, planets and matter." http://www.pitt.edu/~jdnorton/Goodie...age/index.html John Norton: "A common belief among philosophers of physics is that the passage of time of ordinary experience is merely an illusion. The idea is seductive since it explains away the awkward fact that our best physical theories of space and time have yet to capture this passage. I urge that we should resist the idea. We know what illusions are like and how to detect them. Passage exhibits no sign of being an illusion....Following from the work of Einstein, Minkowski and many more, physics has given a wonderfully powerful conception of space and time. Relativity theory, in its most perspicacious form, melds space and time together to form a four-dimensional spacetime. The study of motion in space and and all other processes that unfold in them merely reduce to the study of an odd sort of geometry that prevails in spacetime. In many ways, time turns out to be just like space. In this spacetime geometry, there are differences between space and time. But a difference that somehow captures the passage of time is not to be found. There is no passage of time. There are temporal orderings. We can identify earlier and later stages of temporal processes and everything in between. What we cannot find is a passing of those stages that recapitulates the presentation of the successive moments to our consciousness, all centered on the one preferred moment of "now." At first, that seems like an extraordinary lacuna. It is, it would seem, a failure of our best physical theories of time to capture one of time's most important properties. However the longer one works with the physics, the less worrisome it becomes....I was, I confess, a happy and contented believer that passage is an illusion. It did bother me a little that we seemed to have no idea of just how the news of the moments of time gets to be rationed to consciousness in such rigid doses.....Now consider the passage of time. Is there a comparable reason in the known physics of space and time to dismiss it as an illusion? I know of none. The only stimulus is a negative one. We don't find passage in our present theories and we would like to preserve the vanity that our physical theories of time have captured all the important facts of time. So we protect our vanity by the stratagem of dismissing passage as an illusion." However Sean Carroll has not yet taken or does not want to take any notice of what clever Jos Uffink teaches: http://philsci-archive.pitt.edu/archive/00000313/ Jos Uffink: "This summary leads to the question whether it is fruitful to see irreversibility or time-asymmetry as the essence of the second law. Is it not more straightforward, in view of the unargued statements of Kelvin, the bold claims of Clausius and the strained attempts of Planck, to give up this idea? I believe that Ehrenfest- Afanassjewa was right in her verdict that the discussion about the arrow of time as expressed in the second law of the thermodynamics is actually a RED HERRING." Pentcho Valev |
#2
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Hi, Pantcho here. I have some more Einstein stuff for you. I've givenit a new title again. Hope this doesn't annoy and confuse. Goodbye.
Pentcho Valev wrote:
http://www.wired.com/wiredscience/2010/02/what-is-time/ "Sean Carroll is a theoretical physicist at Caltech where he focuses on theories of cosmology, field theory and gravitation by studying the evolution of the universe. Carroll's latest book, From Eternity to He The Quest for the Ultimate Theory of Time, is an attempt to bring his theory of time and the universe to physicists and nonphysicists alike. (...) Sean Carroll: I'm trying to understand how time works. And that's a huge question that has lots of different aspects to it. A lot of them go back to Einstein and spacetime and how we measure time using clocks. But the particular aspect of time that I'm interested in is the arrow of time: the fact that the past is different from the future. We remember the past but we don't remember the future. There are irreversible processes. There are things that happen, like you turn an egg into an omelet, but you can't turn an omelet into an egg. And we sort of understand that halfway. The arrow of time is based on ideas that go back to Ludwig Boltzmann, an Austrian physicist in the 1870s. He figured out this thing called entropy. Entropy is just a measure of how disorderly things are. And it tends to grow. That's the second law of thermodynamics: Entropy goes up with time, things become more disorderly. So, if you neatly stack papers on your desk, and you walk away, you're not surprised they turn into a mess. You'd be very surprised if a mess turned into neatly stacked papers. That's entropy and the arrow of time. Entropy goes up as it becomes messier." Unlike Brian Greene who is still procrusteanizing his mind into conformity with Einstein's time-is-an-illusion idiocy, Seal Carroll seems to have taken notice of what clever John Norton teaches: http://www.salem-news.com/articles/j...dj_6-22-09.php "For those of us who believe in physics, this separation between past, present and future is only an illusion, however tenacious" - Albert Einstein http://www.geekitude.com/gl/public_h...50422141509987 Brian Greene: "I certainly got very used to the idea of relativity, and therefore I can go into that frame of mind without it seeming like an effort. But I feel and think about the world as being organized into past, present and future. I feel that the only moment in time that's really real is this moment right now. And I feel [that what happened a few moments ago] is gone, and the future is yet to be. It still feels right to me. But I know in my mind intellectually that's wrong. Relativity establishes that that picture of the universe is wrong, and if I work hard, I can force myself to recognize the fallacy in my view or thinking; but intuitively it's still what I feel. So it's a daily struggle to keep in mind how the world works, and juxtapose that with experience that [I get] a thousand, even million times a day from ordinary comings and goings." http://www.newscientist.com/article/...erse-tick.html "General relativity knits together space, time and gravity. Confounding all common sense, how time passes in Einstein's universe depends on what you are doing and where you are. Clocks run faster when the pull of gravity is weaker, so if you live up a skyscraper you age ever so slightly faster than you would if you lived on the ground floor, where Earth's gravitational tug is stronger. "General relativity completely changed our understanding of time," says Carlo Rovelli, a theoretical physicist at the University of the Mediterranean in Marseille, France.....It is still not clear who is right, says John Norton, a philosopher based at the University of Pittsburgh, Pennsylvania. Norton is hesitant to express it, but his instinct - and the consensus in physics - seems to be that space and time exist on their own. The trouble with this idea, though, is that it doesn't sit well with relativity, which describes space-time as a malleable fabric whose geometry can be changed by the gravity of stars, planets and matter." http://www.pitt.edu/~jdnorton/Goodie...age/index.html John Norton: "A common belief among philosophers of physics is that the passage of time of ordinary experience is merely an illusion. The idea is seductive since it explains away the awkward fact that our best physical theories of space and time have yet to capture this passage. I urge that we should resist the idea. We know what illusions are like and how to detect them. Passage exhibits no sign of being an illusion....Following from the work of Einstein, Minkowski and many more, physics has given a wonderfully powerful conception of space and time. Relativity theory, in its most perspicacious form, melds space and time together to form a four-dimensional spacetime. The study of motion in space and and all other processes that unfold in them merely reduce to the study of an odd sort of geometry that prevails in spacetime. In many ways, time turns out to be just like space. In this spacetime geometry, there are differences between space and time. But a difference that somehow captures the passage of time is not to be found. There is no passage of time. There are temporal orderings. We can identify earlier and later stages of temporal processes and everything in between. What we cannot find is a passing of those stages that recapitulates the presentation of the successive moments to our consciousness, all centered on the one preferred moment of "now." At first, that seems like an extraordinary lacuna. It is, it would seem, a failure of our best physical theories of time to capture one of time's most important properties. However the longer one works with the physics, the less worrisome it becomes....I was, I confess, a happy and contented believer that passage is an illusion. It did bother me a little that we seemed to have no idea of just how the news of the moments of time gets to be rationed to consciousness in such rigid doses.....Now consider the passage of time. Is there a comparable reason in the known physics of space and time to dismiss it as an illusion? I know of none. The only stimulus is a negative one. We don't find passage in our present theories and we would like to preserve the vanity that our physical theories of time have captured all the important facts of time. So we protect our vanity by the stratagem of dismissing passage as an illusion." However Sean Carroll has not yet taken or does not want to take any notice of what clever Jos Uffink teaches: http://philsci-archive.pitt.edu/archive/00000313/ Jos Uffink: "This summary leads to the question whether it is fruitful to see irreversibility or time-asymmetry as the essence of the second law. Is it not more straightforward, in view of the unargued statements of Kelvin, the bold claims of Clausius and the strained attempts of Planck, to give up this idea? I believe that Ehrenfest- Afanassjewa was right in her verdict that the discussion about the arrow of time as expressed in the second law of the thermodynamics is actually a RED HERRING." Pentcho Valev |
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