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The Fabric of the Cosmos
Now, when I say "easy," this is, like so much of Greene's book, relative. It's taken me three weeks to wade through the concepts and often humorous prose that goes along with them. Being something of a physics geek, I have a basic concept of relativity and quantum mechanics. Greene takes his time laying out classical physics, from Newton to Einstein, exploring the version of the universe presented by the laws of the very large. He then dedicates just as much room enumerating the precepts of the standard model as well as those of quantum mechanics. With these two pillars of modern physics established, we are next whisked on a journey through cosmology, delving further and further back into the history of the universe until both quantum mechanics and relativity break down and we are introduced to strings.
Greene's attention to strings does not overwhelm the book, as in The Elegant Universe, and he doesn't delve deeply into the concepts and math behind any of the theories of physics as in the latter half of his earlier text. What he does present is a very good conceptual overview of modern physics, all the while using the frameworks provided to drive at the central question: What are space and time? (Or "spacetime" as relativity puts it).
This sophomore effort is actually better, I believe, than The Elegant Universe. Greene has a way of explaining things in terms that non-physicists can grasp. His use of pop-culture icons to drive his points home are as masterful as they are funny. It would be my bet that should this book be made into its own television special (and it should) it will have to be a joint work by PBS and Fox. After seeing Greene present his Elegant Universe on PBS, and reading this book, I'm beginning to see him as a new Carl Sagan, or perhaps the illegitimate love child of Sagan and Matt Groening, if such a thing were possible.
In the end, though, the book has left me with more questions than answers. To be sure, Greene and the theories that he covers provide answers, but to conceptualize and understand them is my current difficulty. I'm sure that some of my own problems arise from learning through allegory. Not having the mathematical background to understand these concepts on a more fundamental level is, I'm sure, leading to my own habit of taking an allegory too far. Would the book benefit from a deeper analysis of physics? I don't think so. To take things much deeper would lose those of us without a deep rooting in mathematics. If anything, Greene's work should inspire us to learn more, to grasp the concepts at a deeper level, to understand them in a more fundamental way, if this is indeed possible with the strange world of quantum mechanics.
Greene does delve into what the future of physics could hold. This is, in my opinion, the weakest part of the book. While it is interesting to be exposed to what the 'next big thing' could be, without the grounding that Greene enjoyed in the previous four sections of the book the final chapters prove less fulfilling than the ones that worked towards them. It's not that Greene doesn't explain the concepts expertly, but knowing that we're reading about a theory that hasn't even been fully formed, that is only a step away from speculation, means they don't stand as tall as the previous chapters. People may say this about string theory as well, because it is still very much an evolving theory.
Still, this accounts for no more than the denouement of an otherwise thrilling, work. Having traveled once again with Greene on a journey through physics I can say that I understand what Feynman meant when he spoke of The Pleasure of Finding Things Out; thankfully Greene is a good bit easier to follow than Feynman.
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If you haven't seen the series of PBS specials, "The Elegant Universe", I recommend that you do. They're free for download from the PBS website IIRC. It's an excellent and very informative discussion of some very interesting concepts.
It's kind of an ugly plaid corduroy, with elbow patches.
Recently I joined the local astronomy club in Santa Cruz, CA. The night I joined the feature was a lecture, "The Mystery of the Ultimate Fate of Small Black Holes" presented by Donald Coyne. The scope of matter, energy and time necessary for various things to take place is baffling, at least to me. Black Holes take a lot of time to be created. The Universe is estimated to be 13 billion years old. The theories put forth were such that black holes have formed and are dissipating (something about reaching a critical mass then collapsing in upon themselves, and kicking out staggering amounts of energy in radiation.) It seemed to me that for some of these things to have taken place the Universe would have to be older (as some of the processes would take longer than the universe has been in existence for.)
It's fascinating stuff, but a little goes a long way.
Oo! My widdo bwain, it bwoo my widdo bwain! Oo! Oo!
A feeling of having made the same mistake before: Deja Foobar
According to this daring young thinker, our whole silly idea of time being a continuum from past thru present onto the future may be bunk. With the abolition of the time interval and precise measurements of place at a certain time, it solves some of the great mathematical paradoxes. You can read a better layman's summary and explanation here.
The concept of time is so passe...
Karma Police, come arrest this man...
I have found the concept of special relativity particularly fascinating. The way that Einstein described spacetime I still find to be quite neat, even though it's a (relatively) old theory at this point. It seems like we're on a speed-of-light course through this universe, and when you're relative velocity is 0, then you are traveling through time at the speed of light (if such a concept can be grasped), and conversely, when you travel at the speed of light, then time is stopped for you (so that the vector sums of velocity through space and time always add up to the speed of light). The simplistic genious of that blows me away, and I love reading any material that has any more insight or explanation into relativity. I even find quantum mechanics to be interesting to study (though the math sucks).
I bought The Elegant Universe a few years ago, and I loved it. I think this is definitely going to be worth checking out at the library.
Disclaimer: I'm not a physicist, and don't even know that much about physics, but I'm very interested in the philosophical implications of Greene's view of time, or what little I read of it.
I briefly read one of this book's chapters on time, and it doesn't seem to explain much. Greene argues that time doesn't flow by pointing out how, due to special relativity, events in my future may be in someone else's past.
Therefore, Greene concludes, all events, past, present, and future, must already exist and must always exist. And our sense that time flows is an illusion.
Interestingly, Greene explicitly REJECTS the notion of a "projector" illuminating one cross-section of this frozen river of time one piece at a time. He rightly sees the problem with this analogy: when does the projector operate? It would have to operate at no time at all, so the concept is incoherent.
How does Greene account for flow? He says that the feelings, thoughts, and perceptions one has at any particular point in time contain sufficient context that one senses their relationship to the past and to the future. This we call flow.
My problem with this explanation is that I don't think you can have thought without change. I don't think there is reason to believe that there is a fundamental unit of time, within which some kind of fundamental unit of thought would exist.
Thought is inherently based on movement or change in our mental landscape, and this movement must happen in time. There is no possibility for thinking without flow. Thinking cannot account for flow, but rather assumes it.
Also, if we take the frozen river hypothesis, how do we find ourselves at one point in time and then at another point in time... how does this movement ever occur? And to whom? Wouldn't we be locked helplessly at our one "point" in time?
Finally, even if special relativity does show that events in one person's future may subjectively be perceived in another person's past, the very fact that we can correlate these two pieces of information: does that not show that there is some master set of times that relates everything to everything else?
On this subject, I always liked Max Tegmark's speculations on the topic, which includes some assessment of why we have only one, and not zero or two or more temporal dimensions.
There's lots of other cool stuff on Max Tegmark's site too if you want to procrastinate on whatever else you're doing. (He's a physics (astrophysics?) professor at U.Penn.)
--LP
Time is what you lost when you started reading /.'s stories.
Space is what you lost when you started downloading things.
Just common knowledge...no need fo a book to grasp that.
Wait ! I got it !
Money is what you lost when you bought the book when you could have just read my post.
=P
... not to mention other important questions, such as "When is the universe?", "Who is matter?", and "Where the hell is the remote?"
Use Ctrl-C instead of ESC in Vim!
there was an interesting NPR interview with greene about his new book last week:
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http://freshair.npr.org/day_fa.jhtml?display=da
It's one line, but the backslashes should take care of it, if your browser doesn't insert needless spaces:
a 1a1afb6ae049ae214fc034aad839a9198\f 362d841a61948bf2688f01f87fb\b /nova_eu_30[12-14]c[01-\
curl -f "http://a768.g.akamai.net/5/768/142/3f9e\
9589/1
5ea187bea5786
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08]_mp4_300.mov" -O
First off, this stuff is hard. No, really hard. You need to focus down and study this stuff for years before you can really get up to speed and read the preprint server with any understanding. Oh, and did I mention those years need to be spent hanging around people who already understand it?
Secondly, overviews are hard -- and hard to write well. The value of a good overview is respected by everyone in the field. You need maps with different grades of detail.
Thirdly, first hand experience: at least one of the string theory people I know read the first Greene book when she was starting out and loved it. Plenty of other physicists and astronomers I work with have read it just to get a sense for what is going on in this rather abstracted part of physics they don't have the time to catch up on.
Oh, and fourthly, this kind of book does wonders for scientific literacy and interest in the general public. Selfishly, it helps build the case for continued public funding of this kind of thing. Better put, it is a sort of 'return' to the public that repays them for their support by working hard to generate a story both intellectually respectable and comprehensible to the educated and motivated layman.
Protect your liberties. Donate to the ACLU
What's 1+1? Have you ever seen a 1? Then how do you know two 1s make a 2?
What's a zero? What's the very concept of nothing? Have you ever seen nothing? Then how do you know it exists?
I'm sure the scientists both in favor of and against String theory would have a few choice bits of evidence to offer up in support of their theory.
Instead of reciting the scientific method like a third-grade science teacher to a class, why not offer something more substantial, and, dare I say, SCIENTIFIC to support your hypothesis?