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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.
You can purchase The Fabric of the Cosmos from bn.com. Slashdot welcomes readers' book reviews -- to see your own review here, read the book review guidelines, then visit the submission page.
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.
Why, it should be obvious to even the most dim-witted individual who holds an advanced degree in hyperbolic topology, ng-bwui.
I particularly enjoyed the cast of Simpsons characters throughout the book. While I'm sure it would have been just as informative had he used different personalities, it might not have been quite as entertaining.
...it's got a real problem with static cling.
effect
I still havn't got through Hawkins history, and that was supposed to be brief!
And if you thought that was boring you obviously havn't read my Journal ;-)
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
see?
why is space?
why is random?
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...
ok, lame subject... just wnated to say that every review i read on this book has be drooling. I ordered it last Saturday, and it may even arrive this afternoon. After reading the preface standing in Borders, I've been psyched to get to the rest...
this has to be, by far, the subject I have the most interest in.
now if I could only figure out a way to write a novel about deism, mysticism, quantum physics, and some young computer hacker, all together, THEN ID BE RICH!
If I had a million dollars...
"I think, therefore I get paid."
I like The Illustrated Brief History of Time more than the none illustrated version. I saw Elegant Universe on PBS and really liked the visuals. Mr. Greene - give us non-geniuses more visuals to help understand this stuff.
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.
Time is what prevents everything from happening at once.
Atomic batteries to power! Turbines to speed!
I finished Elegant Universe a few weeks ago, after having put it down for most of a year because I couldn't stand to read another rehashing of QM, relativitiy, isn't this weird. After skipping those chapters, the second half was quite engrossing.
Is it worth reading this if you already read and enjoyed Elegant Universe, or is it just a watered down version without explaining the math?
I would hope a reviewer would give a little more insight into whether to read it or not.
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 a unix machine type $cal 9 1752
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Explain - is not a bug. That was when the Colonies switched from Julian to Gregorian calender.
try { do() || do_not(); } catch (JediException err) { yoda(err); }
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
Yeah. Popularizing science and maybe getting more people interested in it. Sounds real terrible.
Dumbass.
... 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!
Time is what keeps everything from happening all at once.
Simple as that.
Nobodies Prefect
Tidbits for Techs Technology Blog
What can be bad about more people being less afraid of science (or math, for that matter)?
Will it infringe on your elitist clique?
the direction where Entropy is increasing...
Great definition !
I hope it helps....
I just love Thermodynamic
^_~
(Beware: people who don't understand mathematics need not apply.)
You answered your own question. People who don't know higher math (like me) need some interpretation to understand it. And in fact, most of us don't need to understand the pure math to be struck by these concepts, and maybe use them to place ourselves a little better in the universe.
You sound like one of Heinlein's elitist characters.
Or were you just posting to brag that you know higher math? Whew, sometimes nerds with knowledge of "cutting-edge physics" seem to miss the boat when interacting with us mere mortals.
there was an interesting NPR interview with greene about his new book last week:
y &t odayDate=03/16/2004
http://freshair.npr.org/day_fa.jhtml?display=da
I miss Jon. I always viewed him something like how the upper crust society types view the writer of the society page in the newspaper. I found him amusing, and kind of cute about how he seemed to think he was part of the techno-culture, and really wanted to belong, but all he really did was write, badly ABOUT the techno-culture.
Miss you, Jon. Hugs and Kisses.
Mod down people who tell people how to mod in their sigs
to tackle the very question of 'why is time?'
I never thought time was a terribly complicated topic. It boils down to change. If nothing, and I mean nothing at all, ever changed, then time hasn't passed.
How can you say it has? If nothing has changed, you have no way of judging, measuring, or scaling 'time'. Time is the difference between one moment and another.
Think about dimensions. I've often heard the '4th' dimension referred to as time. Well take an object in the 3rd dimension and 'graph' its changes. Those changes are the 4th dimension of the object - what happens to it over time.
It's all about change, as far as I'm concerned. How can you say time has passed if nothing has changed.
-kidlinux.
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
6fdf0e7ceb61c22186f
08]_mp4_300.mov" -O
Kaku, but if you want to go to the horse's mouth, read or try to attend a general talk by either Witten or David Gross.
TSITP.
"Does anyone else hate popularisations of science?"
Sort of, which is why I treated this article somewhat flippantly. I hate popularizations of science that are misleading and get it wrong. To be fair though, whenever you summarize something innevitably you will leave out some important details. But even "real" scientific papers have summaries and abstracts, so popular articles and books have their place as long as they document their sources. The beauty of science is that ultimately anyone can verify the truth by looking for themselves.
Where are other good sites to see shows like Nova online? Streaming or not, it's pretty interesting.
Is that true? Would it be enough for me to just buy "The Elegant Universe"?. I have an electrical engineering level from University, so I am in no ways a Physics illiterate, so I don't need everything chewed up and explained to me as if I were a retard (but of course, I enjoy witty analogies and clever commentaries).
What is mind? No matter. What is matter? Never mind.
" if you don't shut up i will fucking hunt you down and shit in your heartvalves."
That would be a rather unpleasant example of cause and effect.
Cause I don't have time to read it.
There's a growing sense that even if The Future comes,
most of us won't be able to afford it.
-- Lemmy
is "religion for scientists".
it's certainly not science.
Take the cheese to sickbay, the doctor should see it as soon as possible - B'Elanna Torres, "Learning Curve"
Time first began with Prince in the 80's and ceased to exist by 1990.
Perhaps you could define 'quality' for me?
Here's a hint, your knowledge of math wont help you.
Point: You cannot learn everything from a textbook. Concepts such as time and space belong as much in the world of philosophy as they do physics. Mastering scale-invariant general relativity gets you nowhere in your understanding of why more information was exchanged with the person across the crowded room with two tenths of a second of eye contact, than there was in the five minute conversation you just had with your boss.
truss me. I hate technicalisations of philosophy, but occasionally I'm capable of appreciating them
The basic answer is that creation is all about change, and change can only happen with respect to time.
Now, I know that this sounds simple (and it is, in a way), but there are some very important ideas about change via time that people should understand, namely that this entire creation is created for us, the human beings, and that our ability to utilize the creation to its fullest depends upon how we *consciously* change over time.
How do I know this? Well, believe it or not, our Creator *wants* us to know about this creation. This is why we have been given this great mind: to understand this creation (including ourselves). Our free will, on the other hand, has been given to us as the gift that allows us to explore creation via our mind at our own discretion.
BTW, time ends when the universe stops expanding. Closely following the stoppage, the kinetic energy of the universe (so-called 'dark energy' which prevents the matter from collapsing back upon itself) will no longer be able to hold gravity in check and then comes the Big Crunch, though that is much more highly accelerated than the expansion phase.
[Puts on flame suit]
After that, comes the viewing of our *two* life films (as to how we used our free will), one for actions and one for thoughts (for the judgement of intention, which gives weight to our actions).
For those of you who doubt this, just ask your Creator; that is, if you believe "knock and the door shall be opened, seek and ye shall find".
Mathematics will never *explain* these facts, thought mathematical models may describe this process.
For more info, check out www.mihr.com.
Peace & Blessings,
bmac
When will they learn that every thing you need to know can be learned by reading science fiction. "Time is an illusion, lunch time doubly so."
HAHA dumbass... YHBT !HAND now you have lost karma, jerk!
Goddamn it. With your karma bonus, the mods will waste 3 points on your post before we don't have to see that obscenity.
The important thing is, this book is written by a scientist, not a scientific correspondent.
I've definitely noticed that ideas tend to propagate into literature pretty quickly these days. "Chaos theory" is, well, you can't spit in a bookstore without hitting fiction that mentions it. Unfortunately, chaos theory is a bit of niche (potentially rich, don't want to offend anyone) -- whereas the recent science shelves have been much more wide ranging. The Gribben book came out in (um) 1989?
Hopefully we will get some good Stephenson-esque stuff out of this when authors get around to reading the new crop. I hope we get stuff that actually engages with the analogies and metaphors and the mechanisms of the ideas, as opposed to stuff that just renames the 'warp drive' the 'dilaton drive.' It really is wild.
Protect your liberties. Donate to the ACLU
"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."
Great theory! And it also goes to show why sometimes a relative outsider or unknown can be best at uncovering truly novel solutions.
Those too well-versed in a certain field have often, by definition, already "drank the Kool-Aid" and bought into the belief system prevalent in said field at the time. As such their views and investigations are already prejudiced and pre-directed.
Those who dare stray are then likely to be quickly herded back into place by colleagues who "know better".
For example this guy, who went through all kinds of hell from his peers who "knew" that a bacteria could not possibly cause ulcers.
BTW, time ends when the universe stops expanding. Closely following the stoppage, the kinetic energy of the universe (so-called 'dark energy' which prevents the matter from collapsing back upon itself) will no longer be able to hold gravity in check and then comes the Big Crunch, though that is much more highly accelerated than the expansion phase.
However, current evidence indicates that, instead of slowing down as predicted by "Big Crunch" models, the expansion of the universe is speeding up. So no end of time after all.
Unfortunately, "popularisations" lend themselves to misunderstanding. My favorite subject (theology) is the frequent victim of uneducated assault by people who have managed to parse the simplistic ideas offered in Sunday School or similar settings, and so believe themselves to be experts.
Very few people have the time or inclination to understand enough of the fundamental "tools of the trade" to actually understand what scientists are talking about, but they are still curious. It would be nice if everyone had enough leisure time to become experts in mathematics so they could genuinely understand what scholars are talking about, but that just isn't going to happen. Do we then deny people any understanding at all because they can't understand everything? If so, what on earth for? Just so a few elitists can protect knowledge in an ivory tower from the unwashed masses?
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
IIRC (and this is via other scifi fan friends), Heinlein was in many cases poking fun at his own family with those characters. His wife was something of a polymath. Thus, Heinlein himself was one of the math unknowing "tolerable subhumans who have learned to not make messes on the floor"
I know enough math to keep up with a fair bit of the theory (though it's a little rusty). So, I suppose I qualify for this ones standards.
On the other hand, I don't know that much about running a pharmacy. No one disses me for not knowing that. So, why should someone who, for example, is a pharmacist be dissed as an ignoramus for not knowing advanced physics?
Fourteen years of Physics didn't tell me - although I only got a BS. (No, it didn't take me that long, I studied on my own before college...)
Now I study my mind using Buddhist meditation methods (as opposed as from a Psychology book).
These were my favorite links I found:
the Gandavyuha and Kadampa view
Considering my office is right down the hall from his, and I finished his book a couple weeks ago, I'll throw in my recommendation for JR Gott's "Time Travel in Einstein's Universe".
:>
Very interesting read which explains things in a manner that I could understand (sysadmin, not astrophysicist, though I'm surrounded by them daily). Maybe I should send in a Slashdot book review too
Three dits, four dits, two dits, dah!
Radio, radio, rah rah rah!
You know, I could finish reading your rant, or I could get back to Ethel the Aardvark Goes Quantity Surveying. Tough decision, really.
A feeling of having made the same mistake before: Deja Foobar
The "scientific" method is this;
1. Observe some aspect of the universe.
2. Invent a tentative description, called a hypothesis, that is consistent with what you have observed.
3. Use the hypothesis to make predictions.
4. Test those predictions by experiments or further observations and modify the hypothesis in the light of your results.
5. Repeat steps 3 and 4 until there are no discrepancies between theory and experiment and/or observation
Has strings ever been (or can be) observed in nature??
They have not.
Physics without a testable hypothesis is Philosophy.
String theory is not science.
Take the cheese to sickbay, the doctor should see it as soon as possible - B'Elanna Torres, "Learning Curve"
Yes and no. You could think of this as "The Elegant Universe" Rev 2. It is dumbed down a bit (not terribly) but I think it more comes from Greene refining his delivery than from deliberately appealing to a lower intellect. If you don't like thinking about Bart Simpson racing a beam of light it's not for you. Real stick up brainiacs might see the alegories that Greene uses as 'dumbing down', but I find them amusing and a good way to suck geeks into his world.
What if it is just turtles all the way down?
This is all very intriguing but I have a lot to do. I'll look at it yesterday when I have more time.
It will download the files.
...is "The Gifts of the Jews," by Thomas Cahill. In it, he postulates that the Jewish people were the first to introduce the concept of linear time into a world of circular time. It's a very humanitarian treatment of time, as opposed to something Hawking might put out. It's definitely an interesting read, regardless of how twitchy your Godometer is.
But dealing with the content of the book... Is the material covered in TFOTC just a subset of TEU? Is there something new in it as I have already read it? I would like to know if it is worth the buy. Sorry if I ask so much, buy I'm overseas and it's really expensive and slow to have this book delivered here...
Just kind of wondering, do you consider thought to be fundamental to the point of working on all scales?
The way I would resolve that kind of issue would be to think of thought as basically a chemical process which doesn't arise until time scales so large that the difference between time being a flip-book and time being continuos are irrelevent. (I.e. for thoughts that take significant fractions of a second, time being cut into sub-femto-second slices or being truly continuos doesn't make much of a difference.)
Say for example it is possible to make a true AI out of a Turing machine. This is a bit of a leap, but would you accept this? If that were possible, then somewhere deep in the guts of those thoughts, operations would be happening in discrete chunks. So, for that thinking entity there is no meaningful possibility of time less than the period of the clock running its hardware. Of course, stuff is still happening, the hardware is moving from state to state, but the way that is happening could be discontinuos and it wouldn't make any difference to the AI.
Perhaps this raises the question, would it be possible for a thinking entity to operate at such high speed that it would percieve time differently? Or would you consider that the experience of time is so fundamental that it must operate the same no matter how fast one thinks?
Time is an illusion. Lunchtime doubly so.
As a species, we're not big enough to understand time. We mark it, we plot seasons, and we slice it up and pare it out. We understand a relationship between time and resources because our species climbed to sentience with that understanding.
We are incapable of understanding ourselves.
Our species is literally incapable of understanding itself. This isn't an accident, it's a joke biology plays at the insistence of the genes to prevent the organism from interferring with the need to make better code. Even though we have the undestanding of what genes are there's an endless list of things we're not supposed to do because some divine bogey-man is going to jump out of the closet and bitch-slap us. Ha. Hahah. Riiight. If detonating atomic weapons didn't bring the ass-whipping we'd had coming since the Romans invented the Catholic Church nothing is.
We understand very little about gravity which is a seemingly tangible concept that doesn't need to clip its toenails or do the dishes. It's there all the time and we're clueless.
Gravity is often described as a distortion of space and time.
It could be said that the complete ignorance of the most lethal species on the planet creates very real distortions in space and time.
Often, we hear things from people who steep themselves in white-boarded rooms thick with the odor of Dry-Erase markers and stale sweat/breath/ass-dreads and coffee that within an 11, or 15 dimensional universe everything makes sense. This could be the fumes talking for the person.
In much the same way as all the poets before them, the authors of "knowledge for masses" books don't come out and proclaim,
"There's the answer you seek. Right there. With that kernel of information you can move worlds."
Their dance is the mastrubatory romp of students and scientists and the audience is either expected to descreetly turn away or get the lotion and bring their own towel.
You do know where your towel is? Right?
Every new form of media has it's own Requirimento
Comment removed based on user account deletion
Yes there is new ground covered in TFOTC, specifically more coverage of the 'braneworld' theory of strings, a large secton on cosmology, inflation, and what that means, as well as a section at the end detailing a little bit of what the future holds and the possibility for experimental evidence of string theory. For me this didn't amount to much more than what I'd already read in 'Faster than the Speed of Light' and Scientific American, but it was good to have it in context. Some of the stuff on quantum mechanics was also better than TEU.
For me it was worth the buy, but as I stated I'm a physics geek. (And I could pick it up at my local B&N)
What if it is just turtles all the way down?
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When someone really is trying to understand science and asking hard questions (but without an axe to grind either way), the first question is what makes scientific "fact" better than something just made up. This is the question you answered. Theories must be falsifiable.
The second question though is much harder. Basically, how can you be sure your theory really "explains" things sufficiently (whatever that means). Even though Kepler's Laws are observationally sound, still somehow they dont really explain what is happening with planetary motion the way universal gravitation does.
So, the second question is the hard one. Just because QM makes testable, correct predictions, does it really "explain" what is going on?
This is the value of string theory. Before we could have universal gravitation, we needed the fuzzy non-observational concept of potential energy. Perhaps before we can really explain physics on the smallest scales of space and time, we need a fuzzy non-observational string theory.
"This film gets my highest rating, 7 out of 10!"
--Jay Sherman
"A great democracy must be progressive or it will soon cease to be a great democracy." --Theodore Roosevelt
1. Observe some aspect of nature via /.
2. Google the subject matter
3. Prove the material right or wrong by linking to what you found
4. Offer your unsolicited political or philosophical view
5. Wait for the same story to appear six months from now
6. Lather, rinse, repeat
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Now, first off, I consider bmac a friend and a very enlightened fellow, so please don't take this as me saying "Oh, this guy doesn't know what he's talking about."
I don't know exactly what to think about free will. It seems impossible to me on the one hand, and indispensable on the other. In the end, I think my beliefe comes down to, "We should believe in free will and act as if it is real, even though it isn't." See, free will has to come from some place. Where do the individual impulses to will originate from? They must originate within the interconnected system we call the universe. These impulses originate within the system, not outside it. By definition, anything that interacts with the universe is part of it. If our free will is shaped by external forces, it isn't ours. What is ours? Nothing. Everything we consider to be 'self' in fact originates from non-self. There is in fact no true division between self and non-self, just the comfortable illusion of same. Yet we need to believe in free will in order to function effectively in the universe.
Now, bmac and I have had some conversations in our respective journals, and I know his philosophy and respect it, but I ask, bmac or anyone else who cares to respond, where does our free will originate, and how exactly is it ours? Every composite thing comes together due to circumstances, and when those circumstances disappear, so does the thing. Nothing has self-existence apart from it's interaction with the all. Everything originates in the same ground of being. So again, how is our free wil actually ours?
Now I know the concept of free will is a hot-button topic, so let's just consider this a philisophical excercise and not an excuse for a flame-fest. Anyone have any ideas on the matter?
- None can love freedom heartily, but good men; the rest love not freedom, but license. -- John Milton
Just after the PBS special was made available online, I put together a page with links to all the segments here. That way my friends who were interested could download them and watch them later.
- sm
Ok, I think I will buy it. Do you have any recommendations for a wannabe physics geek :)?
I have read books as "Superforce", "Runaway Universe" by Paul Davies, works and essays from Asimov, books by Carl Sagan, etc., but obviously science must have progressed a lot since all that was written :) !
Any other good quality books or authors I should look for?
You're on.
Killing vectors: take a clock with you on your spaceship. Fly from star A to star B, and time it. Now, you get a new mission: fly from star A to star B along a slightly altered path, displaced at each point by a small amount determined by a particular vector field. (Yeah, in my million dollar PBS special, I get to have cartoons to make this easier to see.) To your amazement, your clock measures the same time!
Some spacetimes have the strange property that you can define an entire vector field (cue cartoon) with this property. Some spacetimes are even weirder! They have multiple vector fields like this. Actually, perhaps they are no so weird (cue cartoon of flat space.)
"diffeomorphism-invariance" is a scary-sounding way to express the fact that physical facts are unchanged by a shift in coordinate system. If I were to write a book, I'd start with the idea of gauge invariance and the difference between coordinates and events.
"You [me] wrote: "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." That's all well and good. I'm simply saying that people who work as theoretical physicists/mathemagicians wouldn't read it since they'd never stop picking holes in it. Popularizations, sadly, do have a place in our world."
By "sadly," you seem to imply that anybody -- including other scientists -- who is not at the tail end of a Ph. D. in string theory (which is the level we are talking about) -- is in a sad state. I'm sorry, but this is just crazy.
Your attitude is sufficiently condescending as to be absolutely insane.
Protect your liberties. Donate to the ACLU
with the both of you.
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If one now says that time is discrete and they postulate the unit of duration and;
Space is discrete and they have a unit of space and;
We know how long the Universe has been around and;
We know how big it is;
How many discrete bits does it take to describe it all and at what rate do we need to add more bits?
Faster Than the Speed of Light just came out on paperback and is a good read AND a good intro to cosmology.
The End of Time is also available in paperback. I never managed to get though more than 4 chapters, but Barbour has some very intriguing ideas about time, and I've seen him mentioned along with Loop Quantum Gravity, which is a good sign.
Hyperspace was written before TEU, and suffers from age a bit. It was written before Witten unleashed M-Theory on everyone (or just after) I read it immediately after TEU so I bored me, the rehash of Relativity and QM can get a bit tedious in these books unless you spice it up like Greene does.
Three Roads to Quantum Gravity looks promising, and details String Theory's main competitor on the Quantum Gravity front, Loop Quantum Gravity. I picked it up, but couldn't get into it.
I've read Hawking and a few others, but I've never been able to get into things from the 'classical' side of the equasion. Feynman is REALLY difficut to get into, his prose just doesn't flow like Greene's. Perhaps I'm a mass consumer and so esoteric physisits don't appeal to me as authors.
What if it is just turtles all the way down?
Actually, with a few extra words (like including subsets of the path), what I wrote is a workable definition of Killing vectors as they are used in General Relativity. A few more words, and I'd cover even pathological cases.
Weinberg's book eschews the whole talk of manifolds and makes it rather hard to see the issues in a cartoony way. I prefer MTW. Ironically, I think your point would be better made for particle physics, which is a lot less tractable in cartoons. I like those books a lot less, and have not seen a satisfactory one, because it takes a mind the order of Feynman's to really get at the heart of the issues without a huge amount of notation.
Furthermore, had you bothered to address the part of my post that came after "Popularizations, sadly, do have a place in our world," you'd have to admit that I wasn't being condescending at all. Rather, it was a roundabout way of lamenting the continuing fall in the numbers of students deciding to pursue careers in the sciences.
I object to the attitude of your posts on this subject. Scientists have had enough trouble in the past for their arrogance, and I think these popularizations are the best possible news. Essential aspects of high-level science can be conveyed with a minimum of mathematics by those with the skill, and that should be praised to the skies, not damned.
By the way, I know many people around here who loved Greene's book but were less keen on the PBS version. I haven't seen it, but I suggest you give Greene a chance, and try to distinguish between gosh-whiz BS and serious efforts at popularization. Look at the regulars on sci.physics.research, and the amount you can accomplish with a minimum of required background.
Protect your liberties. Donate to the ACLU
As Stephen Wright said, "On a scale of 1 to 10, with 6 being the highest, am I weird?".
Who is John Cabal?
I just saw that NOVA is running "The Elegant Universe" this evening.
Great ideas often receive violent opposition from mediocre minds. - Albert Einstein
Also add in the number of bits to describe the all various elementary particles.
Rather, it was a roundabout way of lamenting the continuing fall in the numbers of students deciding to pursue careers in the sciences.
The point is, of course, that were more money invested in introducing people to science properly, without all the bells and whistles that Brian Greene felt were necessary to make his PBS series palatable to the public, perhaps we wouldn't have to endure things like the cancelling of the SSC during the mid 90s.
One significant thing a book like this can do is generate interest in the pursuit of scientific careers. For instance, my wife, after devouring a couple of these 'popularisations', one of which being The Elegant Universe by Mr. Greene, is now pursuing a degree in physics, primarily due to increased interest these books instilled in her.
These books function well as what they are: an overview of the subjects within. After reading them, one can choose whether to be satisfied with that, or to further pursue the subject with more advanced physics texts. For myself, and perhaps I am biased by the close anecdotal evidence, is seems to be that books like this encourage the pursuit of careers in the sciences.
First of all, the basics: There is the One, of which we are all a part.
My 'feeling' is that the One is probably a very lonely individual.
So the One turned inward, (like a lonely child), but with an imagination of limitless bounds! It split It's awareness countless times so that all perspectives, all thoughts, all experiences are percieved, thought and experienced. A wonderful distraction from the Lonliness and Boredom of being the One!
Thus, each tiny fragment of Itself gets to interact with the other pieces, each forgetting its origin so that the meetings can be vital and engaging and new! The sense of having, 'free will' is important to this illusion, otherwise, there would be no vitality; no sense of life and death importance to each, 'decision'.
And since each and every possible combination of interaction is out there being experienced, Free Will is probably important as it keeps each of the scenarios separate; (my feeling is that there are no duplications, that each experience is a one-of-a-kind, even if the differences between them are very small.) Thus, exercising Free Will, while it would not be 'important' in the ways many might think, is nonetheless an integral action within the giant ball of All required for the whole process to work.
My one concern is that We, once we all rise to the top and reunite with the One, (as the journey appears to be), that we will be done and alone once more. What then?
We will find out, I am sure. Indeed, if my model is anything close to correct, then we probably already know!
Cheers to you, my fellow fragment! Good journeys.
-FL
Quick! Explain entropy. Explain the arrow of time. Describe string theory. A little foggy? Then read the damn book! Greene lays it out easy for anyone who wants to get up to speed because they did hangover time in physics class. This is the first great, popular, cutting edge physics book of this millennium. The other six or seven dimensions may be out there and can be tested soon. If you snooze you lose.
"...while history is usually explicable it is often irrational" --Roger Spiller
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It would be nice to travel backward in time to the mid 80's before all this India offshore shit hit.
" Everyone understands the concept of time to some degree, yet to explain why time is, is a mental puzzle that has played in the outskirts of my mind for years now"
if you can't explant it, you don't understand it.
The Kruger Dunning explains most post on
Isn't it funny how science fiction has become science fact? More than three dimensions... Parralel universes... Wormholes...
At this point I think it is entirely possible that at some point in the not too distant future, say a hundred years from now, we could have star trek like transporters. And not ones which pull your atoms apart and send them at light speed to another destination, but ones which operate using prinicples we learn from stirng theory which allow us to create small stable wormholes without using huge amounts of energy.
Sounds impossible now, but this stuff is so crazy that just maybe we will discover that it is indeed possible to travel to another location almost instantly, without dissasembling ourselves.
If nothing changes, no time...no?
This is actually a few responses rolled into one...
The first is, that I love it when somebody who has a full grasp of a profoundly exciting and difficult to understand field, like advanced physics, breaks down the critical concepts and presents them for general consumption. It's important to understand the way our universe is put together. It gives you a better idea of your place in the universe, how one actually relates to all things... the great and the infinitesimal. It also demands that you build up the mental muscles necessary to appreciate a complex and diverse existence... the lack of critical or rigorous thinking, is one of the greatest failings of our current culture.
I had the profound pleasure last night to listen to a lively conversation being given by one of the top nuclear scientists of the last century (a Fermi Prize winner, and a person who knew Eistein personally.) Listening to him talk about both theory and the state of the current nuclear situations in the world, listening to him speak with certainty, clarity, and simple unavoidable logic... left me awed at his vision, and intelligence. If we can't be these people, we should at least bother to understand what it is that they bring to us in appreciating our universe, our world, and ourselves.
When really bright people create literature like this, it make's me yearn for the time that this stuff will be available in electronic format. In addition, these "books" should have the ability to provide levels of interaction. Provide user levels from the commonplace monologue, and simple illustrations that make the concepts easy to grasp, to richer interactions including maybe video and some of the more challenging math. This way, it's up to the reader to dig into the topic at any level they're comfortable with, and we can be simply entertained or fully enlightened. Anyhow, it would be a great way to use college undergrads (folks always in the chase for extra credit and desire to understand a subject fully), not to mention, when the time to go into the work world happens, they can always point to their contribution in a published work... prospective employers eat than stuff up!
Genda
We are all really, really broken in the head. Time, as we experience it, is a total illusion. --But it is an illusion which allows for the perception of physicality; --if you were aware of all possibilities existing at the same time, you would perceive of yourself as being something rather like an ever-evolving smear.
Every choice you make in your current brain-damaged, "single-frame advance" form is what takes you from one step to the next. In the fully aware version, physicality becomes variable, because you can focus on a reality and pull it into being by exercising choices across an entire 'life-time'. Existing in that form, I suspect, probably comes with it's own version of 'time', because that level is probably just a brain-damaged version of the next one above it.
Don't bend your mind trying to picture this stuff. You are mentally impaired and you can't do it. Things are changing though. All those little introns are wiggling around and beginning to come active in those who are struggling to wake up! Lots of perceptive abilities which haven't been expressed yet. .
Some of you will have already started experiencing brief bleed-throughs as the paradigm shift rushes ever-nearer. --Here are a three of the multiple reality 'encounters' I know of, (the last two of which I've directly experienced).
Stuff like that. Yes, quite terrifying, but they only last a few hair-raising moments, and you can snap out of them at will, (for the time being anyway.) Watch for them and learn from them; you'll need to be able to stay calm if you make the transit. And yes, all of this while not on drugs. Drugs are for idiots; they'll just weaken your ability to deal when the shit hits! Gettin' closer real fast, kids!
When? Well, the shit is supposed to hit at the same time as the big cloud of comets wipes out everything on this planet. Be a nice time to be able to morph your reality, eh? Otherwise, it's apocalyptic fire storms for you! (But don't sweat it. You'll just reincarnate where you need to. It'd be cool to actually make the transition without dying, though! And certainly into a reality where there isn't an ice age in full swing and nothing left but smoking rubble and black glass.)
Final note: I don't care what you believe, no collection plate will be passed, there is no book to buy and no representative will come to your door. Deal with it. (And no, I have no relation to 'Time Cube' guy. He's just insane. Whereas I'm the guy who is going to haunt your thoughts every time you trip over something which jars your reality. --Unless, of course, you're already way ahead of me, in which case, 'Cheers!')
-FL
If time didn't exist, we would have no use for our serial ports.
I am anarch of all I survey.
... String Theory is really the way the Universe works. Personally, I don't think it is. Quantum Loop Gravity is slowly working it's way into mainstream physics and perhaps it is a more correct description of Space-time.
http://www.newtonphysics.on.ca/EINSTEIN/index.html
Jamey Kirby
There is change, and time is just our perception of the change.
You can measure the change, but if you are familiar with the popular thought experiments for relativity, you can see that if you give up this idea that time is something that exists on its own, the paradoxes (I'm older than my twin brother, how astounding!) melt away.
C'mon, this is Duck Dogers in the 21st and a half century (almost)!! Give up on that low-tech, retrograde Chevy Impala type thinking.
.signature: No such file or directory
Maybe I can help, since I know mathematics well enough, but not these specific concepts:
1) Okay, so which vectors are the "killing vectors"? You never said, exactly? I assume they're the vectors of this vector field? I assume that these two missions left at the same time?
And is this vector/vector field a property of the spacetime, or no? Is it some kind of unique "signature" of the spacetime? Can you give me some examples of the killing vectors for commonly used spacetimes? What good is it, exactly?
2) I'm not clear on how coordinates and events could be the same to begin with, exactly, so saying that they're different doesn't help much. What physical facts remain unchanged, by the way?
I assume you mean forces and their tensors and things like that? Such as, under classical mechanics, you can do all the math in, say, spherical coordinates or polar coordinates or cartesian coordinates, depending on whichever is simplest for your problem, provided you do all the proper transforms so that you're using the same forces/laws of physics in each of the models?
Time truly doesN't exist. The universe is timeless, eternal. By nature, time is a dualistically fabricated concept. What you consider the past is nothing more than the present fact of you recalling your memories. What you call the future is nothing more than the present fact of you holding expectations. What is real is now. The universe manifests itself in an endless cycle of now moments.
The universe perishes and is reborn an untold number of times per second -- it essentially changes configuration endlessly, perfectly.
There are some who hold that the universe began X billion years ago. Some also hold that the universe never began, and thus never ends. Still more hold that the universe begins when you're born and ends when you die, since the idea of a universe and consciousness to them are not mutually exclusive.
How about I suggest a book? The Spectrum of Consciousness by Ken Wilber. Read him.
- IP
Last night you were all "Wow, your time has no points," but now you are like "Man, I need my phase-space."
Time is *supposed* to keep everything from happening at once.
It's not working, and hasn't been for some time now.
Bill Stewart
New Fast-Compression-only CPR http://preview.tinyurl.com/dy575ks
The answer is 42.
First a little bit on the "elegant universe" hype. In this regard we come to the extreme edge of cosmological speculation: string cosmology. These models are based on an alternative to the standard quark model of elementary particle physics. So-called string theory (or M-theory) conceives of the fundamental building blocks of matter to be, not particles like quarks, but tiny vibrating strings of energy. String theory is so complicated and embryonic in its development that all its equations have not yet even been stated, much less solved. But that has not deterred some cosmologists from trying to craft cosmological models based on concepts of string theory to try to avert the beginning predicted by standard Big Bang cosmology.
The most celebrated of these scenarios in the popular press has been the so-called ekpyrotic scenario championed by Paul Steinhardt. In the most recent revision, the cyclic ekpyrotic model, we are asked to envision two three-dimensional membranes (or "branes" for short) existing in a five-dimensional space-time. One of these branes is our universe. These two branes are said to be in an eternal cycle in which they approach each other, collide, and retreat again from each other. It is the collision of the other brane with ours that causes the expansion of our universe. With each collision, the expansion is renewed. Thus, even though our three-dimensional universe is expanding, it never had a beginning.
Now apart from its speculative nature the ekpyrotic scenario is plagued with problems. For example, the Horava-Witten version of string theory on which the scenario is based requires that the brane on which we live have a positive tension. But in the ekpyrotic scenario it has a negative tension in contradiction to the theory. Attempts to rectify this have been unsuccessful. Second, the model requires an extraordinary amount of ad hoc fine tuning. For example, the two branes have to be so perfectly aligned that even at a distance of 10^30 greater than the space between them, they cannot deviate from being parallel by more than 10^-60. There is no explanation at all for this extraordinary setup. Third, the collapsing and retreating branes are the equivalent of a 4-D universe which goes through an eternal cycle of contractions and expansions. In this sense, the cyclic ekpyrotic model is just the old oscillating model writ large in 5 dimensions. As such, it faces exactly the same problem as the original: there is no way for the universe to pass through a singularity at the end of each cycle to begin a new cycle and no physics to cause a non-singular bounce. Finally, even if the branes could bounce back, there is no means of the physical information in one cycle being carried through to the next cycle, so that the ekpyrotic scenario has been unable to deliver on its promises to explain the large-scale structure of the observable universe. These are just some of the problems afflicting the model. It is no wonder that Andrei Linde has recently complained that while the cyclic ekpyrotic scenario is "very popular among journalists," it has remained "rather unpopular among scientists."
But let all that pass. Perhaps all these problems can be somehow solved. The more important point is that it turns out that, like the chaotic inflationary model, the cyclic ekpyrotic scenario cannot be eternal in the past. In September of 2001 Borde and Vilenkin, in cooperation with Alan Guth, were able to generalize their earlier results on inflationary models in such a way to extend their conclusion to other models. Specifically, they note, "Our argument can be straightforwardly extended to cosmology in higher dimensions," specifically brane-cosmology. According to Vilenkin, "It follows from our theorem that the cyclic universe is past-incomplete," that is to say, the need for an initial singularity has not been eliminated. Therefore, such a universe cannot be past-eternal.
OK, now that the hype is out of the way, let's talk a little bit about time. Philosophers of ti
but I'm pretty sure Who is on first.
Karma: NaN
Related site about physics
Jhon Baez site
especially interesting
Open Questions in Physics
Alternative approach - quantum gravity without strings Building Spacetime from Spin - this theory have some troubles - they arn't able to get a flat space-time as a classical limit of their theory, but now they are tryng apply the same approch to strings - a lot of math which I don't understand, but little part which I understand fascinating...
Sigh. I really wish there would be fewer, but weightier attempts at making science understandable to people. The trend in recent years to try to make everything in the form of infotainment simply hurts everybody's understanding of things - people end up having a kind of view of science that only fits into a Superman cartoon - you know, where 'mutations' can magically change a person into a slimy monster, temporarily, and where 'X ray vision' can look through 10 miles of granite, but not 1 millimeter of lead, etc etc. Even Startrek did a better job of popularising science than much of what I have seen recently.
As for the fundamental understanding of time and space - there is literally nobody, I'd claim, who understands this, which is why we see such concepts launched as eg. 'quantisation of space and time', which is profoundly nonsensical. (the reason, if you must know, is that since we live 'inside' space, we have some considerable difficulty seeing space from 'outside', which is where this discontinuity would be apparent).
The truth is - physics is stuck in a rut, and we need a fundamental change in viewpoint before we can progress any further. String theory and quantum mechanics are all very well, but they all build on ideas that are now about a century old, and which have been stretched to their limits. The Copenhagen interpretation hasn't really helped either - this massive block of philosophy stating that 'there is nothing smaller than whichever quantum limit' has been a religion that has done a lot to block our progress towards a better understanding of things on a small scale. In case you'd care to know - all quantum mechanics really says (in this respect) is that because of the dual wave-particle nature of matter, it is impossible to measure things on an arbitrarily small scale using only particle interactions; this clearly doesn't mean that there is nothing going on there.
To compare: imagine that we try to observe ships in the ocean by standing on the beach and making waves - we wouldn't be able to 'see' ships smaller than the length of the waves. So to se better, we create shorter waves, but since they contain more energy, they push the smallest ships around, so we can't locate them precisely. Does this means that there's nothing smaller than what we can observe? Of course not - we just need to find another way to observe them. The limitations in quantum mechanics are more about limitations in the observation methods than about reality.
Everyone understands the concept of time to some degree, yet to explain why time is, is a mental puzzle that has played in the outskirts of my mind for years now.
... As long as nobody asks me, I know; when someone asks me and I try to explain, I do not know any more.
May I refer you to Saint Augustin who lived roughly in the fourth century? See this link (sorry, French only -- ask Google for a, ahem, translation).
Here's the epigraph:
What is, indeed, time? Who could explain it clearly and briefly?
Saint Augustin, Confessions, XI, 14, 17
The most eloquent of the group promoting loop quantum gravity as an alternative to string theory, Lee Smolin, makes what I believe to be a significant point that string theories, like quantum theory but unlike general relativity, are background dependent, that is they just assume the existence of spacetime rather than establish it.
Yet there is something about all current approaches that smacks of epicycles. Great scientific theories have an elegance which appears to be missing from current attempts to bridge the gap between the micro and macro domains. Theory needs that kind of elegance and the wider comprehensibility which comes with it to be accessible to real critique.
If those who have not shared a lifetime of indoctrination are unable to play in the sand pit, the "experts" can get away with ever more circular cases of theoretical blinkers and instrumental blindness which only ever return the answers they are looking for, as well as all the funding advantages that come from having sidelined the nay sayers.
One side of me wants to suggest that our current infatuation with anything to do with information really might produce A New Kind of Science which breaks down a few barriers, but the only honest position is that the jury is still out on that one too.
Some of my own work hints that computer models of seemingly irreversible systems readily generate local time reversibility and that starting inflation may be a lot easier than stopping it, but leaves some other fundamental phenomena needing to be explained within the same frrame of reference. I mainly try such experiments to get a better feel for the state of play and right now my best estimate is that the next real revolution in physics might still be a generation away, but that one is coming.
-- Our systemic servants do not good masters make.
This guy might have the answers if you have any questions about the nature of time.
The problem is that pop-sci movies/books are made to make money. They're not made to educate. So, obviously they're selling to the lowest common denomenator. That's the point.
Somewhere I read that the publishers told Hawking that every equation in his book would cut sales in half. Clearly the man could have put math in his books. IIRC, he avoided using math altogether and the book was a best-seller.
I imagine every integral in a book cuts sales by 90%. At least that's what it did to my Calculus class.
What do you mean my sig is repetitive? What do you mean my sig is repetitive? What do you mean....
string theory describes nor predicts nothing that is not explained by another larger theory
There is always an infinite number of hypotheses that are consistent with all available observations. To pick among those, science relies on two principles:
1) Falsifiability: for a hypothesis to be the subject of scientific discourse, there must be some experiment or observation that could disprove it. This eliminates hypotheses such as "God made it so" and "our universe is just the holodeck of the Enterprise" from the realm of science, since they can never be falsified: *any* new observation will fit into them. A hypothesis that survives tests that could have falsified it is called a theory.
Falsifiability is also used to prioritize science: a hypothesis which cannot be tested in the foreseeable future is not worth putting too much effort in at this point. A lot of high-energy physics works that way: the hypotheses that can be tested by the next generation of accelerators receive the most attention.
2) Occam's Razor: among competing theories or hyptheses, the simplest is preferred. Kepler's heliocentric model of the solar system didn't fit the observations any better than a sufficiently elaborate system of Ptolemaeic epicycles, but it was much simpler, therefore better.
Now the problem with string theories is that while individual string theories are falsifiable, the space of possible string theories is so vast that for any possible universe a string theory that fits it can be found. It would therefore be more accurate to speak of the "string hypothesis" at this point. Whether it survives will depend on will depend on Occam's Razor: will the simplest string theory that remains standing (i.e., consistent with all observations) be simpler than the simplest non-string theory, or not?
At the moment the string theories are ahead, but only because we do not have a reasonably simple non-string theory that fits our observations. Nobody (including string theorists) is terribly happy about it, but it's what we've got. Are we chasing Ptolemaeic epicycles? Time will tell.
Be faithful to your obsessions. Identify them and be faithful to them, let them guide you like a sleepwalker. JG Ballard
As Supreme Court justice Potter Stewart famously said of pornography, "I can't define it, but I know it when I see it."
I became aware of the book when Greene was interviewed on "All Things Considered" a while back. I'm about 1/3 through the book (sadly, I do not have _enough_ time to read for pleasure) and it's enjoyable because the author provides just enough disequilibrium to keep me thinking as I read. So far, the sequence of the presentation has helped me work out my own [limited] understanding of the theories. Unlike others, I don't however find his humor appealing nor do I find his use of the Simpson's characters anything more than a distraction. Greene uses too many "Let's ignore that for now" escapes in his explanations for my tastes (I know the subject is complex, but he does such a good job explaining things, I expect more from him as I read). As far as using footnotes to move the more obtuse stuff out of the main body of the text, he could look to Alfie Kohn ("Punished By Rewards", an excellent book about how we learn best) as a model for technical footnotes done well for this kind of popular presentation. Still, it's an excellent and compelling read I would not hesitate to recommend it to anyone with an interest in the subject.
"I believe in Karma. That means I can do bad things to people all day long and I assume they deserve it." : Dogbert
Take it from this Scientician! Scientician: uhm,... That's right, you'd have to be a grade-A moron not to understand superstring theory!
The me that exists at this moment is not the me that will exist the next moment or the me that existed a moment ago. Sentient existence only lasts for one moment in time. Therefore, each sentient being only lasts for one moment. The sentient being the next moment is a different being. Have you ever had the feeling of "Gee, out of all the time in existence, isn't it great that it happens to be now? Well, it happens to be now because all nows have their own existence. In the string of my life, each now has it's own "me". Each me is glad that it happens to live in the current now.
My brain has information about the past that is active in the current now for my brain. Concurrently it has information about now. Concurrently it projects into the future. There is the experience of flow. The real question is, how is the binding problem solved? How are different parts of the brain experienced subjectively as a single consciousness in a particular now?
The Moore-Murphy Law: The number of things that will go wrong will double every 2 years.
Time is the measurement of movement. It's that simple.
Have you read my journal today?
Okay, it's late, but...
Pay him no mind, he hated LOTR because it was such ligher fare than the Silmarillion. If Tolkien hadn't sold out to the Publishers we'd be reading all of his works in their original Quenya.
What if it is just turtles all the way down?
I heard somwhere that the number of atoms in the universe is something a bit less than a Googol.
By a bit less I mean like a 1 with 70 0's after it rather than 100.
Anyhow, if you assume that there are 10^100 atoms in the universe, you still have to store more than one bit each.
Of course it's silly to worry about that isn't it? I mean 1 googol, 10 googol, what's the difference when you're talking about numbers that big?
The only way you'd be able to simulate our universe on a computer is if you were a god like being living outside our universe with access to far more matter and energy than is in our universe. In other words, you would need to live in a super-universe where our universe is to you, not much larger than your PC. Then you would be able to store enough data and do enough caulations to simulate it, presuming that you did not have the same speed of light limitation that we do.
It may sound far fetched, but who is to say that we don't actually live in a little universe with relatively little energy that seems like a whole lot to us but is almost nothing compared to that which a "god" has access to? What if every tiny string is another universe with it's own store of energy and it's own little ripples that work just fine to create a universe with that miniscule amount of energy?
Read my keyboard review.
Yup, this stuff is really science fiction. Greene, Kaku, etc. are P.R. men for this string/brane theory stuff and there is hope that the approach might suceed because it may unify QT and (Orthodox) Relativity.
Also, your points about time are good and I agree. The spacetime interpretation of Relativity if taken realistically is ridiculous. Alternative (neo-) Lorentzian ones are just as simple if one counts postulates (H. Ives demonstrated this in the 1940s), they don't fuse space and time into that absurd notion of "spacetime", and they are more "physical" in the sense that these Lorentzian interpretations postulate time dilation and length contraction as effects due to movement through a scalar field of an absolute frame where absolute simultaneity is real. This absolute frame is compatible with things like the nonlocal effects of Quantum Theory and gravitational examples given by Newton that indicate an absolute frame.
Also, Einsteins STR isn't really the basic overall theory anyway, since it doesn't take mass/gravitational effects into account like GTR. Instead it ignores them! So STR is just a local idealization/approximation and can't be considered real at this point. Relativizing GTR has never succeeded and the this theory should really be called Einsteins theory of gravitation, it's not a relativistic theory like STR.
Historically, the main reason the Lorentzian view was dismissed was because of a philosophy of language that was dominant at the time called "positivism" or "verificationism". In this philosophy, being is equated with directly observable/physically measurable!! Nowdays, this view is considered so wrongheaded in the philosophy of science, one wonders who would have won the battle between Lorentz and Einstein if those debates occurred today.
" The important thing is, this book is written by a scientist, not a scientific correspondent."
science writers usually have a fairly good grasp on the topics they cover and talk to many scientists to get a good feel for various theories. As long as science writers are not espousing their own theories without a good scientific basis, then you shouldn't hold any bias against their work.
Of course this book is simply springboarding off of Greene's (mindless, tiresome) television series - there really isn't much here to even justify a second book.
Please don't just mod this book up because of the (apparently cool) subject matter - this book adds so much in terms of obfuscating metaphors that it subtracts from the topic.
I just read this paper.
I didn't, but I will respond to your question.
He claims there cannot be both discrete events and continuity because if there were discrete events then there cannot be continuity... How about something, anything to back up this idea?
How about the Uncertainty Principle? To measure a "discrete" time for an event to occur, it requires a very precise time measurement. By the Uncertainty Principle this requires that the uncertainty in energy be very large. If the uncertainty in energy is sufficiently large, then there really isn't much "continuity" between one time and a following time.
This of course isn't really anything new, it's just a matter of philosophical interpretation.
ack sorry, should have clicked no karma bonus when responding.
Lynds is so obviously right it's not funny. Some of you are either so jealous, ignorant or just plain crazy it is. It makes me think of the craziness and negativity Einstein probably faced with s.r. Watch this boy Lynds...mark my words.
And my time is a piece of wax fallin' on a termite Who's chokin' on the splinters
Yup, it's a new speculation almost every few months in Scientific American. I don't mind that physics has been much more open to talk (or admit) metaphysical aspects of it's views. This has been the case for about thirty years. When done with well established and worked out ideas that rise to the level of being called a "scientific theory" then this talk is very interesting. However, these latest crop of speculations don't even come close to being called scientific theories -- at laest the way I like to think of them. They really are science-fiction dressed up with technical jargon from from other established theories. As fictions go they're terrible so I wonder why people even bother reading this stuff. I suspect they think these ideas are more than what they really are.
Maybe I'm missing some over-arching physics theory, but I reckon time in the universe and time as we experience it are two very different things. Time in the universe is just another dimension, with a few unusual rules to separate it from the three of space. Time as we experience it is about ordering - our consciousness seems to move forwards through time (this is different from the intuitive notion that we are static, and time is moving).