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oddeye
Canada716 Posts
I tried to explain it to someone myself and no matter how hard I tried he wouldn't understand anything over the 4th dimension saying it was bullshit (perhaps it is...). So well this flash is a great explanation to the String Theory, I recommand watching it if you have time on your hand. http://tenthdimension.com/flash2.php | ||
thedeadhaji
39489 Posts
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Smurg
Australia3818 Posts
On December 07 2006 17:50 thedeadhaji wrote: the leading string theorists are now starting to think that string theory wont hold up though. Ahh, scissor theory. | ||
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Mindcrime
United States6899 Posts
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Kennigit
Canada19447 Posts
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pr0n
United States277 Posts
On December 07 2006 17:48 oddeye wrote: "String theory is a model of fundamental physics whose building blocks are one-dimensional extended objects (strings) rather than the zero-dimensional points (particles) that are the basis of the Standard Model of particle physics." I tried to explain it to someone myself and no matter how hard I tried he wouldn't understand anything over the 4th dimension saying it was bullshit (perhaps it is...). So well this flash is a great explanation to the String Theory, I recommand watching it if you have time on your hand. http://tenthdimension.com/flash2.php Since it is physically impossible for the human mind to visually comprehend anything beyond the 3rd spacial dimension, that would be the likely response by most people. Also, welcome to the 1990s. | ||
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dancefayedance!~
396 Posts
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Haemonculus
United States6980 Posts
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sith
United States2474 Posts
Go read Brian Greene's books. Elegant Universe + The Fabric of the Cosmos. Very informative. | ||
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useLess
United States4781 Posts
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ieatkids5
United States4628 Posts
Rofl Just curious - why don't they think the string theory will hold up? | ||
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HeadBangaa
United States6512 Posts
So... invoking "string theory" is when you explain physical phenomenon in the context of n-dimensions, where 1<n<10 ? Just sounds like a formal definition of reference points. I thought string theory was, well, highly theoretical. If I'm right (which I'm probably not, this is my first exposure to details on the topic), it simply looks like a method to reduce verbose explanations of conditional branches with respect to time. | ||
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skyglow1
New Zealand3962 Posts
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EAGER-beaver
Canada2799 Posts
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garandou
Germany518 Posts
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aseq
Netherlands3977 Posts
On December 07 2006 19:36 garandou wrote: As my math prof used to say: Imagining higher dimensions is easy. First, you have one dimension. The second dimension is perpendicular to the first one, the third dimension is perpendicular to the second dimension. Now, the fourth dimension is simply perpendicular to the third dimension, the fifth perpendicular to the fourth, and so on.... Every next dimension is perpendicular to ALL preceding ones, otherwise some could coincide. | ||
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ic.Ichigo101
United States152 Posts
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KodoU-
United States129 Posts
On December 07 2006 19:36 garandou wrote: As my math prof used to say: Imagining higher dimensions is easy. First, you have one dimension. The second dimension is perpendicular to the first one, the third dimension is perpendicular to the second dimension. Now, the fourth dimension is simply perpendicular to the third dimension, the fifth perpendicular to the fourth, and so on.... First off, I dont even understand, What is 1D. I know 2D and 3D but not 1D, and your math prof. Did he ever try to convince you parallel lines can cross? because, mine tried, and im still stumped. | ||
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azndsh
United States4447 Posts
![[image loading]](http://imgs.xkcd.com/comics/string_theory.png) String theory is one possible explanation to the way things work. Some guy came up with it, and decided that it wasn't completely contradicted by the observable universe. Still I think it's too complicated to be right. On December 07 2006 19:44 aseq wrote: Every next dimension is perpendicular to ALL preceding ones, otherwise some could coincide. That's because you're restricting yourself to three dimensions, thus they don't coincide when you add new dimensions. | ||
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BuGzlToOnl
United States5918 Posts
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ic.Ichigo101
United States152 Posts
maybe jump into a blackhole? maybe travel to the end of the universe? maybe use a lot of energy to push an atom into itself so that it turns into nothing? a vacum is nothing right? nothing is inside a vaccum container. so if there is nothing then what is there? dunno | ||
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iNcontroL
USA29055 Posts
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Purind
Canada3562 Posts
I guess what I'm confused about is what is contained between those two points? | ||
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ToT)Testie(
Canada723 Posts
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Myxomatosis
United States2392 Posts
I was also wondering why ichigo was unbanned, people have gotten permabanned for a hell of a lot less than the way he posts. | ||
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DarK]N[exuS
China1441 Posts
On December 07 2006 20:12 {88}iNcontroL wrote: Why were you unbanned? What was the last non one liner post you made? When was the last post you made that wasn't just some crude insult of someone else? | ||
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z7-TranCe
Canada3158 Posts
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skyglow1
New Zealand3962 Posts
On December 07 2006 19:53 ic.Ichigo101 wrote:a vacum is nothing right? nothing is inside a vaccum container. so if there is nothing then what is there? dunno Lots and lots of vacuum energy yay! | ||
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Alborz
Canada1551 Posts
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Kennigit
Canada19447 Posts
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evanthebouncy!
United States12796 Posts
Thanks a billion. | ||
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BalloonFight
United States2007 Posts
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Cascade
Australia5405 Posts
What he should make a lot more clear is the thing he hides in the preambe: "The "theory of reality" that I advance on this website and in the book "Imagining the Tenth Dimension" is not the one that is commonly accepted by today's physicists." This representation of the 10 space dimensions may be funny to listen to, but it is simply pure bs. Sorry guys... In real physics all the 10 dimensions (and the time as well btw) are on an equal footing, and there is no way you can say that they represent different things. A 10 dimensional space is just a space where you need 10 coordinates to specify a point... I do not like to rant, but I really can't hold myself back this time: 1) string theory is in 1+ 9 dimensions. So 9 space dimension, not 10 as he states. M-theory, though, an extension of strings, have 1+10. 2) As he tries to describe the SPACE dimensions it is ridiculous that he uses time as one of those dimensions. 3) This concept of intrudcing new dimensions by allowing teleportation from folding has a very high wtf-factor. It doesn't help you understand anything, he could just continue and make abritrarily many dimensions by always allowing this teleportation in his new space... 4) introducing sum over histories (the thing where the guy ends up in different futures) would be not one, but infinitely many new dimensions. Just FYI. 5) To compensate for his idiocy in number 4), he introduces that effect two times: one time for different histories of the guy, and one time for histories of the universe. When you look at different histories of the universe, you would of course inculde all histories of the guy as well... 6) Same thing as 4) and 5), but for the starting conditions. 7) Calling the space of all possible histories of the universe "an infinity" maxes out my wtf-meter. Yes, it is an infinite dimesnional space, you call it an 8 or 9 dimensional space or whatever, but you still call it an infinity by some reason. An infinity is a very interesting thing, but in no way you can compare it to the space of all histories... 8) The 7:th and 8:th dimensions (i think) he introduces are the same one. He just draws the explanation out over two numbers. And the list goes on, trust me! If he would have just stated already on the first page that this is bs, not remotely connected to what real scientists think, then it would be ok, but this... Oh, my.... [/rant] But I like that someone bothered to make a theoretical physics thread. <3 | ||
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Faerie
39 Posts
Cascade kinda knows what he is talking about, he does these things for a living. Im alot less hardcore physicist than he is but even I cringe at some of the statements made. Its very easy to take a concept people cant wrap their heads around and use it to claim all sorts of things. Its really like a bluff in poker, if you dont know somebody cards he can make them out to be all kinds of things. Until someone calls that is, think thats what Cascade just did. | ||
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RequieScat
Australia99 Posts
On December 07 2006 19:36 garandou wrote: As my math prof used to say: Imagining higher dimensions is easy. First, you have one dimension. The second dimension is perpendicular to the first one, the third dimension is perpendicular to the second dimension. Now, the fourth dimension is simply perpendicular to the third dimension, the fifth perpendicular to the fourth, and so on.... I prefer the explanation of the lower dimension being the intersection of a higherdimension. ie, two lines intersect and make a point, 2 squares intersect and make a line, ect. dimensions really interest me, I have to say if you find an interest you should really read a book called Flatland <written by Edwin A.Abbott 100 years ago> you can find it here It gives you an idea of how we would percieve a 4-dimensional shape. Flatterland is also a good read <expects j/ks of OMG FLATTEST LAND IS NEXT> it was written by Ian Stewart. I like some things in M-theory, but not others, but i dont claim to understand it. I find it interesting though. Edit:i just read my post and decided it sounded like an advertisment T_T;; | ||
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evanthebouncy!
United States12796 Posts
Just try to imagine w/e his logic is, I'm sure it's flawed like everything else but when I followed his logic I liked it alot, it's a mind bending excercise that makes you smarter GOGO :D And requiscat I like that thought about 2 plane int to make line... Hmmm Is a curved line in 2 demention or 1? imagine u have 2 curved surface and they intersect but O WAIT 2 curved surface is in the 3rd! Brilliant! | ||
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evanthebouncy!
United States12796 Posts
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ic.Ichigo101
United States152 Posts
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Aukai
United States1183 Posts
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Sadir
Vatican City State1176 Posts
On December 07 2006 19:51 azndsh wrote: String theory is one possible explanation to the way things work. Some guy came up with it, and decided that it wasn't completely contradicted by the observable universe. Still I think it's too complicated to be right. That's because you're restricting yourself to three dimensions, thus they don't coincide when you add new dimensions. omfg .....that really made me laugh....hahahha quite interessting the thing with the dimensions | ||
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Passion
Netherlands1486 Posts
On December 08 2006 01:49 Cascade wrote: a lot thanks, i was getting a bit frustrated by this thread ;D and theoratical threads are fun as long as they are some what realistic. else i d like to share my theory of the flying purple monkeys that live inside my ass. | ||
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RequieScat
Australia99 Posts
On December 08 2006 02:50 evanthebouncy~ wrote: Lol don't poke it to death like ... Just try to imagine w/e his logic is, I'm sure it's flawed like everything else but when I followed his logic I liked it alot, it's a mind bending excercise that makes you smarter GOGO :D And requiscat I like that thought about 2 plane int to make line... Hmmm Is a curved line in 2 demention or 1? imagine u have 2 curved surface and they intersect but O WAIT 2 curved surface is in the 3rd! Brilliant! a circle is 2 dimensional... it has length and width but no height. the intersection of 2 spheres makes a circle what i like about this the most is that it shows that say (n-1)dimensional space is an infinitesimally<sp?> small slice of n dimensional space. Im sorry im going off the topic of the thread >.> i just find the maths of this so interesting. | ||
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Cascade
Australia5405 Posts
A line is 1 dimensional, no matter how it is bent. So for example a circle is one dimensional as you only need one number to specify where on the circle you are. You could use for example the angle. That number(s) you use to specify where in the space you are is(are) called the coordinate(s). number of dimensions of a space = number of coordinates you need to use to specify a point in the space. Another example is the space consisting of TWO lines. You can number all points in that space with just one number. For example, we can use numbers 0 up to 1 for one of the lines and 1 up to 2 for the other. Then we can specify any point on BOTH lines with a number between 0 and 2. So contrary to what that page says, the space of two lines is also one dimensional. (add that to the previous list if you want...) However the PLANE, SPANNED by the two lines (assuming they are not paralell...) is two dimensional. ok, so I'm starting to rant again towards the end, sorry. Better stop here. | ||
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HnR)hT
United States3468 Posts
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WhizKid77
China682 Posts
for me, i can imagine everything up to 5 dimensions, but beyond that is kinda weird. we have x,y,z,t for your current position in space and time, and then another variable, say "u", to specify which timeline you are on. note that there is no relationship between the dimension and the "dimension +/- 1"...imo the way you specify the next dimension is totally arbitrary...that is, the ordering of the dimensions doesnt matter. to convince someone of this, you can arbitrarily fix any value of x,y,z,t,u and drop down one dimension. it can be t and u, which is the most common, and then we argue that we are living in a 3D world. but theres nothing wrong with fixing a value of z and saying "my state is x,y,t,u - i live on a flat plane that transcends time, and i believe that multiple timelines exist". its akin to some of the previous posts about intersecting 3D objects and getting 2D objects, or intersecting 2D planes and getting 1D lines. you fix the vars as constants when you solve the intersection equation, thereby converting one variable (possibly *any* var) into a constant and reducing dimension (assuming the equation has exactly one solution). note that this requires all variables to be linearly independent of each other, aka orthogonal or "perpendicular". without linear independence, what appears to be two dimensions can actually collapse down into one. so for me, the real challenge is to find a real world representation of the 6th dimension, one that is orthogonal to x,y,z,t, and u. but i believe most physicists dont even attempt to do this, and simply work in the abstract. in reality, these dimensions are all simply state variables to which u can assign values to determine the current state. the video alluded to viewing this whole thing as a state machine, in which u can reach one dimension higher simply by altering the initial state of the machine. i kind of buy that, but still confused... =/ as with the belief of multiple timelines/universes, u can only convince yourself that higher order dimensions exist thru pure faith. "oh, i believe that i am living in universe X, and there are multiple universes, therefore i attribute a new dimension to that, and assign myself a value of X for it." | ||
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Luhh
Sweden2974 Posts
The string theory holds true for 0.5*0.9 of the population. Ask any guy what he prefers and you'll see.  | ||
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infinity21
Canada6683 Posts
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alphaentity
United States525 Posts
On December 07 2006 17:53 pr0n wrote: Since it is physically impossible for the human mind to visually comprehend anything beyond the 3rd spacial dimension, that would be the likely response by most people. Also, welcome to the 1990s. Don't you mean "welcome to the 1970's" String theory is older than you think.... Don't be so cocky to other ppl. | ||
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HeavenS
Colombia2259 Posts
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MaNNeRDex
United States169 Posts
On December 07 2006 19:53 ic.Ichigo101 wrote: any idea how we can go from one D to another D?? maybe jump into a blackhole? maybe travel to the end of the universe? maybe use a lot of energy to push an atom into itself so that it turns into nothing? a vacum is nothing right? nothing is inside a vaccum container. so if there is nothing then what is there? dunno Well.... A black hole will simply kill you. It is a dead star that has so much mass that it becomes black because it sucks up all the light that we need reflecting off the surface so that we can see it. Actually, we can't even see black holes, we just see how it reacts with different planets, like if two dancers with dancing with one another spinning in circles and one of them were invisible, you could still tell that there is another dancer. When you come into the orbit of a black whole your are just sucked into it and then you die because you are moving with a strength that not even light can escape. Everyone seems to think that a black whole is some mystical slit in the fabric of space. But, something interesting is that it slows down time drastically. If you stand on a black whole, an hour could be like a minute... or is that backwards? Lol, anyway I don't believe that using a black hole will help jump from one dimension to another unless your goal is to bend time. | ||
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skyglow1
New Zealand3962 Posts
On December 08 2006 19:48 MaNNeRDex wrote: Well.... A black hole will simply kill you. It is a dead star that has so much mass that it becomes black because it sucks up all the light that we need reflecting off the surface so that we can see it. Actually, we can't even see black holes, we just see how it reacts with different planets, like if two dancers with dancing with one another spinning in circles and one of them were invisible, you could still tell that there is another dancer. When you come into the orbit of a black whole your are just sucked into it and then you die because you are moving with a strength that not even light can escape. Everyone seems to think that a black whole is some mystical slit in the fabric of space. But, something interesting is that it slows down time drastically. If you stand on a black whole, an hour could be like a minute... or is that backwards? Lol, anyway I don't believe that using a black hole will help jump from one dimension to another unless your goal is to bend time. Ya all you're gonna do is smack into the black hole, or you might be channeled into the polar jets and fly off at sub-speed light. If you hold a watch while you're heading close towards a black hole, and someone from a far away distance looks at your watch, the watch will seem to be stuck because it will seem that time has slowed down for you. But as you yourself look at the watch, it continues to go as normal until you go splat and hit the back hole. This is cause you're going at extremely high speeds when you're close to a black hole. On December 08 2006 19:27 eG)HeavenS wrote: heres a link to The elegant universe part 2: strings the thing. Take some time out of your day to watch this series its extremely interesting and it makes a lot more sense than that flash animation. If you wanna watch the first part of elegant universe you can find the links on the right side of the page. Enjoy http://www.youtube.com/watch?v=_YpRyKbeIz8&mode=related&search= Sweet I'm watching all 5 parts of this now. | ||
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DTDominion
United States2148 Posts
Rather than bitch because it's written by Osron Scott Card, a Science Fiction author, acctually read it, as it is damned interesting, as is his entire column, even though I don't always agree with him. | ||
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Clutch3
United States1344 Posts
On December 08 2006 23:26 DTDominion wrote: Group Think and the Intellectual Elite Rather than bitch because it's written by Osron Scott Card, a Science Fiction author, acctually read it, as it is damned interesting, as is his entire column, even though I don't always agree with him. Wow, that was a good read. Thanks for the link. I always loved Card's novels, and this was quite interesting as well. I've been around string theorists for about ten years now and I've always had a healthy skepticism of the field, maybe because it's just different from the physics (actually, all the science) that I am used to: where you can use your ideas to make testable predictions and then test them and start again from scratch if it isn't working out. It's hard to tell if string theory really defines itself purposely so that it's untestable, but it's certainly true that it is. And in the absence of this critical "feedback method" for making sure you're on the right track, it seems that the people working in it are deciding who's right simply by which theory is most mathematically elegant. That's worked before on occasion, but it's a dangerous thing when so many people are working along those lines. Once there's no data to check yourself, politics becomes very important, and that's never a good thing for doing good science. Perhaps I'm just sick of string theory being the most recognizable thing as far as modern physics goes. People working on string theory are a small minority of all physicists, and most physicists don't fall into the pigeonhole that Card's laid out. Anyway, as a result there's hundreds of physics majors who want to do string theory because it's "cool" or maybe because it's all they've heard of. And really, we need fewer string theorists and more people doing other things in physics (or maybe not doing physics at all?). Anyway, it's good that someone's talking about it. | ||
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Wonders
Australia753 Posts
And to imagine the 4th dimension, just think that if you cut a four dimensional solid with a three dimensional knife, the cross section is three dimensional. Think of a relationship between three dimensional and two dimensional objects and chances are it'd be the same for three and four dimensional objects. For example, a two dimensional object that looks like a "T" with a bit protruding above the T can be thought of as a 'net' for a cube; you fold it along the one dimensional edges to form a three dimensional object. A 'net' for a four dimensional cube would look like this: http://content.answers.com/main/content/wp/en/thumb/4/4b/180px-Tesseract2.png and the end result would look something like this: http://www.daviddarling.info/images/tesseract.jpg which is a cube inside a cube with the corresponding corners joining to each other, much in the same way that a cube can be represented by a square inside a square with corresponding corners being joined. | ||
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Mora
Canada5235 Posts
I don't see any other dimension other than height, length, and depth. | ||
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RequieScat
Australia99 Posts
On December 09 2006 15:37 Teroru wrote: i understand the point behind those diagrams, but they are all in 3D... I don't see any other dimension other than height, length, and depth. imagining another direction other than up/down, sidways, backwards/forwards Is completely impossible for us, as we are beings of 3-dimensions. We can create representations of 4dimensional shapes but all they are is representations. prehaps what we would see, were we to view a shape of 4-dimensions. Trying to imagine shapes of 4-dimensions in their whole would be like trying to imagine another primary colour. higher dimensions have applications in maths, and you can have as many as you want in maths. In physics, as far as i am aware, they are of no use. | ||
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HnR)hT
United States3468 Posts
On December 10 2006 03:46 RequieScat wrote: Trying to imagine shapes of 4-dimensions in their whole would be like trying to imagine another primary colour. higher dimensions have applications in maths, and you can have as many as you want in maths. In physics, as far as i am aware, they are of no use. It depends on what you mean by the term dimension. If you just mean the number of parameters needed to specify the state of a system, then it's used all the time (of course). For example for a system as simple as a ball confined to roll on a plane, you need 4 numbers (2 angles for orientation and 2 coordinates for the position on the plane). In quantum mechanics, the state of any system is specified by an infinite dimensional wave function (ignoring things like spin states). These "dimensions" are just abstract mathematical constructs and have nothing to do with actual, physical dimesions from real life. Time in relativity is quite different since it plays a role very symmetric (antisymmetric?) to the three space dimensions, rather than being just a number you need to tack on to the spacial coordinates to fully describe a point. In general relativity this goes further, because space-time itself is a 4-dimensional surface curved by the presence of energy. You can't coherently reformulate this picture if you treat time separately at all. | ||
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HnR)hT
United States3468 Posts
On December 08 2006 23:26 DTDominion wrote: Group Think and the Intellectual Elite Rather than bitch because it's written by Osron Scott Card, a Science Fiction author, acctually read it, as it is damned interesting, as is his entire column, even though I don't always agree with him. Well, I think the suggestion that string theorists purposely obfuscate and create the theory to be untestable amounts to slander. If this were the case in such a highly visible field, it would have been exposed a long, long time ago. The notion that string theory will turn out to be a complete disaster - nothing but a distraction - is not a new one, and there are plenty of smart young people looking for glory to go around to produce competing alternatives. It's just that most come to the conclusion that string theory really is by far the most promising direction for theoretical physics today. Furthermore, practicing string theorists are extremely brilliant people and many of them routinely make meaningful contributions to other areas of physics. It may be unfortunate that there are far more students who want to go into string theory than there ought to be, but maybe that's the fault of physics educators who are concerned only with research and fail to be inspiring whatsoever. And anyway, what are Card's qualifications to comment on this matter? | ||
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Cascade
Australia5405 Posts
On December 10 2006 03:46 RequieScat wrote: higher dimensions have applications in maths, and you can have as many as you want in maths. In physics, as far as i am aware, they are of no use. They are of use i physics as well.  Actually very few areas of mathematics does not have an application in physics I think. Even a very abstract thing as group theory is at the centre of particle physics...Some uses of more dimensions in physics: Kaluza-Klein: By introducing a fifth (spacelike, not timelike) dimension, and then rolling it up really tight like a thin tube, (cyclic condition with really small, or infinitesimal, period) they could deduce the entire electromagnetism! strings in QCD: To explain the forces between the quarks in a proton or neutron one tried (about 197x) to introduce string-like objects to mediate the force. The theory turned out to be selfconsistent only in 27 (1+ 26) dimensions. It is now used for approximations at best.Superstring theory: The famous theory...The idea is similiar to the one in QCD, only that we replace ALL particles with strings. And we require supersymmtry. The supersymmetry reduces the number of neccesary dimensions to 1 + 9. (then, extending to M-theory, we will need a tenth space dimension) Dimensional renormalisation in quantum field theory (QFT): In QFT you find a lot of infinities. But they cancel out. To see that they do, one of the most common tricks is to make the calculations not in 4 (1 + 3) dimensions, but JUST above 4 dimensions. 4 + e dimensions, where e is a small (infinitesimal) number. Or just below 4, depending on what type of infinity it is. So the number of dimensions doesn't even have to be a whole number. The Hilbert space of states: This is the infinite dimensional space of states a quantum mechanical particle can be in. This is not an extension of the dimension we live our life in, but rather an abstract space used for calculation. In fact almost all calculations in quantum mechanics involves this space a lot. ok, that is enough for now I think... | ||
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BluzMan
Russian Federation4235 Posts
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jacen
Austria3644 Posts
but after that .. i can't really see how you can deduct a 6th dimension out of it, as a 5th would already cover all possible timelines and to get a 6th dimension you would have to find something other than time to continue your journey. i think you could introduce differnt starting conditions here, but with different starting conditions, things like time and space become irellevant, so i can't see how they can "build up" on our established system. | ||
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jacen
Austria3644 Posts
do you think this whole string/m theory issue can be resolved with the new cern cyclotron? will it be able to pack enough energy to give us not only even more particles, but what and how they are? /edit: and yeah. i would very much like to see all this mathematical talent in nero nets, where i still think it really belongs. T_T | ||
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jacen
Austria3644 Posts
On December 08 2006 23:26 DTDominion wrote: Group Think and the Intellectual Elite Rather than bitch because it's written by Osron Scott Card, a Science Fiction author, acctually read it, as it is damned interesting, as is his entire column, even though I don't always agree with him. you know ... feynman was ALWAYS saying that. now that he is dead 20 years it seems people forgot how to work just after he died ... interesting. | ||
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Cascade
Australia5405 Posts
On December 10 2006 13:17 jacen wrote: @ cascade: do you think this whole string/m theory issue can be resolved with the new cern cyclotron? will it be able to pack enough energy to give us not only even more particles, but what and how they are? /edit: and yeah. i would very much like to see all this mathematical talent in nero nets, where i still think it really belongs. T_T Common, we have to spread to word, no? I'll take it from the begining so as many as possible can understand. [img]http://www.phys.ufl.edu/~matchev/LHCJC/cern-lhc.jpg[/img] LHC (large hadron collider) is a huge ring of magnets, 27 kilometers around, that accelerates protons around very fast, and antiprotons around in the other direction. These two beams are made to collide at a few selected points in the ring around which they have placed detectors to see what comes out. It will go online next year, and start giving data in about a year. What is new with the LHC is that it collides the particles at an higher energy than has been done before, so heavier particles can be created in the collisions. Mass is just another form of energy. Up to now we have looked for particles of a mass up to around 100GeV (100 Giga electron Volt, or the energy an electron gains when accelerated by an electric field of 100 000 000 000 Volt), but with LHC we can find particles with a mass up to around 1000GeV (or 1 TeV). So the new particles we will find are the particles with a mass between 100GeV and 1TeV. We expect to find the Higgs particle at around 150 GeV. The Higgs is not very connected to string theory, so I will not go into this. We also expect to find supersymmetric (SUSY) particles. We expect the supersymmtric particles to exist by some reasons not connected to strings. (For example the running coupling constants will intesect much nicer in a grand unification theory if we have SUSYs...) But if we want superstrings we will need supersymmetry. In fact, the "super" of superstrings is for supersymmetry. So if we do not find SUSYs, that is a sign that we maybe do not have supersymmetry, which also implies that we do not have superstrings. I am not sure on exactly how strong sign though. We could imagine that by some reason all the SUSY are at an even energies (above 1TeV), or maybe that we can not detect them properly, or the maybe will not be created in proton-antiproton collisions... But it would defenitely be a sign that we have no SUSY, I'm sure! So finding SUSY will in no way prove superstring theory, but it will be a sign that we may be looking in more or less the right direction. Not finding SUSYs will however be a sign that the direction might be all wrong, and that we should start looking even more for alternate solutions. To actually create isolated strings we would need to go to energies of around 10^13 TeV. For that we would need an accelerator the size of the entire solar system. Which will be hard to do with todays international particle physics economy. We hope to find other more subtle means to confirm/disprove superstrings. Maybe cosmlogy may be the answer? Who knows? | ||
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jacen
Austria3644 Posts
On December 10 2006 14:06 Cascade wrote: We expect to find the Higgs particle at around 150 GeV. The Higgs is not very connected to string theory, so I will not go into this. see ... ordinary people don't know how "heavy" higgs particles are expected to be nor how much energy currently used cyclotrons are using. thats what i was asking :> thx higgs ... isn't higgs a graviton? or somewhat related to it? On December 10 2006 14:06 Cascade wrote: We also expect to find supersymmetric (SUSY) particles. We expect the supersymmtric particles to exist by some reasons not connected to strings. (For example the running coupling constants will intesect much nicer in a grand unification theory if we have SUSYs...) But if we want superstrings we will need supersymmetry. In fact, the "super" of superstrings is for supersymmetry. So if we do not find SUSYs, that is a sign that we maybe do not have supersymmetry, which also implies that we do not have superstrings. I am not sure on exactly how strong sign though. We could imagine that by some reason all the SUSY are at an even energies (above 1TeV), or maybe that we can not detect them properly, or the maybe will not be created in proton-antiproton collisions... But it would defenitely be a sign that we have no SUSY, I'm sure! wait ... so not finding SUSY with the new lhc might also mean that they don't appear until over 1TeV? whats the reason for making the lhc only limited to 1TeV and not waiting another 10 years to be able to make a bigger collider with ... lets say 5TeV and be sure? can you clarify this? sure it has to do with economics, but it sounds a little wierd you know ... knowing i build a device that might not be strong enough to detect what i am REALLY looking for. | ||
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Konni
Germany3044 Posts
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Clutch3
United States1344 Posts
On December 10 2006 05:20 HnR)hT wrote: Well, I think the suggestion that string theorists purposely obfuscate and create the theory to be untestable amounts to slander. If this were the case in such a highly visible field, it would have been exposed a long, long time ago. The notion that string theory will turn out to be a complete disaster - nothing but a distraction - is not a new one, and there are plenty of smart young people looking for glory to go around to produce competing alternatives. It's just that most come to the conclusion that string theory really is by far the most promising direction for theoretical physics today. Furthermore, practicing string theorists are extremely brilliant people and many of them routinely make meaningful contributions to other areas of physics. It may be unfortunate that there are far more students who want to go into string theory than there ought to be, but maybe that's the fault of physics educators who are concerned only with research and fail to be inspiring whatsoever. And anyway, what are Card's qualifications to comment on this matter? Yes, I agree that purposely making the theory untestable is probably taking it too far. But I'm glad someone's talking about the field. Perhaps Card doesn't have the qualifications you'd like, but if you're requiring everyone who comments about the validity of string theory to have a strong background in string theory, then in some sense you're biasing the discussion. Anyone who's spent a good deal of time on string theory (and it certainly requires a large investment of time), will most likely not agree that the whole field might be highly suspect. And yes, the fact that lots of people want to do string theory isn't really the fault of string theorists, but neither do I think it's the fault of too heavy an emphasis on research. (I do agree that the emphasis on research over teaching is really a terrible problem for physics; this is one of my biggest issues with academia.) I know there's too many grad students at Brown and other places who want to do high-energy theory, and I think it's part how the curriculum is biased towards paper-and-pencil work, and partly how overexposed string theory is in general. To expand on the latter reason, it seems to me there's something about string theory that makes it perfect for writing books and pontificating. The possible reasons I can come up with are: 1. String theorists have more time to consider the elegance of their theory, because (as I mentioned) the absence of experimental checks on the theory leaves much more room for politics and egos to drive the field. As a result, it's much likelier that the sexiest, most elegant theories are the ones which are adopted. And those are tailor-made for consumption by the mass market audience. In contrast, the physics I know about is harder to summarize by a set of equations, and it's got a lot more "ifs" and "buts", which makes for bad pop science reading. This is almost always the case where you're trying to understand the behavior of 10^18 atoms (condensed matter physics) than of just a few particles (theoretical particle physics). 2. Because string theory has no immediate commercial impact, the money supporting it comes much more heavily from government funding. And the competition for that funding is intense. So people doing string theory have to learn to package and sell their ideas much better than those in, say, semiconductor physics. This also translates into more, and better, self-promotion. | ||
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Clutch3
United States1344 Posts
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jacen
Austria3644 Posts
On December 10 2006 14:38 Clutch3 wrote: This also translates into more, and better, self-promotion. this bothers me. scientists should think about their field. not about how to present that field. | ||
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Cascade
Australia5405 Posts
I'm getting a bit mathematical now: A normal mass term (in the lagrangian, that is THE equation describing the theory...) is not invariant under a gauge transformation. And the entire theory is built upon being gauge invariant. To compensate, we need another particle that transforms in exactly the opposite way to cancel out the assymetry from the mass terms. This particle is the Higgs particle. And particle physics are in quite big trouble if we do not find it. And it will (imo) be the greatest success in the history of particle physics if it turns out that we predicted correctly. So check the newspappers in late 2007. And for the record: A graviton is the particle mediating the gravitational force. It is massless, but still not detected due to it's VERY weak coupling to everything. It does however "bend reality" more or less in the way black holes and the like does in movies and cartoons. They try to measure this smal distortion by putting up mirrors and have light bounce between them and measure the time it takes to bounce back and forth. If a big distortion enough passes by, then we can measure that the distance between the mirrors changes oh so little. they have to measure the distance with an accuracy of just a fraction the size of an atom, but they do. This experiment is in Pisa Italy, iirc.Yes, If we do not find SUSY they MIGHT still be somewhere over 1TeV. But I think (not sure here...) that we got quite strong arguments for why at least some should be below 1TeV. It is like IF they would be heavier, then they would have interfered in other reactions which we would have noticied. And yes, economy is the reason we do not build a bigger accelerator. 27km is enough for now imo. ffs, get people in africa non-piosonous water first...Allready a LOT of countries have teamed up to build the LHC, so we ARE pushing the limits for what the economy can take. going up a factor 10 in energy is actually a lot. Imagine that they first planned to build a 300GeV accelerator, and then reconsidered: "Why build an 300GeV, when we could gather up some more money and build a 1TeV instead?". Would that make you happier? And again for the record. The center of mass energy of the proton and antiproton is 14TeV, but since only one of the quarks in each (anti)proton collides at a time, only a fraction of the total proton energy will be used, so the effectiv energy will be about 1TeV. | ||
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jacen
Austria3644 Posts
On December 10 2006 14:58 Cascade wrote: No, Higgs isn't a graviton. The Higgs is needed to give mass to the other particles without breaking the oh so precious gauge symmetry. I'm getting a bit mathematical now: A normal mass term (in the lagrangian, that is THE equation describing the theory...) is not invariant under a gauge transformation. And the entire theory is built upon being gauge invariant. To compensate, we need another particle that transforms in exactly the opposite way to cancel out the assymetry from the mass terms. This particle is the Higgs particle.see, thats the reason why i read physics literature for fun and you deal with this for a living On December 10 2006 14:58 Cascade wrote: Imagine that they first planned to build a 300GeV accelerator, and then reconsidered: "Why build an 300GeV, when we could gather up some more money and build a 1TeV instead?". Would that make you happier? i just mean't: "why build a new collider when it may not even bring new deeper insight?" i know these things cost a little money (well ... depends on your financial scale i guess ), but your mention of SUSY might beeing out of reach with the new collider gave me a downer. but if you say that the new collider will most likely proof or disproof SUSY either way (by either showing or not showing up) it seems reasonable to build it now. | ||
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Smurg
Australia3818 Posts
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Cascade
Australia5405 Posts
But as I said: If we do not see them, it is a sign that they do not exist. I personally dont know exactly how strong sign, but I've gotten the impression that it would be fairly strong. And sorry about the maths. | ||
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jacen
Austria3644 Posts
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Asta
Germany3491 Posts
On December 10 2006 14:58 Cascade wrote: It is like IF they would be heavier, then they would have interfered in other reactions which we would have noticied. I know almost nothing about the subject but afaik at some weight it will become unlikely that such heavy particles have been created naturally, right? Theoretically there could be particles weighing as much as the Planck mass (≈ 1.2209 × 10^19 GeV/c2 according to wikipedia) but they will never be produced by any natural event. | ||
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SolaR-
United States2685 Posts
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jacen
Austria3644 Posts
On December 10 2006 15:29 Asta wrote: I know almost nothing about the subject but afaik at some weight it will become unlikely that such heavy particles have been created naturally, right? Theoretically there could be particles weighing as much as the Planck mass (≈ 1.2209 × 10^19 GeV/c2 according to wikipedia) but they will never be produced by any natural event. isn't this a non-issue? we wan't to know how the complete system of how mass is "generated" and how this connects to gravity and timespace works ... and not only how it works in most cases. right? | ||
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Cascade
Australia5405 Posts
On December 10 2006 15:29 Asta wrote: I know almost nothing about the subject but afaik at some weight it will become unlikely that such heavy particles have been created naturally, right? Theoretically there could be particles weighing as much as the Planck mass (≈ 1.2209 × 10^19 GeV/c2 according to wikipedia) but they will never be produced by any natural event. Well, it depends on what you mean by naturally. In normal everyday life for you and me, we will not be dealing with energies close to creating any particles at all. In the core of the sun there are energies of the scale a few MeV (1000MeV = 1GeV), which is enough to created a few of the lightest particles, for example electrons. LHC will be at 1TeV which will create quite a lot of particles, even if we find nothing new. If you go back in time to the big bang we will arrive at high energies enough to create anything. Including for example elephants. Heavy particled would probably not be stable though, in the sence that they would decay into other light particles, if that is what you mean? So we do not expect to see them as even if they were created, they would have decayed by now. We have some ideas of what particles may exist up to the planck energy (planck mass, w/e, same shit). For example we may find SUSYs and many belive that we will find a set of particles at around 10^15GeV. Above that energy, quantum gravity will come into play seriously, and then we have no idea at all what may exist. String theory is our best guess for energies above that, but as we all know by now: string theory is not experimentally verified so... Don't know if I answered your question. | ||
Bill307
Canada9103 Posts
I did some reading on Wikipedia and the reason String Theory predicts the existence of 10 dimensions (or 11 for M-Theory) is because that is the only way a photon can have no mass. Since String Theory is just a theory and far from fact, there might not be 10 dimensions at all. There might be only 4. But I wouldn't dismiss higher dimensions as "bullshit" just because we can't perceive them. For example, in medieval times europeans believed that the sun revolved around the earth partly because they could not perceive the motion of the earth. Nowadays we know better, but back then people would have called bullshit: "If the earth is moving then why don't we fly off?" | ||
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Bill307
Canada9103 Posts
On December 10 2006 14:06 Cascade wrote: We also expect to find supersymmetric (SUSY) particles. We expect the supersymmtric particles to exist by some reasons not connected to strings. (For example the running coupling constants will intesect much nicer in a grand unification theory if we have SUSYs...) But if we want superstrings we will need supersymmetry. In fact, the "super" of superstrings is for supersymmetry. So if we do not find SUSYs, that is a sign that we maybe do not have supersymmetry, which also implies that we do not have superstrings. I am not sure on exactly how strong sign though. We could imagine that by some reason all the SUSY are at an even energies (above 1TeV), or maybe that we can not detect them properly, or the maybe will not be created in proton-antiproton collisions... But it would defenitely be a sign that we have no SUSY, I'm sure! So finding SUSY will in no way prove superstring theory, but it will be a sign that we may be looking in more or less the right direction. Not finding SUSYs will however be a sign that the direction might be all wrong, and that we should start looking even more for alternate solutions. The article in Wikipedia leans more in the direction of "if supersymmetry isn't found then it's not a problem": For example, while supersymmetry is now seen as a vital ingredient of string theory, supersymmetric models with no obvious connection to string theory are also studied. Therefore, if supersymmetry were detected at the Large Hadron Collider it would not be seen as a direct confirmation of the theory. More importantly, if supersymmetry were not detected, there are vacua in string theory in which supersymmetry would only be seen at much higher energies, so its absence would not falsify string theory. http://en.wikipedia.org/wiki/String_theory#Problems_and_controversy | ||
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Cascade
Australia5405 Posts
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pr0n
United States277 Posts
On December 07 2006 18:23 skyglow1 wrote: I understood the explanantion for 4th dimension, but beyond that its too hard to really visualize or understand. Cool stuff anyway Actually, as I said, its is 100% impossible to visually comprehend anything beyond 3 spacial dimensions. The best you can hope to do is visualize the 3-dimensional shadow of a 4-dimensional object. | ||
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Foresaken_Foreskin
Canada92 Posts
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IIICodeIIIIIII
China1101 Posts
On December 07 2006 20:58 DarK]N[exuS wrote: What was the last non one liner post you made? When was the last post you made that wasn't just some crude insult of someone else? i second that. | ||
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Foresaken_Foreskin
Canada92 Posts
bcus the more i thought about this question the longer the goosebump feeling lasted maybe its just chemical reaction? lol stupid question but im curious anyways. | ||
Nyovne
Netherlands19135 Posts
Feud feud!!! Go back on picking on Steve, control. At least hes funny unlike nexus! | ||
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Foresaken_Foreskin
Canada92 Posts
Welcome To The Eleventh Dimension honestly i never knew stuff like this existed, and made me cry ahahah now how long does it take to learn everything n general seeing as i put myself knowwhere maybe i cud make a living starting today huh.. heat a the moment if a good poster comes on who knows. | ||
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Kroc.
Peru95 Posts
On December 11 2006 06:34 Foresaken_Foreskin wrote: i just watch taht elegant univers thing: Welcome To The Eleventh Dimension honestly i never knew stuff like this existed, and made me cry ahahah now how long does it take to learn everything n general seeing as i put myself knowwhere maybe i cud make a living starting today huh.. heat a the moment if a good poster comes on who knows. First of all, you should have in mind the huge difference there is between learning this stuff from a general audience point of view, as a hobby, and making a living out of this. If you want to do the former, watching stuff like The Elegant Universe and reading science articles like the ones that appear in Nature will suffice. To do the latter, you MUST go all the way through graduate school, get a Ph.D. in either physics or math, and then pursue a career in research and academia, meaning that you have to be prepared to study, pretty much your whole life. And if you want to specifically do research in String Theory, the math requirements are much, much higher than in other branches in physics. So, if you do like physics and math, A LOT, go for it. | ||
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Foresaken_Foreskin
Canada92 Posts
i do belive u can learn anything u put ur life into look at koreans and starcraft, the famous musicians. etc...but this is different math, and physics w.e that is. But yeah it sounds appealing to the max like astranomy, i like things that dont have answers, cus it makes you think and come up with interesting stuff that you might never know for sure if tahts the final answer someone called me a philosipher one time because i always made up in-depth opinion ons almost any subject that he would throw at me. but i am two sided so i also think that every person is this way.. so i aint nothing special. we all had shit happen to us that gives us a newer outlook each time for the future et.c.. | ||
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Foresaken_Foreskin
Canada92 Posts
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Kroc.
Peru95 Posts
On December 11 2006 07:50 Foresaken_Foreskin wrote: can anyone learn this if they put the time into it? i do belive u can learn anything u put ur life into look at koreans and starcraft, the famous musicians. etc...but this is different math, and physics w.e that is. But yeah it sounds appealing to the max like astranomy, i like things that dont have answers, cus it makes you think and come up with interesting stuff that you might never know for sure if tahts the final answer someone called me a philosipher one time because i always made up in-depth opinion ons almost any subject that he would throw at me. but i am two sided so i also think that every person is this way.. so i aint nothing special. we all had shit happen to us that gives us a newer outlook each time for the future et.c.. Damn, I should not have bothered. | ||
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Foresaken_Foreskin
Canada92 Posts
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Mora
Canada5235 Posts
i feel your pain.  | ||
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