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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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