String Theory

[Needle Noggin]

http://tenthdimension.com/

Go to the Navigation bar and click Imagining the Tenth Dimension.

It's a flash animation explaining the 10 dimensions. Thoughts? I don't exactly buy the complete string theory, and I think I only believe up to the 4th dimension...but hey. At least it's kinda interesting.

Quantum physics are interesting, if a little worthless.

[Debitt]

I don't necessarily think quantum physics is worthless, but it has a different sort of worth than what most people would find applicable to our lives. XD; But that's a rant for another day.

I've tried to wrap my head around the string theory so many times it's ridiculous, the most recent attempt (outside of watching that video, which btw made me go @_@!!!) involved my asking my astronomy professor to explain it to me. It hurt. My head. So much. Stuff like this is fascinating to me - the abstraction is several levels about what I can comprehend at this point, but it's a real trip trying to figure things out.

[Warrior4Christ]

Probability wave... what??

Interesting theory... I wonder if it's valid for the "let's just ignore a dimension for a moment and work in 2D, which behaves differently when it's in 3D" analogy to be extrapolated to higher dimensions...

With the "sets of universes with different starting conditions" thing, I thought that our universe was perfectly tweaked (by God) such that a universe would actually exist! And that it's highly likely that all the other universes with other starting conditions would either all collapse or infinitely expand...

[Dante]

Meh, while people like to talk about string theory, few really actually look at it. The popularizations are cute but don't do the subject justice. Y'all come back once you've read a bit of Weinberg's Quantum Theory of Fields... Or you could read of all of Griffiths Quantum Mechanics (fear the evil). Yes children, you are all probability waves... This means that you have a certain "probability", albeit small, of "diffracting" and being found as a diffracted piece of matter when you walk towards your bedroom door. Or you may tunnel through the Earth to be found in China or even outside of Earth in Alpha Century... It's just a very small probability. Generally speaking everything we see here and touch is just a result of our collapsing of some other poor bunch of particles probability wave packets into delta functions. What? You thought the particles were just there, and that was how things were...

Nope, everytime you look at your chair, you are making a measurement... and there is something VERY special about making a measurement. You are requiring every one of those particles to take a stand on WHERE they are... before then they didn't have a definite "position" or "energy level" just a probability. Now generally speaking in our world, nothing changes. But in happy quantum land where the h bar rules the world, things are... different.

As far as ten dimensions being wierd, meh... I think I've seen stranger things, and will continue to believe that the universe is even more strange. Take the Casimir Effect, where mere boundary conditions and small spaces involved work to create a force from nothing but the zero point energy field in that space. No, I don't think we'll gain energy from this field any time soon as the forces SO FAR have been found to be conservative. However, the forces are incredible quarky and we have yet to be able to truly predict how they will react with each new geometry or material.

Or consider space-like time intervals, the world outside of our light-cone in which time becomes imaginary and particles move at velocities greater than c? Or the negative pressure associated with the Casimir Effect which combined with the Einstein Field Equation reveals the presence of a small A__I G_____Y Effect (fill in the blank, I will not use the word here). Or maybe there is the fact that no matter where you are in the universe, the sky always looks the same in that you will always percieve yourself as the center of the universe! (And God didn't want us to become egocentric?)

Of course, unless they create an experiment to test their claims, no one should believe it... of course I'd still give my two front teeth to study it at a good university .

Pascal

[Warrior4Christ]

Oh yeah... can the higher dimensions be specified as a single number (not necessarily discrete) like the first 4? Eg. (1, 2, 3, 4) would be 1 metre in x dir, 2m in y dir, 3m in z dir from say, the centre of the earth, and 4 seconds from beginning of time (arbitrarily chosen units and origins).

[Dante]

Oh yeah... can the higher dimensions be specified as a single number (not necessarily discrete) like the first 4? Eg. (1, 2, 3, 4) would be 1 metre in x dir, 2m in y dir, 3m in z dir from say, the centre of the earth, and 4 seconds from beginning of time (arbitrarily chosen units and origins).

What in the world do you mean by that? If you're asking whether you can ask for the coordinates of a five or N dimensional point than of course... (x_0,x_1,x_2,x_3,x_4)=(1,52,21,-21,0)... easy, why wouldn't you? As far as declaring time as a unit of time, you can easily show that time is a unit of space as well by means of -c*t, where c is in m/s and t is in s... thus c*t=m/s*s=m resulting in the proper units. Time and space are combined into one concept by means of relativity. As a consequence of this, when you measure the length of a rod that's moving at v/c where v approaches c, the length of the rod appears to be stretched or contracted depending on whether the rod is approaching you or moving away. This isn't just an optical illusion either, as you would be able to touch and feel the rod there as well just as it appears, but it isn't because the rod itself changed in any manner either, as the rod measuring itself would still show that it had the same length it started out with. Thus the result is purely a consequence of the rod being an ellement within 4-space and not simple 3-space that we use to measure the rod in. The exact formula is,

L'=yL or L/y

Where, y=1/sqrt(1-v^2/c^2), L' is the length we measure and L is the length of the rod in it's own reference frame (or the rods length when it appears at rest with us), v is the rods velocity with respect to our reference frame and the formula uses y when the rod is moving away from us, and 1/y when the rod is moving towards us. c by the way is approximately 3.0E8 m/s and is the speed of light. Did I leave anything out?

Oh, but there is so much more! What about 1.25 fractal dimensions . Yes, I said 1.25 dimensions! Of course, this makes use of a different definition than most people are used to working with to describe the term dimension... but it still yields 1, 2, 3 and 4 dimensions we know and love when describing spaces holding these dimensional rules. But when the rule is used on fractals, it results in non-integer dimensions.

[LorentzForce]

http://xkcd.com/c171.html <-- Explains absolutely everything about String Theory.

[CreatureArt]

You know, I'm only understanding a very small level of what's been discussed here. But I'm loving it. I love taking a look and being exposed to the wonders of this world, even if I can't grasp it all yet.

Just another reason to praise God, and a chance to attempt to expand the mind He has given me.

God bless and a very Merry Christmas to everyone.

[Warrior4Christ]

What in the world do you mean by that? If you're asking whether you can ask for the coordinates of a five or N dimensional point than of course... (x_0,x_1,x_2,x_3,x_4)=(1,52,21,-21,0)... easy, why wouldn't you?

Of course, but is there obvious meaning attached to values in the fifth, sixth, seventh, etc dimensions?

*already did special relativity* XD

http://xkcd.com/c171.html <-- Explains absolutely everything about String Theory.

Exactly! XDD

[Warrior 4 Jesus]

I don't understand a word of it. But it is interesting how they can make random nonsense sound intelligent - sort of like Hitchhiker's Guide to the Galaxy.

[Slater]

String Theory is very interesting. The only problem with it is that no faucet of it has been tested or thuroughly documented and observed. My physics teachers (Quantum and Theoretical Physics) say that it hasn't passed from philosophy to science yet.

[Technomancer]

I wouldn't completely agree with that assesment. It is based on rigorous mathematical principles, so I wouldn't call it philosophy.

[Dante]

Physics is philosophy, or the philosophy of natural science that is . That stated, it should be based off of logic. However, it goes a step beyond this, declaring even human logic as fallable by means of error in assumptions or method. To correct for this, it corrects it's own errors by testing them against some point in reality. Every point in science must be tested against something in reality to prove it's validity, otherwise we would be building a house of cards upon theory... and should any one of those cards fail, the rest built upon it would come tumbling down. Thus, until it makes a prediction that can be tested by reality, it cannot even begin the move from theory to fact... wherein the term fact hardly means that the idea is set in stone. Only once the idea has undergone an infinite number of every form of test, can it possibly be reffered to as absolute fact within science... however, if we managed to find several it would be good enough for government work .

[Technomancer]

Physics is philosophy, or the philosophy of natural science that is . That stated, it should be based off of logic. However, it goes a step beyond this, declaring even human logic as fallable by means of error in assumptions or method. To correct for this, it corrects it's own errors by testing them against some point in reality. Every point in science must be tested against something in reality to prove it's validity, otherwise we would be building a house of cards upon theory... and should any one of those cards fail, the rest built upon it would come tumbling down. Thus, until it makes a prediction that can be tested by reality, it cannot even begin the move from theory to fact... wherein the term fact hardly means that the idea is set in stone. Only once the idea has undergone an infinite number of every form of test, can it possibly be reffered to as absolute fact within science... however, if we managed to find several it would be good enough for government work .

I'm well aware of the need for testability. However, while I might hesitate to describe string theory as fully scientific given its currently untestable nature, I would still shy away from calling it philosophy for the reasons that I alluded to above.