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Evidence of 6 Dimensions or More?
shelflife writes "Nature.com is reporting that there may be evidence of 6 dimensions. Galaxies seem to behave as there were more matter in them than is actually visible. 'One explanation, they say, is that three extra dimensions, in addition to the three spatial ones to which we are accustomed, are altering the effects of gravity over very short distances of about a nanometre.'" Update by J : Like most of string theory, this is acknowledged by its authors to be "extremely speculative."
But then again, if they do manage to actually find solid evidence (not just its apparent invisibility in our traditional 3 or 4 dimensions) of matter in an unexpected dimension, I will be extremely impressed. It's an interesting theory at any rate, and worth looking into.
superstring theory and yang-mills theory deal with 11-D subspaces and their intersection with 2D string worldsheets (think a 1 dimensional string flying through the air, but extended along the temporal dimension, forming a 2 dimensional sheet).
This has been worked on for a while, and the equations are getting there. If you think about it though, a fifth dimension can be easily produced from the equations of general relativity, and maxwells equations of electro-mag produce yet another micro-dimension to govern the electromagnetic force.
So this isn't that surprising, the problem is the math for 11 dimensions doesn't work well yet, because it's freaking hard to do energy waveform equations in 11 dimensions, when you don't even know how those 11 dimensions are laid out.
The next breakthrough in physics will be a model for at least some of the underlying dimensional geometry, leading to a final m-theory, likely the long sought theory of everything.
I just like the fact that the standard model is showing it's flaws, trying to write theory to fit your experiments is never as good as trying to understand the underlying causes and drawing conclusions from the emergent properties of the basic model.
The first rule of USENET is you do not talk about USENET.
is this in anyway related to the string theory?
The only problem is that when the calculation is done, the universe's dimensionality is not four as one may expect (three axes of space and one of time), but twenty-six. More precisely, bosonic string theories are 26-dimensional, while superstring and M-theories turn out to involve 10 or 11 dimensions.
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I agree, that's how it is done. Lots of times that produces pretty good results, sometimes less than stellar.
One of the things they had us do in college, and it is interesting IMO, is to take a sport you know nothing about and observe it. Try to formulate the rules of game based on observation (that is, create the model). Then look the actual rules up and compare them.
It's not a perfect experiment - there are things common amongst nearly all games that we simply just know, but it was interesting how correct you would normally get some things and how wrong others (this is even more true because we *do* have correct preconcieved notions, it gets worse when going blind into something). It's also interesting how you can be correct and wrong at the same time - accuratly predict the outcome but for totally incorrect reasons. And, in some sense, it raises the question of if it really matters if the path to get to the correct point is wrong. If you are correct 100% of the time that it is "pass interference" (in American Football) does it matter that you definition of "pass interference" is wrong?
In really really complicated scenarios I always wonder which side is thier model on (though, of course, it's a sliding scale not just an absolute two sides). Especially given the magnitude that some of the models will evnetually have in our lifes.
Of course, this is what makes these fields so interesting to me, the combination of "right or wrong" with the amount of "feel" and "intuition" in the system.
------- Sorry about the spelling, I suffer from two problems. Dyslexia makes it difficult to spell well, lazy makes it
... not new! String theory has been around for decades (Kaluza-Klein theory dates back to about 1920). For all my time in grad school, about four years ago, the fashionable space-time had dimension 10, 4 for "usual" space time plus 6 for a tiny little compact Calabi-Yau threefold (this is a complex manifold of dimension three, hence six real dimensions). Of course I was sitting around with algebraic geometers too much, and it might have just been a way to get the NSF to fund their projects by creating some applications for their abstract nonsense (time will tell...) One of my favorite memories from that time is a series of lectures given by a colleague on the basics of string theory. She gave a heuristic derivation of the dimension of space time (that time the dimension was 11, I apologize if it sounds inconsistent). She wrote down the series of all integers (the sum of n, for n from -infinity to +infinity, n being an integer) and said it was equal to -1/23; she took a short pause, thinking... then apologized, she forgot to mention: one should take the sum over n being a NONZERO integer! From that day on I quit going to that seminar (shouldn't that sum be -1/... 42 anyway?)
I watched this DVD and it gave me a really good introduction to Relativity, String Theory and Quantum Mechanics. I'm no physicist, but I am able to understand the key ideas through the video.
Or you may prefer to visit their homepage here.
w00t
Quoting from the wikipedia link you provided:
- "When multiple explanations are available for a phenomenon, the simplest version is preferred"
Occam's Razor is a tool to, when faced with multiple explanations for the same situation, help one choose the best one.
It is not some sort of philosophical statement on how there should be a simple explanation for everything.
Although i too feel unconfortable with the increasing complexity of scientificy theories (and judging from the current moderation on your post i suspect many others also yearn for simplicity), i cannot stand by and see you missuse Occam's Razor (one of the first things i learned in philosophy).
PS: At the risk of spoiling this post, i have to state a theory of mine: I suspect one of the things that turns some scientific minds to the belief on a "higher power" (aka almighty) is a yearning for simplicity and/or an inability/unwillingness to accept complex explanations to the mind-bogling complexity of the world.