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."

Comments

One can dream

[bl968]

That in at least one of the six that hopefully the geeks get the girls :P

So if we can't see it, it's in another dimension?

[Hannah E. Davis]

There may well be many more dimensions than those we're used to dealing with, but basically saying that if we can't see it, it must be in a different dimension makes part of me wonder if the scientists are trying to take the easy way out.

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.

How dimensions wrap themselves up

[ReformedExCon]

The way I understood this phenomenon, as it was explained in Kaku's book, was that the extra dimensions were curled up on themselves so that they were smaller than could be detected.

The thought experiment was similar to the following. Imagine a sheet of paper with a line crossing from one edge to the opposite edge. You can see that the line exists when viewing the sheet in two dimensions. However, imagine if you rolled the sheet of paper up tightly with the line not directly aligned with the roll. Now you would have instead of a line a single dot or a series of evenly-spaced dots. The line hasn't gone anywhere, it has simply been rolled onto itself so that it seems to have become small and barely detectable.

Now extend that idea to multiple spatial dimensions beyond just two or three. Since we humans can only perceive three spatial dimensions, it is hard to imagine what multiple extra dimensions would be like. However, if we can take the extra dimensions and "roll" them into themselves, we can make a little more sense of the concept.

Re:So if we can't see it, it's in another dimensio

[Anonymous Coward]

It's simple: They plug what they observe into a mathematical model and see if they can come up with a model that matches observation. It's not simple blind guesswork.

Someone came up with a model called string theory that includes systems with multiple "hidden" dimensions.

The dark matter they're talking about in the article is behaving in a way predicted by one of the current string theory models, which doesn't fit the more traditional models, thus the assertion that it must be 6 dimensions at work.

Re:Well i thought it was at least 11

[william_w_bush]

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.

Re:ObTime Cube

[Anonymous Coward]

Sufficiently advanced satire is indistinguishable from reality.

Re:So if we can't see it, it's in another dimensio

[bm_luethke]

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.

Everyone abuses Occam's razor

[PsiPsiStar]

I'm starting to think that Occam's razor is abused more often than it is used correctly.

Parent asserted;
Occam's Razor, which is a basic tenent of modern scientific thought says that the simplest explanation is the best.

This is an abuse of the version of Occham's Razor used in modern scientific thought, though an oft repeated misinterpretation.

A better way of phrasing the desire for elegance in modern science is; "Given two identically predictive models, choose the one which requires the fewest assumptions." Reducing the number of assumptions is not always the same as 'simplifying' the problem.

Also, remember that the purpose of science is to generate predictive value. If one of those models is more complex but also more predictive, then it is ALWAYS the better model, no matter how complex.

The original version of Occam's Razor, as correctly expressed in the Wiki article, is "Entities should not be multiplied beyond necessity" where 'necessity' equates to generating the maximum level of predictive value.

Check out the following link, which gives a better summation of the role of Occham's razor in science than the wiki article does.

http://www.physics.adelaide.edu.au/~dkoks/Faq/Gene ral/occam.html