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."

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.

Re:How dimensions wrap themselves up

[Anonymous Coward]

Maybe the other three dimensions are curled up as well, it's just that they're big enough that we can see an understand them.

think about it mathmatically, the larger a circle gets the closer it will coincide with a tangent line along the circumferance.

thats the whole reason the earth seems flat, the curve is gentle enough over enough space that we can't percieve it whilst walking on it.

now in the case of the universe, we'd be talking about a circle billions of light years in diametre and alot bigger in circumferance. the three demensions returning back on themselves would be at such a great length that we could never traverse it in one lifetime.

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.

string theory?

[krunk4ever]

is this in anyway related to the string theory [wikipedia.org]?

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.

Re:How dimensions wrap themselves up

[kohaku]

what I don't understand is how we can only perceive three dimensions and yet we must exist in the other six as well, but we can't see them. There are no objects or life-forms that exist in one or two dimensions, so how can we exist in just three? I would imagine from a sixth-dimensional perspective we look how a piece of paper with no width (2 dimensional) would look to us. If we do exist in six dimensions, but can only sense three, what properties do we have in six?

If you're interested in this stuff....

[BigAlexK]

Try reading 'The Field' by Lynne McTaggart.

I can't recommend it highly enough, and it'll tell you a lot of what you need to know.

And yes, it is scientifically based and discusses real results from real establishment (and in many cases highly lauded) scientists.

Higher Dimensions and Fermions

[Beautyon]

It's all explained vividly here [indiadaily.com].

And I quoth:

"The Physical Universe is connected with the underlying Hyperspace by some sparsely distributed particle size small windows called Fermions. These Fermions literally connect our universe with the 5-D Hyperspace."

Dimension is just a definition

[Anonymous Coward]

I think one of the problems here is how you actually define a dimension. Most people when they think about dimensions think about three spatial dimensions. Some people will then go on to say that time is a fourth type of dimension, yet time is very different to spatial dimensions. Likewise these new so called extra "dimensions" are only so because of the label we give them, they are obviously different again to spatial or time dimensions as most people understand them. So before the mind starts to boggle (like wow man) over these so called extra dimensions, one should understand that very simply "dimension" is just a word, and a word with a seemingly rather open definition.

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.

The idea of extra dimensions is...

[martiojd]

... 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?)

Re:For the actual reference

[Mr_Dyqik]

More indirect data on galaxy clustering and galaxy dynamics (especially of small galaxies) to help constrain the properties of dark matter (in particular the interaction of dark matter with other dark matter) would also be useful, as is noted in the paper.

This probably requires a number of astronomical surveys (mainly Sunyaev-Zeldovich effect surveys for galaxy clusters at microwave/mm-wave frequencies, and optical and radio surveys for galaxy dynamics) to give large datasets from which the statistical properties can be used to infer properties of dark matter over a range of length scales.

In Oxford we're also developing the instruments to carry out these surveys. In particular, various people will be developing the Square Kilometer Array http://www.skatelescope.org/ [skatelescope.org] which will be the primary radio survey instrument from 2020, extremely large optical telescopes such as OWL, and technology for the next generation of S-Z effect surveys at mm wavelengths.

Dark matter particle direct search experiments, such as CRESST II are also under development, and should start operating on a similar timescale to the LHC.

Re:Whatever happened to Occam's Razor?

[RedLaggedTeut]

Well, adding new dimensions is very simple mathematically.

To compare it with the situation of 3 vs 2 dimensions, most people couldn't plot a path from the surface of the Earth to the moon in 3+1(time) dimensions, so it's not like things suddenly get completely easy just because fewer dimensions are involved.

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

[JRIsidore]

One possible way to detect those additional dimensions are artifical black holes created in particle accelerators. These black holes cannot be created unless the gravitation becomes stronger on small scales than predicted by the classical 4-dim theory, due to the additional dimensions. Only if this increase is present the required mass density for the formation of artifical black holes can be reached (by LHC for example). So if they can ideed produce these little black holes that's a pretty good indication of extra dimensions.

PBS Nova: The Elegant Universe

[cciRRus]

I watched this DVD [shoppbs.org] 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 [pbs.org].

Re:How dimensions wrap themselves up

[m50d]

An amoeba under a slide has a pretty much two-dimensional existence - it can't sense anything above or below, and won't interact with the glass on either side. They seem to live well enough, as far as we can tell. You can't get complex lifeforms in just one or two dimensions because there's not enough "room" - e.g. a complete intestine would make a 2-d animal fall apart. With 4 complete spatial dimensions, however, you run into other difficulties. For one thing, there would be no stable solar systems, because gravity would be an inverse cube law rather than an inverse square law, so there is no stable orbit around a star.

Re:Whatever happened to Occam's Razor?

[Aceticon]

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.

Re:Well i thought it was at least 11

[lasindi]

This was my first thought but if you read the article it mentions this at the end:

The most popular versions of string theory suggest that there are as many as eight extra dimensions, not just three.

Yes, exactly. Three space dimensions we know exist plus eight extra (including time) equals eleven total dimensions. So apparently, there's no inconsistency between this research and current string theory.

Re:One can dream

[Haydn Fenton]

I thought the universe had 11 dimensions (before anyone goes all crazy, there the 3 spatial (macroscopic sized) and 1 time we are familiar with, and another 7 tiny, tiny, tiny, curled up dimensions, which 'explains' why we only know of 4)?
String theory has come a long way and has the power\simplicity to explain a lot of things in the universe which simply wasnt possible before. AFAIK, other theories, forumlas and phenomenon emerge naturally out of the theory (i.e. if we only knew string theory, the rest would follow in time). It's fully compatible with both 'the standard model' and quantum theorems.

Still, IANAP. But this story doesn't seem anything new. There's a whole bunch of different theories and people who think the universe has different number of dimensions.

Re:Excuse the lunatic fringe rant, but...

[scratchresistor]

The problem is, aside from string/m-/p-/superstring- etc. theories, we haven't really come that far since Schroedinger, Planck, Dirac, Heisenberg, Einstein et al.. Most of modern physics is based on purely mathematical theory, with little discernable basis in the physical world. Hence, for all of the things that modern physics has accomplished, we're still without a unified theory.

For all of the extra dimensions, predictions of superstrings, dark matter (and the associated WIMPS, MACHOs etc.), dark energy and so on, these things are, on the whole, educated guesses, and more importantly, none of these things has been observed! Unfortunately, it seems to be endemic in the physics community that is is acceptable to spend years forming fantastic theories based on these guesses. Just because the math seems to be significant, it may not have any real-world basis whatsoever.

I liken it to a mathematical integration: choose appropriate boundary conditions and variables, and you will reach a logical, structured, useful result. Choose the wrong parameters, and you can carry on the calculation forever, and, while it may seem like you are making progress toward a solution, you will never reach the answer. Modern atomic, nuclear and sub-nuclear physics was born from Schroedingers equation of the wavefunction of the hydrogen atom. The boundary condition he used states that the amplitude of the wavefunction goes to zero as the domain approaches infinity - leading to all the things we know and love about particle physics (probability waves, uncertainty, wave-particle duality etc.) Unfortunately, that boundary condition was a *guess*, which happened to give meaningful answers, which in turn led people to believe that it was CORRECT and it developed into aforementioned sprawling wierdness. However, use a different boundary condition (quantized non-radiation of radially accelerated charges, i.e. electrons not radiating while in particular energy levels, a theorem provable in several ways using Maxwell's equations and experimentally well verified) and you get a much simpler answer which only uses Newtonian mechanics, Maxwellian electromagnetism and momentum/energy conservation. From this approach, you can come up with stuff that the other theories lay awake at night sweating about.

Sorry about the rant, I spent 5 years of my life immersed in this (vis a vis, I've done my research ;) ). THEREFORE: (there is a point to all this...), perhaps the scientific community ought not to so readily resort to the "my theory's got [more dimensions / more dangly Kaluza-Klein thingies / leakier m-branes] than yours" game, and have a look at the physical reality of their theories...