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Evidence of 6 Dimensions or More?

ScuttleMonkey posted about 9 years ago | from the so-thats-where-all-the-socks-go dept.

Space 277

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."

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One can dream (5, Funny)

bl968 (190792) | about 9 years ago | (#13475390)

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

Re:One can dream (1)

frinkacheese (790787) | about 9 years ago | (#13475467)

That's dimensions, not parallel universea - fool. You think mayb the geeks get the girls up and down rather than left or right? Or maybe we only get them in time and not in space ;-) Gee, some of us geeks have had to rationalise our network infrastructure you know (i.e. we got married...)

Re:One can dream (0)

Anonymous Coward | about 9 years ago | (#13475601)

Duh, we already knew this. (0, Redundant)

elucido (870205) | about 9 years ago | (#13475397)

This is slashdot! Most of us already know that theres multiple dimesions. Time itself is a dimension.

It's more important to figure out how to best use each dimension. We have only mastered the physical dimension with little knowledge about the quantum world. Perhaps computers will assist us in the future to determine the functions of the other dimensions.

Re:Duh, we already knew this. (0)

Anonymous Coward | about 9 years ago | (#13475512)

It's my understanding that Quantum Physics implied the existence of either seven or nine dimensions when unifying the weaker/greater nuclear forces with electromagnetism and Newtonian Physics. String theory presently suggests eleven dimensions, IIRC, but it may be as many as fifteen... that physics class was a few years back, haha.

As a side note, I cannot find any sources on Google, and Wikipedia doesn't bring mention of increasing dimensions. I do recall something along the lines of "when you have more dimensions, things become more probable" or some such.

ObTime Cube (4, Funny)

zerblat (785) | about 9 years ago | (#13475400)

I am flabbergasted that the "big brother" hired pedants can brainwash and indoctrinate the powerful antipode human mind to ignore the simple math of 4 simultaneous 24 hour days within a single rotation of Earth, to worship one and trash three. Magnificient evil job by teachers.

This is clearly false and evil. The Time Cube has exactly 4 dimensions.

An open mind is a slop bucket, "THINK CUBIC [timecube.com] ".

Re:ObTime Cube (1)

ColaMan (37550) | about 9 years ago | (#13475421)

Hmm. Not enough use of the words dumb, stupid, blind. Plenty of evil, that's fine.

Please repost your TimeCube comment again below, with more vitriol this time.

Re:ObTime Cube (0)

Anonymous Coward | about 9 years ago | (#13475492)

time travel back about 500 years and you'd be seeing similir comments along the lines of:

"you heretic, you should be burned for presuming that the world is round!!! that is clearly not what the mother church has taught us unfortunate sinners!!"

lets remember to keep an open mind here, there still alot that our SIMPLE theories can't explain in this, quiet, little, corner of the big universe.

Re:ObTime Cube (1)

KDR_11k (778916) | about 9 years ago | (#13475539)

The Time Cube is a joke. That post was a joke. The inquisition was not joking.

Re:ObTime Cube (5, Funny)

Anonymous Coward | about 9 years ago | (#13475559)

Sufficiently advanced satire is indistinguishable from reality.

Re:ObTime Cube (0)

Anonymous Coward | about 9 years ago | (#13475644)

sufficiently retarded reality is indisinguishable from even the crudest satire.

c.f. bush admnistration, war on terror, federal rescue chaos NOLA

On the moon (0)

Anonymous Coward | about 9 years ago | (#13475401)

But on the Moon we have five...THOUSAND dimensions.

Re:On the moon (1)

Alystair (617164) | about 9 years ago | (#13475542)

... and our vertical leap is beyond all measurement.

Re:On the moon (1)

Beardydog (716221) | about 9 years ago | (#13475632)

And we're excellent spellers.

Re:On the moon (1)

FatSean (18753) | about 9 years ago | (#13475707)

Don't question it!

So if we can't see it, it's in another dimension? (5, Interesting)

Hannah E. Davis (870669) | about 9 years ago | (#13475402)

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:So if we can't see it, it's in another dimensio (0)

Anonymous Coward | about 9 years ago | (#13475429)

But then again, if they do manage to actually find solid evidence (not just its apparent invisibility in our traditional 3 or 4 dimensions)

There is no "apparent invisibility". Their equations give answers that don't match reality. This is normal, it means there's stuff we don't know yet. But instead of saying "yeah, there's a lot of stuff we don't know yet" they make up some crap about invisible matter and hidden dimensions. It's just modern superstition.

It's the same as saying "god did it" or "fairy magic" but for a "scientifically" minded audience. It's a made up explanation with nothing going for it.

Re:So if we can't see it, it's in another dimensio (3, Informative)

taniwha (70410) | about 9 years ago | (#13475602)

no what they have is a bunch of conjectures that they think explain what's happening elsewhere in the universe better that the others we have at the moment (aka string theories) problems are that they posit extra dimensions (mostly more than 6) - so how to prove ones conjecture? - start hypothesis: "existence of tiny extra dimensions will also cause macroscopic (ie galaxy sized) things that can't normally be explained or microscopic (ie nanometer sized at the size of the dimension) things that can't normally be explained" - at this point one goes off and looking for proofs of your hypothesis ...

That IS the scientific method - you start with a 'conjecture' which IS a made up explanation and look for ways to prove or disprove it. If you think it's done by fairies at the bottom of the garden you race down there and start looking under leaves. "God did it"? start looking for gods to photograph and measure. Extra dimensions? start looking for evidence of them

Re:So if we can't see it, it's in another dimensio (1)

spottedkangaroo (451692) | about 9 years ago | (#13475615)

Way smaller than nanometers... if they're there, they're at the plank length...

Re:So if we can't see it, it's in another dimensio (5, Informative)

Anonymous Coward | about 9 years ago | (#13475432)

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:So if we can't see it, it's in another dimensio (5, Interesting)

bm_luethke (253362) | about 9 years ago | (#13475604)

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.

Re:So if we can't see it, it's in another dimensio (2, Interesting)

JRIsidore (524392) | about 9 years ago | (#13475692)

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.

Yeah... (-1, Troll)

Anonymous Coward | about 9 years ago | (#13475403)

Our theories don't work. I know there must be some invisible matter in extra dimensions that we can't see that's doing it! Probably the dimensions where the elves live that build the toys for Santa Clause.

Great Reporting... (0, Redundant)

martian67 (892569) | about 9 years ago | (#13475404)

I for one would like to thank slashdot for this amazing, Multi-Dimentional report...

How dimensions wrap themselves up (5, Informative)

ReformedExCon (897248) | about 9 years ago | (#13475405)

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:How dimensions wrap themselves up (1, Interesting)

Anonymous Coward | about 9 years ago | (#13475465)

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:How dimensions wrap themselves up (2, Interesting)

kohaku (797652) | about 9 years ago | (#13475544)

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?

Re:How dimensions wrap themselves up (1)

SixTwelve (451492) | about 9 years ago | (#13475616)

we can only perceive three dimensions and yet we must exist in the other six as well

More like they'd exist within us. The article describes them as mostly existing at the nanometer scale. Nanometers certainly do exist within us, and I surely can't perceive them. I'll grant you that that doesn't jibe with my understanding of dimentions, having only the other 4 to work with as reference.

but we can't see them

Lot's of stuff we can't directly perceive. For instance, I believe in UV radiation, but I can only infer it from the pain of my white irish ass getting about 4 minutes exposure to the sun.

life-forms that exist in one or two dimensions, so how can we exist in just three?

I don't know where life-forms come into this. Your sentiocentricity gives me great pleasure in coining a word.

Well, I guess you didn't specify sentients. But babelfish doens't have english to latin so I got nothin. I wonder, though, how many dimentions a sea cucumber percieves? Maybe time? That doesn't mean it doesn't exist in at least 3 more.

Re:How dimensions wrap themselves up (1)

strider44 (650833) | about 9 years ago | (#13475624)

The point of it is that as the GGP said the dimensions are wrapped up. I don't pretend to actually understand or comprehend it, and possibly noone truly does since it's a mathematical model, however just think of "why can't we see stuff in other dimensions" this way: in the other dimensions if something goes a few millionths of a nanometre forward it gets back to where it is. Just think how we could comprehend something like this when our smallest cells are hundreds of nanometres big?!

Re:How dimensions wrap themselves up (1)

Phantom Zmoove (893297) | about 9 years ago | (#13475638)

You know, I've always wondered if the universe is spherical. If I wonder long enough I run into some problems.

If it is spherical, are we inside it, like a bubble? Or on the surface of it, like a planet?

If we are inside it, what happens when you get to the edge? Is it like a fly bumping into glass? Or more like just passing through it, like Earth's atmosphere? Either case, what's on the other side?

So if we are on the surface, like a planet. Does that mean there are multiple spherical universes grouped together, like a solar system? Maybe orbiting something else, like a sun universe or something.

I'm going to stop now, my head is starting to hurt.

Re:How dimensions wrap themselves up (1)

PsiPsiStar (95676) | about 9 years ago | (#13475782)

The string theorists have certainly been rolling somthing...

String Theory is a joke (0, Flamebait)

kakos (610660) | about 9 years ago | (#13475409)

This is why string theory is a joke. Whenever they run into a problem, they throw in more dimensions or some other kludge, like gravitons leaking out of the universe.

Re:String Theory is a joke (0)

Anonymous Coward | about 9 years ago | (#13475425)

whats the string theory?

lol (0)

mnemonic_ (164550) | about 9 years ago | (#13475431)

lol what

Re:String Theory is a joke (4, Funny)

BetterThanCaesar (625636) | about 9 years ago | (#13475439)

This is why the theory of relativity is a joke. Whenever they run into a problem, they throw in more gammas or some other kludge, like gravitation being the same as acceleration.

This is why Newtonian physics is a joke. Whenever they run into a problem, they throw in more integrals or some other kludge, like momentum being preserved.

This is why bakery is a joke. Whenever they run into a problem, they throw in more meal or some other kludge, like lowering the temperatur of the oven.

Re:String Theory is a joke (1)

kakos (610660) | about 9 years ago | (#13475460)

The difference is that Relativity and Newtonian physics has evidence to backup the "kludges" it has. String Theory has ZERO evidence backing it up.

Before you get modded into oblivion .... (0)

Anonymous Coward | about 9 years ago | (#13475459)

and congratulations on the first -2 post ever.

I'd observe that if everything that can't be directly seen with the naked eye, and is thus infered by the mind's keener eye, must be a kludge among other jokes you'll find, atoms, photons, electrons, molecules, and all manner of small organisms.

Re:String Theory is a joke (1)

Hope Thelps (322083) | about 9 years ago | (#13475477)

How is that flamebait? How many people could be provoked into a flamewar over string theory?

If you disagree with him then maybe you should consider making a reasoned reply.

Re:String Theory is a joke (1)

JoshRosenbaum (841551) | about 9 years ago | (#13475523)

The reason it's flamebait in my opinion is because string theory is a theory like any other, and is open to changes. Saying that it's a problem that they change the theory when the model doesn't work just isn't a smart comment. String theory is dealing with stuff that we don't understand, and they'd better be open to changing the model when needed. There's actually many different models anyway if I remember correctly.

I'm sure many of our current scientific theories with sound models went through a few non-working models as well.

Re:String Theory is a joke (1)

Decaff (42676) | about 9 years ago | (#13475536)

How is that flamebait?

I agree - it is a valid point of view.

How many people could be provoked into a flamewar over string theory?

Pretty easily in my experience! String Theory is highly controversial in some ways. For many physicists it is the way forward in explaining just about everything. For other scientists (like me) it looks like nothing more than mathematical games, playing about with weird ideas at energy scales so high that it is unlikely they can ever be tested.

Re:String Theory is a joke (2, Insightful)

TopSpin (753) | about 9 years ago | (#13475514)

This is why string theory is a joke. Whenever they run into a problem, they throw in more dimensions or some other kludge, like gravitons leaking out of the universe.

The meme "string theory" means something because a few brilliant people continue to believe the math involved is actually applicable to modeling reality. It may yet be dismissed as luminiferous aether. In the meantime it serves as a possibility that can be studied. Does this status justify ridicule? Certainly not from me.

Re:String Theory is a joke (1)

Billly Gates (198444) | about 9 years ago | (#13475563)

Also String theory is not just a crack job like it was 20 years ago.

Its very popular and has many followers in physics. Einstien himself came up with the field of relativity by mathmatics as well.

Re:String Theory is a joke (1)

william_w_bush (817571) | about 9 years ago | (#13475537)

err, yes, but all knowledge is just total bullshit that hasn't been exposed as such yet.

gravitons leaking out of the universe... part of the attempted quantum gravity reconciliation?

string theory isn't done yet, so it's hard to say it's all being added as a kludge, you want to see a kludge, look at the damn standard model sometime, half the particles are "uhh, we don't know what happens here, so we have particle q come in and take care of whatever exchange is happening" and none of the underlying problems are solved.

string theory seems very promising for a TOE, but the problem is thinking in 11-26 dimensions is surprisingly hard.

oh, fyi:

1-3 dimensions - space
4th dimension - time
5-10th dimensions - kaluza-klein hyperspace manifold (tiny dimensions enfolded to roughly 1 plank length each)
11th dimension - nobody is quite sure but they like to call it probability, has to do with extended quantum interaction modes.

Re:String Theory is a joke (1)

maxwell demon (590494) | about 9 years ago | (#13475795)

the problem is thinking in 11-26 dimensions is surprisingly hard.

Given that is is already quite hard to think in just four dimensions, I consider it not at all surprising that thinking in 11 or more dimensions is even harder.

Re:String Theory is a joke (2, Funny)

empaler (130732) | about 9 years ago | (#13475582)

Yeah, they should 'stay the course' instead. That's what real men do when they're proved wrong.

Great! (3, Funny)

Frodo Crockett (861942) | about 9 years ago | (#13475413)

Now I'll be getting email about increasing the size of my penis' fourth, fifth, and sixth dimensions!

Very old news. - link (0)

Anonymous Coward | about 9 years ago | (#13475427)

India Daily reported this back in July.

Keep up Westerners!

http://www.indiadaily.com/editorial/3799.asp [indiadaily.com]
""The superstring theory in contemporary physics proves the existence of parallel universe with many higher dimensions where advanced alien civilizations prosper ""

You know the drill... (0)

PrivateDonut (802017) | about 9 years ago | (#13475428)

if it doesn't make sense, blame it on another dimension.

Re:You know the drill... (1)

yobbo (324595) | about 9 years ago | (#13475627)

But wasn't the alleged Star Trek 5 filmed in our dimension?!

dotted... (4, Funny)

mmThe1 (213136) | about 9 years ago | (#13475435)

Alert: The fourth, fifth, and sixth dimensions were slashdotted today due to uncontrollable inflow of nerds, geeks, and other creatures.

To keep the traffic flow normal, mirrors have been provided on the seventh, eighth, and ninth dimensions for the earthlings...

Well i thought it was at least 11 (3, Insightful)

Tomah4wk (553503) | about 9 years ago | (#13475441)

An old professor of mine who was a string theory expert (i very much am not) once told me most of the maths he does deals with 11 dimensions.

Re:Well i thought it was at least 11 (1)

AC-x (735297) | about 9 years ago | (#13475506)

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. But thankfully this needn't be a problem. There's no reason why, in addition to the three large extra dimensions predicted by Silk and colleagues, there might not be several other small ones too.

Re:Well i thought it was at least 11 (5, Interesting)

william_w_bush (817571) | about 9 years ago | (#13475516)

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:Well i thought it was at least 11 (0)

lasindi (770329) | about 9 years ago | (#13475532)

An old professor of mine who was a string theory expert (i very much am not) once told me most of the maths he does deals with 11 dimensions.

Yup, string theory [wikipedia.org] (or more specifically M-theory [wikipedia.org] ) requires 11 dimensions. Since string theorists have yet to find truly compelling experimental evidence for the theory, could this possibly provide such evidence (anyone who knows more about string theory?)? (No, I didn't RTFA.)

I see sequels.... (0)

Anonymous Coward | about 9 years ago | (#13475448)

This is only setting up for Cube V, of course...

Nope, won't believe this... until... (3, Funny)

geoff lane (93738) | about 9 years ago | (#13475452)

Some lawyer sues someone citing some imagined harm caused by the additional dimensions.

This is way old news (3, Funny)

Macphisto (62181) | about 9 years ago | (#13475480)

There are like twelve dimensions here. Don't feel jealous though, they are really boring. There is not even any ketchup, and not in the extra dimensions. When I went to the car, then the gravity was different, so I thought so. There is another dimension, but it is oriented left on top, so arranged laterally. With the extra dimensions, lucidity is beneficial but orthogonal to our clear destination. I anticipate an increase in coherency, thought may suffer but I think a good drive will clear my mind. There is health but in the yellow, it is vaporous, and at such speed some clouds are quite hard. Be oviparous, but not before it hatches!

Oh please. (0, Flamebait)

destx (856327) | about 9 years ago | (#13475501)

You can't just pull dimensions out of your ass like that.

string theory? (4, Interesting)

krunk4ever (856261) | about 9 years ago | (#13475526)

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.

So..... (1)

Varun Soundararajan (744929) | about 9 years ago | (#13475528)

we are expecting a 'n'D revolution next?
---
This space intentionally left blank

Re:So..... (1)

lustforlike (867068) | about 9 years ago | (#13475653)

My graphics card already accelerates 6D graphics - it runs Doom 3 at such a high frame rate in 6D that I can only perceive 10 of those frames a second with my puny human 3D vision.

somewhere to start (2, Informative)

martian67 (892569) | about 9 years ago | (#13475534)

If you need somewhere to start, and don't know any physics, try one of the free introductory physics books listed here [theassayer.org] . After that, if you want to try to bring yourself up to the level a book like the "road to reality" by Penrose is shooting for, try some of these:
  • Relativity Simply Explained by Martin Gardner
  • Black Holes and Time Warps: Einstein's Outrageous Legacy by Kip Thorne
  • Spacetime Physics by Taylor and Wheeler (special relativity, with a little more math)
  • Exploring Black Holes: Introduction to General Relativity by by Taylor and Wheeler (general relativity, with a little more math)
  • QED: The Strange Theory of Light and Matter by Richard Feynman
  • Three Roads to Quantum Gravity by Lee Smolin

PBS Nova: The Elegant Universe (3, Interesting)

cciRRus (889392) | about 9 years ago | (#13475803)

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] .

So when (1)

Jaro (4361) | about 9 years ago | (#13475540)

can we expect to get this for our home cinema experience?

I wonder... (1)

The Great Wazzoo (798980) | about 9 years ago | (#13475543)

...who's gonna patent them?

For the actual reference (4, Informative)

volsung (378) | about 9 years ago | (#13475545)

The actual paper this article is about is here:
Observational Evidence for Extra Dimensions from Dark Matter [arxiv.org]

(It's actually a draft of a paper submitted to Physical Review Letters, not yet approved.)

It's a nice phenomenology paper without any heavy math that puts together a bunch of theoretical ideas floating around. Even better, it has testable hypotheses! (unlike many papers these days)

  1. Gravity should deviate from the inverse-square law at the nanometer scale.
  2. Dark matter should be composed of a particle with mass 3e-16 GeV/c^2. (For comparison, mass of electron is 5e-4 GeV/c^2.)
  3. The large extra dimensions assumptions all this is based on would require us to see all sorts of quantum gravity interactions at the LHC.
Now short-range gravity experiments are just approaching the micron scale, so we're 3 orders of magnitude away from testing hypothesis #1. I doubt anyone has an idea how to close that gap right now.

Checking hypothesis #2 would require some independent way of determining the mass of dark matter particles. I don't know what the sensitivity range of the various dark matter experiments running or planned are. Maybe they would be able to see something this light.

#3 however is going to start running in 2 years, and then we'll get some good information either way.

Re:For the actual reference (2, Interesting)

Mr_Dyqik (156524) | about 9 years ago | (#13475614)

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:For the actual reference (1)

volsung (378) | about 9 years ago | (#13475655)

Found some talks on CRESST II, and it doesn't seem like they will be sensitive to dark matter in the mass range predicted by this paper.

Looks like the astrophysical observations will have to save the day. :)

If you're interested in this stuff.... (2, Interesting)

BigAlexK (398239) | about 9 years ago | (#13475549)

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.

I thought it was well known that (0)

Anonymous Coward | about 9 years ago | (#13475551)

I thought it was well known that the weakness of gravity can be explained if there are 11 dimensions. I mean, geez, I read stuff like this in Discover magazine like 10-15 years ago.

Simplest explanation? (3, Funny)

mikiN (75494) | about 9 years ago | (#13475556)

Occam: I seem to have misplaced my razor...

String Theory? (1)

VincenzoRomano (881055) | about 9 years ago | (#13475566)

It would be great now if the Superstring theory [wikipedia.org] people could provide us with some interesting explaination.
In any case thay have never thought about such an evidence ... if the quoted info is really true.

From TFA (1)

mrjb (547783) | about 9 years ago | (#13475579)

"This has never been tested experimentally: no one has measured how gravity behaves over distances below about a hundredth of a millimetre."

On atomic scale, 1/100 mm is still pretty huge and I understand science itself has progressed enough to have the means to make such measurements. So before speculating any further, it seems it would make sense to start doing that first then, wouldn't it?

...and if you call before the dupe is posted... (3, Funny)

mattkime (8466) | about 9 years ago | (#13475580)

...and if you call before the dupe is posted, we'll include an extra 2 dimentions at NO ADDITIONAL COST!*

(*old people in korea need not apply)

Higher Dimensions and Fermions (2, Interesting)

Beautyon (214567) | about 9 years ago | (#13475583)

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 (2, Interesting)

Anonymous Coward | about 9 years ago | (#13475592)

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:Dimension is just a definition (1)

wolverine1999 (126497) | about 9 years ago | (#13475629)

What some erroneously call a dimension, is actually a parallel universe. I think it's the fault of bad sci-fi... :)
Real-life scientific "dimensions" are something else entirely.

Re:Dimension is just a definition (1)

benjamindees (441808) | about 9 years ago | (#13475729)

An extra dimension could be analogous to a string of parallel universes.

A dimension is really just a layer of reality. It's an escape. It's another variable in the equation and it's value affects all the other variables.

Think about a multiverse with two universes. Assuming each universe is composed of three spatial dimensions and one time dimension, how many dimensions does the multiverse contain? Eight? Five?

Oops... (1)

benjamindees (441808) | about 9 years ago | (#13475774)

and it's value affects all the other variables.

Sorry, but this is bullshit. Should have said it is independent of other variables.

Whatever happened to Occam's Razor? (3, Insightful)

TheNarrator (200498) | about 9 years ago | (#13475603)

Occam's Razor [wikipedia.org] , which is a basic tenent of modern scientific thought says that the simplest explanation is the best. It seems that these dark matter explanations get more and more complex. When a theory is very complex it becomes suspect. For instance, when the Earth was though to be the center of the universe, Mars moving backwards in the sky caused much grief to astronomers. They invented all kinds of head spinning mathematics to describe the motion of mars and the other planets. Of course when the Sun was put in the center of the solar system and the laws of gravity were unearthed everything turned out to be far simpler than the theorists, working with broken premises had made it out to be. In the same way, something smells funny with String theory, and multi-dimensional explanations for dark matter, etc. Isn't science about experimentation and testing hypothesises in a laboratory instead of endless mathematical tricks to get theories to fit observations?

Re:Whatever happened to Occam's Razor? (0)

Anonymous Coward | about 9 years ago | (#13475650)

Actually, its just a lack of information about the "dark matter" equivalents of mars' movement that has us stumped.

Scientists these days are all about simple explanations - in fact the gratest quest currently is to unify QM with Relativity - probably ending up with a nice elegant explanation like m-theory.

Re:Whatever happened to Occam's Razor? (1)

Decaff (42676) | about 9 years ago | (#13475690)

probably ending up with a nice elegant explanation like m-theory.

That is not elegant as I understand the word!

Trying to explain real-world phenomena and physical properties such as (for example) vibration and tension using microscopic strings (the 2D aspect of M-Theory) which themselves are supposed to experience vibration and tension is kind of pointless[sic] and circular to me...

Re:Whatever happened to Occam's Razor? (0)

Anonymous Coward | about 9 years ago | (#13475724)

Its not circular - the vibrations of strings is well defined with an extremely elegant forumla - circular strings are slightly different, but still very elegantly defined.

As for larger objects - they are defined in terms of smaller ones - Also very elegantly.

I don't see why you think it is circular. Perhaps because ones vibration is defined in terms of the vibration of the other? Thats not circular!

Re:Whatever happened to Occam's Razor? (2, Interesting)

RedLaggedTeut (216304) | about 9 years ago | (#13475677)

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:Whatever happened to Occam's Razor? (2, Insightful)

random name 6721 (876265) | about 9 years ago | (#13475683)

No, its not getting more complex. In fact, having more dimensions explaines the stuff _nicely_, that means without too many additional assumptions. No need for an arbitrary particle which, by chance, excatly behaves like dark matter on large distances, but is not observable otherwise. The problem only is, that the simple ideas of the string theory (which is usually the physical theory behind the multiple dimensional universe explainations) is mathematically difficult, and complex, and hence, all articles etc. which try to explain it, or parts of it, are ususally somewhat mind boggling. Its somewhat like taking Maxwells equations (which are beautufully simple) and start to explain why the sun looks red while rising - Ugh! Let some years pass, and as understanding of String theory and implications gets better, it will look simplier...

Everyone abuses Occam's razor (5, Informative)

PsiPsiStar (95676) | about 9 years ago | (#13475772)

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 [adelaide.edu.au]

I just bought Axe Dimensions bodyspray! (-1, Redundant)

Anonymous Coward | about 9 years ago | (#13475607)

What a coincidence!

I just bought Axe Dimensions bodyspray... it's guaranteed to send women to your dimension :)
It works...

The idea of extra dimensions is... (3, Interesting)

martiojd (820719) | about 9 years ago | (#13475609)

... 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:The idea of extra dimensions is... (1)

maxwell demon (590494) | about 9 years ago | (#13475731)

Of course the sum should be exactly 42. She probably summed up the numbers in incorrect order.

Maybe? (1)

slasho81 (455509) | about 9 years ago | (#13475610)

Is there evidence, or not? Is this a concrete advance in our understanding of nature, or is it just another article in Nature?

dark matter? (1)

unfunk (804468) | about 9 years ago | (#13475623)

Whatever happened to the Cold Dark Matter (each pound of which weighs over 10,000 pounds!) theory, where gravitational & mass anomolies were explained by the existance of such a substance?

Re:dark matter? (0)

Anonymous Coward | about 9 years ago | (#13475662)

That's what this is, but the article relates to a theory that this dark matter (dark because we can't detect it) exists in other dimensions and that's why we can't see it.

evidence? (1)

calyptos (752073) | about 9 years ago | (#13475643)

The subject says there is evidence. The article only points out that there is a "gravitational tug", and then gives us a theory on why. Don't present something as evidence when it isn't.

"My power supply stopped working, therefor the power company is sending me too much electricity." The power supply not working is the problem, not the evidence. The "gravitational tug" is the problem, not the evidence.

Excuse the lunatic fringe rant, but... (1)

scratchresistor (882878) | about 9 years ago | (#13475645)

And all for the sake of maintaining the initial (unnecessary and insufficient) postulate that phi(x)->0 as x-->infinity in the Schrodinger equation... (http://www.blacklightpower.com/ [blacklightpower.com] - read the book, it's good...) Unlike, err, Time Cubes (sorry), the math checks out on this one - sub-ground state hydrogen makes up the dark matter, we don't need extra dimensions, quantum mechanics is fundamentally, well, wrong, etc. etc. etc. P.S. I did four years of physics at a very good university, and my conclusion was this: mainstream physics is barking up the wrong tree...

Not an expert (1)

rolfwind (528248) | about 9 years ago | (#13475667)

I'm probably not bright enough to really comprehend this subject but does this theory fit in with Occam's razor premise that the simplest answer is usually correct?

It seems that sometimes fanciful theories pop up that seem to just shoot wildly in the dark for lack of observable/obtainable info.

At least it's not a human-centric nonfalsiable unlimited paralell universes or time travel can't alter history theory........

Wouldnt there be 8 now then? (1)

Bizzeh (851225) | about 9 years ago | (#13475680)

i thought there were already 4? length, depth, bredth and time?... so, really there would be 8 now. length, depth, bredth and time.. AND dark length, dark depth, dark bredth and dark time... 8...

Then again... (1)

Scooter (8281) | about 9 years ago | (#13475737)

....another explanation is that you just can't see it BECAUSE IT'S VERY DARK. :P

explaination (2, Informative)

Shinaku (757671) | about 9 years ago | (#13475759)

I watched a stream yesterday which explained how dimensions can be interweaved into our own, and how the laws of gravity and Quantum physics can be combined with string theory,

http://www.pbs.org/wgbh/nova/elegant/ [pbs.org]
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