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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."
That in at least one of the six that hopefully the geeks get the girls :P
"GET / HTTP/1.0" 200 51230 "-" "Mozilla/4.0 (compatible; Setec Astronomy)"
This is clearly false and evil. The Time Cube has exactly 4 dimensions.
An open mind is a slop bucket, "THINK CUBIC".
Please alter my pants as fashion dictates.
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.
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.
Jesus saved me from my past. He can save you as well.
Now I'll be getting email about increasing the size of my penis' fourth, fifth, and sixth dimensions!
"The newly born animals are then whisked off for a quick run through a giant baking oven." --heard on Food Network
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.
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...
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.
"Stop failing the Turing test!" -- Dilbert
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.
Some lawyer sues someone citing some imagined harm caused by the additional dimensions.
Greene's Elegant Universe
The Mechanical Universe
Last book I enjoyed, Three Roads to Quantum Gravity by L. Smolin... ya, ya, I know, nothing fits, is, isn't, yo momma... no yo momma... can, can't... I'm not touching you!
"Academicians are more likely to share each other's toothbrush than each other's nomenclature."
Cohen
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!
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.
Lurking at the bottom of the gravity well, getting old
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.
HD Trailers
Observational Evidence for Extra Dimensions from Dark Matter
(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)
- Gravity should deviate from the inverse-square law at the nanometer scale.
- 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.)
- 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.
Occam: I seem to have misplaced my razor...
The Hacker's Guide To The Kernel: Don't panic()!
...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)
Know what I like about atheists? I've yet to meet one that believes God is on their side.
Yeah, they should 'stay the course' instead. That's what real men do when they're proved wrong.
And I quoth:
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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.
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
Occam's Razor, 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?
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?)
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.
:w!q
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/
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I'm starting to think that Occam's razor is abused more often than it is used correctly.
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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/Gen
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It's the end of my comment as I know it and I feel fine.
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
That's wha the NASA is currently preparing to deploy the Very Lage Flashlight (VLF), which will give us insight even into quite dark matter.
Unfortunately, they still have problems figuring out how to exchange the twenty million AA batteries powering it once it's in space.
USE HOT GRITS WITH STATUE OF NATALIE PORTMAN (NAKED AND PETRIFIED)
The alternative to complicating the universe with dark mattter, dark energy, and multiple dimensions is replacing General Relativity with a more complicated theory. Which we know needs to be done on the quantum scale at least, but which hasn't been successfully done yet.
So, right now, we have GR. Which needs undiscovered "dark" matter to explain why galaxies are rotating faster than expected. And extra dimensions to solve the problem of different-sized galaxies. And "dark" energy to explain why these galaxies are separating from each other than they should given our estimates of their mass.
The most serious alternative to that is Modified Newtonian Dynamics (MOND), which assumes that at very low accelerations (lower than any body in the Solar System experiences, because of solar gravitational acceleration), F=ma is wrong. This explains away dark mattter easily, and there's even been a suggestion that the TeVeS version of MOND can explain away dark energy, too.
Now, if somebody can come up with a successful model of quantum gravity that also reduces to MOND on a galactic scale . . . well, he'll get a Nobel, and probably replace "Einstein" as a synonym for "genius".
Read the interview here.
Mostly random stuff.
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.
;) ). 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...
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
it may dominate the large scale structure and behavior of the universe (star formation, galaxy formation, intergalactic structures . .
Check out the following:
Plasma Cosmology
Plasma Universe
Guided Tour of the Plasma Universe
Electric Currents and Transmission Lines in Space
Immense Flows of Charged Particles Discovered Between the Stars
Interesting quote from Hubble regarding redshift:
Thuderbolts.info
Thunderbolts' Picture of the Day
Picture of the Day Archive
A few very interesting selections from the archive:
The Picture that Won't Go Away
Quasars in Infrared are Still Nearby
Predictions on "Deep Impact"
Electric Stars
Of Pith Balls and Plasma
Space Shuttle Struck by Megalightning?
The website of Halton Arp
The Observational Impetus For Le Sage Gravity
IC XC NIKA