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View Full Version : Our Universe Favours Three and Seven Dimensions

Fraser
2005-Sep-28, 06:03 PM
SUMMARY: Scientists working to understand the nature of the Universe have developed some interesting theories that propose we have many more dimensions curled up inside the three we're comfortable with. A pair of researchers have done the math to calculate how the Universe could shape up after the Big Bang, and found that it favours three and seven dimensions. In a seven dimension Universe, gravity would diminish greatly with distance, and planets would have difficulty forming stable orbits around stars.

iantresman
2005-Sep-29, 01:13 PM
Sorry, mathematical balderdash. If you need more than three dimensions, then you need a new theory.

Regards,
Ian Tresman

bigsplit
2005-Sep-29, 04:50 PM
Depth, Width and height....what are the other spatial dimensions called?

I agree with the above, if you need to make up something that has no basis in reality, then you need to look closely at the validity of whatever model or theory that requires such science fiction/fantasy. And to think that mainstream physics refers to other alternative theories as Woowoo and says its because they do not provide the math. Well, the same goes for the other extreme...too much math where excessive reasoning causes science to fall off that slippery slope in the other direction is also woowoo.

Mosheh Thezion
2005-Sep-29, 05:07 PM
Ive been screaming about dimensions for how long?

and they come in groups of 4.. as in 4 90 degree angles.. making one full circle.
as in 360 degrees...
and i would say for simplicity that we can discuss 16 dimensions.. a 4 circle pattern.

or if your really interested we could talk about 7 circles, and upto 28 dimensions.

and it has nothing to do with cosmic foam.
-MT

Duane
2005-Sep-30, 01:17 AM
I think this is is an interesting story. The idea of scalar branes has arisen in part through applied mathematics, and one of the big questions was why we only felt the 3-d of our universe. This may explain why.

This is completely different from what you're talking about Mosheh.

Greg
2005-Sep-30, 03:34 AM
Theories backed up with mathematical models that look good on paper are one thing. The bottom line is that in order for the mainstream to give them any credence then we need evidence. Specifically the models need to make predictions about some phenomenon(a) that can be discovered that is unique to it. Then someone has to fork over the funds to build and launch an instrument or devote some of the previous time on an existing instrument in order to try to validate (or refute) the theory. In essence what I am saying is that talk is cheap and proof is what matters.

agingjb
2005-Sep-30, 01:22 PM
Surely the dimensions of a physical system is simply how many numbers it requires to specify something. It's clear enough that position needs three.

But, given the complexity of the world, it would not be surprising if there were some property associated with every point of space that required more numbers.

It is certainly true that there are topological properties associated with 3 and 7 dimensional spheres that make them special.

bigsplit
2005-Sep-30, 01:56 PM
I still want to know what we call other spacial dimension. We have depth width and height....What are the others called? How can another dimension not be found in these 3?

agingjb
2005-Sep-30, 03:00 PM
I'm not persuaded that, if there other dimensions, we would be disposed to call them "spatial".

Time is quite adequately treated as a dimension; physicists even manage to combine it with space, as "space-time". And yet our perception of time is completely different from our perception of space. So we might expect our intuitions (clearly we are unlikely to have perceptions) about more dimensions to differ at least as much as our concepts of space and time.

ToSeek
2005-Sep-30, 03:17 PM
Theories backed up with mathematical models that look good on paper are one thing. The bottom line is that in order for the mainstream to give them any credence then we need evidence. Specifically the models need to make predictions about some phenomenon(a) that can be discovered that is unique to it. Then someone has to fork over the funds to build and launch an instrument or devote some of the previous time on an existing instrument in order to try to validate (or refute) the theory. In essence what I am saying is that talk is cheap and proof is what matters.

There have been experiments done to see if the conjecture that gravity is weakened by the existence of additional dimensions too small to be easily detected is true. So far as I know none have had an affirmative result.

bigsplit
2005-Sep-30, 09:23 PM
I'm not persuaded that, if there other dimensions, we would be disposed to call them "spatial".

Time is quite adequately treated as a dimension; physicists even manage to combine it with space, as "space-time". And yet our perception of time is completely different from our perception of space. So we might expect our intuitions (clearly we are unlikely to have perceptions) about more dimensions to differ at least as much as our concepts of space and time.

It was my impression was they were discussing spacial dimensions...they never mentioned time as the 4th.

As for them being too small to detect, that would not make them outside the 3 ordinary spacial dimensions. This entire extra dimesion thing just seems like science fantasy...math or not. Depth, Width and Height....any other spacial dimensions have no basis in reality and therefore are merely intellectual exercises for mathematicians.

BlackStar
2005-Sep-30, 09:35 PM
Interesting skepticism here amongst senior members & moderators!

There was very recent research which postulated that what we see as "sub-atomic particles" here in our 3D world are the ends of "strings". The other ends of these strings appear in a 7D universe.

http://www.aip.org/pnu/2005/split/745-1.html

Superstring theory seems to insist on a 10D universe. Perhaps our 3D past, our 3D present, and our 3D future is linked by one-dimensional time to make ten dimensions? Hmm...

iantresman
2005-Sep-30, 11:21 PM
I still want to know what we call other spacial dimension. We have depth width and height....What are the others called? How can another dimension not be found in these 3?
I think it works the other way around. Flatlanders (http://en.wikipedia.org/wiki/Flatland) who "exist" in the plane of a piece of paper, can not see out of the plane into our three dimensional world.

If see stick our 3D finger through their 2D world, a cross-section materialised from no-where. Consequently, a being in a 4D world can look "down" invisibly on our 3D world.

It's great fun conceptualizing higher dimensions (such as hypercubes (http://en.wikipedia.org/wiki/Hypercube)), but its application to science is purely mental masturbation.

Regards,
Ian Tresman

RUF
2005-Sep-30, 11:36 PM
There was very recent research which postulated that what we see as "sub-atomic particles" here in our 3D world are the ends of "strings". The other ends of these strings appear in a 7D universe.

Superstring theory seems to insist on a 10D universe. Perhaps our 3D past, our 3D present, and our 3D future is linked by one-dimensional time to make ten dimensions? Hmm...

String "Theory" and Superstring "theory" are philosophies, not sciences. (note that I put the word theory in quotes). An idea cannot be a theory if it cannot be tested ecxperimentally, let alone "proven" or "unproven." :naughty:

BlackStar
2005-Oct-01, 12:35 AM
String "Theory" and Superstring "theory" are philosophies, not sciences. (note that I put the word theory in quotes). An idea cannot be a theory if it cannot be tested ecxperimentally, let alone "proven" or "unproven." :naughty:

Agreed.

James Friesen
2005-Oct-01, 04:11 AM
A theory is a theory, as in, "I have a theory, let's see if it is true." If it can be proven to an reasonable degree, then it becomes accepted fact.

Relativity was, and still is a theory. It was a theory when it was introduced. It has been a theory while one experiment after another demonstrated it's accuracey to greater and greater degrees. It will continue to be a theory until it is shown to be inaccurate in some particular situation, just as Newton's theory of gravitation was proven to be innacurate in many situations.

String Theory, or M-Theory, is an attempt to explain all of physics with one mathematical framework. Of course it must be tested. Unfortunatley the theoretical physicists have jumped way ahead of the experimental physicists. Eventualy, experiments will be conducted that will either show innacuracies within the thoery, or else support the theory. If it is shown to be innacurate, then it will be a false theory. If it is shown to be accurate for that particular test, then more tests will be carried out. No theory can be taken on faith as accurate until it is examined thoroughly, but how can we know that we are being thorough if we are still coming up with theories? That means we don't know everything, and thus ANY theory, no matter how well proven and accepted as fact, still has the potential to be disproved.

The whole point of this article is that, while they are waiting for the technology to be developed that may prove or disprove these thoeries-of-everything, some theoretical physicists are trying to strengthen the basis of string theory by challenging the math. Their results show that, given a "theoretical" starting condition, a universe based on string theory would favor 3 or 7 dimensions. If they had come up with a different number of favored dimensions, it would have given them cause for concern. You may challenge their assumptions, but they are doing what they can to test the theory.

Even if string thoery ultimately proves to be total hogwash, the work being done is surely contributing to the fields of mathematics and physics. Consider the pursuit an exercise: it may be wasted effort now, but future theories will benefit from any new knowledge or techniques that result from this research.

Perhaps the point you could make, if you think this is nonsense, is that more young people should pursue fields of study that support the experimental side of physics over the theoretical side. It is akin to the decline of hands-on shop classes being taught in the U.S.

Technology classes now focus more on the use of computers in technology fields and shy away from letting the kids 'get thier hands dirty,' and the possible liabilities involved. Eventually drivers-ed will be taught with computer simulations because the school administrators will be too affraid to let any kids get behind the wheel of a real vehicle. Eventually, kids won't graduate with ANY 'real' skills, just theoretical ones.

Greg
2005-Oct-01, 06:36 AM
Very well said. I think that we may be heading to a point where we could repeat the mistakes of the past. There was an interesting thought article published in the newscientist magazine a few months ago identifying pivotal points in scientific history. One of the first and most important was the foundation of the Royal Society by Charles II which got experimental science off the ground with an air of legitamacy and funding. The society when it was founded had members of the likes of Henry Boyle and Issac Newton and promoted their research and a culture of experimentation to verify theories. More importantly, this came in a time of religious schisms and a culture that could have classified such machinations as proposterous witchcraft or heresy. Before this, the emphasis in science had always been on ever more intricate theorization as the paradigm of true science in the mold of the ancient Greek philosophers as proported by another influential scientist of the period and close advisor to Charles II, Thomas Hobbes. I included a link to the newscientist article below.

http://www.newscientist.com/channel/opinion/mg18725131.800

It would seem that in today's world of litigation-phobia and a religiously motivated anti-science movement which has gained strength in the US, that the legislative impetus and most crucially designated funding for basic science research/experimentation is lacking. What is left is relatively cheap theorization on paper with ever more numerous, refined, but unverified mathematical models backing them up. Maybe we should take heed from the wisdom of Charles II and not repeat the mistakes in science that mimics those that made for such little progress during the dark ages. And yes they did seem to spend alot of funds on the War in France back then.

agingjb
2005-Oct-01, 07:53 AM
Mathematicians call an astonishing variety of abstractions "spaces".

It's true that maths is now usually developed long before it becomes, if ever, applicable. (It was not always the case.)

I would not automatically dismiss theories based on hitherto unapplied mathematics, nor would I dismiss the value of "pure" mathematics.

snowflakeuniverse
2005-Oct-03, 09:45 PM
Here is an example of an extra “large” spatial dimension that results in a rather simple explanation of the property of inertia and , what Einstein called the “intrinsic” rest energy of matter.

Imagine a “flatland universe” moving in an unobserved “vertical” dimension.

Imagine an “object” in this flatland universe that is “stationary” based upon a reference frame of those living in flatland.

For residents of this flatland universe the object would have no momentum since it is “at rest” but from our “eye of God” perspective we can see that in fact the object is moving in an unobserved dimension and hence it has momentum. (mxv).

If a resident in flatland were to “move” the object, the object would be subject to a change in momentum, there would be a velocity term associated with the motion along the flatland universe, and there would be a velocity term from the motion of the flatland universe itself.

The velocity along the unobserved dimension imparts the object with intrinsic momentum, which would generally be experienced as ‘inertia” or an inherent property to resist a change in location.

If the velocity along the unobserved dimension was the square root of two times the speed of light, the Kinetic Energy of the object, KE = 1/2 mv^2 becomes E = mcc.

The “intrinsic” energy of a rest mass is simply the kinetic energy of the object moving along the unobserved dimension.

Extra dimensions can make the explaination or description of nature simple.

Snowflake

Blob
2005-Oct-03, 11:16 PM
Indeed,
The addition of extra dimension just makes thing simpler.
An example would be electron spin – it spins 720 degrees to get back to the same place- add another dimension and it doesn’t seem so strange.

Without extra dimensions the idea that all the forces were actually one super force (GUT) can’t be made to work.

A test for strings and dimensions may be in the LHC if they are about 10,000 trillion times larger than theorists suggest. Usually it is thought that the extra dimensions might be on the order of 10–35 meters.
Or testing for deviations in the inverse square law. Coulomb's law would change at very small distance ranges.

http://xxx.lanl.gov/PS_cache/hep-ph/pdf/9803/9803466.pdf

Other tests may involve the creation a high-energy graviton in an Accelerator, the quantum of gravity; it would move off into extra dimensions and carry away energy and momentum.

"Extra dimensions are here to stay."
(Until they’re proved not to exist or another theory can replace the theory that we have now to explain the creation of space-time and particles etc.)