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Test for String Theory Developed
inexion writes "PhyOrg is reporting that SLAC (Stanford Linear Accelerator Center) scientists have found a way to test the revolutionary theory, which posits that there are 10 or 11 dimensions in our universe. This past December, Joanne Hewett, Thomas Rizzo, and student Ben Lillie published an article in Physical Review Letters which shows theoretically how to measure the number of dimensions that comprise the universe. By determining how many dimensions exist, Hewett and Rizzo hope to either confirm or repudiate string theory under specific conditions which would consist of creating and examining 'micro-black holes', which could be formed by smashing two high energy protons together. Using the predicted decay properties of the emitted neutrinos, Hewett and Rizzo solved equations to find that our universe may have more than 10 or 11 dimensions -- too many dimensions to be explained by string theory."
How many micro-black holes have we measured in a lab?
None.
How many micro-black holes have we even seen?
None, as it turns out.
This is a story of hope and speculation--much like the story of super string theory.
Hell, do we even have the capabilities to smash two high energy protons together?
To be fair, Bosonic Super string theory has room for 25 dimensions but it's flawed with tachyon, the so called imaginary mass.
I'd be interested to know how they intend to measure the micro-black holes.
My work here is dung.
"Black Holes in Many Dimensions at the CERN Large Hadron Collider: Testing Critical String Theory" JoAnne L. Hewett, Ben Lillie, and Thomas G. Rizzo Phys. Rev. Lett. 95, 261603 (2005)
For those with access to PRL, the doi for the paper is: 10.1103/PhysRevLett.95.261603
This is the abstract: For those without access to PRL, you can view a different version of the manuscript on arXiv.
My comments (with the usual disclaimer: while I am a scientist, I'm not a particle physicist/string theorist, so I would appreciate any corrections to what I say): This work appears significant. String theory is incredibly elegant and fits in very well with other (experimentally verified) theories (quantum field theory, etc.). However, what string theory has always lacked, is experimental backup. The fact that there may be a way to experimentally test one of its predictions/requirements (that of extra dimensions) is truly significant, and will allow these fundamental theories to be advanced way beyond their current speculative nature.
As I understand it, one of the current "problems" in string theory is an over-abundance of theories. There are millions (perhaps even an infinite number) of theory-variants that are all consistent with the current string-theory formalism. Of course only one (or possibly zero) of the theories is right. An experimental test would (I hope!) help pick out which theory variant is the right one... or perhaps tell us that string theory is completely wrong! Either way it's a good thing for science and I look forward to this test being performed at the LHC.
> but golly gee whiz, what happens if the the mini black holes don't behave quite exactly like they're supposed to?
Given 11 dimensions to work with, it will be easier to kiss your ass good-bye.
Sheesh, evil *and* a jerk. -- Jade
My work here is dung.
You may not believe this, but the English language is often ambiguous. Some words have two, three, four, or more meanings. The word theory is one of those. One definition of theory is a widely tested and accepted set of principles, as in Einstein's theory of relativity, which gives specific predictions about the universe that have been time and again proven correct to a high degree of accuracy. Another definition of theory is a hypothesis that has not yet been verified, as in string theory, which has not been scientifically verified at all. Yes, this ambiguity causes no end of confusion when one refers to the "theory of evolution". Many of us sit back and chuckle as people refer to it as "just a theory".
What a fool believes, he sees, no wise man has the power to reason away.
All black holes emit Hawking radiation, which is essentially black-body radiation (the object is trying to come into thermal equilibrium with the rest of the universe, so is emitting/absorbing radiation to do so). The origin of Hawking radiation is vacuum pair production, if anyone is interested. This radiation causes the black-hole to slowly "evaporate." The temperature (hence rate of evaporation) is inversely proportional to the black-hole mass (hence size).
Micro-black-holes are (obviously) very small. Thus, they evaporate very, very quickly. In fact, they are well below the sustainable threshold, and will evaporate much faster than they accumulate new mass. Also note that these micro-black-holes have quite low mass, hence their graviational attraction is pretty much nill. They are "black holes" because their mass density is infinite, and they are thus a singularity, but nothing about "black holes" definitely implies "consumes matter indefinitely" (this only happens for black holes of sufficient size).
So, no, there is no danger with micro-black-holes eating up the entire Earth. Yes, our current theories may be incorrent (you never know), but if micro-black-holes were able to grow without bound, then you'd expect the universe to be littered with black holes all over the place (which is not the case). Thus there's no reason to worry: the LHC will not gobble up the Earth.
One should really call it String Hypothesis or String Postulate.
In cases like this, untested ideas about the function of the universe, I personally like the term "model." You can use it to posit the inner workings of the universe and why things happen, but untill the technology is there and the experiments have been run it is not fully a scientific theory. But I believe it does fall within the bounds of model. And the nice thing about this is that with a model, you can make some assumptions that may or may not be true to simply explore how the world would work supposing this is true.
My favorite correlary is light. We have a model of light behaving as a wave, and that model has been proven to be wrong under certain cirumstances. We have a model of light behaving as a particle, and that model can also be proven wrong under certain circumstances. However, the fact that each model is not completely correct does not mean that they are useless. The basis of the model can be used to make further predictions about the way the world works, or even to produce technology through engineering.
I'll never make that mistake again, reading the experts' opinions. - Feynman
Peter Woit, a critic of string theory, points out some of the misleading bits in this article on his blog, "Not Even Wrong: http://www.math.columbia.edu/~woit/wordpress (scroll down for it). A brief discussion of why this isn't quite as exciting as it may sound.
JoAnne Hewett (one of the original authors) also comments in the blog, saying that the journalists tried to make the work a little more accessible by suppressing important details: As for the headline that is blazened on the SLAC home page - I saw it for the first time when someone drew my attention to it. I knew it was going to cause headaches...
So while this may be solid work, it doesn't seem quite so sexy as it has been made out to be...
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