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String Theory Put to the Test
secretsather writes to mention that scientists have come up with a definitive test that could prove or disprove string theory. The project is described as "Similar to the well known U.S. particle collider at Fermi Lab, the Large Hadron Collider, scheduled for November 2007, is expected to be the largest, and highest energy particle accelerator in existence; it will use liquid helium cooled superconducting magnets to produce electric fields that will propel particles to near light speeds in a 16.7 mile circular tunnel. They then introduce a new particle into the accelerator, which collides with the existing ones, scattering many other mysterious subatomic particles about."
Welcome to slashdot; here's your junk science for the day.
You can't prove string theory through experimentation, all you can do is attempt to disprove it.
Liberty you never use is liberty you lose.
http://www.xkcd.com/c171.html
-- Too lazy to get a lower UID.
Oh...Large Hadron Collider. If it was in the Castro district I would really be suspicious.
I think it's funny how the article forgets to mention that the LH collider is located at the CERN (the European nuclear physics institute). As a matter of fact, it is not only in Switzerland, but extends to France as well. The article only mentions it is similar to the U.S. Fermilab accelerator, but then forgets to add that there are many kinds of accelerators world wide.
Funny, ain't it?
The number of dimensions isn't that high. When all of the string theories are combined into M-theory, the total number of dimensions is eleven, IIRC. Harder to understand? Yes. Impossible to visualize? Yep. But not abhorrently high.
You can never go home again... but I guess you can shop there.
It thought this was cleared up years ago:
Scanning/Copying based on a terminator byte pattern is fraught with error and is definitely not secure.
Buffer sizes are terribly problematic when left tot he caller to check on overflow. It must be in the methods, and thus part of the data structure. (see point above).
Strings these days are UTF-7 or 8, which makes them an even better candidate for a object-based construct rather than a memory map.
I'd like to point out the....oh, wait...
Nigel: As you can see, our theories all go to eleven, right across the board. Look: eleven, eleven, eleven.
Marty: Does that mean it's better? Is it any better?
Nigel, well, it's one more, isn't it? Most blokes, their theories only use ten dimensions. They're at ten, where do they have to go from there? When we need that extra push over the cliff, you know what we do?
Marty: Put it up to eleven?
Nigel: Eleven. Exactly. One more!
- None can love freedom heartily, but good men; the rest love not freedom, but license. -- John Milton
Not at all. You merely have to project one of the dimensions down so that you're only considering a 10-dimensional space.
Ben Hocking
Need a professional organizer?
From the wording in the article it sounds like they actually want string theory to fail. . .
.despite the fact that we have few alternatives so far.
A test in which a theory fails is the most useful sort of test.
. .
I cannot accept a theory simply because I don't know what to replace it with. Make the tests, generate failures; and then new theories which take the failures into account. That's how the alternatives come into being in the first place. That's why the "failures" are the most useful.
"Successes" only make us complacent with the state of our knowledge, which might well be wrong anyway. "Failures" let us know where we lack knowledge. Science is not done where we know, but where "here there be dragons." It's about exploring the dark corners of the map, not sitting in our offices diddling with ourselves.
We leave that sort of thing to the engineers.
And think about this:
Who says we need an alternative? The quest for a Unified Field Theory is an asthetic desire on the part of physicists. The universe is well known for taking our asthetic desires and shoving them up our collective arses.
Perhaps there can be only two.
KFG
It's been known since the 1920s that adding extra spacetime dimensions allows you to unify forces; Kaluza and Klein successfully unified classical electromagnetism and gravity that way, with a theory in 5 spacetime dimensions. Unfortunately, this idea can't be readily extended to all the forces in the Standard Model, and the unified theory is at least as difficult to quantize as gravity alone.
From a different perspective, leaving gravity out of it, there are the grand unified theories. They too have "extra dimensions", except that the extra dimensions are not of spacetime, but of an internal "gauge" symmetry space. (Kaluza-Klein theory basically turns these internal gauge dimensions into true space dimensions, paving the way to a gravitational theory.)
String theory also does not add as many "undefinable, physically meaningless constants as possible". Indeed, it has fewer constants than the Standard Model. In fact, it has only one constant, which is certaintly definable: it is the string tension. Furthermore, the dynamics of string theory are unique, unlike the quantum field theories. (You can write down infinitely many different particle physics theories with different particle content and interactions, but all of the string theories are part of the same theory, and all the strings obey the same fundamental laws of interaction.)
In short, string theory is not a totally contrived fudge; pretty much all of the ideas that led to semi-successful unified field theories found their way into string theory in a natural and uniquely determined way.
The energies that will be created in the LHC happen on a daily basis in our upper atmosphere. The only difference is that we will have detectors in the immediate vicinity.
Ben Hocking
Need a professional organizer?
Everyone always seems eager to compare to epicycles any modern physics theory they don't care for. String theory, dark matter, what have you...
Physicists were led to string theory in a search for a consistent theory of quantum gravity, not in a search to make up the most complicated theory possible to fudge arbitrary data. For more on why string theory should be taken seriously as a solution to this problem, you can read a long analysis in a previous post of mine here. String theory itself cannot be modified to "fit" to a model; it is a unique theory with no adjustable parameters or interactions. However, you can construct various string models to fit observations, as you can presently using quantum field theory models like the Standard Model.
It is also not correct that string theory doesn't make testable predictions. This whole story is about testing predictions of certain string models. However, we can't presently test predictions of all string models at once, and thus rule out all of string theory. But then, the same is true of quantum field theory models as well; there are infinitely many such models that could be true but which we can't yet test.
Thou shalt have four dimensions. No more, no less. Four shall be the number of thy dimensions, and the number of the dimensions shall be four. Five shalt thou not have, neither thou have three, excepting that thou then proceed to four. Six is right out.
Unfortunately, that site is totally bogus. Interesting, but it's entirely unrelated to string theory, which the author seems to mention just to lend his ideas some credibility.