ΜΠΟΡΕΙΣ ΝΑ ΕΞΗΓΗΣΕΙΣ ΤΗΝ ΘΕΩΡΙΑ ΤΩΝ ΧΟΡΔΩΝ ΚΑΙ ΓΙΑΤΙ ΑΥΤΟ ΕΊΝΑΙ ΔΥΝΑΤΟΝ;
Jess H. Brewer
Physicist, fisherman, gourmand, Neal Stephenson wannabe.
All I can do is give you a layman’s synopsis, which is probably wrong in some essential ways:
Lots of people on Quora ask if elementary particles are all “made of something”. String theory is as close as we have to an answer. Suppose all the particles were different vibrational states of little loops of some kind of fundamental string. For reasons I can’t explain, this doesn’t work in 3 spatial dimensions + time; but if you postulate that spacetime has 10 or 11 or 26 dimensions, the predicted finite spectrum of allowed vibrational states matches up pretty well with the particles we know in the Standard Model. It also predicts some other particles we’ve been looking for at the LHC (unsuccessfully so far).
Now, you will probably wonder, “Where are all those other dimensions?” Well, they sort of “curl up” so that they are undetectable in our 4-dimensional spacetime. That’s what I’m told. Don’t ask me how it works.
Strings aren’t the only topological species in this theory; there are also “branes” (an N-dimensional analogue of 2D membranes embedded in 3-space) — our spacetime may be a 4D hypersurface embedded in 10- or 11- or 26-dimensional space, something a mathematician or a SF fan will have no trouble visualizing but most others find a little daunting.
Next you may ask, “So what experiments have confirmed this theory?” Well, there’s a problem: most of the predicted phenomena that would test string theory occur at energies so high that it would take an accelerator the size of the Solar system to reach them. So for now we have an army of theorists trying to find more subtle tests that could be performed in ordinary laboratories, another army of theorists trying to refine string theory to make it more elegant, internally consistent and better matched to what we do see, and a third army of skeptics declaring string theory to be a hoax, a waste of time, or “not science” because it can’t be tested.
Lots of people on Quora ask if elementary particles are all “made of something”. String theory is as close as we have to an answer. Suppose all the particles were different vibrational states of little loops of some kind of fundamental string. For reasons I can’t explain, this doesn’t work in 3 spatial dimensions + time; but if you postulate that spacetime has 10 or 11 or 26 dimensions, the predicted finite spectrum of allowed vibrational states matches up pretty well with the particles we know in the Standard Model. It also predicts some other particles we’ve been looking for at the LHC (unsuccessfully so far).
Now, you will probably wonder, “Where are all those other dimensions?” Well, they sort of “curl up” so that they are undetectable in our 4-dimensional spacetime. That’s what I’m told. Don’t ask me how it works.
Strings aren’t the only topological species in this theory; there are also “branes” (an N-dimensional analogue of 2D membranes embedded in 3-space) — our spacetime may be a 4D hypersurface embedded in 10- or 11- or 26-dimensional space, something a mathematician or a SF fan will have no trouble visualizing but most others find a little daunting.
Next you may ask, “So what experiments have confirmed this theory?” Well, there’s a problem: most of the predicted phenomena that would test string theory occur at energies so high that it would take an accelerator the size of the Solar system to reach them. So for now we have an army of theorists trying to find more subtle tests that could be performed in ordinary laboratories, another army of theorists trying to refine string theory to make it more elegant, internally consistent and better matched to what we do see, and a third army of skeptics declaring string theory to be a hoax, a waste of time, or “not science” because it can’t be tested.
ANAΣΗΜΟΣΙΕΥΣΗ ΑΠΟ ΤΟ QUORA 20/6/2017
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