*''[[String theory]]'' is a cutting-edge theory of physics at extremely small scales, postulating that what ordinary quantum mechanics considers to be subatomic particles of size 10<sup>−15</sup> meters are actually closed loops, that is strings, of even smaller size. | *''[[String theory]]'' is a cutting-edge theory of physics at extremely small scales, postulating that what ordinary quantum mechanics considers to be subatomic particles of size 10<sup>−15</sup> meters are actually closed loops, that is strings, of even smaller size. |