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What is the smallest existing thing in theory and law?

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Possible duplicates: and links therein. – Qmechanic May 10 '13 at 21:51

The short answer to this question is that there is no answer because the question makes invalid (classical) assumptions. "Things" start to get blurry. They stop having a definite position, size, and boundary.

Take an electron for example. The electric field extends to infinity and the mass appears, to the best we can measure, to be a point in the center.

Theoretically, the Planck Length may be the smallest length that has any sort of physical meaning.

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If by 'thing' you refer to a physical thing, not a distance (as opposed to what Brandon was thinking of when he mentioned the Planck Length), then I guess the answer is the Preon, which is believed to be the particle that Quarks/Leptons are made of.

But of course, maybe tomorrow some physicist discovers a smaller particle (back when I was in high school, the proton was still considered the smallest)...

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protected by ACuriousMind Oct 5 '15 at 14:56

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