Question: Is there anything smaller than a yoctometer?

Jon Benton answered on 13 Mar 2012:

There are a few things and these are the building blocks of the whole universe. At the moment the smallest measurable and sensible size is the planck legth which is 1-36 m a yoctometre is 1-25 m. A neutrino is about 1 yoctometre. The only thing left is quantum foam from einsteins space-time theory or strings from the string theory of the universe however these haven’t been proved to exist yet.