Question: what are the smallest things in nature?

Harrison Prosper answered on 12 Jun 2019:

As far as we can tell electrons, quarks, etc., are less than a million times smaller than an atom. Indeed, our current best theory assumes that these entities are points, which actually doesn’t really make much sense. Why? Because if Einstein is right, these particles would be black holes. And if the late Stephen Hawking is right, they should have exploded long ago! Clearly, we still have a lot to learn.