How Do We Know How Small An Elementary Particle Is?
When we split something into its most fundamental, indivisible components, are we truly seeing something that’s point-like, or is there a finite minimum size?
Imagine that you wanted to know what the matter around you was made of, at a fundamental level. You might approach the problem by splitting a piece of that matter into smaller chunks, and then splitting a chunk into tinier pieces, and so on and so on, until you could split it no longer. When you reached your limit, that would be the best approximation of “fundamental” you were able to arrive at.
For most of the 19th century, we thought that atoms were fundamental; the Greek word itself, ἄτομος, literally means “uncuttable.” Today, we know that atoms can be split into nuclei and electrons, and that while we cannot split the electron, nuclei can be broken up into protons and neutrons, which can be further subdivided into quarks and gluons. Many of us wonder if they might someday be split further, and how small their size truly is.
