Full Idea
Most of a proton's or neutrino's mass is contained in the interaction energies of a 'sea' of quarks, antiquarks and gluons that bind them. ...You might feel solid, but in fact you're 99 per cent binding energy.
Gist of Idea
The mass of protons and neutrinos is mostly binding energy, not the quarks
Source
New Scientist writers (Why the Universe Exists [2017], 04)
Book Reference
New Scientist writers: 'Why the Universe Exists' [John Murray 2017], p.79
A Reaction
This is because energy is equivalent to mass (although gluons are said to have energy but no mass - puzzled by that). This is a fact which needs a bit of time to digest. Once you've grasped we are full of space, you still have understood it.