Really interesting. I'm not an expert, but I'll armchair speculate here. We need 5-9 photons to merit perception. For us to see one atom, we would need 5+ pho

Really interesting. I'm not an expert, but I'll armchair speculate here. We need 5-9 photons to merit perception. For us to see one atom, we would need 5+ photons to bounce off of that atom directly to our eyeballs in 100ms. Since both these things are so tiny, most photons miss the atom altogether. It's only when you have large numbers of atoms, densely arranged, that conditions create visibility.