A few of the ancient Greeks suspected that the material universe might be composed of collections of very tiny units. To most people, most materials in the world seem internally uniform. Break open a rock and you find rock everywhere inside! So the atom idea, which required gaps between atoms, remained a backwater concept even at the close of the 19th Century! At that time atoms were still rejected even by prominent scientists such as Ernst Mach who insisted an idea be empirically verifiable before being accepted by science. One of Albert Einstein's five 1905 papers (after Mach inspired Einstein's new approach to physics) proposed that observable and measurable Brownian motion must be mathematically consistent with atoms moving as required by the kinetic theory. But as Jean Perrin empirically confirmed the existence of atoms as suggested by Einstein, physicists had already determined that components exist inside atoms: first electrons and later protons and neutrons. There are now few physicists who doubt the evidence that inside protons and neutrons are sub-units that Murray Gell-Mann named quarks. And a growing group of scientists hope that the currently developing idea that everything is composed of strings will be able to explain all properties of all materials in the universe.
But the most significant conclusion of these two new fields of chemistry is that there is no longer any reasonable doubt that the entire knowable cosmos is composed of assemblages of a small variety of very tiny building blocks. And the nature of the universe as we know it is determined by the properties of these little units and the forces and interactions between them.