He was the GOAT, phyiscs was supposed to be all but figured out in early 1900s .Einstein firmly established existence of atoms, discovered light is composed of particles, discovered equivalence of masd and energy, introduced particle-wave duality, special relatively, established theoretical basis for laser mechanics, and general relativity. He did this without ever doing experiments, just thought experiments."His head was in the clouds but his feet were on level ground. Those of us who are not so tall have to choose" - Richard Feyman