Most of the mass — most of the “stuff” — in the visible universe is made of tiny particles called quarks and gluons. We don’t yet fully understand these particles, found in the nucleus of an atom. Nuclear physicists explore their properties, which give us clues about the history of the universe and the Big Bang and also the movement and interactions of everything around us. Nuclear Physicist Renee Fatemi studies the spin of protons and the particles within them. Her work helps us understand the properties of ordinary matter and the fundamental particles within it.