Georges Lemaître was a mathematician, astronomer, and professor of physics. Lemaître was the first person to theorize that the expansion of the universe can be used to explain the recession of nearby galaxies. In 1927, Lemaître published the first estimation of the Hubble constant. He also came up with the Big Bang theory to explain the origin of the universe.
Belgian physicist and mathematician Joseph Plateau was a pioneer of the modern animation and movie industry, as he invented the phenakistiscope, the world’s first device to create an illusion of motion through images. He also laid down the structure of soap films through Plateau's laws.
Belgian-born physicist Ingrid Daubechies was a prodigy of sorts and had started dealing with complicated mathematical concepts before turning 6. She grew up to work at the AT&T Bell Laboratories and also taught at Princeton. She is best known for her research on wavelets and image-compression technology.
Nobel Prize-winning Belgian theoretical physicist François Englert, who teaches at Université libre de Bruxelles, is chiefly known for introducing the idea of the Higgs field. He has previously taught at Cornell University. His contribution to the fields of quantum theory, statistical physics, and cosmology has been massive.
American theoretical physicist Robert Brout contributed immensely to the theory of Higgs Boson, for which François Englert and Peter Ware Higgs received the Nobel Prize. The Sakurai Prize and Wolf Prize-winning scientist also taught physics at the Université Libre de Bruxelles and eventually got a Belgian citizenship.