Gustav Mie was a German physicist known for his significant contributions to the field of optics. He is best recognized for developing the Mie theory, which describes the scattering of light by small particles. This theory is essential in understanding how particles interact with light, influencing various applications in fields like meteorology and astronomy. Mie's work laid the foundation for further research in scattering theory and has implications in areas such as aerosol science and biophysics. His findings help explain phenomena like the blue color of the sky and the white appearance of clouds, showcasing the importance of light interaction with particles.