Johannes Rydberg was a Swedish physicist born on November 8, 1854, in Stockholm. He is best known for his work in atomic physics, particularly for formulating the Rydberg formula, which describes the wavelengths of spectral lines of hydrogen and other elements. His contributions significantly advanced the understanding of atomic structure and spectral analysis. Rydberg's research laid the groundwork for later developments in quantum mechanics. He became a professor at the Royal Institute of Technology in Stockholm and published numerous papers throughout his career. Rydberg passed away on December 28, 1919, leaving a lasting legacy in the field of physics.