Anders Jonas Ångström was a Swedish physicist and astronomer born on August 13, 1814. He is best known for his work in spectroscopy, the study of the interaction between light and matter. Ångström developed a method to measure the wavelengths of light, which significantly advanced the understanding of atomic and molecular structures. Ångström also contributed to the field of solar physics, studying the spectrum of sunlight. His name is honored in the unit of measurement called the angstrom, which is used to express very small distances, particularly in the context of wavelengths of light and atomic scales.