Johannes Rydberg, more known as Janne Rydberg, (1854 - 1919) was a Swedish physicist mostly known for creating the Rydberg formula, which is used to predict which wavelengths that photons (i.e. light) emitted from shifts in the energy level of a certain electron around a certain atomic nucleus will have. The physical constant known as the Rydberg constant is named after him, and a crater on the moon is also named Rydberg in his honour.

He was active at Lund University for all of his life.

''See also: