The first assumption of the Bohr atomic model states that the electrons can only orbit stably, without radiating, in certain orbits (called by Bohr the "stationary orbits") at a certain discrete set of distances from the nucleus. Electrons can only gain and lose energy by jumping from one allowed orbit to another. source
Someone pointed out a conceptual problem with this assumption: "If an electron is in a stationary state, it would not collapse." By calling it a "stationary orbit", does Bohr mean the electron orbital will never increase or decrease in energy or radius?
In other words, does the Bohr model say that the electrons will forever stay in the same stationary orbits? Is this the reason why the Bohr model was determined to be incorrect?
Or, does the Bohr model say that an electron can jump from one orbit to another, and thereby gain and lose energy? If so, under what conditions?
This question differs from this related question because it asks about the Bohr model, not about the planetary model.