How did Bohrs theory save the planetary model… for a while?
Niels Bohr was born in the same year (1885) that Balmer published his formula for the line spectrum of hydrogen. Beginning in 1913, the brilliant Danish physicist published a series of papers that would ultimately derive Balmer’s formula from first principles. Bohr’s first task was to explain why the orbiting electron does not radiate energy as it moves around the nucleus. This energy loss, if it were to occur at all, would do so gradually and smoothly. But Planck had shown that black body radiation could only be explained if energy changes were limited to jumps instead of gradual changes. If this were a universal characteristic of energy- that is, if all energy changes were quantized, then very small changes in energy would be impossible, so that the electron would in effect be “locked in” to its orbit. From this, Bohr went on to propose that there are certain stable orbits in which the electron can exist without radiating and thus without falling into a “death spiral”. This suppositi
