Most popular science accounts and even text-books on the Special theory of Relativity start by describing the Michelson-Morley experiment,which leaves the impression that it played a decisive role in the development of relativity by Einstein.Some books like Kleppner/Kolenkow mention that it probably was of no great significance but fail to mention exactly what experiments,if any led Einstein to relativity.

One book does that.

"An Introduction to Special Relativity" by Robert Resnick describes two experiments that Einstein himself says played a part in the development of relativity-- stellar aberration and Fizeau's observation of the dragging of light by moving water(first predicted by Fresnel).

What is striking about these two experiments is that none of them,in a very clear-cut way,lead to the idea that the ether was a figment of the physicists' imagination.At least,they're not as unambiguous in their conclusions as the Michelson-Morley experiment.Einstein said in an interview,in his later life,that he wasn't quite sure if he knew much about Michelson-Morley when he discovered relativity.He says that at most,he might have been aware of the negative result,but not the actual details.This seems to be the correct version,as he admits having read a book by Lorentz,which mentioned it.

According to any standard physics textbook,it was the "ultraviolet catastrophe" which led Max Planck to hypothesize about quanta.The problem was that the observed spectrum of a blackbody didn't match that predicted by theory--the Rayleigh-Jeans formula.One fine evening,he discovered the power of the energy quantization and the Quantum era began.This story was repeated recently in my physics class,and no doubt happens throughout the world.

That,alas,is fiction.The fact,as always is far stranger.Planck,was in fact,a reluctant revolutionary.

In spite of its prominent role in physics textbooks, the the Rayleigh-Jeans formula played no part at all in the earliest phase of quantum theory. Its derivation was based on the equipartition theorem and Planck did not accept it as fundamental, and therefore ignored it. Incidentally, neither did Rayleigh and Jeans consider the theorem to be universally valid.

Planck's role in the discovery of quantum theory was complex and ambiguous. To credit him alone with the discovery, as is done in physics textbooks, is much too simplistic.Apparently,Planck arrived at the hypothesis from a different direction.He didn't particularly like Boltzmann's statistical interpretation of entropy and instead considered the second law of thermodynamics to be absolutely valid.He even,for along time,doubted the reality of atoms.He was careful not to state exactly what was oscillating,in his derivation of his eponymous law of blackbody radiation.