From the back row of the room, a young man with a lean build and a gaunt face, with an enormous unruly quiff and two lively eyes, stood up.
In very rough German and with a rather surprising manner, he said:
"What Professor Einstein said is not stupid, but the second equation he wrote does not follow from the first. In fact, it requires additional assumptions that have not been made and, what is worse, it does not satisfy a criterion of invariance, as it should".
A glacial silence fell in the room and everyone turned to stare in disbelief and amazement at that bizarre and bold little boy.
Everyone except Einstein, who began to stare absorbedly at the blackboard, stroking his moustache with his hand.
After a minute he turned and, acknowledging his mistake, said:
"The remark of that young man over there is perfectly correct. I therefore ask you to forget everything I have said to you today."
That intrepid young man of 22 years was Lev Davidovich Landau, destined to become the leading theoretical physicist of the Soviet Union, one of the greatest geniuses of all time.
A man who would never have liked periphrases, nor would he have ever cared about the authority and intellectual stature of those against whom he hurled his criticisms, direct, unequivocal and cutting as a sharp blade.
During a conference organized in Bristol, on September 8 of the same year, by the British Association for the Advancement of Science, Paul Dirac presented the ideas he had matured up to that point (namely, that the holes left by electrons passed from negative to positive states of energy should be identified as protons). After listening to the lecture, Landau, who was present at the meeting, sent Bohr a cable with just one word, in German: "Quatsch" (nonsense).
His famous judgment was:
"This work contains many new things and many interesting things. Unfortunately, the new things are not interesting and the interesting things are not new."
Another of his famous quips was:
"Cosmologists are often wrong, but never in doubt."
Frequently, after he had dismissed his interlocutor in a clumsy and hasty way, he would be found standing in the middle of his study, with disheveled hair and a perplexed look, wondering doubtfully:
"But why did he get so angry? I didn't say he was stupid, I just told him that his work is complete nonsense...".
On the other hand, the unwary visitor was warned by the sign on the door of the Soviet physicist's office: "Lev Landau, be careful, he bites!".
