What was Sputnik moment?

A Sputnik moment is a point where people realise that they are threatened of challenged and have to redouble their efforts to catch up. It comes from the time when the Soviet Union launched the first satellite, the Sputnik 1, and beat the USA into space.

Explanation:

the effect of the ming leaders banning ships with more than two masts was that there was no further construction of ships masts, because there was a surplus. ming emperors disallowed foreign exploration