This problem or idea is not that difficult to understand. This hyperbolic colloquialism dates from the mid-twentieth century, as does its synonym,
you don’t have to be a brain surgeon. Clearly they imply that these professions require unusual intellectual acumen. Reporting on an economic forum, the
Boston Globe quoted former President Bill Clinton, “You want to save 4 million lives? Give them the medicine. It’s not rocket science” (Jan. 28, 2005). Also, “And then he got murdered. Doesn’t take a rocket scientist to figure there’s a lot more to it than I thought” (David Baldacci,
Hour Gam, 2004). See also
no-brainer.