Midnight
As soon as the mate takes over , you and Mister Keku get up here . I want to know what the devil has been going on aboard my ship . '' `` You are bloody well not the only one , '' said Mike the Angel . Midnight , ship time . And , as far as the laws of simultaneity would allow , it was midnight in Greenwich , England . At least , when a ship returned from an interstellar trip , the ship 's chronometer was within a second or two , plus or minus , of Greenwich time . Theoretically , the molecular vibration clocks should n't vary at all .