Super memory from age 0 lol.
It's a lot easier to take the out of universe approach. This segment of the story makes little sense. Goku is shown in Raditz's memory as a newborn child when he was sent away. Raditz also makes a point that the majority of Saiyans are sent to other planets to "train" them and teach them how to conquer. Yet somehow only himself, Vegeta, Nappa and Goku were away from Planet Vegeta during its destruction? How does that make any sense if all Saiyans are getting sent out at age 0?