Other source:
As Gohan's training gets harder every day, Goku's training with King Kai has just begun. He has about 158 days to prepare for the Saiyans. It turns out that the monkey is not King Kai, but it is his pet. His first task is to catch the monkey, whose name is Bubbles, but it's not going to be easy. The gravity on this tiny planet is 10 times that of Earth, making it hard for Goku to even stand up. Just when Goku is losing hope, he gets inspired after learning that his people withstand different fighting conditions. After three weeks, Goku conquers the gravity and catches Bubbles.
