above video which you have watched is about planet …. if you got this doubt you need to start learning for beginning … i recommend to go through this playlist if possible https://www.youtube.com/watch?v=4v0GGUghwyE&list=PLvmzzcGHiU3TfI5LO2G1JTHPmT3sZqJZe ep36 explained about planet retrogression … we can not explain all things in comments area.