Congratulations on completing this project! This is no small feat; you've just created your first iOS application. We've introduced a lot of new topics, which include the following:
Enumerations
Enumerations with raw values
Private variables
didSet observers
Adopting and conforming to a Protocol
UIPickerView
Switch statements
The amount of light minutes from Earth to all the other planets
If there ever comes a time when you will be delivering pizza in space, you will have a head start with this app. Maybe not; we first have to figure out a way to travel at the speed of light. Maybe you can figure that out!
The next and final chapter will have you creating another application to store your favorite movies. This application will work on generating a list and displaying it in a UITableViewController.