The Fission Theory: This theory proposes that the Moon was once part of the Earth and somehow separated from the Earth early in the history of the solar system.
When you actually use that class to make a THING, this is what you make. A method is a bit of code that can be called when needed (often as part of an class, but not always) Here's an example: I write a class called Ball. In my main code, I then write a=Ball.new, b=Ball.new, c=Ball.new.
Class methods are methods that are called on a class rather than an instance. They are typically used as part of an object meta-model. I.e, for each class defined an instance of the class object in the meta-model is created. Meta-model protocols allow classes to be created and deleted.