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.
Fields are the data for the class. Methods are the sequences of statements that operate on the data. Fields are normally specific to an object--that is, every object constructed from the class definition will have its own copy of the field. Such fields are known as instance variables.