I think some of the scriptwriters of classic Doctor Who must be Mormons because there are instances where cosmos, universe, galaxy, stellar system, star and planet get shifted around.
So you have a description of a galaxy and it's called the universe, you get a description of a planet and it's called a star.
It's a new faith.
Medieval Christianity was full of similar wobbles, especially when it had to invent the Devil to let God off the hook for doing things people don't approve of.