Tangled up in Pluto

Overheard conversation during homework time:
Sam: I went to another planet today at school.
Gabe: Oh, which one?
Sam: Pluto.
Gabe: An actual planet?
Sam: Mmmhmmm.
Gabe: Pluto's not a planet.
Sam: So? I still went there.
Gabe: During school today?
Sam: Yup.
Gabe: And you got back in time for the bus?
Sam: Yup.
Gabe: No you didn't. Well, I went to Planet X.
Then they continued with their papers...