Earl is looking for his home world, a planet called Earth.

"We have reason to believe she's being held on a planet called Priatia."

In the story, they come from a planet called Cybertron.

There is another force on large planets called gravity that seems to act the same way, though I do not understand it.

We've learned that there's a planet called Dosadi where these people were taken.

"We have just the thing, a little planet called Humboldt."

This story takes place on a planet called Answer.

Tell me: have you ever heard of a planet called Earth?

And around one of them circled a little blue planet called Earth.

Kirk and a few others are on a planet called Sanctuary.