In Guardians of the Galaxy, we see many members of the Nova Corps. All of them look human. Late in the film, they refer to Star-Lord as a Terran, so they know of Earth, but it's clear they themselves are not considered Terran.

Why/how do they look human, if they're not from Earth?

In Guardians of the Galaxy, we see many members of the Nova Corps. All of them look human. Late in the film, they refer to Star-Lord as a Terran, so they know of Earth, but it's clear they themselves are not considered Terran. Rocket also refers to Star-Lord as a 'humie' multiple times, which presumably is short for human.

Why/how do they look human, if they're not from Earth?