The naming schema actually tripped me up for a week or so.
My brain's initial conception of the concepts was earth-relative, so I mapped it as:
Sol = big, it's the sun Luna = medium, in-between sun and earth, space Terra = small, terrestrial
It tripped me up because I was going by distance. I thought Terra was the base model and Luna was the mid model because it’s further away.
Pretty weird when the moon is as much between earth and sun as the earth is between the moon and the sun.