The anthropomorphized version of Earth is in trouble and the other planets assume human form to find a way to help. In the process, the moon gives continuous physics lessons, which can be interesting, but if it's not what you're looking for, it can easily get annoying. The main story, about finding out how to help Earth and the divisions between 'outside' and 'inside', is frequently left behind so that multiple chapters can be devoted to the moon's physics lessons. The story itself is interesting, so I found myself wishing that it had more attention instead of the focus on teaching physics.
As for the characters, the protagonist S-Zawa is a change of pace in that he is pudgy and not at all handsome or extraordinary looking. At the start of the story, he is wearily going along with his job and life when all of this is thrust upon him. It's nice to have a break from the constant focus on teenage protagonists. Where things start to break down is that S-Zawa is a bit of a perverted incel. He's attracted to his co-worker and blames her for distracting him with her sexy body. He also openly states that he prefers the more well-endowed planets (which is a sentence I never thought I'd need to type). I personally find the perverted protagonist trope to be tired and overused, so his behavior was kind of annoying. Although, for better or worse, the physics lessons frequently take precedence over exploring more of his personality.
Almost all the other characters are attractive women, and the female planets frequently don't wear much in the way of clothes, so there's fanservice, which I don't particularly care for. The only thing that keeps it from being a harem is that the planets don't seem to have any interest in S-Zawa. The standout character is probably the moon, who is the resident physics teacher and regularly gets mad at people for not understanding physics or at anime programs for not being realistic.
The art has a "Wizard of Oz" theme to it. Whenever scenes take place in the outside or on the Earth's surface, they are black and white. Scenes that take place in the anime-centric inside are presented in full-color. This helps to present the distinction between the elite-but-idle and those that labor on the outside.
Overall, I think this series has a lot of missed potential since it focuses more on physics lessons than it does on the story of Earth or the divisions between 'outside' and 'inside'. Only four volumes are out, so this could change in the future. There are underlying subtexts on consumerism and ecological responsibility (and the anime industry); if those were explored with more depth, it would greatly improve the story.
