This is a weird little manga. I very much enjoyed my time with it, though. TL;DR, it's not an amazing story, it's really not a good art book but it was fantastic as what is almost a philosophical text. The story focuses on a range of characters who become entranced by the theory of heliocentrism in a geocentric world and are subsequently hunted by the inquisition. They all share their passion for knowledge and truth and struggle against their faith in the face of what they know to be heretical ideas. Oh, right, also a warning. It's a very graphic manga very quickly. The major downside ofOrb's story is that it is far too wordy. Some pages are more on the 'book' part of 'comic book', and basically all of its narrative is told through the dialogue (save for a few rare moments). It can be somewhat of a fatiguing and slow read at times because of it. On top of that, its writing is also mixed. It feels strange that the characters have such thoroughly formed ideas and articulate them so well, referencing philosophical texts far beyond the historical setting.
Despite that, the dialogue is doing something right, because I loved listening (or, reading) the clashing views of each of the characters. These characters each strive to realise their meaning and ultimately find it through knowledge and freedom to different extents, and oftentimes end up debating and coming to terms with the conflict of their incomplete knowledge, which gives plenty to consider in the course of its length. Though, if the manga wanted a more compelling narrative, I feel there are ways it could've been done. I would kill for a story about Jolenta's life instead of just receiving a timeskip and seeing what came of her. Instead, it follows heliocentrism more than it does the principle characters.

The art is honestly not very good, and that is the biggest criticism I can possibly draw. It was bad enough at points that it totally ruined the impact of certain scenes. The worst one was during the emotional climax of the story as the main character of the arc looks out over the sunrise, and we get a panel of them looking like an original character from One. The character designs are also very difficult to tell apart. I don't know why they made one of the last characters we see separate from but identical (including in name) to the first character, but it greatly confused me. There are also some very out there designs, especially with the knights in the latter half of the story which were impossible to take seriously.

Overall, it would have been worth an 8 if the art was of a more standard quality. For any improvements beyond that, it would have needed to be more deft in its storytelling and careful in its writing. Ultimately, it's worth giving a go if it sounds like your thing. Give it 10-20 chapters to really get a feel for it