Osmos and Orbient are both puzzle games with levels. Solar is an open-world sandbox game with the one giant universe, no levels.
For the rest of the differences, get out and play all 3 games. You’ll find they are all quite unique in their own ways and offer very different experiences to the players.
Also, Solar 1 was released 6 months before Osmos was released, so of course I didn’t copy it. Never heard about Orbient nor did I even own a Wii until a year after Solar 1 was released. I still haven’t played either of those games.
How come people don’t complain that all 2D platformers have exactly the same core mechanics anyway. Same with FPS games. Maybe Orbient, Osmos and Solar will be the grandfathers to a whole new genre of games, the 2D top-down circle physics game!