This poem paints a picture, which I love. "Worlds", plural, and "different orbits", alludes that the worlds are separate and contrast each other. It seems the speaker observes another living in a changing (people die, therefore change?) world, but the change is meaningless. While the speaker lives in a world where people refuse change. I've re-read it a few times and I see irony, whether you intended it or not ;D Both worlds appear to be meaningless. One world has meaningless change, and the other has no change; without change the world can not progress, rendering it meaningless... this is a very lonely, empty poem.