[@Aisling] "No," Ioan answered. "Just like we can't live on the Sun. Earth is the only planet we can live on, and Earth is traveling around the Sun, like in our orreries. And Nemesis is also traveling around our Sun. So, it is part of our solar system. Until now, scientists thought that life in a solar system that has more than one star isn't possible because the planets' orbits would change all the time, but now, we know they were wrong."