Upon the discovery of several new planets within our own solar system, astronomers are rethinking their criteria for planets. Among the new planets for consideration are such extraterrestrial bodies as Xena, Sedna Link , and Quarog (I hope I spelled that right). Xena's discovery has prompted the International Astronomical Union to reconsider its definition of a planet. Currently it considers both Pluto and Xena to be trans-Neptunian objects, and says that until it has drawn up its new de...

Upon the discovery of several new planets within our own solar system, astronomers are rethinking their criteria for planets. Among the new planets for consideration are such extraterrestrial bodies as Xena, Sedna, and Quarog (I hope I spelled that right). Xena's discovery has prompted the International Astronomical Union to reconsider its definition of a planet. Currently it considers both Pluto and Xena to be trans-Neptunian objects, and says that until it has drawn up its new definition...