I'm not familiar with that as a Mormon belief. However, I have had upset people tell me "But Mormons and Jehovah's Witnesses believe in the New Earth..." Well, yes, and they also believe in the creation, resurrection and final judgment—but that doesn't mean we shouldn't! On the contrary, we should ask what the Bible actually says. The Bible teaches that there will be not only a new earth, but new celestial heavens. It also teaches that the whole universe fell on the coattails of humanity's sin, and consequently the whole creation (not just the earth) groans, awaiting its redemption, which will come in our resurrection (Romans 8:19-23). Since the whole universe fell under our sin, it implies the whole universe was put under our stewardship. This suggests that God's design for us to rule the new earth could extend to other planets in the new universe. Furthermore, God promises to the overcomer he will give him authority over the nations. Then he says, "I will give him the morning star," which was the name for the planet Venus (Revelation 2:28). This opens the door to my speculation—which is certainly not a direct biblical teaching—that we may rule planets in the new universe.