Uranus has at least 27 moons and more may be discovered. They revolve in the same tilted plane as their parent planet. So they either formed after that "big smack," or they've been pulled into plane by many millennia of tidal gravity.

Until the discoveries of the five largest moons of Uranus, it was conventional to name celestial bodies with either Arabic names (for stars) or names taken from Roman myths (for planets and smaller bodies). But Oberon, Titania, Ariel, Umbriel, and Miranda take their names from the fairy kingdoms of English literature. Titania is the largest moon of Uranus with a diameter of 790 kilometers (491 miles).