I know a lot of people already think that the prophecy has to do with a meteor, but the third moon that comes into the sky only every so often, it might actually be a comet, as comets are made of ice, and would make a lot of noise as it fell, so fall between thunder and ice. The friction of the air as it fell to the ground and the impact of it falling would scorch the ground as it hit the ground, because it would heat up,though it still would be made of ice, because it would hit ground before it had a chance to melt, and it is mostly solid ice. The third moon also appears larger, so it might be closer to the ground than the other moons. Also, comets only come into view after a very long time since the last sighting of it, like halley's comet, which can be seen from the earth every 78 years. As for shake the ground, the impact would already cause the ground to shake. As for lost city, maybe that is where Scalet and her new companion with the scroll are, and the dragons could use darktalker's scroll to stop it from falling. Or, the ancient night might have a comet stopping device.....