I agree with the above. I also think that, somehow, they knew Earwa was the promised land once they found it. They must have had some method of detecting it, or at least the presence of altered metaphysics. Wutteat was on the Ark at least a little while before it got to Earwa, and considering he's "sustained by Hell from within", I feel like they must have had some knowledge of the metaphysics and what to expect. They were either literally just traveling through the cosmos destroying planets (presumably life-bearing ones?) at random, or they knew SOMETHING to give them a form of direction, even if it wasn't a 100% guarantee.