Thank God It's Friday... Again - S1-E6
D'Argo: Perhaps I'm never destined to be happy.
Zhaan: But you were. For five glorious days.
D'Argo: But it wasn't real.
Zhaan: There are no guarantees D'Argo. We take each breath as if it is our last. And hope that the air is sweet.
Chosen answer: It's never explained. John mentions a theory that his less technologically developed craft simply interferes with the wormhole less than the "superior" Vipers, but they never make a concrete determination on that point. But we also have to take into account the fact that Moya traverses wormholes with no ill effect as well.
Garlonuss ★