Have you noticed every little while more of the Traveler is breaking off? Maybe it's a shell or something, but my point is: Does it look similar to a machine? Kinda like cogs on a clock? This could be why the Eliksni (Fallen) called it "The Great Machine". Perhaps they've seen under the shell? There is definitely a radiant light illuminating from the inside, and it is living, so... Are there layers?