Sure, at this point we know what these things are, but they're still pretty insane to see up in the sky.
Yes, this is a rocket spiraling in the atmosphere, just like the one over Norway from last December. The culprit this time is in all likelihood the SpaceX Falcon 9, a private rocket first tested last Friday from Florida. Its path went right over Australia, and the timing is right for the second stage to be happening right then. So the booster falls off, spirals as gas escapes way up in the atmosphere, and you get an insane view like the one in the above video. Not as cool as real aliens, sure, but still pretty neat. [Bad Astronomy via io9]