If it was a comet, in space, and that bright, everyone in Australia would have seen it and we would know what it was here.
It would not have been a comet in our atmosphere either, since the entry velocity of cometary material is relatively fast, ranging from around 25-72
km/s, so it would cross the sky in around 5-20 seconds. Satellites, and any stuff in orbit will have a velocity of around 5-11 km/s if I recall
correctly, so they would usually cross the sky in around 40-100 seconds.
It may have been a satellite/junk re-entry, but you would likely have seen pieces breaking away from it if it was, and again, it's too long lived to
be *that* high altitude.
I think what you may have seen was a high altitude aircraft and contrail. Sometimes the contrails are short due to atmospheric conditions, and they
can often resemble comets, especially under these conditions when they are travelling away or towards you, since the perspective makes them look
shorter/stubbier than usual.
Also, when the sun is close to the horizon, it will illuminate the contrail, making it seem to glow, often a vivid orange-red color, just like clouds
can sometimes look at sunset. That is after all what contrails are - artificially produced clouds.
Some examples:
Do any of those look like what you saw?
Edit to add:
If you want to see what bits of comet look like as they enter our atmosphere, try observing the Leonids on the night of the17th-18th:
The Leonids meteor shower 2009
In your location, you should start observing around midnight, and the best time will be just before it starts to get light on the 18th. Unfortunately,
you will miss the main peaks, but you should get to see most of the buildup to them
[edit on 7-11-2009 by C.H.U.D.]
