This incident occurred about two years ago in December 2010 in Brisbane, Australia. On a clear night I was standing on my window gazing stars which seemed amazingly bright that night. After standing there for about 10 minutes I noticed an extra bright yellowish light hanging in south-west sky.
The light was not blinking, so it couldn’t have been an aircraft and it was too bright (and seemed to be close) to be ISS (I’ve seen ISS from here and it dosen't look anything like this). So my first thought was that it could be a space rocket flying in such an angle that I could only see its exhaust, thus making it look like a round, floating flame in the sky. Intrigued by the idea of seeing a spacecraft flying towards the space, I kept staring at that light for another 10-15 minutes when suddenly it started changing colour from constant yellow to blue and yellow (it was still not flicking. The colour was solid and changing rapidly, almost 4 cycles per second). Now I am not a scientist but I know that this phenomenon can also occur when the rocket progresses into different stage of its propulsion, or when entering different atmospheric layer. In that 15-20 minute of citing, I convinced myself that it is nothing but an earth-based spacecraft or a weather-balloon but having said that, there were still few things which I couldn’t find the reason for.
Firstly, if it was a spacecraft/weather balloon, why was it hanging at exact same spot for 15 long minutes without moving and without changing its shape (as it should have gotten smaller in case of a spacecraft moving further away). Secondly, the rapid colour changing of a solid ball of light without any flickers. This usually is the case with any light source high-up or beyond the atmosphere which could only mean that the light source was close to earth surface. And finally, as I mentioned before that the light source wasn’t moving at all, but when I went to call my roommates to witness this phenomenon and came back (30-40 sec), the light source just disappeared.
Now I know that there could be a dozen of explanations but still I find this incident intriguing because such incident has never happened to me before and therefore it was easy for me to get fascinated by it